PIC16F1827-I/P

PIC16(L)F1826/27 Data Sheet 18/20/28-Pin Flash Microcontrollers with nanoWatt XLP Technology  2011 Microchip Technology Inc. DS41391D Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, dsPIC, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART, PIC32 logo, rfPIC and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor, MXDEV, MXLAB, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit, PICtail, REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, UniWinDriver, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2011, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. ISBN: 978-1-61341-124-7 Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified. DS41391D-page 2  2011 Microchip Technology Inc. PIC16(L)F1826/27 18/20/28-Pin Flash Microcontrollers with nanoWatt XLP Technology High-Performance RISC CPU: • C Compiler Optimized Architecture • 256 bytes Data EEPROM • Up to 8 Kbytes Linear Program Memory Addressing • Up to 384 bytes Linear Data Memory Addressing • Interrupt Capability with Automatic Context Saving • 16-Level Deep Hardware Stack with Optional Overflow/Underflow Reset • Direct, Indirect and Relative Addressing modes: - Two full 16-bit File Select Registers (FSRs) - FSRs can read program and data memory Flexible Oscillator Structure: • Precision 32 MHz Internal Oscillator Block: - Factory calibrated to ± 1%, typical - Software selectable frequencies range of 31 kHz to 32 MHz • 31 kHz Low-Power Internal Oscillator • Four Crystal modes up to 32 MHz • Three External Clock modes up to 32 MHz • 4X Phase-Lock Loop (PLL) • Fail-Safe Clock Monitor: - Allows for safe shutdown if peripheral clock stops • Two-Speed Oscillator Start-up • Reference Clock Module: - Programmable clock output frequency and duty-cycle Special Microcontroller Features: • • • • • • • • • • • 1.8V-5.5V Operation – PIC16F1826/27 1.8V-3.6V Operation – PIC16LF1826/27 Self-Programmable under Software Control Power-on Reset (POR), Power-up Timer (PWRT) and Oscillator Start-up Timer (OST) Programmable Brown-out Reset (BOR) Extended Watchdog Timer (WDT): - Programmable period from 1ms to 268s Programmable Code Protection In-Circuit Serial Programming™ (ICSP™) via two pins In-Circuit Debug (ICD) via two pins Enhance Low-Voltage Programming Power-Saving Sleep mode  2011 Microchip Technology Inc. Extreme Low-Power Management PIC16LF1826/27 with nanoWatt XLP: • • • • Operating Current: 75 A @ 1 MHz, 1.8V, typical Sleep mode: 30 nA Watchdog Timer: 500 nA Timer1 Oscillator: 600 nA @ 32 kHz Analog Features: • Analog-to-Digital Converter (ADC) Module: - 10-bit resolution, 12 channels - Auto acquisition capability - Conversion available during Sleep • Analog Comparator Module: - Two rail-to-rail analog comparators - Power mode control - Software controllable hysteresis • Voltage Reference Module: - Fixed Voltage Reference (FVR) with 1.024V, 2.048V and 4.096V output levels - 5-bit rail-to-rail resistive DAC with positive and negative reference selection Peripheral Highlights: • 15 I/O Pins and 1 Input Only Pin: - High current sink/source 25 mA/25 mA - Programmable weak pull-ups - Programmable interrupt-on- change pins • Timer0: 8-Bit Timer/Counter with 8-Bit Prescaler • Enhanced Timer1: - 16-bit timer/counter with prescaler - External Gate Input mode - Dedicated, low-power 32 kHz oscillator driver • Up to three Timer2-types: 8-Bit Timer/Counter with 8-Bit Period Register, Prescaler and Postscaler • Up to two Capture, Compare, PWM (CCP) Modules • Up to two Enhanced CCP (ECCP) Modules: - Software selectable time bases - Auto-shutdown and auto-restart - PWM steering • Up to two Master Synchronous Serial Port (MSSP) with SPI and I2CTM with: - 7-bit address masking - SMBus/PMBusTM compatibility • Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) Module • mTouch™ Sensing Oscillator Module: - Up to 12 input channels • Data Signal Modulator Module: - Selectable modulator and carrier sources • SR Latch: - Multiple Set/Reset input options - Emulates 555 Timer applications DS41391D-page 3 PIC16(L)F1826/27 I/O’s(1) 10-bit ADC (ch) CapSense (ch) Comparators Timers (8/16-bit) EUSART MSSP ECCP (Full-Bridge) ECCP (Half-Bridge) CCP SR Latch 256 256 256 256 16 16 16 16 12 12 12 12 12 12 12 12 2 2 2 2 2/1 2/1 4/1 4/1 1 1 1 1 1 1 2 2 1 1 1 1 — — 1 1 — — 2 2 Yes Yes Yes Yes Data Memory SRAM (bytes) Words Device Program Memory Data EEPROM (bytes) PIC16(L)F1826/27 Family Types PIC16LF1826 2K 256 PIC16F1826 2K 256 PIC16LF1827 4K 384 PIC16F1827 4K 384 Note 1: One pin is input only. Pin Diagram – 18-Pin PDIP, SOIC (PIC16(L)F1826/27) PDIP, SOIC 1 18 RA1 RA3 2 17 RA0 16 RA7 15 RA6 14 VDD 13 RB7 12 RB6 RB5 RB4 RA4 3 RA5/MCLR/VPP 4 VSS 5 RB0 6 RB1 7 PIC16(L)F1826/27 RA2 RB2 8 11 RB3 9 10 Pin Diagram – 20-Pin SSOP (PIC16(L)F1826/27) SSOP DS41391D-page 4 1 20 RA1 RA3 2 19 RA0 RA4 3 18 RA7 RA5/MCLR/VPP 4 17 RA6 VSS 5 16 VDD VSS 6 15 VDD RB0 7 14 RB7 RB1 8 13 RB6 RB2 9 12 RB5 RB3 10 11 RB4 PIC16(L)F1826/27 RA2  2011 Microchip Technology Inc. PIC16(L)F1826/27 Pin Diagram – 28-Pin QFN/UQFN (PIC16(L)F1826/27) NC RA1 RA0 RA2 23 22 24 25 28 27 26 NC RA4 RA3 QFN/UQFN 1 NC VSS 2 3 20 19 NC 4 PIC16(L)F1826/27 NC 5 6 7 18 17 16 15  2011 Microchip Technology Inc. RA7 RA6 VDD NC VDD NC RB7 RB6 RB5 RB4 RB3 RB2 RB1 NC RB0 21 11 12 13 14 VSS 8 9 10 RA5/MCLR/VPP DS41391D-page 5 18-Pin PDIP/SOIC 20-Pin SSOP 28-Pin QFN/UQFN ANSEL A/D Reference Cap Sense Comparator SR Latch Timers CCP EUSART MSSP Interrupt Modulator Pull-up Basic  2011 Microchip Technology Inc. RA0 17 19 23 Y AN0 — CPS0 C12IN0- — — — — SDO2(2) — — N — RA1 18 20 24 Y AN1 — CPS1 C12IN1- — — — — SS2(2) — — N — RA2 1 1 26 Y AN2 VREFDACOUT CPS2 C12IN2C12IN+ — — — — — — — N — RA3 2 2 27 Y AN3 VREF+ CPS3 C12IN3C1IN+ C1OUT SRQ — CCP3(2) — — — — N — RA4 3 3 28 Y AN4 — CPS4 C2OUT SRNQ T0CKI CCP4(2) — — — — N — RA5 4 4 1 N — — — — — — — — SS1(1) — — Y(3) MCLR, VPP RA6 15 17 20 N — — — — — — P1D(1) P2B(1,2) — SDO1(1) — — N OSC2 CLKOUT CLKR RA7 16 18 21 N — — — — — — P1C(1) CCP2(1,2) P2A(1,2) — — — — N OSC1 CLKIN RB0 6 7 7 N — — — — SRI T1G CCP1(1) P1A(1) FLT0 — — INT IOC — Y — RB1 7 8 8 Y AN11 — CPS11 — — — — RX(1,4) DT(1,4) SDA1 SDI1 IOC — Y — RB2 8 9 9 Y AN10 — CPS10 — — — — RX(1),DT(1) TX(1,4) CK(1,4) SDA2(2) SDI2(2) SDO1(1,4) IOC MDMIN Y — RB3 9 10 10 Y AN9 — CPS9 — — — CCP1(1,4) P1A(1,4) — — IOC MDOUT Y — RB4 10 11 12 Y AN8 — CPS8 — — — — — SCL1 SCK1 IOC MDCIN2 Y — RB5 11 12 13 Y AN7 — CPS7 — — — P1B TX(1) CK(1) SCL2(2) SCK2(2) SS1(1,4) IOC — Y — RB6 12 13 15 Y AN5 — CPS5 — — T1CKI T1OSI P1C(1,4) CCP2(1,2,4) P2A(1,2,4) — — IOC — Y ICSPCLK/ ICDCLK RB7 13 14 16 Y AN6 — CPS6 — — T1OSO P1D(1,4) P2B(1,2,4) — — IOC MDCIN1 Y ICSPDAT/ ICDDAT VDD 14 Vss 5 Note 1: 2: 3: 4: 15,16 17,19 5,6 3,5 — — — — — — — — — — — — — VDD — — — — — — — — — — — — — VSS Pin functions can be moved using the APFCON0 or APFCON1 register. Functions are only available on the PIC16(L)F1827. Weak pull-up always enabled when MCLR is enabled, otherwise the pull-up is under user control. Default function location. PIC16(L)F1826/27 18/20/28-PIN SUMMARY (PIC16(L)F1826/27) I/O DS41391D-page 6 TABLE 1: PIC16(L)F1826/27 Table of Contents 1.0 Device Overview .......................................................................................................................................................................... 9 2.0 Enhanced Mid-Range CPU ........................................................................................................................................................ 15 3.0 Memory Organization ................................................................................................................................................................. 17 4.0 Device Configuration .................................................................................................................................................................. 43 5.0 Oscillator Module (With Fail-Safe Clock Monitor)....................................................................................................................... 51 6.0 Reference Clock Module ............................................................................................................................................................ 69 7.0 Resets ........................................................................................................................................................................................ 73 8.0 Interrupts .................................................................................................................................................................................... 81 9.0 Power-Down Mode (Sleep) ........................................................................................................................................................ 95 10.0 Watchdog Timer (WDT) ............................................................................................................................................................. 97 11.0 Data EEPROM and Flash Program Memory Control ............................................................................................................... 101 12.0 I/O Ports ................................................................................................................................................................................... 117 13.0 Interrupt-on-Change ................................................................................................................................................................. 131 14.0 Fixed Voltage Reference (FVR) ............................................................................................................................................... 135 15.0 Temperature Indicator .............................................................................................................................................................. 137 16.0 Analog-to-Digital Converter (ADC) Module .............................................................................................................................. 139 17.0 Digital-to-Analog Converter (DAC) Module .............................................................................................................................. 153 18.0 SR Latch................................................................................................................................................................................... 157 19.0 Comparator Module.................................................................................................................................................................. 163 20.0 Timer0 Module ......................................................................................................................................................................... 173 21.0 Timer1 Module ......................................................................................................................................................................... 177 22.0 Timer2/4/6 Modules.................................................................................................................................................................. 191 23.0 Data Signal Modulator (DSM) .................................................................................................................................................. 193 24.0 Capture/Compare/PWM (ECCP1, ECCP2, ECCP3, CCP4) Modules ..................................................................................... 203 25.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 231 26.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 285 27.0 Capacitive Sensing Module...................................................................................................................................................... 315 28.0 In-Circuit Serial Programming™ (ICSP™) ................................................................................................................................ 321 29.0 Instruction Set Summary .......................................................................................................................................................... 325 30.0 Electrical Specifications............................................................................................................................................................ 339 31.0 DC and AC Characteristics Graphs and Tables....................................................................................................................... 371 32.0 Development Support............................................................................................................................................................... 379 33.0 Packaging Information.............................................................................................................................................................. 383 Appendix A: Revision History............................................................................................................................................................. 393 Appendix B: Device Differences ........................................................................................................................................................ 393 Index .................................................................................................................................................................................................. 395 The Microchip Web Site ..................................................................................................................................................................... 403 Customer Change Notification Service .............................................................................................................................................. 403 Customer Support .............................................................................................................................................................................. 403 Reader Response .............................................................................................................................................................................. 404 Product Identification System ............................................................................................................................................................ 405  2011 Microchip Technology Inc. DS41391D-page 7 PIC16(L)F1826/27 TO OUR VALUED CUSTOMERS It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and enhanced as new volumes and updates are introduced. If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via E-mail at docerrors@microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We welcome your feedback. Most Current Data Sheet To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at: http://www.microchip.com You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page. The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000). Errata An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision of silicon and revision of document to which it applies. To determine if an errata sheet exists for a particular device, please check with one of the following: • Microchip’s Worldwide Web site; http://www.microchip.com • Your local Microchip sales office (see last page) When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are using. Customer Notification System Register on our web site at www.microchip.com to receive the most current information on all of our products. DS41391D-page 8  2011 Microchip Technology Inc. PIC16(L)F1826/27 1.0 DEVICE OVERVIEW The PIC16(L)F1826/27 are described within this data sheet. They are available in 18/20/28-pin packages. Figure 1-1 shows a block diagram of the PIC16(L)F1826/27 devices. Table 1-2 shows the pinout descriptions. Reference Table 1-1 for peripherals available per device. Peripheral PIC16(L)F1827 DEVICE PERIPHERAL SUMMARY PIC16F/LF1826 TABLE 1-1: ADC ● ● Capacitive Sensing Module ● ● Digital-to-Analog Converter (DAC) ● ● Digital Signal Modulator (DSM) ● ● EUSART ● ● Fixed Voltage Reference (FVR) ● ● Reference Clock Module ● ● SR Latch ● ● ● ● Capture/Compare/PWM Modules ECCP1 ECCP2 ● CCP3 ● CCP4 ● Comparators C1 ● ● C2 ● ● ● ● Master Synchronous Serial Ports MSSP1 MSSP2 ● Timers Timer0 ● ● Timer1 ● ● Timer2 ● ● Timer4 ● Timer6 ●  2011 Microchip Technology Inc. DS41391D-page 9 PIC16(L)F1826/27 FIGURE 1-1: PIC16(L)F1826/27 BLOCK DIAGRAM Program Flash Memory CLKR EEPROM RAM Clock Reference Timing OSC2/CLKOUT Generation OSC1/CLKIN PORTA CPU INTRC Oscillator (Figure 2-1) PORTB MCLR SR Latch ADC 10-Bit Timer0 Timer1 Timer2Types DAC Comparators ECCPx CCPx MSSPx Modulator EUSART FVR CapSense Note 1: 2: DS41391D-page 10 See applicable chapters for more information on peripherals. See Table 1-1 for peripherals available on specific devices.  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 1-2: PIC16(L)F1826/27 PINOUT DESCRIPTION Name RA0/AN0/CPS0/C12IN0-/ SDO2(2) RA1/AN1/CPS1/C12IN1-/SS2(2) RA2/AN2/CPS2/C12IN2-/ C12IN+/VREF-/DACOUT RA3/AN3/CPS3/C12IN3-/C1IN+/ VREF+/C1OUT/CCP3(2)/SRQ RA4/AN4/CPS4/C2OUT/T0CKI/ CCP4(2)/SRNQ RA5/MCLR/VPP/SS1(1,2) Function Input Type RA0 TTL AN0 AN Output Type Description CMOS General purpose I/O. — A/D Channel 0 input. CPS0 AN — Capacitive sensing input 0. C12IN0- AN — Comparator C1 or C2 negative input. SDO2 — RA1 TTL CMOS SPI data output. CMOS General purpose I/O. AN1 AN — CPS1 AN — Capacitive sensing input 1. C12IN1- AN — Comparator C1 or C2 negative input. SS2 ST — Slave Select input 2. RA2 TTL AN2 AN — CPS2 AN — Capacitive sensing input 2. C12IN2- AN — Comparator C1 or C2 negative input. C12IN+ AN — Comparator C1 or C2 positive input. VREF- AN — A/D Negative Voltage Reference input. AN Voltage Reference output. DACOUT — RA3 TTL A/D Channel 1 input. CMOS General purpose I/O. A/D Channel 2 input. CMOS General purpose I/O. AN3 AN — CPS3 AN — A/D Channel 3 input. Capacitive sensing input 3. C12IN3- AN — Comparator C1 or C2 negative input. C1IN+ AN — Comparator C1 positive input. — A/D Voltage Reference input. VREF+ AN C1OUT — CMOS Comparator C1 output. CCP3 ST CMOS Capture/Compare/PWM3. SRQ — CMOS SR latch non-inverting output. RA4 TTL AN4 AN — A/D Channel 4 input. CPS4 AN — Capacitive sensing input 4. C2OUT — CMOS General purpose I/O. CMOS Comparator C2 output. T0CKI ST CCP4 ST CMOS Capture/Compare/PWM4. — Timer0 clock input. SRNQ — CMOS SR latch inverting output. RA5 TTL CMOS General purpose I/O. MCLR ST — Master Clear with internal pull-up. VPP HV — Programming voltage. SS1 ST — Slave Select input 1. Legend: AN = Analog input or output CMOS = CMOS compatible input or output OD = Open Drain TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C HV = High Voltage XTAL = Crystal levels Note 1: Pin functions can be moved using the APFCON0 or APFCON1 register. 2: Functions are only available on the PIC16(L)F1827. 3: Default function location.  2011 Microchip Technology Inc. DS41391D-page 11 PIC16(L)F1826/27 TABLE 1-2: PIC16(L)F1826/27 PINOUT DESCRIPTION (CONTINUED) Name RA6/OSC2/CLKOUT/CLKR/ P1D(1)/P2B(1,2)/SDO1(1) RA7/OSC1/CLKIN/P1C(1)/ CCP2(1,2)/P2A(1,2) (1) (1) RB0/T1G/CCP1 /P1A /INT/ SRI/FLT0 RB1/AN11/CPS11/RX(1,3)/ DT(1,3)/SDA1/SDI1 RB2/AN10/CPS10/MDMIN/ TX(1,3)/CK(1,3)/RX(1)/DT(1)/ SDA2(2)/SDI2(2)/SDO1(1,3) Function Input Type RA6 TTL Output Type Description CMOS General purpose I/O. OSC2 — CLKOUT — CMOS FOSC/4 output. XTAL Crystal/Resonator (LP, XT, HS modes). CLKR — CMOS Clock Reference Output. P1D — CMOS PWM output. CMOS PWM output. P2B — SDO1 — RA7 TTL OSC1 XTAL CLKIN CMOS P1C — CMOS PWM output. CCP2 ST CMOS Capture/Compare/PWM2. P2A — CMOS PWM output. RB0 TTL T1G ST CCP1 ST CMOS Capture/Compare/PWM1. P1A — CMOS PWM output. INT ST — External interrupt. SRI ST — SR latch input. — ECCP Auto-Shutdown Fault input. CMOS SPI data output 1. CMOS General purpose I/O. — Crystal/Resonator (LP, XT, HS modes). — External clock input (EC mode). CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. — Timer1 Gate input. FLT0 ST RB1 TTL AN11 AN — A/D Channel 11 input. CPS11 AN — Capacitive sensing input 11. — USART asynchronous input. RX ST DT ST SDA1 I2C™ SDI1 CMOS RB2 TTL CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. CMOS USART synchronous data. OD I2C™ data input/output 1. — SPI data input 1. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. AN10 AN — A/D Channel 10 input. CPS10 AN — Capacitive sensing input 10. MDMIN — CMOS Modulator source input. TX — CMOS USART asynchronous transmit. CK ST CMOS USART synchronous clock. RX ST DT ST SDA2 I2C™ SDI2 ST SDO1 — — USART asynchronous input. CMOS USART synchronous data. OD I2C™ data input/output 2. — SPI data input 2. CMOS SPI data output 1. Legend: AN = Analog input or output CMOS = CMOS compatible input or output OD = Open Drain TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C HV = High Voltage XTAL = Crystal levels Note 1: Pin functions can be moved using the APFCON0 or APFCON1 register. 2: Functions are only available on the PIC16(L)F1827. 3: Default function location. DS41391D-page 12  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 1-2: PIC16(L)F1826/27 PINOUT DESCRIPTION (CONTINUED) Name RB3/AN9/CPS9/MDOUT/ CCP1(1,3)/P1A(1,3) RB4/AN8/CPS8/SCL1/SCK1/ MDCIN2 Function Input Type RB3 TTL RB6/AN5/CPS5/T1CKI/T1OSI/ P1C(1,3)/CCP2(1,2,3)/P2A(1,2,3)/ ICSPCLK RB7/AN6/CPS6/T1OSO/ P1D(1,3)/P2B(1,2,3)/MDCIN1/ ICSPDAT Description CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. AN9 AN — A/D Channel 9 input. CPS9 AN — Capacitive sensing input 9. MDOUT — CMOS Modulator output. CCP1 ST CMOS Capture/Compare/PWM1. P1A — RB4 TTL CMOS PWM output. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. AN8 AN — A/D Channel 8 input. CPS8 AN — Capacitive sensing input 8. OD I2C™ clock 1. SCL1 RB5/AN7/CPS7/P1B/TX(1)/CK(1)/ SCL2(2)/SCK2(2)/SS1(1,3) Output Type 2 I C™ SCK1 ST MDCIN2 ST RB5 TTL CMOS SPI clock 1. — Modulator Carrier Input 2. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. AN7 AN — A/D Channel 7 input. CPS7 AN — Capacitive sensing input 7. P1B — CMOS PWM output. TX — CMOS USART asynchronous transmit. CK ST CMOS USART synchronous clock. SCL2 I2C™ SCK2 ST SS1 ST RB6 TTL OD I2C™ clock 2. CMOS SPI clock 2. — Slave Select input 1. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. AN5 AN — CPS5 AN — Capacitive sensing input 5. T1CKI ST — Timer1 clock input. T1OSO XTAL P1C — CMOS PWM output. CCP2 ST CMOS Capture/Compare/PWM2. P2A — CMOS PWM output. ICSPCLK ST RB7 TTL XTAL — A/D Channel 5 input. Timer1 oscillator connection. Serial Programming Clock. CMOS General purpose I/O. Individually controlled interrupt-on-change. Individually enabled pull-up. AN6 AN — CPS6 AN — T1OSO XTAL XTAL P1D — CMOS PWM output. CMOS PWM output. P2B — MDCIN1 ST ICSPDAT ST — A/D Channel 6 input. Capacitive sensing input 6. Timer1 oscillator connection. Modulator Carrier Input 1. CMOS ICSP™ Data I/O. Legend: AN = Analog input or output CMOS = CMOS compatible input or output OD = Open Drain TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C HV = High Voltage XTAL = Crystal levels Note 1: Pin functions can be moved using the APFCON0 or APFCON1 register. 2: Functions are only available on the PIC16(L)F1827. 3: Default function location.  2011 Microchip Technology Inc. DS41391D-page 13 PIC16(L)F1826/27 TABLE 1-2: PIC16(L)F1826/27 PINOUT DESCRIPTION (CONTINUED) Function Input Type Output Type VDD VDD Power — Positive supply. VSS VSS Power — Ground reference. Name Description Legend: AN = Analog input or output CMOS = CMOS compatible input or output OD = Open Drain TTL = TTL compatible input ST = Schmitt Trigger input with CMOS levels I2C™ = Schmitt Trigger input with I2C HV = High Voltage XTAL = Crystal levels Note 1: Pin functions can be moved using the APFCON0 or APFCON1 register. 2: Functions are only available on the PIC16(L)F1827. 3: Default function location. DS41391D-page 14  2011 Microchip Technology Inc. PIC16(L)F1826/27 2.0 ENHANCED MID-RANGE CPU This family of devices contain an enhanced mid-range 8-bit CPU core. The CPU has 49 instructions. Interrupt capability includes automatic context saving. The hardware stack is 16 levels deep and has Overflow and Underflow Reset capability. Direct, Indirect, and Relative addressing modes are available. Two File Select Registers (FSRs) provide the ability to read program and data memory. • • • • Automatic Interrupt Context Saving 16-level Stack with Overflow and Underflow File Select Registers Instruction Set 2.1 Automatic Interrupt Context Saving During interrupts, certain registers are automatically saved in shadow registers and restored when returning from the interrupt. This saves stack space and user code. See Section 8.5 “Automatic Context Saving”, for more information. 2.2 16-level Stack with Overflow and Underflow These devices have an external stack memory 15 bits wide and 16 words deep. A Stack Overflow or Underflow will set the appropriate bit (STKOVF or STKUNF) in the PCON register, and if enabled will cause a software Reset. See section Section 3.4 “Stack” for more details. 2.3 File Select Registers There are two 16-bit File Select Registers (FSR). FSRs can access all file registers and program memory, which allows one Data Pointer for all memory. When an FSR points to program memory, there is one additional instruction cycle in instructions using INDF to allow the data to be fetched. General purpose memory can now also be addressed linearly, providing the ability to access contiguous data larger than 80 bytes. There are also new instructions to support the FSRs. See Section 3.4 “Stack”for more details. 2.4 Instruction Set There are 49 instructions for the enhanced mid-range CPU to support the features of the CPU. See Section 29.0 “Instruction Set Summary” for more details.  2011 Microchip Technology Inc. DS41391D-page 15 PIC16(L)F1826/27 FIGURE 2-1: CORE BLOCK DIAGRAM 15 Configuration 15 MUX Flash Program Memory Program Bus 16-Level 8 Level Stack Stack (13-bit) (15-bit) 14 Instruction Instruction Reg reg 8 Data Bus Program Counter RAM Program Memory Read (PMR) 12 RAM Addr Addr MUX Direct Addr 7 5 Indirect Addr 12 12 BSR FSR Reg reg 15 FSR0reg Reg FSR FSR1 Reg FSR reg 15 STATUS Reg reg STATUS 8 3 Power-up Timer OSC1/CLKIN OSC2/CLKOUT Instruction Decodeand & Decode Control Timing Generation Oscillator Start-up Timer Power-on Reset Watchdog Timer Brown-out Reset MUX ALU 8 W reg Internal Oscillator Block VDD DS41391D-page 16 VSS  2011 Microchip Technology Inc. PIC16(L)F1826/27 3.0 MEMORY ORGANIZATION There are three types of memory in PIC16(L)F1826/27: Data Memory, Program Memory and Data EEPROM Memory(1). • Program Memory • Data Memory - Core Registers - Special Function Registers - General Purpose RAM - Common RAM - Device Memory Maps - Special Function Registers Summary • Data EEPROM memory(1) The following features are associated with access and control of program memory and data memory: • PCL and PCLATH • Stack • Indirect Addressing 3.1 Program Memory Organization The enhanced mid-range core has a 15-bit program counter capable of addressing a 32K x 14 program memory space. Table 3-1 shows the memory sizes implemented for the PIC16(L)F1826/27 family. Accessing a location above these boundaries will cause a wrap-around within the implemented memory space. The Reset vector is at 0000h and the interrupt vector is at 0004h (see Figures 3-1 and 3-2). Note 1: The Data EEPROM Memory and the method to access Flash memory through the EECON registers is described in Section 11.0 “Data EEPROM and Flash Program Memory Control”. TABLE 3-1: DEVICE SIZES AND ADDRESSES Device Program Memory Space (Words) Last Program Memory Address PIC16(L)F1826 2,048 07FFh PIC16(L)F1827 4,096 0FFFh  2011 Microchip Technology Inc. DS41391D-page 17 PIC16(L)F1826/27 FIGURE 3-1: PROGRAM MEMORY MAP AND STACK FOR PIC16(L)F1826 FIGURE 3-2: PC CALL, CALLW RETURN, RETLW Interrupt, RETFIE On-chip Program Memory PROGRAM MEMORY MAP AND STACK FOR PIC16(L)F1827 PC CALL, CALLW RETURN, RETLW Interrupt, RETFIE 15 15 Stack Level 0 Stack Level 1 Stack Level 0 Stack Level 1 Stack Level 15 Stack Level 15 Reset Vector 0000h Reset Vector 0000h Interrupt Vector 0004h 0005h Interrupt Vector 0004h 0005h Page 0 Rollover to Page 0 Wraps to Page 0 07FFh 0800h On-chip Program Memory Page 0 07FFh 0800h Page 1 Rollover to Page 0 Wraps to Page 0 0FFFh 1000h Wraps to Page 0 Rollover to Page 0 DS41391D-page 18 7FFFh Rollover to Page 1 7FFFh  2011 Microchip Technology Inc. PIC16(L)F1826/27 3.1.1 READING PROGRAM MEMORY AS DATA There are two methods of accessing constants in program memory. The first method is to use tables of RETLW instructions. The second method is to set an FSR to point to the program memory. 3.1.1.1 RETLW Instruction The RETLW instruction can be used to provide access to tables of constants. The recommended way to create such a table is shown in Example 3-1. EXAMPLE 3-1: constants BRW RETLW RETLW RETLW RETLW DATA0 DATA1 DATA2 DATA3 RETLW INSTRUCTION ;Add Index in W to ;program counter to ;select data ;Index0 data ;Index1 data my_function ;… LOTS OF CODE… MOVLW DATA_INDEX call constants ;… THE CONSTANT IS IN W The BRW instruction makes this type of table very simple to implement. If your code must remain portable with previous generations of microcontrollers, then the BRW instruction is not available so the older table read method must be used.  2011 Microchip Technology Inc. DS41391D-page 19 PIC16(L)F1826/27 3.1.1.2 Indirect Read with FSR The program memory can be accessed as data by setting bit 7 of the FSRxH register and reading the matching INDFx register. The MOVIW instruction will place the lower 8 bits of the addressed word in the W register. Writes to the program memory cannot be performed via the INDF registers. Instructions that access the program memory via the FSR require one extra instruction cycle to complete. Example 3-2 demonstrates accessing the program memory via an FSR. The HIGH directive will set bit if a label points to a location in program memory. EXAMPLE 3-2: ACCESSING PROGRAM MEMORY VIA FSR constants RETLW DATA0 ;Index0 data RETLW DATA1 ;Index1 data RETLW DATA2 RETLW DATA3 my_function ;… LOTS OF CODE… MOVLW LOW constants MOVWF FSR1L MOVLW HIGH constants MOVWF FSR1H MOVIW 0[FSR1] ;THE PROGRAM MEMORY IS IN W 3.2 3.2.1 CORE REGISTERS The core registers contain the registers that directly affect the basic operation. The core registers occupy the first 12 addresses of every data memory bank (addresses x00h/x08h through x0Bh/x8Bh). These registers are listed below in Table 3-2. For for detailed information, see Table 3-5. TABLE 3-2: CORE REGISTERS Addresses BANKx x00h or x80h x01h or x81h x02h or x82h x03h or x83h x04h or x84h x05h or x85h x06h or x86h x07h or x87h x08h or x88h x09h or x89h x0Ah or x8Ah x0Bh or x8Bh INDF0 INDF1 PCL STATUS FSR0L FSR0H FSR1L FSR1H BSR WREG PCLATH INTCON Data Memory Organization The data memory is partitioned in 32 memory banks with 128 bytes in a bank. Each bank consists of (Figure 3-3): • • • • 12 core registers 20 Special Function Registers (SFR) Up to 80 bytes of General Purpose RAM (GPR) 16 bytes of common RAM The active bank is selected by writing the bank number into the Bank Select Register (BSR). Unimplemented memory will read as ‘0’. All data memory can be accessed either directly (via instructions that use the file registers) or indirectly via the two File Select Registers (FSR). See Section 3.5 “Indirect Addressing” for more information. Data Memory uses a 12-bit address. The upper 7-bit of the address define the Bank address and the lower 5-bits select the registers/RAM in that bank. DS41391D-page 20  2011 Microchip Technology Inc. PIC16(L)F1826/27 3.2.1.1 STATUS Register The STATUS register, shown in Register 3-1, contains: • the arithmetic status of the ALU • the Reset status The STATUS register can be the destination for any instruction, like any other register. If the STATUS register is the destination for an instruction that affects the Z, DC or C bits, then the write to these three bits is disabled. These bits are set or cleared according to the device logic. Furthermore, the TO and PD bits are not writable. Therefore, the result of an instruction with the STATUS register as destination may be different than intended. REGISTER 3-1: U-0 For example, CLRF STATUS will clear the upper three bits and set the Z bit. This leaves the STATUS register as ‘000u u1uu’ (where u = unchanged). It is recommended, therefore, that only BCF, BSF, SWAPF and MOVWF instructions are used to alter the STATUS register, because these instructions do not affect any Status bits. For other instructions not affecting any Status bits (Refer to Section 29.0 “Instruction Set Summary”). Note 1: The C and DC bits operate as Borrow and Digit Borrow out bits, respectively, in subtraction. STATUS: STATUS REGISTER U-0 — — U-0 R-1/q R-1/q R/W-0/u R/W-0/u R/W-0/u — TO PD Z DC(1) C(1) bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition bit 7-5 Unimplemented: Read as ‘0’ bit 4 TO: Time-out bit 1 = After power-up, CLRWDT instruction or SLEEP instruction 0 = A WDT time-out occurred bit 3 PD: Power-down bit 1 = After power-up or by the CLRWDT instruction 0 = By execution of the SLEEP instruction bit 2 Z: Zero bit 1 = The result of an arithmetic or logic operation is zero 0 = The result of an arithmetic or logic operation is not zero bit 1 DC: Digit Carry/Digit Borrow bit (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1) 1 = A carry-out from the 4th low-order bit of the result occurred 0 = No carry-out from the 4th low-order bit of the result bit 0 C: Carry/Borrow bit(1) (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1) 1 = A carry-out from the Most Significant bit of the result occurred 0 = No carry-out from the Most Significant bit of the result occurred Note 1: For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order bit of the source register.  2011 Microchip Technology Inc. DS41391D-page 21 PIC16(L)F1826/27 3.2.2 SPECIAL FUNCTION REGISTER The Special Function Registers are registers used by the application to control the desired operation of peripheral functions in the device. The Special Function Registers occupy the 20 bytes after the core registers of every data memory bank (addresses x0Ch/x8Ch through x1Fh/x9Fh). The registers associated with the operation of the peripherals are described in the appropriate peripheral chapter of this data sheet. 3.2.3 FIGURE 3-3: 7-bit Bank Offset 0Bh 0Ch GENERAL PURPOSE RAM Core Registers (12 bytes) Special Function Registers (20 bytes maximum) 1Fh 20h Linear Access to GPR The general purpose RAM can be accessed in a non-banked method via the FSRs. This can simplify access to large memory structures. See Section 3.5.2 “Linear Data Memory” for more information. 3.2.4 Memory Region 00h There are up to 80 bytes of GPR in each data memory bank. The Special Function Registers occupy the 20 bytes after the core registers of every data memory bank (addresses x0Ch/x8Ch through x1Fh/x9Fh). 3.2.3.1 BANKED MEMORY PARTITIONING General Purpose RAM (80 bytes maximum) COMMON RAM There are 16 bytes of common RAM accessible from all banks. 6Fh 70h Common RAM (16 bytes) 7Fh 3.2.5 DEVICE MEMORY MAPS The memory maps for the device family are as shown in Table 3-3 and Table 3-4. DS41391D-page 22  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. TABLE 3-3: PIC16(L)F1826/27 MEMORY MAP BANK 0 000h BANK 1 080h Core Registers (Table 3-2) 00Bh 00Ch 00Dh 00Eh 00Fh 010h 011h 012h 013h 014h 015h 016h 017h 018h 019h 01Ah 01Bh 01Ch 01Dh 01Eh 01Fh 020h — CPSCON0 CPSCON1 General Purpose Register 96 Bytes Core Registers (Table 3-2) 08Bh 08Ch 08Dh 08Eh 08Fh 090h 091h 092h 093h 094h 095h 096h 097h 098h 099h 09Ah 09Bh 09Ch 09Dh 09Eh 09Fh 0A0h TRISA TRISB — — — PIE1 PIE2 PIE3(1) PIE4(1) OPTION PCON WDTCON OSCTUNE OSCCON OSCSTAT ADRESL ADRESH ADCON0 ADCON1 — Core Registers (Table 3-2) 10Bh 10Ch 10Dh 10Eh 10Fh 110h 111h 112h 113h 114h 115h 116h 117h 118h 119h 11Ah 11Bh 11Ch 11Dh 11Eh 11Fh 120h General Purpose Register 80 Bytes 0EFh 0F0h Legend: Note 1: LATA LATB — — — CM1CON0 CM1CON1 CM2CON0 CM2CON1 CMOUT BORCON FVRCON DACCON0 DACCON1 SRCON0 SRCON1 — APFCON0 APFCON1 — 16Fh 170h 0FFh 19Dh 19Eh 19Fh 1A0h ANSELA ANSELB — — — EEADRL EEADRH EEDATL EEDATH EECON1 EECON2 — — RCREG TXREG SPBRGL SPBRGH RCSTA TXSTA BAUDCON 20Bh 20Ch 20Dh 20Eh 20Fh 210h 211h 212h 213h 214h 215h 216h 217h 218h 219h 21Ah 21Bh 21Ch 21Dh 21Eh 21Fh 220h 26Fh 270h Accesses 70h – 7Fh 1FFh BANK 5 280h Core Registers (Table 3-2) General Purpose Register 80 Bytes(1) Accesses 70h – 7Fh = Unimplemented data memory locations, read as ‘0’ Available only on PIC16(L)F1827. 18Bh 18Ch 18Dh 18Eh 18Fh 190h 191h 192h 193h 194h 195h 196h 197h 198h 199h 19Ah 19Bh 19Ch 1EFh 1F0h 17Fh BANK 4 200h Core Registers (Table 3-2) General Purpose Register 80 Bytes Accesses 70h – 7Fh 07Fh BANK 3 180h WPUA WPUB — — — SSP1BUF SSP1ADD SSP1MASK SSP1STAT SSP1CON SSP1CON2 SSP1CON3 — SSP2BUF(1) SSP2ADD(1) SSP2MASK(1) SSP2STAT(1) SSP2CON(1) SSP2CON2(1) SSP2CON3(1) General Purpose Register 48 Bytes(1) Unimplemented Read as ‘0’ Core Registers (Table 3-2) 28Bh 28Ch 28Dh 28Eh 28Fh 290h 291h 292h 293h 294h 295h 296h 297h 298h 299h 29Ah 29Bh 29Ch 29Dh 29Eh 29Fh 2A0h — — — — — CCPR1L CCPR1H CCP1CON PWM1CON CCP1AS PSTR1CON — CCPR2L(1) CCPR2H(1) CCP2CON(1) PWM2CON(1) CCP2AS(1) PSTR2CON(1) CCPTMRS(1) — 30Bh 30Ch 30Dh 30Eh 30Fh 310h 311h 312h 313h 314h 315h 316h 317h 318h 319h 31Ah 31Bh 31Ch 31Dh 31Eh 31Fh 320h — Core Registers (Table 3-2) 38Bh 38Ch 38Dh 38Eh 38Fh 390h 391h 392h 393h 394h 395h 396h 397h 398h 399h 39Ah 39Bh 39Ch 39Dh 39Eh 39Fh 3A0h Unimplemented Read as ‘0’ Accesses 70h – 7Fh 2FFh — — — — — CCPR3L(1) CCPR3H(1) CCP3CON(1) — — — — CCPR4L(1) CCPR4H(1) CCP4CON(1) — — — — 36Fh 370h 2EFh 2F0h BANK 7 380h Core Registers (Table 3-2) Unimplemented Read as ‘0’ Accesses 70h – 7Fh 27Fh BANK 6 300h Unimplemented Read as ‘0’ 3EFh 3F0h Accesses 70h – 7Fh 37Fh — — — — — — — — IOCBP IOCBN IOCBF — — — CLKRCON — MDCON MDSRC MDCARL MDCARH Accesses 70h – 7Fh 3FFh DS41391D-page 23 PIC16(L)F1826/27 06Fh 070h PORTA PORTB — — — PIR1 PIR2 PIR3(1) PIR4(1) TMR0 TMR1L TMR1H T1CON T1GCON TMR2 PR2 T2CON BANK 2 100h PIC16(L)F1826/27 MEMORY MAP (CONTINUED) BANK 8 400h BANK 9 480h Core Registers (Table 3-2) 40Bh BANK 10 500h Core Registers (Table 3-2) 48Bh BANK 11 580h Core Registers (Table 3-2) 50Bh BANK 12 600h Core Registers (Table 3-2) 58Bh BANK 13 680h Core Registers (Table 3-2) 60Bh BANK 14 700h Core Registers (Table 3-2) 68Bh BANK 15 780h Core Registers (Table 3-2) 70Bh Core Registers (Table 3-2) 78Bh 40Ch 40Dh 40Eh 40Fh 410h 411h 412h 413h 414h — — — — — — — — — 48Ch 48Dh 48Eh 48Fh 490h 491h 492h 493h 494h — — — — — — — — — 50Ch 50Dh 50Eh 50Fh 510h 511h 512h 513h 514h — — — — — — — — — 58Ch 58Dh 58Eh 58Fh 590h 591h 592h 593h 594h — — — — — — — — — 60Ch 60Dh 60Eh 60Fh 610h 611h 612h 613h 614h — — — — — — — — — 68Ch 68Dh 68Eh 68Fh 690h 691h 692h 693h 694h — — — — — — — — — 70Ch 70Dh 70Eh 70Fh 710h 711h 712h 713h 714h — — — — — — — — — 78Ch 78Dh 78Eh 78Fh 790h 791h 792h 793h 794h — — — — — — — — — 415h TMR4(1) 495h — 515h — 595h — 615h — 695h — 715h — 795h — 416h PR4(1) 496h — 516h — 596h — 616h — 696h — 716h — 796h — 417h 418h 419h 41Ah 41Bh T4CON(1) — — — — 497h 498h 499h 49Ah 49Bh — — — — — 517h 518h 519h 51Ah 51Bh — — — — — 597h 598h 599h 59Ah 59Bh — — — — — 617h 618h 619h 61Ah 61Bh — — — — — 697h 698h 699h 69Ah 69Bh — — — — — 717h 718h 719h 71Ah 71Bh — — — — — 797h 798h 799h 79Ah 79Bh — — — — — 41Ch TMR6(1) 49Ch — 51Ch — 59Ch — 61Ch — 69Ch — 71Ch — 79Ch — 41Dh PR6(1) 49Dh — 51Dh — 59Dh — 61Dh — 69Dh — 71Dh — 79Dh — 41Eh 41Fh 420h T6CON(1) — 49Eh 49Fh 4A0h — — 51Eh 51Fh 520h — — 59Eh 59Fh 5A0h — — 61Eh 61Fh 620h — — 69Eh 69Fh 6A0h — — 71Eh 71Fh 720h — — 79Eh 79Fh 7A0h — — Unimplemented Read as ‘0’ 46Fh 470h Unimplemented Read as ‘0’ 4EFh 4F0h  2011 Microchip Technology Inc. Accesses 70h – 7Fh 47Fh Legend: Unimplemented Read as ‘0’ 56Fh 570h Accesses 70h – 7Fh 4FFh Unimplemented Read as ‘0’ 5EFh 5F0h Accesses 70h – 7Fh 57Fh = Unimplemented data memory locations, read as ‘0’ Unimplemented Read as ‘0’ 66Fh 670h Accesses 70h – 7Fh 5FFh Unimplemented Read as ‘0’ 6EFh 6F0h Accesses 70h – 7Fh 67Fh Unimplemented Read as ‘0’ 76Fh 770h Accesses 70h – 7Fh 6FFh Unimplemented Read as ‘0’ 7EFh 7F0h Accesses 70h – 7Fh 77Fh Accesses 70h – 7Fh 7FFh PIC16(L)F1826/27 DS41391D-page 24 TABLE 3-3:  2011 Microchip Technology Inc. TABLE 3-3: PIC16(L)F1826/27 MEMORY MAP (CONTINUED) BANK16 800h BANK17 880h Core Registers (Table 3-2) 80Bh 80Ch Core Registers (Table 3-2) 88Bh 88Ch Unimplemented Read as ‘0’ 86Fh 870h 87Fh Common RAM (Accesses 70h – 7Fh) 8EFh 8F0h 90Bh 90Ch 8FFh Common RAM (Accesses 70h – 7Fh) 96Fh 970h Core Registers (Table 3-2) 98Bh 98Ch 97Fh Common RAM (Accesses 70h – 7Fh) 9EFh 9F0h Core Registers (Table 3-2) A0Bh A0Ch 9FFh Common RAM (Accesses 70h – 7Fh) A6Fh A70h Core Registers (Table 3-2) A8Bh A8Ch A7Fh Common RAM (Accesses 70h – 7Fh) AEFh AF0h Core Registers (Table 3-2) B0Bh B0Ch AFFh Common RAM (Accesses 70h – 7Fh) Core Registers (Table 3-2) B6Fh B70h B7Fh Core Registers (Table 3-2) C8Bh D0Bh D8Bh E0Bh E8Bh F0Bh D0Ch D8Ch E0Ch E8Ch F0Ch C6Fh C70h CEFh CF0h C7Fh Legend: Accesses 70h – 7Fh CFFh DEFh DF0h Accesses 70h – 7Fh D7Fh = Unimplemented data memory locations, read as ‘0’ Unimplemented Read as ‘0’ E6Fh E70h Accesses 70h – 7Fh DFFh Unimplemented Read as ‘0’ EEFh EF0h Accesses 70h – 7Fh E7Fh BANK 31 F80h F6Fh F70h F7Fh Core Registers (Table 3-2) F8Bh F8Ch Unimplemented Read as ‘0’ Accesses 70h – 7Fh EFFh BFFh Common RAM (Accesses 70h – 7Fh) Common RAM (Accesses 70h – 7Fh) Unimplemented Read as ‘0’ F9Fh FA0h FEFh FF0h FFFh See Table 3-4 for more information Common RAM (Accesses 70h – 7Fh) DS41391D-page 25 PIC16(L)F1826/27 Accesses 70h – 7Fh D6Fh D70h Unimplemented Read as ‘0’ BEFh BF0h Core Registers (Table 3-2) C8Ch Unimplemented Read as ‘0’ Common RAM (Accesses 70h – 7Fh) Unimplemented Read as ‘0’ BANK 30 C0Bh Unimplemented Read as ‘0’ B8Bh B8Ch F00h C0Ch Unimplemented Read as ‘0’ Core Registers (Table 3-2) Unimplemented Read as ‘0’ BANK 29 E80h BANK23 B80h Core Registers (Table 3-2) Unimplemented Read as ‘0’ BANK 28 E00h BANK22 B00h Core Registers (Table 3-2) Unimplemented Read as ‘0’ BANK 27 D80h BANK21 A80h Core Registers (Table 3-2) Unimplemented Read as ‘0’ BANK 26 D00h BANK20 A00h Core Registers (Table 3-2) Unimplemented Read as ‘0’ BANK 25 C80h BANK19 980h Core Registers (Table 3-2) Unimplemented Read as ‘0’ BANK 24 C00h BANK18 900h PIC16(L)F1826/27 TABLE 3-4: PIC16(L)F1826/27 MEMORY MAP (CONTINUED) Bank 31 F80h Core Registers (Table 3-2) F8Bh F8Ch Unimplemented Read as ‘0’ FE3h FE4h FE5h FE6h FE7h FE8h FE9h FEAh FEBh FECh FEDh FEEh FEFh FF0h FFFh STATUS_SHAD WREG_SHAD BSR_SHAD PCLATH_SHAD FSR0L_SHAD FSR0H_SHAD FSR1L_SHAD FSR1H_SHAD — STKPTR TOSL TOSH Common RAM (Accesses 70h – 7Fh) = Unimplemented data memory locations, read as ‘0’, DS41391D-page 26  2011 Microchip Technology Inc. PIC16(L)F1826/27 3.2.6 CORE FUNCTION REGISTERS SUMMARY The Core Function registers listed in Table 3-5 can be addressed from any Bank. TABLE 3-5: Addr Name CORE FUNCTION REGISTERS SUMMARY Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets Bank 0-31 x00h or INDF0 x80h Addressing this location uses contents of FSR0H/FSR0L to address data memory (not a physical register) xxxx xxxx uuuu uuuu x01h or INDF1 x81h Addressing this location uses contents of FSR1H/FSR1L to address data memory (not a physical register) xxxx xxxx uuuu uuuu x02h or PCL x82h Program Counter (PC) Least Significant Byte 0000 0000 0000 0000 ---1 1000 ---q quuu x03h or STATUS x83h — — — TO PD Z DC C x04h or FSR0L x84h Indirect Data Memory Address 0 Low Pointer 0000 0000 uuuu uuuu x05h or FSR0H x85h Indirect Data Memory Address 0 High Pointer 0000 0000 0000 0000 x06h or FSR1L x86h Indirect Data Memory Address 1 Low Pointer 0000 0000 uuuu uuuu x07h or FSR1H x87h Indirect Data Memory Address 1 High Pointer 0000 0000 0000 0000 ---0 0000 ---0 0000 0000 0000 uuuu uuuu -000 0000 -000 0000 0000 0000 0000 0000 x08h or BSR x88h — x09h or WREG x89h — BSR4 BSR3 BSR2 BSR1 BSR0 Working Register x0Ah or PCLATH x8Ah — x0Bh or INTCON x8Bh GIE Legend: — Write Buffer for the upper 7 bits of the Program Counter PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, read as ‘0’, r = reserved. Shaded locations are unimplemented, read as ‘0’.  2011 Microchip Technology Inc. DS41391D-page 27 PIC16(L)F1826/27 TABLE 3-6: Address SPECIAL FUNCTION REGISTER SUMMARY Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets Bank 0 00Ch PORTA RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0 xxxx xxxx xxxx xxxx 00Dh PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 xxxx xxxx xxxx xxxx 00Eh — Unimplemented — — 00Fh — Unimplemented — — 010h — Unimplemented — — 011h PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF 012h PIR2 TMR1IF 0000 0000 0000 0000 CCP2IF(1) 0000 0--0 0000 0--0 OSFIF C2IF C1IF EEIF BCL1IF — — 013h (1) PIR3 — — CCP4IF CCP3IF TMR6IF — TMR4IF — --00 0-0- --00 0-0- 014h PIR4(1) — — — — — — BCL2IF SSP2IF ---- --00 ---- --00 015h TMR0 Timer0 Module Register xxxx xxxx uuuu uuuu 016h TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register xxxx xxxx uuuu uuuu 017h TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register 018h T1CON TMR1CS1 TMR1CS0 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC — TMR1ON 0000 00-0 uuuu uu-u 019h T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/ DONE T1GVAL T1GSS1 T1GSS0 0000 0x00 uuuu uxuu 01Ah TMR2 Timer2 Module Register 01Bh PR2 Timer2 Period Register 01Ch T2CON — T2OUTPS3 xxxx xxxx uuuu uuuu 0000 0000 0000 0000 1111 1111 1111 1111 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON 01Dh — 01Eh CPSCON0 CPSON — — — 01Fh CPSCON1 — — — — CPSCH3 CPSCH2 T2CKPS1 T2CKPS0 -000 0000 -000 0000 Unimplemented — CPSRNG1 CPSRNG0 CPSOUT — T0XCS 0--- 0000 0--- 0000 CPSCH1 CPSCH0 ---- 0000 ---- 0000 Bank 1 08Ch TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 1111 1111 1111 1111 08Dh TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111 08Eh — Unimplemented — — 08Fh — Unimplemented — — 090h — Unimplemented — — 091h PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE 092h PIE2 TMR1IE 0000 0000 0000 0000 CCP2IE(1) 0000 0--0 0000 0--0 OSFIE C2IE C1IE EEIE BCL1IE — — 093h (1) PIE3 — — CCP4IE CCP3IE TMR6IE — TMR4IE — 094h PIE4(1) — — — — — — BCL2IE SSP2IE ---- --00 ---- --00 095h OPTION_REG WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 1111 1111 1111 1111 096h PCON STKOVF STKUNF — — RMCLR RI POR BOR 00-- 11qq qq-- qquu 097h WDTCON — — WDTPS4 WDTPS3 WDTPS2 WDTPS1 WDTPS0 098h OSCTUNE — — TUN5 TUN4 TUN3 TUN2 TUN1 TUN0 --00 0000 --00 0000 099h OSCCON SPLLEN IRCF3 IRCF2 IRCF1 IRCF0 — SCS1 SCS0 0011 1-00 0011 1-00 T1OSCR PLLR OSTS HFIOFR HFIOFL MFIOFR LFIOFR HFIOFS 10q0 0q00 qqqq qq0q 09Ah OSCSTAT 09Bh ADRESL A/D Result Register Low 09Ch ADRESH A/D Result Register High 09Dh ADCON0 09Eh ADCON1 09Fh — Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1: DS41391D-page 28 --00 0-0- --00 0-0- SWDTEN --01 0110 --01 0110 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu — CHS4 CHS3 CHS2 CHS1 CHS0 GO/DONE ADFM ADCS2 ADCS1 ADCS0 — ADNREF ADPREF1 Unimplemented ADON -000 0000 -000 0000 ADPREF0 0000 -000 0000 -000 —  2011 Microchip Technology Inc. — PIC16(L)F1826/27 TABLE 3-6: Address Name SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets Bank 2 10Ch LATA LATA7 LATA6 — LATA4 LATA3 LATA2 LATA1 LATA0 xx-x xxxx uu-u uuuu 10Dh LATB LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0 xxxx xxxx uuuu uuuu 10Eh — Unimplemented — — 10Fh — Unimplemented — — 110h — Unimplemented — — 111h CM1CON0 C1ON C1OUT C1OE C1POL — 112h CM1CON1 C1INTP C1INTN C1PCH1 C1PCH0 — — 113h CM2CON0 C2ON C2OUT C2OE C2POL — C2SP 114h CM2CON1 C2INTP C2INTN C2PCH1 C2PCH0 — — 115h CMOUT — — — — — — 116h BORCON SBOREN — — — — — — 117h FVRCON FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 0qrr 0000 0qrr 0000 118h DACCON0 DACEN DACLPS DACOE — DACPSS1 DACPSS0 — DACNSS 000- 00-0 000- 00-0 C1SP C1HYS C1SYNC C1NCH C2HYS 0000 -100 0000 -100 0000 --00 0000 --00 C2SYNC 0000 -100 0000 -100 C2NCH1 C2NCH0 0000 --00 0000 --00 MC2OUT MC1OUT ---- --00 ---- --00 BORRDY 1--- ---q u--- ---u 119h DACCON1 — — — DACR4 DACR3 DACR2 DACR1 DACR0 ---0 0000 ---0 0000 11Ah SRCON0 SRLEN SRCLK2 SRCLK1 SRCLK0 SRQEN SRNQEN SRPS SRPR 0000 0000 0000 0000 11Bh SRCON1 SRSPE SRSCKE SRSC2E SRSC1E SRRPE SRRCKE SRRC2E SRRC1E 0000 0000 0000 0000 11Ch — 11Dh APFCON0 P1DSEL P1CSEL CCP1SEL 0000 0000 0000 0000 11Eh APFCON1 — — TXCKSEL ---- ---0 ---- ---0 11Fh — Unimplemented — RXDTSEL SDO1SEL SS1SEL — — — P2BSEL(1) CCP2SEL(1) — — Unimplemented — — — Bank 3 18Ch ANSELA — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 ---1 1111 ---1 1111 18Dh ANSELB ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — 1111 111- 1111 111- 18Eh — Unimplemented — — 18Fh — Unimplemented — — 190h — Unimplemented — — 191h EEADRL EEPROM / Program Memory Address Register Low Byte 192h EEADRH 193h EEDATL 194h EEDATH 195h EECON1 196h EECON2 EEPROM control register 2 197h — Unimplemented — — 198h — Unimplemented — — 199h RCREG USART Receive Data Register 0000 0000 0000 0000 19Ah TXREG USART Transmit Data Register 0000 0000 0000 0000 19Bh SPBRGL Baud Rate Generator Data Register Low 0000 0000 0000 0000 19Ch SPBRGH Baud Rate Generator Data Register High 19Dh RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 0000 000x 0000 000x 19Eh TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 0000 0010 0000 0010 19Fh BAUDCON ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN 01-0 0-00 01-0 0-00 Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1: — 0000 0000 0000 0000 EEPROM / Program Memory Address Register High Byte -000 0000 -000 0000 EEPROM / Program Memory Read Data Register Low Byte — — EEPGD CFGS  2011 Microchip Technology Inc. xxxx xxxx uuuu uuuu EEPROM / Program Memory Read Data Register High Byte LWLO FREE WRERR WREN WR --xx xxxx --uu uuuu RD 0000 x000 0000 q000 0000 0000 0000 0000 0000 0000 0000 0000 DS41391D-page 29 PIC16(L)F1826/27 TABLE 3-6: Address SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets Bank 4 20Ch WPUA — — WPUA5 — — — — — --1- ---- --1- ---- 20Dh WPUB WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0 1111 1111 1111 1111 20Eh — Unimplemented — — 20Fh — Unimplemented — — 210h — Unimplemented — — 211h SSP1BUF Synchronous Serial Port Receive Buffer/Transmit Register xxxx xxxx uuuu uuuu 212h SSP1ADD ADD7 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0 0000 0000 0000 0000 213h SSP1MSK MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0 1111 1111 1111 1111 214h SSP1STAT SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000 215h SSP1CON1 WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000 216h SSP1CON2 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 0000 0000 0000 0000 217h SSP1CON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN 0000 0000 0000 0000 218h — Unimplemented 219h SSP2BUF(1) Synchronous Serial Port Receive Buffer/Transmit Register 21Ah SSP2ADD(1) ADD7 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0 0000 0000 0000 0000 21Bh SSP2MSK(1) MSK7 MSK6 MSK5 MSK4 MSK3 MSK2 MSK1 MSK0 1111 1111 1111 1111 — — xxxx xxxx uuuu uuuu 21Ch SSP2STAT(1) SMP CKE D/A P S R/W UA BF 0000 0000 0000 0000 21Dh SSP2CON1(1) WCOL SSPOV SSPEN CKP SSPM3 SSPM2 SSPM1 SSPM0 0000 0000 0000 0000 21Eh SSP2CON2(1) GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN 0000 0000 0000 0000 21Fh SSP2CON3(1) ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN 0000 0000 0000 0000 Bank 5 28Ch — Unimplemented — — 28Dh — Unimplemented — — 28Eh — Unimplemented — — 28Fh — Unimplemented — — 290h — Unimplemented — — 291h CCPR1L Capture/Compare/PWM Register 1 (LSB) 292h CCPR1H Capture/Compare/PWM Register 1 (MSB) 293h CCP1CON P1M1 P1M0 DC1B1 DC1B0 CCP1M3 CCP1M2 CCP1M1 CCP1M0 0000 0000 0000 0000 294h PWM1CON P1RSEN P1DC6 P1DC5 P1DC4 P1DC3 P1DC2 P1DC1 P1DC0 0000 0000 0000 0000 295h CCP1AS CCP1ASE CCP1AS2 CCP1AS1 CCP1AS0 PSS1AC1 296h PSTR1CON — — — STR1SYNC STR1D 297h — Unimplemented 298h CCPR2L(1) Capture/Compare/PWM Register 2 (LSB) 299h CCPR2H(1) Capture/Compare/PWM Register 2 (MSB) 29Ah CCP2CON(1) P2M1 P2M0 DC2B1 DC2B0 CCP2M3 CCP2M2 CCP2M1 CCP2M0 0000 0000 0000 0000 29Bh PWM2CON(1) P2RSEN P2DC6 P2DC5 P2DC4 P2DC3 P2DC2 P2DC1 P2DC0 0000 0000 0000 0000 29Ch CCP2AS(1) CCP2ASE CCP2AS2 CCP2AS1 CCP2AS0 PSS2AC1 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu PSS1AC0 PSS1BD1 PSS1BD0 0000 0000 0000 0000 STR1C STR1B — — xxxx xxxx uuuu uuuu PSS2AC0 PSS2BD1 PSS2BD0 0000 0000 0000 0000 29Dh PSTR2CON(1) — — — STR2SYNC STR2D STR2C STR2B CCPTMRS(1) C4TSEL1 C4TSEL0 C3TSEL1 C3TSEL0 C2TSEL1 C2TSEL0 C1TSEL1 29Fh — Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. DS41391D-page 30 ---0 0001 ---0 0001 xxxx xxxx uuuu uuuu 29Eh Note 1: STR1A Unimplemented STR2A ---0 0001 ---0 0001 C1TSEL0 0000 0000 0000 0000 —  2011 Microchip Technology Inc. — PIC16(L)F1826/27 TABLE 3-6: Address SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets Bank 6 30Ch — Unimplemented — — 30Dh — Unimplemented — — 30Eh — Unimplemented — — 30Fh — Unimplemented — — 310h — Unimplemented — — 311h CCPR3L(1) Capture/Compare/PWM Register 3 (LSB) 312h CCPR3H(1) Capture/Compare/PWM Register 3 (MSB) 313h CCP3CON(1) 314h — Unimplemented — — 315h — Unimplemented — — 316h — Unimplemented — — 317h — Unimplemented — — 318h CCPR4L(1) Capture/Compare/PWM Register 4 (LSB) 319h CCPR4H(1) Capture/Compare/PWM Register 4 (MSB) 31Ah CCP4CON(1) 31Bh — Unimplemented — — 31Ch — Unimplemented — — 31Dh — Unimplemented — — 31Eh — Unimplemented — — 31Fh — Unimplemented — — — — — — DC3B1 DC4B1 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu DC3B0 CCP3M3 CCP3M2 CCP3M1 CCP3M0 --00 0000 --00 0000 xxxx xxxx uuuu uuuu xxxx xxxx uuuu uuuu DC4B0 CCP4M3 CCP4M2 CCP4M1 CCP4M0 --00 0000 --00 0000 Bank 7 38Ch — Unimplemented — — 38Dh — Unimplemented — — 38Eh — Unimplemented — — 38Fh — Unimplemented — — 390h — Unimplemented — — 391h — Unimplemented — — 392h — Unimplemented — — 393h — Unimplemented — — 394h IOCBP IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0 0000 0000 0000 0000 395h IOCBN IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0 0000 0000 0000 0000 396h IOCBF IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0 0000 0000 0000 0000 397h — Unimplemented — — 398h — Unimplemented — — 399h — Unimplemented — — 39Ah CLKRCON CLKREN CLKROE CLKRSLR CLKRDC1 CLKRDC0 MDSLR MDOPOL — — — MDBIT 0010 ---0 0010 ---0 CLKRDIV2 CLKRDIV1 CLKRDIV0 0011 0000 0011 0000 39Bh — 39Ch MDCON MDEN 39Dh MDSRC MDMSODIS — — — MDMS3 MDMS2 MDMS1 MDMS0 x--- xxxx u--- uuuu 39Eh MDCARL MDCLODIS MDCLPOL MDCLSYNC — MDCL3 MDCL2 MDCL1 MDCL0 xxx- xxxx uuu- uuuu 39Fh MDCARH MDCHODIS MDCHPOL MDCHSYNC — MDCH3 MDCH2 MDCH1 MDCH0 xxx- xxxx uuu- uuuu Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1: Unimplemented  2011 Microchip Technology Inc. — MDOE DS41391D-page 31 — PIC16(L)F1826/27 TABLE 3-6: Address Name SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets Bank 8 40Ch — Unimplemented — — 40Dh — Unimplemented — — 40Eh — Unimplemented — — 40Fh — Unimplemented — — 410h — Unimplemented — — 411h — Unimplemented — — 412h — Unimplemented — — 413h — Unimplemented — — 414h — Unimplemented — — 415h TMR4(1) Timer4 Module Register 416h PR4(1) Timer4 Period Register 417h T4CON(1) 418h — Unimplemented — — 419h — Unimplemented — — 41Ah — Unimplemented — — 41Bh — Unimplemented — — 41Ch TMR6(1) Timer6 Module Register 41Dh PR6(1) Timer6 Period Register 41Eh T6CON(1) 41Fh — Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1: DS41391D-page 32 — — T4OUTPS3 T6OUTPS3 0000 0000 0000 0000 1111 1111 1111 1111 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 -000 0000 -000 0000 0000 0000 0000 0000 1111 1111 1111 1111 T6OUTPS2 T6OUTPS1 T6OUTPS0 TMR6ON Unimplemented T6CKPS1 T6CKPS0 -000 0000 -000 0000 —  2011 Microchip Technology Inc. — PIC16(L)F1826/27 TABLE 3-6: Address Name SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Value on POR, BOR Value on all other Resets Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Bank 9 48Ch — 49Fh — Bank 10 50Ch — 51Fh — Bank 11 58Ch — 59Fh — Bank 12 60Ch — 61Fh — Bank 13 68Ch — 69Fh — Bank 14 70Ch — 71Fh — Bank 15 78Ch — 79Fh — Bank 16 80Ch — 86Fh — Bank 17 88Ch — 8EFh — Bank 18 90Ch — 96Fh — Bank 19 98Ch — 9EFh — Bank 20 A0Ch — A6Fh — Bank 21 A8Ch — AEFh — Bank 22 B0Ch — B6Fh — Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1:  2011 Microchip Technology Inc. DS41391D-page 33 PIC16(L)F1826/27 TABLE 3-6: Address Name SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Value on POR, BOR Value on all other Resets Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Unimplemented — — Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Bank 23 B8Ch — BEFh — Bank 24 C0Ch — C6Fh — Bank 25 C8Ch — CEFh — Bank 26 D0Ch — D6Fh — Bank 27 D8Ch — DEFh — Bank 28 E0Ch — E6Fh — Bank 29 E8Ch — EEFh — Bank 30 F0Ch — F6Fh — Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1: DS41391D-page 34  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 3-6: Address SPECIAL FUNCTION REGISTER SUMMARY (CONTINUED) Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Value on POR, BOR Value on all other Resets — — Bank 31 F8Ch — FE3h FE4h — Unimplemented STATUS_ — — — — — Z_SHAD SHAD FE5h WREG_ Working Register Shadow DC_ SHAD C_SHAD ---- -xxx ---- -uuu 0000 0000 uuuu uuuu SHAD FE6h BSR_ — — — Bank Select Register Shadow ---x xxxx ---u uuuu SHAD FE7h PCLATH_ — Program Counter Latch High Register Shadow -xxx xxxx uuuu uuuu SHAD FE8h FSR0L_ Indirect Data Memory Address 0 Low Pointer Shadow xxxx xxxx uuuu uuuu Indirect Data Memory Address 0 High Pointer Shadow xxxx xxxx uuuu uuuu Indirect Data Memory Address 1 Low Pointer Shadow xxxx xxxx uuuu uuuu Indirect Data Memory Address 1 High Pointer Shadow xxxx xxxx uuuu uuuu SHAD FE9h FSR0H_ SHAD FEAh FSR1L_ SHAD FEBh FSR1H_ SHAD FECh FEDh — STKPTR Unimplemented — — — — Current Stack pointer FEEh TOSL FEFh TOSH Legend: x = unknown, u = unchanged, q = value depends on condition, - = unimplemented, r = reserved. Shaded locations are unimplemented, read as ‘0’. PIC16(L)F1827 only. Note 1: Top-of-Stack Low byte —  2011 Microchip Technology Inc. Top-of-Stack High byte — ---1 1111 ---1 1111 xxxx xxxx uuuu uuuu -xxx xxxx -uuu uuuu DS41391D-page 35 PIC16(L)F1826/27 3.3 3.3.3 PCL and PCLATH COMPUTED FUNCTION CALLS The Program Counter (PC) is 15 bits wide. The low byte comes from the PCL register, which is a readable and writable register. The high byte (PC) is not directly readable or writable and comes from PCLATH. On any Reset, the PC is cleared. Figure 3-4 shows the five situations for the loading of the PC. A computed function CALL allows programs to maintain tables of functions and provide another way to execute state machines or look-up tables. When performing a table read using a computed function CALL, care should be exercised if the table location crosses a PCL memory boundary (each 256-byte block). FIGURE 3-4: If using the CALL instruction, the PCH and PCL registers are loaded with the operand of the CALL instruction. PCH is loaded with PCLATH. PC LOADING OF PC IN DIFFERENT SITUATIONS 14 PCH 6 7 14 PCH PCL 0 PCLATH PC 8 ALU Result PCL 0 4 0 11 OPCODE PC 14 PCH PCL 0 CALLW 6 PCLATH PC Instruction with PCL as Destination GOTO, CALL 6 PCLATH 0 14 7 0 PCH 8 W PCL 0 BRW 14 PCH 3.3.4 BRANCHING The branching instructions add an offset to the PC. This allows relocatable code and code that crosses page boundaries. There are two forms of branching, BRW and BRA. The PC will have incremented to fetch the next instruction in both cases. When using either branching instruction, a PCL memory boundary may be crossed. If using BRW, load the W register with the desired unsigned address and execute BRW. The entire PC will be loaded with the address PC + 1 + W. If using BRA, the entire PC will be loaded with PC + 1 +, the signed value of the operand of the BRA instruction. 15 PC + W PC The CALLW instruction enables computed calls by combining PCLATH and W to form the destination address. A computed CALLW is accomplished by loading the W register with the desired address and executing CALLW. The PCL register is loaded with the value of W and PCH is loaded with PCLATH. PCL 0 BRA 15 PC + OPCODE 3.3.1 MODIFYING PCL Executing any instruction with the PCL register as the destination simultaneously causes the Program Counter PC bits (PCH) to be replaced by the contents of the PCLATH register. This allows the entire contents of the program counter to be changed by writing the desired upper 7 bits to the PCLATH register. When the lower 8 bits are written to the PCL register, all 15 bits of the program counter will change to the values contained in the PCLATH register and those being written to the PCL register. 3.3.2 COMPUTED GOTO A computed GOTO is accomplished by adding an offset to the program counter (ADDWF PCL). When performing a table read using a computed GOTO method, care should be exercised if the table location crosses a PCL memory boundary (each 256-byte block). Refer to Application Note AN556, “Implementing a Table Read” (DS00556). DS41391D-page 36  2011 Microchip Technology Inc. PIC16(L)F1826/27 3.4 3.4.1 Stack The stack is available through the TOSH, TOSL and STKPTR registers. STKPTR is the current value of the Stack Pointer. TOSH:TOSL register pair points to the TOP of the stack. Both registers are read/writable. TOS is split into TOSH and TOSL due to the 15-bit size of the PC. To access the stack, adjust the value of STKPTR, which will position TOSH:TOSL, then read/write to TOSH:TOSL. STKPTR is 5 bits to allow detection of overflow and underflow. All devices have a 16-level x 15-bit wide hardware stack (refer to Figures 3-5 through 3-8). The stack space is not part of either program or data space. The PC is PUSHed onto the stack when CALL or CALLW instructions are executed or an interrupt causes a branch. The stack is POPed in the event of a RETURN, RETLW or a RETFIE instruction execution. PCLATH is not affected by a PUSH or POP operation. The stack operates as a circular buffer if the STVREN bit is programmed to ‘0‘ (Configuration Word 2). This means that after the stack has been PUSHed sixteen times, the seventeenth PUSH overwrites the value that was stored from the first PUSH. The eighteenth PUSH overwrites the second PUSH (and so on). The STKOVF and STKUNF flag bits will be set on an Overflow/Underflow, regardless of whether the Reset is enabled. Note: Care should be taken when modifying the STKPTR while interrupts are enabled. During normal program operation, CALL, CALLW and Interrupts will increment STKPTR while RETLW, RETURN, and RETFIE will decrement STKPTR. At any time STKPTR can be inspected to see how much stack is left. The STKPTR always points at the currently used place on the stack. Therefore, a CALL or CALLW will increment the STKPTR and then write the PC, and a return will unload the PC and then decrement STKPTR. Note 1: There are no instructions/mnemonics called PUSH or POP. These are actions that occur from the execution of the CALL, CALLW, RETURN, RETLW and RETFIE instructions or the vectoring to an interrupt address. FIGURE 3-5: ACCESSING THE STACK Reference Figure 3-5 through Figure 3-8 for examples of accessing the stack. ACCESSING THE STACK EXAMPLE 1 TOSH:TOSL STKPTR = 0x1F 0x0F Stack Reset Disabled (STVREN = 0) 0x0E 0x0D 0x0C 0x0B 0x0A 0x09 Initial Stack Configuration: 0x08 After Reset, the stack is empty. The empty stack is initialized so the Stack Pointer is pointing at 0x1F. If the Stack Overflow/Underflow Reset is enabled, the TOSH/TOSL registers will return ‘0’. If the Stack Overflow/Underflow Reset is disabled, the TOSH/TOSL registers will return the contents of stack address 0x0F. 0x07 0x06 0x05 0x04 0x03 0x02 0x01 0x00 TOSH:TOSL  2011 Microchip Technology Inc. 0x1F 0x0000 STKPTR = 0x1F Stack Reset Enabled (STVREN = 1) DS41391D-page 37 PIC16(L)F1826/27 FIGURE 3-6: ACCESSING THE STACK EXAMPLE 2 0x0F 0x0E 0x0D 0x0C 0x0B 0x0A This figure shows the stack configuration after the first CALL or a single interrupt. If a RETURN instruction is executed, the return address will be placed in the Program Counter and the Stack Pointer decremented to the empty state (0x1F). 0x09 0x08 0x07 0x06 0x05 0x04 0x03 0x02 0x01 TOSH:TOSL FIGURE 3-7: 0x00 Return Address STKPTR = 0x00 ACCESSING THE STACK EXAMPLE 3 0x0F 0x0E 0x0D After seven CALLs, or six CALLs and an interrupt, the stack looks like the figure on the left. A series of RETURN instructions will repeatedly place the return addresses into the Program Counter and pop the stack. 0x0C 0x0B 0x0A 0x09 0x08 0x07 TOSH:TOSL DS41391D-page 38 0x06 Return Address 0x05 Return Address 0x04 Return Address 0x03 Return Address 0x02 Return Address 0x01 Return Address 0x00 Return Address STKPTR = 0x06  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 3-8: ACCESSING THE STACK EXAMPLE 4 TOSH:TOSL 3.4.2 0x0F Return Address 0x0E Return Address 0x0D Return Address 0x0C Return Address 0x0B Return Address 0x0A Return Address 0x09 Return Address 0x08 Return Address 0x07 Return Address 0x06 Return Address 0x05 Return Address 0x04 Return Address 0x03 Return Address 0x02 Return Address 0x01 Return Address 0x00 Return Address When the stack is full, the next CALL or interrupt will set the Stack Pointer to 0x10. This is identical to address 0x00 so the stack will wrap and overwrite the return address at 0x00. If the Stack Overflow/Underflow Reset is enabled, a Reset will occur and location 0x00 will not be overwritten. STKPTR = 0x10 OVERFLOW/UNDERFLOW RESET If the STVREN bit in Configuration Word 2 is programmed to ‘1’, the device will be reset if the stack is PUSHed beyond the sixteenth level or POPed beyond the first level, setting the appropriate bits (STKOVF or STKUNF, respectively) in the PCON register. 3.5 Indirect Addressing The INDFn registers are not physical registers. Any instruction that accesses an INDFn register actually accesses the register at the address specified by the File Select Registers (FSR). If the FSRn address specifies one of the two INDFn registers, the read will return ‘0’ and the write will not occur (though Status bits may be affected). The FSRn register value is created by the pair FSRnH and FSRnL. The FSR registers form a 16-bit address that allows an addressing space with 65536 locations. These locations are divided into three memory regions: • Traditional Data Memory • Linear Data Memory • Program Flash Memory  2011 Microchip Technology Inc. DS41391D-page 39 PIC16(L)F1826/27 FIGURE 3-9: INDIRECT ADDRESSING 0x0000 0x0000 Traditional Data Memory 0x0FFF 0x1000 0x1FFF 0x0FFF Reserved 0x2000 Linear Data Memory 0x29AF 0x29B0 FSR Address Range 0x7FFF 0x8000 Reserved 0x0000 Program Flash Memory 0xFFFF Note: 0x7FFF Not all memory regions are completely implemented. Consult device memory tables for memory limits. DS41391D-page 40  2011 Microchip Technology Inc. PIC16(L)F1826/27 3.5.1 TRADITIONAL DATA MEMORY The traditional data memory is a region from FSR address 0x000 to FSR address 0xFFF. The addresses correspond to the absolute addresses of all SFR, GPR and common registers. FIGURE 3-10: TRADITIONAL DATA MEMORY MAP Direct Addressing 4 BSR 0 6 Indirect Addressing From Opcode 7 0 0 Bank Select Location Select 0000 0001 0010 FSRxH 0 0 0 7 FSRxL 0 0 Bank Select Location Select 1111 0x00 0x7F Bank 0 Bank 1 Bank 2  2011 Microchip Technology Inc. Bank 31 DS41391D-page 41 PIC16(L)F1826/27 3.5.2 3.5.3 LINEAR DATA MEMORY The linear data memory is the region from FSR address 0x2000 to FSR address 0x29AF. This region is a virtual region that points back to the 80-byte blocks of GPR memory in all the banks. Unimplemented memory reads as 0x00. Use of the linear data memory region allows buffers to be larger than 80 bytes because incrementing the FSR beyond one bank will go directly to the GPR memory of the next bank. The 16 bytes of common memory are not included in the linear data memory region. FIGURE 3-11: 7 FSRnH 0 0 1 LINEAR DATA MEMORY MAP 0 7 FSRnL 0 PROGRAM FLASH MEMORY To make constant data access easier, the entire program Flash memory is mapped to the upper half of the FSR address space. When the MSB of FSRnH is set, the lower 15 bits are the address in program memory which will be accessed through INDF. Only the lower 8 bits of each memory location is accessible via INDF. Writing to the program Flash memory cannot be accomplished via the FSR/INDF interface. All instructions that access program Flash memory via the FSR/INDF interface will require one additional instruction cycle to complete. FIGURE 3-12: 7 1 FSRnH PROGRAM FLASH MEMORY MAP 0 Location Select Location Select 0x2000 7 FSRnL 0x8000 0 0x0000 0x020 Bank 0 0x06F 0x0A0 Bank 1 0x0EF 0x120 Program Flash Memory (low 8 bits) Bank 2 0x16F 0xF20 Bank 30 0x29AF DS41391D-page 42 0xF6F 0xFFFF 0x7FFF  2011 Microchip Technology Inc. PIC16(L)F1826/27 4.0 DEVICE CONFIGURATION Device Configuration consists of Configuration Word 1 and Configuration Word 2, Code Protection and Device ID. 4.1 Configuration Words There are several Configuration Word bits that allow different oscillator and memory protection options. These are implemented as Configuration Word 1 at 8007h and Configuration Word 2 at 8008h. Note: The DEBUG bit in Configuration Word is managed automatically by device development tools including debuggers and programmers. For normal device operation, this bit should be maintained as a '1'.  2011 Microchip Technology Inc. DS41391D-page 43 PIC16(L)F1826/27 REGISTER 4-1: CONFIGURATION WORD 1 R/P-1 R/P-1 R/P-1 FCMEN IESO CLKOUTEN R/P-1 R/P-1 R/P-1/1 BOREN CPD bit 13 R/P-1 R/P-1 R/P-1 CP MCLRE PWRTE bit 8 R/P-1 R/P-1 R/P-1 WDTE R/P-1 R/P-1 FOSC bit 7 bit 0 Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘1’ ‘0’ = Bit is cleared ‘1’ = Bit is set -n = Value when blank or after Bulk Erase bit 13 FCMEN: Fail-Safe Clock Monitor Enable bit 1 = Fail-Safe Clock Monitor is enabled 0 = Fail-Safe Clock Monitor is disabled bit 12 IESO: Internal External Switchover bit 1 = Internal/External Switchover mode is enabled 0 = Internal/External Switchover mode is disabled bit 11 CLKOUTEN: Clock Out Enable bit If FOSC configuration bits are set to LP, XT, HS modes: This bit is ignored, CLKOUT function is disabled. Oscillator function on the CLKOUT pin. All other FOSC modes: 1 = CLKOUT function is disabled. I/O function on the CLKOUT pin. 0 = CLKOUT function is enabled on the CLKOUT pin bit 10-9 BOREN: Brown-out Reset Enable bits 11 = BOR enabled 10 = BOR enabled during operation and disabled in Sleep 01 = BOR controlled by SBOREN bit of the BORCON register 00 = BOR disabled bit 8 CPD: Data Code Protection bit(2) 1 = Data memory code protection is disabled 0 = Data memory code protection is enabled bit 7 CP: Code Protection bit 1 = Program memory code protection is disabled 0 = Program memory code protection is enabled bit 6 MCLRE: MCLR/VPP Pin Function Select bit If LVP bit = 1: This bit is ignored. If LVP bit = 0: 1 = MCLR/VPP pin function is MCLR; Weak pull-up enabled. 0 = MCLR/VPP pin function is digital input; MCLR internally disabled; Weak pull-up under control of WPUE3 bit. bit 5 PWRTE: Power-up Timer Enable bit 1 = PWRT disabled 0 = PWRT enabled bit 4-3 WDTE: Watchdog Timer Enable bit 11 = WDT enabled 10 = WDT enabled while running and disabled in Sleep 01 = WDT controlled by the SWDTEN bit in the WDTCON register 00 = WDT disabled DS41391D-page 44  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 4-1: bit 2-0 CONFIGURATION WORD 1 (CONTINUED) FOSC: Oscillator Selection bits 111 = ECH: External Clock, High-Power mode (4-20 MHz): device clock supplied to CLKIN pin 110 = ECM: External Clock, Medium-Power mode (0.5-4 MHz): device clock supplied to CLKIN pin 101 = ECL: External Clock, Low-Power mode (0-0.5 MHz): device clock supplied to CLKIN pin 100 = INTOSC oscillator: I/O function on CLKIN pin 011 = EXTRC oscillator: External RC circuit connected to CLKIN pin 010 = HS oscillator: High-speed crystal/resonator connected between OSC1 and OSC2 pins 001 = XT oscillator: Crystal/resonator connected between OSC1 and OSC2 pins 000 = LP oscillator: Low-power crystal connected between OSC1 and OSC2 pins  2011 Microchip Technology Inc. DS41391D-page 45 PIC16(L)F1826/27 REGISTER 4-2: CONFIGURATION WORD 2 R/P-1 (1) LVP R/P-1 DEBUG (2) U-1 R/P-1 R/P-1 R/P-1/1 — BORV STVREN PLLEN bit 13 bit 8 U-1 U-1 U-1 R/P-1/1 U-1 U-1 — — — Reserved — — R/P-1 R/P-1 WRT bit 7 bit 0 Legend: R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘1’ ‘0’ = Bit is cleared ‘1’ = Bit is set -n = Value when blank or after Bulk Erase bit 13 LVP: Low-Voltage Programming Enable bit 1 = Low-voltage programming enabled 0 = High-voltage on MCLR must be used for programming bit 12 DEBUG: In-Circuit Debugger Mode bit 1 = In-Circuit Debugger disabled, ICSPCLK and ICSPDAT are general purpose I/O pins 0 = In-Circuit Debugger enabled, ICSPCLK and ICSPDAT are dedicated to the debugger bit 11 Unimplemented: Read as ‘1’ bit 10 BORV: Brown-out Reset Voltage Selection bit 1 = Brown-out Reset voltage set to 1.9V (typical) 0 = Brown-out Reset voltage set to 2.5V (typical) bit 9 STVREN: Stack Overflow/Underflow Reset Enable bit 1 = Stack Overflow or Underflow will cause a Reset 0 = Stack Overflow or Underflow will not cause a Reset bit 8 PLLEN: PLL Enable bit 1 = 4xPLL enabled 0 = 4xPLL disabled bit 7-5 Unimplemented: Read as ‘1’ bit 4 Reserved: This location should be programmed to a ‘1’. bit 3-2 Unimplemented: Read as ‘1’ bit 1-0 WRT: Flash Memory Self-Write Protection bits 2 kW Flash memory (PIC16(L)F1826 only): 11 = Write protection off 10 = 000h to 1FFh write-protected, 200h to 7FFh may be modified by EECON control 01 = 000h to 3FFh write-protected, 400h to 7FFh may be modified by EECON control 00 = 000h to 7FFh write-protected, no addresses may be modified by EECON control 4 kW Flash memory (PIC16(L)F1827 only): 11 = Write protection off 10 = 000h to 1FFh write-protected, 200h to FFFh may be modified by EECON control 01 = 000h to 7FFh write-protected, 800h to FFFh may be modified by EECON control 00 = 000h to FFFh write-protected, no addresses may be modified by EECON control Note 1: 2: The LVP bit cannot be programmed to ‘0’ when Programming mode is entered via LVP. The DEBUG bit in Configuration Word is managed automatically by device development tools including debuggers and programmers. For normal device operation, this bit should be maintained as a '1'. DS41391D-page 46  2011 Microchip Technology Inc. PIC16(L)F1826/27 4.2 Code Protection Code protection allows the device to be protected from unauthorized access. Program memory protection and data EEPROM protection are controlled independently. Internal access to the program memory and data EEPROM are unaffected by any code protection setting. 4.2.1 PROGRAM MEMORY PROTECTION The entire program memory space is protected from external reads and writes by the CP bit in Configuration Word 1. When CP = 0, external reads and writes of program memory are inhibited and a read will return all ‘0’s. The CPU can continue to read program memory, regardless of the protection bit settings. Writing the program memory is dependent upon the write protection setting. See Section 4.3 “Write Protection” for more information. 4.2.2 DATA EEPROM PROTECTION The entire data EEPROM is protected from external reads and writes by the CPD bit. When CPD = 0, external reads and writes of data EEPROM are inhibited. The CPU can continue to read and write data EEPROM regardless of the protection bit settings. 4.3 Write Protection Write protection allows the device to be protected from unintended self-writes. Applications, such as bootloader software, can be protected while allowing other regions of the program memory to be modified. The WRT bits in Configuration Word 2 define the size of the program memory block that is protected. 4.4 User ID Four memory locations (8000h-8003h) are designated as ID locations where the user can store checksum or other code identification numbers. These locations are readable and writable during normal execution. See Section 11.5 “User ID, Device ID and Configuration Word Access” for more information on accessing these memory locations. For more information on checksum calculation, see the “PIC16F/LF1826/27 Memory Programming Specification” (DS41390).  2011 Microchip Technology Inc. DS41391D-page 47 PIC16(L)F1826/27 4.5 Device ID and Revision ID The memory location 8006h is where the Device ID and Revision ID are stored. The upper nine bits hold the Device ID. The lower five bits hold the Revision ID. See Section 11.5 “User ID, Device ID and Configuration Word Access” for more information on accessing these memory locations. Development tools, such as device programmers and debuggers, may be used to read the Device ID and Revision ID. DS41391D-page 48  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 4-3: DEVICEID: DEVICE ID REGISTER(1) R R R R R R DEV bit 13 R R bit 8 R R R DEV R R R REV bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘1’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared P = Programmable bit bit 13-5 DEV: Device ID bits DEVICEID Values Device bit 4-0 DEV REV PIC16F1826 10 0111 100 x xxxx PIC16F1827 10 0111 101 x xxxx PIC16LF1826 10 1000 100 x xxxx PIC16LF1827 10 1000 101 x xxxx REV: Revision ID bits These bits are used to identify the revision. Note 1: This location cannot be written.  2011 Microchip Technology Inc. DS41391D-page 49 PIC16(L)F1826/27 NOTES: DS41391D-page 50  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.0 OSCILLATOR MODULE (WITH FAIL-SAFE CLOCK MONITOR) 5.1 Overview The oscillator module has a wide variety of clock sources and selection features that allow it to be used in a wide range of applications while maximizing performance and minimizing power consumption. Figure 5-1 illustrates a block diagram of the oscillator module. Clock sources can be supplied from external oscillators, quartz crystal resonators, ceramic resonators and Resistor-Capacitor (RC) circuits. In addition, the system clock source can be supplied from one of two internal oscillators and PLL circuits, with a choice of speeds selectable via software. Additional clock features include: • Selectable system clock source between external or internal sources via software. • Two-Speed Start-up mode, which minimizes latency between external oscillator start-up and code execution. • Fail-Safe Clock Monitor (FSCM) designed to detect a failure of the external clock source (LP, XT, HS, EC or RC modes) and switch automatically to the internal oscillator. • Oscillator Start-up Timer (OST) ensures stability of crystal oscillator sources  2011 Microchip Technology Inc. The oscillator module can be configured in one of eight clock modes. 1. 2. 3. 4. 5. 6. 7. 8. ECL – External Clock Low-Power mode (0 MHz to 0.5 MHz) ECM – External Clock Medium-Power mode (0.5 MHz to 4 MHz) ECH – External Clock High-Power mode (4 MHz to 32 MHz) LP – 32 kHz Low-Power Crystal mode. XT – Medium Gain Crystal or Ceramic Resonator Oscillator mode (up to 4 MHz) HS – High Gain Crystal or Ceramic Resonator mode (4 MHz to 20 MHz) RC – External Resistor-Capacitor (RC). INTOSC – Internal oscillator (31 kHz to 32 MHz). Clock Source modes are selected by the FOSC bits in the Configuration Word 1. The FOSC bits determine the type of oscillator that will be used when the device is first powered. The EC clock mode relies on an external logic level signal as the device clock source. The LP, XT, and HS clock modes require an external crystal or resonator to be connected to the device. Each mode is optimized for a different frequency range. The RC clock mode requires an external resistor and capacitor to set the oscillator frequency. The INTOSC internal oscillator block produces low, medium, and high frequency clock sources, designated LFINTOSC, MFINTOSC, and HFINTOSC. (see Internal Oscillator Block, Figure 5-1). A wide selection of device clock frequencies may be derived from these three clock sources. DS41391D-page 51 PIC16(L)F1826/27 SIMPLIFIED PIC® MCU CLOCK SOURCE BLOCK DIAGRAM FIGURE 5-1: External Oscillator LP, XT, HS, RC, EC OSC2 Sleep 4 x PLL Oscillator Timer1 FOSC = 100 T1OSO IRCF HFPLL 500 kHz Source 16 MHz (HFINTOSC) Postscaler Internal Oscillator Block 500 kHz (MFINTOSC) 31 kHz Source 31 kHz 31 kHz (LFINTOSC) DS41391D-page 52 16 MHz 8 MHz 4 MHz 2 MHz 1 MHz 500 kHz 250 kHz 125 kHz 62.5 kHz 31.25 kHz MUX T1OSI T1OSCEN Enable Oscillator Sleep T1OSC MUX OSC1 CPU and Peripherals Internal Oscillator Clock Control FOSC SCS Clock Source Option for other modules WDT, PWRT, Fail-Safe Clock Monitor Two-Speed Start-up and other modules  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.2 Clock Source Types Clock sources can be classified as external or internal. External clock sources rely on external circuitry for the clock source to function. Examples are: oscillator modules (EC mode), quartz crystal resonators or ceramic resonators (LP, XT and HS modes) and Resistor-Capacitor (RC) mode circuits. Internal clock sources are contained internally within the oscillator module. The internal oscillator block has two internal oscillators and a dedicated Phase-Lock Loop (HFPLL) that are used to generate three internal system clock sources: the 16 MHz High-Frequency Internal Oscillator (HFINTOSC), 500 kHz (MFINTOSC) and the 31 kHz Low-Frequency Internal Oscillator (LFINTOSC). The system clock can be selected between external or internal clock sources via the System Clock Select (SCS) bits in the OSCCON register. See Section 5.3 “Clock Switching” for additional information. 5.2.1 FIGURE 5-2: OSC1/CLKIN Clock from Ext. System PIC® MCU FOSC/4 or I/O(1) Note 1: EXTERNAL CLOCK (EC) MODE OPERATION OSC2/CLKOUT Output depends upon CLKOUTEN bit of the Configuration Word 1. EXTERNAL CLOCK SOURCES An external clock source can be used as the device system clock by performing one of the following actions: • Program the FOSC bits in the Configuration Word 1 to select an external clock source that will be used as the default system clock upon a device Reset. • Write the SCS bits in the OSCCON register to switch the system clock source to: - Timer1 Oscillator during run-time, or - An external clock source determined by the value of the FOSC bits. See Section 5.3 “Clock Switching”for more information. 5.2.1.1 The Oscillator Start-up Timer (OST) is disabled when EC mode is selected. Therefore, there is no delay in operation after a Power-on Reset (POR) or wake-up from Sleep. Because the PIC® MCU design is fully static, stopping the external clock input will have the effect of halting the device while leaving all data intact. Upon restarting the external clock, the device will resume operation as if no time had elapsed. EC Mode The External Clock (EC) mode allows an externally generated logic level signal to be the system clock source. When operating in this mode, an external clock source is connected to the OSC1 input. OSC2/CLKOUT is available for general purpose I/O or CLKOUT. Figure 5-2 shows the pin connections for EC mode. 5.2.1.2 LP, XT, HS Modes The LP, XT and HS modes support the use of quartz crystal resonators or ceramic resonators connected to OSC1 and OSC2 (Figure 5-3). The three modes select a low, medium or high gain setting of the internal inverter-amplifier to support various resonator types and speed. LP Oscillator mode selects the lowest gain setting of the internal inverter-amplifier. LP mode current consumption is the least of the three modes. This mode is designed to drive only 32.768 kHz tuning-fork type crystals (watch crystals). XT Oscillator mode selects the intermediate gain setting of the internal inverter-amplifier. XT mode current consumption is the medium of the three modes. This mode is best suited to drive resonators with a medium drive level specification. HS Oscillator mode selects the highest gain setting of the internal inverter-amplifier. HS mode current consumption is the highest of the three modes. This mode is best suited for resonators that require a high drive setting. Figure 5-3 and Figure 5-4 show typical circuits for quartz crystal and ceramic resonators, respectively. EC mode has 3 power modes to select from through Configuration Word 1: • High-power, 4-32 MHz (FOSC = 111) • Medium power, 0.5-4 MHz (FOSC = 110) • Low-power, 0-0.5 MHz (FOSC = 101)  2011 Microchip Technology Inc. DS41391D-page 53 PIC16(L)F1826/27 FIGURE 5-3: QUARTZ CRYSTAL OPERATION (LP, XT OR HS MODE) FIGURE 5-4: CERAMIC RESONATOR OPERATION (XT OR HS MODE) PIC® MCU PIC® MCU OSC1/CLKIN C1 Note 1: 2: C1 To Internal Logic Quartz Crystal C2 OSC1/CLKIN RS(1) RF(2) Sleep RP(3) OSC2/CLKOUT A series resistor (RS) may be required for quartz crystals with low drive level. 2: Always verify oscillator performance over the VDD and temperature range that is expected for the application. 3: For oscillator design assistance, reference the following Microchip Applications Notes: • AN826, “Crystal Oscillator Basics and Crystal Selection for rfPIC® and PIC® Devices” (DS00826) • AN849, “Basic PIC® Oscillator Design” (DS00849) • AN943, “Practical PIC® Oscillator Analysis and Design” (DS00943) • AN949, “Making Your Oscillator Work” (DS00949) RF(2) C2 Ceramic RS(1) Resonator Note 1: The value of RF varies with the Oscillator mode selected (typically between 2 M to 10 M. Note 1: Quartz crystal characteristics vary according to type, package and manufacturer. The user should consult the manufacturer data sheets for specifications and recommended application. To Internal Logic Sleep OSC2/CLKOUT A series resistor (RS) may be required for ceramic resonators with low drive level. 2: The value of RF varies with the Oscillator mode selected (typically between 2 M to 10 M. 3: An additional parallel feedback resistor (RP) may be required for proper ceramic resonator operation. 5.2.1.3 Oscillator Start-up Timer (OST) If the oscillator module is configured for LP, XT or HS modes, the Oscillator Start-up Timer (OST) counts 1024 oscillations from OSC1. This occurs following a Power-on Reset (POR) and when the Power-up Timer (PWRT) has expired (if configured), or a wake-up from Sleep. During this time, the program counter does not increment and program execution is suspended. The OST ensures that the oscillator circuit, using a quartz crystal resonator or ceramic resonator, has started and is providing a stable system clock to the oscillator module. In order to minimize latency between external oscillator start-up and code execution, the Two-Speed Clock Start-up mode can be selected (see Section 5.4 “Two-Speed Clock Start-up Mode”). 5.2.1.4 4X PLL The oscillator module contains a 4X PLL that can be used with both external and internal clock sources to provide a system clock source. The input frequency for the 4X PLL must fall within specifications. See the PLL Clock Timing Specifications in Section 30.0 “Electrical Specifications”. The 4X PLL may be enabled for use by one of two methods: 1. 2. DS41391D-page 54 Program the PLLEN bit in Configuration Word 2 to a ‘1’. Write the SPLLEN bit in the OSCCON register to a ‘1’. If the PLLEN bit in Configuration Word 2 is programmed to a ‘1’, then the value of SPLLEN is ignored.  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.2.1.5 5.2.1.6 TIMER1 Oscillator External RC Mode The Timer1 Oscillator is a separate crystal oscillator that is associated with the Timer1 peripheral. It is optimized for timekeeping operations with a 32.768 kHz crystal connected between the T1OSO and T1OSI device pins. The external Resistor-Capacitor (RC) modes support the use of an external RC circuit. This allows the designer maximum flexibility in frequency choice while keeping costs to a minimum when clock accuracy is not required. The Timer1 Oscillator can be used as an alternate system clock source and can be selected during run-time using clock switching. Refer to Section 5.3 “Clock Switching” for more information. The RC circuit connects to OSC1. OSC2/CLKOUT is available for general purpose I/O or CLKOUT. The function of the OSC2/CLKOUT pin is determined by the state of the CLKOUTEN bit in Configuration Word 1. FIGURE 5-5: QUARTZ CRYSTAL OPERATION (TIMER1 OSCILLATOR) Figure 5-6 shows the external RC mode connections. FIGURE 5-6: VDD PIC® MCU PIC® MCU REXT OSC1/CLKIN T1OSI C1 To Internal Logic 32.768 kHz Quartz Crystal Internal Clock CEXT VSS FOSC/4 or I/O(1) C2 EXTERNAL RC MODES OSC2/CLKOUT T1OSO Recommended values: 10 k  REXT  100 k, 20 pF, 2-5V Note 1: Quartz crystal characteristics vary according to type, package and manufacturer. The user should consult the manufacturer data sheets for specifications and recommended application. 2: Always verify oscillator performance over the VDD and temperature range that is expected for the application. 3: For oscillator design assistance, reference the following Microchip Applications Notes: • AN826, “Crystal Oscillator Basics and Crystal Selection for rfPIC® and PIC® Devices” (DS00826) • AN849, “Basic PIC® Oscillator Design” (DS00849) • AN943, “Practical PIC® Oscillator Analysis and Design” (DS00943) • AN949, “Making Your Oscillator Work” (DS00949) • TB097, “Interfacing a Micro Crystal MS1V-T1K 32.768 kHz Tuning Fork Crystal to a PIC16F690/SS” (DS91097) • AN1288, “Design Practices for Low-Power External Oscillators” (DS01288)  2011 Microchip Technology Inc. Note 1: Output depends upon CLKOUTEN bit of the Configuration Word 1. The RC oscillator frequency is a function of the supply voltage, the resistor (REXT) and capacitor (CEXT) values and the operating temperature. Other factors affecting the oscillator frequency are: • threshold voltage variation • component tolerances • packaging variations in capacitance The user also needs to take into account variation due to tolerance of external RC components used. DS41391D-page 55 PIC16(L)F1826/27 5.2.2 INTERNAL CLOCK SOURCES The device may be configured to use the internal oscillator block as the system clock by performing one of the following actions: • Program the FOSC bits in Configuration Word 1 to select the INTOSC clock source, which will be used as the default system clock upon a device Reset. • Write the SCS bits in the OSCCON register to switch the system clock source to the internal oscillator during run-time. See Section 5.3 “Clock Switching”for more information. In INTOSC mode, OSC1/CLKIN is available for general purpose I/O. OSC2/CLKOUT is available for general purpose I/O or CLKOUT. The function of the OSC2/CLKOUT pin is determined by the state of the CLKOUTEN bit in Configuration Word 1. The internal oscillator block has two independent oscillators and a dedicated Phase-Lock Loop, HFPLL that can produce one of three internal system clock sources. 1. 2. 3. The HFINTOSC (High-Frequency Internal Oscillator) is factory calibrated and operates at 16 MHz. The HFINTOSC source is generated from the 500 kHz MFINTOSC source and the dedicated Phase-Lock Loop, HFPLL. The frequency of the HFINTOSC can be user-adjusted via software using the OSCTUNE register (Register 5-3). The MFINTOSC (Medium-Frequency Internal Oscillator) is factory calibrated and operates at 500 kHz. The frequency of the MFINTOSC can be user-adjusted via software using the OSCTUNE register (Register 5-3). The LFINTOSC (Low-Frequency Internal Oscillator) is uncalibrated and operates at 31 kHz. 5.2.2.1 HFINTOSC The High-Frequency Internal Oscillator (HFINTOSC) is a factory calibrated 16 MHz internal clock source. The frequency of the HFINTOSC can be altered via software using the OSCTUNE register (Register 5-3). The output of the HFINTOSC connects to a postscaler and multiplexer (see Figure 5-1). One of nine frequencies derived from the HFINTOSC can be selected via software using the IRCF bits of the OSCCON register. See Section 5.2.2.7 “Internal Oscillator Clock Switch Timing” for more information. The HFINTOSC is enabled by: • Configure the IRCF bits of the OSCCON register for the desired HF frequency, and • FOSC = 100, or • Set the System Clock Source (SCS) bits of the OSCCON register to ‘1x’. The High Frequency Internal Oscillator Ready bit (HFIOFR) of the OSCSTAT register indicates when the HFINTOSC is running and can be utilized. The High Frequency Internal Oscillator Status Locked bit (HFIOFL) of the OSCSTAT register indicates when the HFINTOSC is running within 2% of its final value. The High Frequency Internal Oscillator Status Stable bit (HFIOFS) of the OSCSTAT register indicates when the HFINTOSC is running within 0.5% of its final value. 5.2.2.2 MFINTOSC The Medium-Frequency Internal Oscillator (MFINTOSC) is a factory calibrated 500 kHz internal clock source. The frequency of the MFINTOSC can be altered via software using the OSCTUNE register (Register 5-3). The output of the MFINTOSC connects to a postscaler and multiplexer (see Figure 5-1). One of nine frequencies derived from the MFINTOSC can be selected via software using the IRCF bits of the OSCCON register. See Section 5.2.2.7 “Internal Oscillator Clock Switch Timing” for more information. The MFINTOSC is enabled by: • Configure the IRCF bits of the OSCCON register for the desired HF frequency, and • FOSC = 100, or • Set the System Clock Source (SCS) bits of the OSCCON register to ‘1x’ The Medium Frequency Internal Oscillator Ready bit (MFIOFR) of the OSCSTAT register indicates when the MFINTOSC is running and can be utilized. DS41391D-page 56  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.2.2.3 Internal Oscillator Frequency Adjustment The 500 kHz internal oscillator is factory calibrated. This internal oscillator can be adjusted in software by writing to the OSCTUNE register (Register 5-3). Since the HFINTOSC and MFINTOSC clock sources are derived from the 500 kHz internal oscillator a change in the OSCTUNE register value will apply to both. The default value of the OSCTUNE register is ‘0’. The value is a 6-bit two’s complement number. A value of 1Fh will provide an adjustment to the maximum frequency. A value of 20h will provide an adjustment to the minimum frequency. When the OSCTUNE register is modified, the oscillator frequency will begin shifting to the new frequency. Code execution continues during this shift. There is no indication that the shift has occurred. OSCTUNE does not affect the LFINTOSC frequency. Operation of features that depend on the LFINTOSC clock source frequency, such as the Power-up Timer (PWRT), Watchdog Timer (WDT), Fail-Safe Clock Monitor (FSCM) and peripherals, are not affected by the change in frequency. 5.2.2.4 LFINTOSC The Low-Frequency Internal Oscillator (LFINTOSC) is an uncalibrated 31 kHz internal clock source. The output of the LFINTOSC connects to a postscaler and multiplexer (see Figure 5-1). Select 31 kHz, via software, using the IRCF bits of the OSCCON register. See Section 5.2.2.7 “Internal Oscillator Clock Switch Timing” for more information. The LFINTOSC is also the frequency for the Power-up Timer (PWRT), Watchdog Timer (WDT) and Fail-Safe Clock Monitor (FSCM). The LFINTOSC is enabled by selecting 31 kHz (IRCF bits of the OSCCON register = 000) as the system clock source (SCS bits of the OSCCON register = 1x), or when any of the following are enabled: 5.2.2.5 Internal Oscillator Frequency Selection The system clock speed can be selected via software using the Internal Oscillator Frequency Select bits IRCF of the OSCCON register. The output of the 16 MHz HFINTOSC and 31 kHz LFINTOSC connects to a postscaler and multiplexer (see Figure 5-1). The Internal Oscillator Frequency Select bits IRCF of the OSCCON register select the frequency output of the internal oscillators. One of the following frequencies can be selected via software: • • • • • • • • • • • • 32 MHz (requires 4X PLL) 16 MHz 8 MHz 4 MHz 2 MHz 1 MHz 500 kHz (Default after Reset) 250 kHz 125 kHz 62.5 kHz 31.25 kHz 31 kHz (LFINTOSC) Note: Following any Reset, the IRCF bits of the OSCCON register are set to ‘0111’ and the frequency selection is set to 500 kHz. The user can modify the IRCF bits to select a different frequency. The IRCF bits of the OSCCON register allow duplicate selections for some frequencies. These duplicate choices can offer system design trade-offs. Lower power consumption can be obtained when changing oscillator sources for a given frequency. Faster transition times can be obtained between frequency changes that use the same oscillator source. • Configure the IRCF bits of the OSCCON register for the desired LF frequency, and • FOSC = 100, or • Set the System Clock Source (SCS) bits of the OSCCON register to ‘1x’ Peripherals that use the LFINTOSC are: • Power-up Timer (PWRT) • Watchdog Timer (WDT) • Fail-Safe Clock Monitor (FSCM) The Low Frequency Internal Oscillator Ready bit (LFIOFR) of the OSCSTAT register indicates when the LFINTOSC is running and can be utilized.  2011 Microchip Technology Inc. DS41391D-page 57 PIC16(L)F1826/27 5.2.2.6 32 MHz Internal Oscillator Frequency Selection The Internal Oscillator Block can be used with the 4X PLL associated with the External Oscillator Block to produce a 32 MHz internal system clock source. The following settings are required to use the 32 MHz internal clock source: • The FOSC bits in Configuration Word 1 must be set to use the INTOSC source as the device system clock (FOSC = 100). • The SCS bits in the OSCCON register must be cleared to use the clock determined by FOSC in Configuration Word 1 (SCS = 00). • The IRCF bits in the OSCCON register must be set to the 8 MHz HFINTOSC set to use (IRCF = 1110). • The SPLLEN bit in the OSCCON register must be set to enable the 4xPLL, or the PLLEN bit of the Configuration Word 2 must be programmed to a ‘1’. Note: When using the PLLEN bit of the Configuration Word 2, the 4xPLL cannot be disabled by software and the 8 MHz HFINTOSC option will no longer be available. The 4xPLL is not available for use with the internal oscillator when the SCS bits of the OSCCON register are set to ‘1x’. The SCS bits must be set to ‘00’ to use the 4xPLL with the internal oscillator. DS41391D-page 58 5.2.2.7 Internal Oscillator Clock Switch Timing When switching between the HFINTOSC, MFINTOSC and the LFINTOSC, the new oscillator may already be shut down to save power (see Figure 5-7). If this is the case, there is a delay after the IRCF bits of the OSCCON register are modified before the frequency selection takes place. The OSCSTAT register will reflect the current active status of the HFINTOSC, MFINTOSC and LFINTOSC oscillators. The sequence of a frequency selection is as follows: 1. 2. 3. 4. 5. 6. 7. IRCF bits of the OSCCON register are modified. If the new clock is shut down, a clock start-up delay is started. Clock switch circuitry waits for a falling edge of the current clock. The current clock is held low and the clock switch circuitry waits for a rising edge in the new clock. The new clock is now active. The OSCSTAT register is updated as required. Clock switch is complete. See Figure 5-7 for more details. If the internal oscillator speed is switched between two clocks of the same source, there is no start-up delay before the new frequency is selected. Clock switching time delays are shown in Table 5-1. Start-up delay specifications are located in the oscillator tables of Section 30.0 “Electrical Specifications”.  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 5-7: HFINTOSC/ MFINTOSC INTERNAL OSCILLATOR SWITCH TIMING LFINTOSC (FSCM and WDT disabled) HFINTOSC/ MFINTOSC Start-up Time 2-cycle Sync Running LFINTOSC IRCF 0 0 System Clock HFINTOSC/ MFINTOSC LFINTOSC (Either FSCM or WDT enabled) HFINTOSC/ MFINTOSC 2-cycle Sync Running LFINTOSC 0 IRCF 0 System Clock LFINTOSC HFINTOSC/MFINTOSC LFINTOSC turns off unless WDT or FSCM is enabled LFINTOSC Start-up Time 2-cycle Sync Running HFINTOSC/ MFINTOSC IRCF =0 0 System Clock  2011 Microchip Technology Inc. DS41391D-page 59 PIC16(L)F1826/27 5.3 Clock Switching 5.3.3 TIMER1 OSCILLATOR The system clock source can be switched between external and internal clock sources via software using the System Clock Select (SCS) bits of the OSCCON register. The following clock sources can be selected using the SCS bits: The Timer1 Oscillator is a separate crystal oscillator associated with the Timer1 peripheral. It is optimized for timekeeping operations with a 32.768 kHz crystal connected between the T1OSO and T1OSI device pins. • Default system oscillator determined by FOSC bits in Configuration Word 1 • Timer1 32 kHz crystal oscillator • Internal Oscillator Block (INTOSC) The Timer1 oscillator is enabled using the T1OSCEN control bit in the T1CON register. See Section 21.0 “Timer1 Module with Gate Control” for more information about the Timer1 peripheral. 5.3.1 SYSTEM CLOCK SELECT (SCS) BITS The System Clock Select (SCS) bits of the OSCCON register selects the system clock source that is used for the CPU and peripherals. • When the SCS bits of the OSCCON register = 00, the system clock source is determined by value of the FOSC bits in the Configuration Word 1. • When the SCS bits of the OSCCON register = 01, the system clock source is the Timer1 oscillator. • When the SCS bits of the OSCCON register = 1x, the system clock source is chosen by the internal oscillator frequency selected by the IRCF bits of the OSCCON register. After a Reset, the SCS bits of the OSCCON register are always cleared. Note: 5.3.4 TIMER1 OSCILLATOR READY (T1OSCR) BIT The user must ensure that the Timer1 Oscillator is ready to be used before it is selected as a system clock source. The Timer1 Oscillator Ready (T1OSCR) bit of the OSCSTAT register indicates whether the Timer1 oscillator is ready to be used. After the T1OSCR bit is set, the SCS bits can be configured to select the Timer1 oscillator. Any automatic clock switch, which may occur from Two-Speed Start-up or Fail-Safe Clock Monitor, does not update the SCS bits of the OSCCON register. The user can monitor the OSTS bit of the OSCSTAT register to determine the current system clock source. When switching between clock sources, a delay is required to allow the new clock to stabilize. These oscillator delays are shown in Table 5-1. 5.3.2 OSCILLATOR START-UP TIME-OUT STATUS (OSTS) BIT The Oscillator Start-up Time-out Status (OSTS) bit of the OSCSTAT register indicates whether the system clock is running from the external clock source, as defined by the FOSC bits in the Configuration Word 1, or from the internal clock source. In particular, OSTS indicates that the Oscillator Start-up Timer (OST) has timed out for LP, XT or HS modes. The OST does not reflect the status of the Timer1 Oscillator. DS41391D-page 60  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.4 5.4.1 Two-Speed Clock Start-up Mode Two-Speed Start-up mode provides additional power savings by minimizing the latency between external oscillator start-up and code execution. In applications that make heavy use of the Sleep mode, Two-Speed Start-up will remove the external oscillator start-up time from the time spent awake and can reduce the overall power consumption of the device. This mode allows the application to wake-up from Sleep, perform a few instructions using the INTOSC internal oscillator block as the clock source and go back to Sleep without waiting for the external oscillator to become stable. Two-Speed Start-up provides benefits when the oscillator module is configured for LP, XT, or HS modes. The Oscillator Start-up Timer (OST) is enabled for these modes and must count 1024 oscillations before the oscillator can be used as the system clock source. TWO-SPEED START-UP MODE CONFIGURATION Two-Speed Start-up mode is configured by the following settings: • IESO (of the Configuration Word 1) = 1; Internal/External Switchover bit (Two-Speed Start-up mode enabled). • SCS (of the OSCCON register) = 00. • FOSC bits in the Configuration Word 1 configured for LP, XT or HS mode. Two-Speed Start-up mode is entered after: • Power-on Reset (POR) and, if enabled, after Power-up Timer (PWRT) has expired, or • Wake-up from Sleep. If the oscillator module is configured for any mode other than LP, XT or HS mode, then Two-Speed Start-up is disabled. This is because the external clock oscillator does not require any stabilization time after POR or an exit from Sleep. If the OST count reaches 1024 before the device enters Sleep mode, the OSTS bit of the OSCSTAT register is set and program execution switches to the external oscillator. However, the system may never operate from the external oscillator if the time spent awake is very short. Note: Executing a SLEEP instruction will abort the oscillator start-up time and will cause the OSTS bit of the OSCSTAT register to remain clear. TABLE 5-1: OSCILLATOR SWITCHING DELAYS Switch From Switch To Frequency Oscillator Delay LFINTOSC(1) Sleep/POR MFINTOSC(1) HFINTOSC(1) 31 kHz 31.25 kHz-500 kHz 31.25 kHz-16 MHz Oscillator Warm-up Delay (TWARM) Sleep/POR EC, RC(1) DC – 32 MHz 2 cycles LFINTOSC EC, RC(1) DC – 32 MHz 1 cycle of each Sleep/POR Timer1 Oscillator LP, XT, HS(1) 32 kHz-20 MHz 1024 Clock Cycles (OST) Any clock source MFINTOSC(1) HFINTOSC(1) 31.25 kHz-500 kHz 31.25 kHz-16 MHz 2 s (approx.) Any clock source LFINTOSC(1) 31 kHz 1 cycle of each Any clock source Timer1 Oscillator 32 kHz 1024 Clock Cycles (OST) PLL inactive PLL active 16-32 MHz 2 ms (approx.) Note 1: PLL inactive.  2011 Microchip Technology Inc. DS41391D-page 61 PIC16(L)F1826/27 5.4.2 1. 2. 3. 4. 5. 6. 7. TWO-SPEED START-UP SEQUENCE 5.4.3 Wake-up from Power-on Reset or Sleep. Instructions begin execution by the internal oscillator at the frequency set in the IRCF bits of the OSCCON register. OST enabled to count 1024 clock cycles. OST timed out, wait for falling edge of the internal oscillator. OSTS is set. System clock held low until the next falling edge of new clock (LP, XT or HS mode). System clock is switched to external clock source. FIGURE 5-8: CHECKING TWO-SPEED CLOCK STATUS Checking the state of the OSTS bit of the OSCSTAT register will confirm if the microcontroller is running from the external clock source, as defined by the FOSC bits in the Configuration Word 1, or the internal oscillator. TWO-SPEED START-UP INTOSC TOST OSC1 0 1 1022 1023 OSC2 Program Counter PC - N PC PC + 1 System Clock DS41391D-page 62  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.5 5.5.3 Fail-Safe Clock Monitor The Fail-Safe Clock Monitor (FSCM) allows the device to continue operating should the external oscillator fail. The FSCM can detect oscillator failure any time after the Oscillator Start-up Timer (OST) has expired. The FSCM is enabled by setting the FCMEN bit in the Configuration Word 1. The FSCM is applicable to all external Oscillator modes (LP, XT, HS, EC, Timer1 Oscillator and RC). FIGURE 5-9: FSCM BLOCK DIAGRAM External Clock LFINTOSC Oscillator ÷ 64 31 kHz (~32 s) 488 Hz (~2 ms) S Q R Q Sample Clock 5.5.1 RESET OR WAKE-UP FROM SLEEP The FSCM is designed to detect an oscillator failure after the Oscillator Start-up Timer (OST) has expired. The OST is used after waking up from Sleep and after any type of Reset. The OST is not used with the EC or RC Clock modes so that the FSCM will be active as soon as the Reset or wake-up has completed. When the FSCM is enabled, the Two-Speed Start-up is also enabled. Therefore, the device will always be executing code while the OST is operating. Clock Failure Detected FAIL-SAFE DETECTION The FSCM module detects a failed oscillator by comparing the external oscillator to the FSCM sample clock. The sample clock is generated by dividing the LFINTOSC by 64. See Figure 5-9. Inside the fail detector block is a latch. The external clock sets the latch on each falling edge of the external clock. The sample clock clears the latch on each rising edge of the sample clock. A failure is detected when an entire half-cycle of the sample clock elapses before the external clock goes low. 5.5.2 The Fail-Safe condition is cleared after a Reset, executing a SLEEP instruction or changing the SCS bits of the OSCCON register. When the SCS bits are changed, the OST is restarted. While the OST is running, the device continues to operate from the INTOSC selected in OSCCON. When the OST times out, the Fail-Safe condition is cleared and the device will be operating from the external clock source. The Fail-Safe condition must be cleared before the OSFIF flag can be cleared. 5.5.4 Clock Monitor Latch FAIL-SAFE CONDITION CLEARING Note: Due to the wide range of oscillator start-up times, the Fail-Safe circuit is not active during oscillator start-up (i.e., after exiting Reset or Sleep). After an appropriate amount of time, the user should check the Status bits in the OSCSTAT register to verify the oscillator start-up and that the system clock switchover has successfully completed. FAIL-SAFE OPERATION When the external clock fails, the FSCM switches the device clock to an internal clock source and sets the bit flag OSFIF of the PIR2 register. Setting this flag will generate an interrupt if the OSFIE bit of the PIE2 register is also set. The device firmware can then take steps to mitigate the problems that may arise from a failed clock. The system clock will continue to be sourced from the internal clock source until the device firmware successfully restarts the external oscillator and switches back to external operation. The internal clock source chosen by the FSCM is determined by the IRCF bits of the OSCCON register. This allows the internal oscillator to be configured before a failure occurs.  2011 Microchip Technology Inc. DS41391D-page 63 PIC16(L)F1826/27 FIGURE 5-10: FSCM TIMING DIAGRAM Sample Clock Oscillator Failure System Clock Output Clock Monitor Output (Q) Failure Detected OSCFIF Test Note: DS41391D-page 64 Test Test The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in this example have been chosen for clarity.  2011 Microchip Technology Inc. PIC16(L)F1826/27 5.6 Oscillator Control Registers REGISTER 5-1: R/W-0/0 OSCCON: OSCILLATOR CONTROL REGISTER R/W-0/0 SPLLEN R/W-1/1 R/W-1/1 IRCF R/W-1/1 U-0 R/W-0/0 — R/W-0/0 SCS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 SPLLEN: Software PLL Enable bit If PLLEN in Configuration Word 1 = 1: SPLLEN bit is ignored. 4x PLL is always enabled (subject to oscillator requirements) If PLLEN in Configuration Word 1 = 0: 1 = 4x PLL Is enabled 0 = 4x PLL is disabled bit 6-3 IRCF: Internal Oscillator Frequency Select bits 000x =31 kHz LF 0010 =31.25 kHz MF 0011 =31.25 kHz HF(1) 0100 =62.5 kHz MF 0101 =125 kHz MF 0110 =250 kHz MF 0111 =500 kHz MF (default upon Reset) 1000 =125 kHz HF(1) 1001 =250 kHz HF(1) 1010 =500 kHz HF(1) 1011 =1 MHz HF 1100 =2 MHz HF 1101 =4 MHz HF 1110 =8 MHz or 32 MHz HF(see Section 5.2.2.1 “HFINTOSC”) 1111 =16 MHz HF bit 2 Unimplemented: Read as ‘0’ bit 1-0 SCS: System Clock Select bits 1x = Internal oscillator block 01 = Timer1 oscillator 00 = Clock determined by FOSC in Configuration Word 1. Note 1: Duplicate frequency derived from HFINTOSC.  2011 Microchip Technology Inc. DS41391D-page 65 PIC16(L)F1826/27 REGISTER 5-2: OSCSTAT: OSCILLATOR STATUS REGISTER R-1/q R-0/q R-q/q R-0/q R-0/q R-q/q R-0/0 R-0/q T1OSCR PLLR OSTS HFIOFR HFIOFL MFIOFR LFIOFR HFIOFS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared q = Conditional bit 7 T1OSCR: Timer1 Oscillator Ready bit If T1OSCEN = 1: 1 = Timer1 oscillator is ready 0 = Timer1 oscillator is not ready If T1OSCEN = 0: 1 = Timer1 clock source is always ready bit 6 PLLR 4x PLL Ready bit 1 = 4x PLL is ready 0 = 4x PLL is not ready bit 5 OSTS: Oscillator Start-up Time-out Status bit 1 = Running from the clock defined by the FOSC bits of the Configuration Word 1 0 = Running from an internal oscillator (FOSC = 100) bit 4 HFIOFR: High Frequency Internal Oscillator Ready bit 1 = HFINTOSC is ready 0 = HFINTOSC is not ready bit 3 HFIOFL: High Frequency Internal Oscillator Locked bit 1 = HFINTOSC is at least 2% accurate 0 = HFINTOSC is not 2% accurate bit 2 MFIOFR: Medium Frequency Internal Oscillator Ready bit 1 = MFINTOSC is ready 0 = MFINTOSC is not ready bit 1 LFIOFR: Low Frequency Internal Oscillator Ready bit 1 = LFINTOSC is ready 0 = LFINTOSC is not ready bit 0 HFIOFS: High Frequency Internal Oscillator Stable bit 1 = HFINTOSC is at least 0.5% accurate 0 = HFINTOSC is not 0.5% accurate DS41391D-page 66  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 5-3: OSCTUNE: OSCILLATOR TUNING REGISTER U-0 U-0 — — R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 TUN bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 Unimplemented: Read as ‘0’ bit 5-0 TUN: Frequency Tuning bits 011111 = Maximum frequency 011110 = • • • 000001 = 000000 = Oscillator module is running at the factory-calibrated frequency. 111111 = • • • 100000 = Minimum frequency TABLE 5-2: SUMMARY OF REGISTERS ASSOCIATED WITH CLOCK SOURCES Name Bit 6 Bit 5 OSCCON SPLLEN IRCF3 IRCF2 IRCF1 IRCF0 — SCS1 SCS0 65 OSCSTAT T1OSCR PLLR OSTS HFIOFR HFIOFL MFIOFR LFIOFR HFIOFS 66 — — TUN5 TUN4 TUN3 TUN2 TUN1 TUN0 67 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(1) 94 (1) OSCTUNE PIE2 OSFIF PIR2 T1CON Legend: Note 1: CONFIG1 Legend: Bit 3 Bit 2 Bit 1 Bit 0 C1IF EEIF BCL1IF — — CCP2IF 97 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC — TMR1ON 187 — = unimplemented locations read as ‘0’. Shaded cells are not used by clock sources. PIC16(L)F1827 only. TABLE 5-3: Name C2IF TMR1CS1 TMR1CS0 Bit 4 Register on Page Bit 7 Bits SUMMARY OF CONFIGURATION WORD ASSOCIATED WITH CLOCK SOURCES Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 Bit 10/2 Bit 9/1 Bit 8/0 13:8 — — FCMEN IESO CLKOUTEN BOREN1 BOREN0 CPD 7:0 CP MCLRE PWRTE WDTE1 WDTE0 FOSC2 FOSC1 FOSC0 Register on Page 50 — = unimplemented locations read as ‘0’. Shaded cells are not used by clock sources.  2011 Microchip Technology Inc. DS41391D-page 67 PIC16(L)F1826/27 NOTES: DS41391D-page 68  2011 Microchip Technology Inc. PIC16(L)F1826/27 6.0 REFERENCE CLOCK MODULE 6.3 Conflicts with the CLKR Pin The reference clock module provides the ability to send a divided clock to the clock output pin of the device (CLKR) and provide a secondary internal clock source to the modulator module. This module is available in all oscillator configurations and allows the user to select a greater range of clock submultiples to drive external devices in the application. The reference clock module includes the following features: There are two cases when the reference clock output signal cannot be output to the CLKR pin, if: • • • • • • 6.3.1 System clock is the source Available in all oscillator configurations Programmable clock divider Output enable to a port pin Selectable duty cycle Slew rate control The reference clock module is controlled by the CLKRCON register (Register 6-1) and is enabled when setting the CLKREN bit. To output the divided clock signal to the CLKR port pin, the CLKROE bit must be set. The CLKRDIV bits enable the selection of 8 different clock divider options. The CLKRDC bits can be used to modify the duty cycle of the output clock(1). The CLKRSLR bit controls slew rate limiting. Note 1: If the base clock rate is selected without a divider, the output clock will always have a duty cycle equal to that of the source clock, unless a 0% duty cycle is selected. If the clock divider is set to base clock/2, then 25% and 75% duty cycle accuracy will be dependent upon the source clock. For information on using the reference clock output with the modulator module, see Section 23.0 “Data Signal Modulator”. 6.1 • LP, XT or HS Oscillator mode is selected. • CLKOUT function is enabled. Even if either of these cases are true, the module can still be enabled and the reference clock signal may be used in conjunction with the modulator module. OSCILLATOR MODES If LP, XT or HS oscillator modes are selected, the OSC2/CLKR pin must be used as an oscillator input pin and the CLKR output cannot be enabled. See Section 5.2 “Clock Source Types” for more information on different oscillator modes. 6.3.2 CLKOUT FUNCTION The CLKOUT function has a higher priority than the reference clock module. Therefore, if the CLKOUT function is enabled by the CLKOUTEN bit in Configuration Word 1, FOSC/4 will always be output on the port pin. Reference Section 4.0 “Device Configuration” for more information. 6.4 Operation During Sleep As the reference clock module relies on the system clock as its source, and the system clock is disabled in Sleep, the module does not function in Sleep, even if an external clock source or the Timer1 clock source is configured as the system clock. The module outputs will remain in their current state until the device exits Sleep. Slew Rate The slew rate limitation on the output port pin can be disabled. The slew rate limitation can be removed by clearing the CLKRSLR bit in the CLKRCON register. 6.2 Effects of a Reset Upon any device Reset, the reference clock module is disabled. The user's firmware is responsible for initializing the module before enabling the output. The registers are reset to their default values.  2011 Microchip Technology Inc. DS41391D-page 69 PIC16(L)F1826/27 6.5 Reference Clock Control Register REGISTER 6-1: CLKRCON: REFERENCE CLOCK CONTROL REGISTER R/W-0/0 R/W-0/0 R/W-1/1 CLKREN CLKROE CLKRSLR R/W-1/1 R/W-0/0 R/W-0/0 CLKRDC R/W-0/0 R/W-0/0 CLKRDIV bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 CLKREN: Reference Clock Module Enable bit 1 = Reference Clock module is enabled 0 = Reference Clock module is disabled bit 6 CLKROE: Reference Clock Output Enable bit(3) 1 = Reference Clock output is enabled on CLKR pin 0 = Reference Clock output disabled on CLKR pin bit 5 CLKRSLR: Reference Clock Slew Rate Control limiting enable bit 1 = Slew Rate limiting is enabled 0 = Slew Rate limiting is disabled bit 4-3 CLKRDC: Reference Clock Duty Cycle bits 11 = Clock outputs duty cycle of 75% 10 = Clock outputs duty cycle of 50% 01 = Clock outputs duty cycle of 25% 00 = Clock outputs duty cycle of 0% bit 2-0 CLKRDIV Reference Clock Divider bits 111 = Base clock value divided by 128 110 = Base clock value divided by 64 101 = Base clock value divided by 32 100 = Base clock value divided by 16 011 = Base clock value divided by 8 010 = Base clock value divided by 4 001 = Base clock value divided by 2(1) 000 = Base clock value(2) Note 1: In this mode, the 25% and 75% duty cycle accuracy will be dependent on the source clock duty cycle. 2: In this mode, the duty cycle will always be equal to the source clock duty cycle, unless a duty cycle of 0% is selected. 3: To route CLKR to pin, CLKOUTEN of Configuration Word 1 = 1 is required. CLKOUTEN of Configuration Word 1 = 0 will result in FOSC/4. See Section 6.3 “Conflicts with the CLKR Pin” for details. DS41391D-page 70  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 6-1: SUMMARY OF REGISTERS ASSOCIATED WITH REFERENCE CLOCK SOURCES Name CLKRCON Legend: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 CLKREN CLKROE CLKRSLR CLKRDC1 CLKRDC0 CLKRDIV2 CONFIG1 Legend: Bit 0 CLKRDIV1 CLKRDIV0 Register on Page 70 — = unimplemented locations read as ‘0’. Shaded cells are not used by reference clock sources. TABLE 6-2: Name Bit 1 Bits SUMMARY OF CONFIGURATION WORD WITH REFERENCE CLOCK SOURCES Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 Bit 10/2 Bit 9/1 Bit 8/0 13:8 — — FCMEN IESO CLKOUTEN BOREN1 BOREN0 CPD 7:0 CP MCLRE PWRTE WDTE1 WDTE0 FOSC2 FOSC1 FOSC0 Register on Page 44 — = unimplemented locations read as ‘0’. Shaded cells are not used by reference clock sources.  2011 Microchip Technology Inc. DS41391D-page 71 PIC16(L)F1826/27 NOTES: DS41391D-page 72  2011 Microchip Technology Inc. PIC16(L)F1826/27 7.0 RESETS There are multiple ways to reset this device: • • • • • • • • Power-on Reset (POR) Brown-out Reset (BOR) MCLR Reset WDT Reset RESET instruction Stack Overflow Stack Underflow Programming mode exit To allow VDD to stabilize, an optional power-up timer can be enabled to extend the Reset time after a BOR or POR event. A simplified block diagram of the On-Chip Reset Circuit is shown in Figure 7-1. FIGURE 7-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT Programming Mode Exit RESET Instruction Stack Stack Overflow/Underflow Reset Pointer External Reset MCLRE MCLR Sleep WDT Time-out Device Reset Power-on Reset VDD Brown-out Reset BOR Enable PWRT Zero LFINTOSC 64 ms PWRTEN  2011 Microchip Technology Inc. DS41391D-page 73 PIC16(L)F1826/27 7.1 Power-on Reset (POR) 7.2 Brown-Out Reset (BOR) The POR circuit holds the device in Reset until VDD has reached an acceptable level for minimum operation. Slow rising VDD, fast operating speeds or analog performance may require greater than minimum VDD. The PWRT, BOR or MCLR features can be used to extend the start-up period until all device operation conditions have been met. The BOR circuit holds the device in Reset when Vdd reaches a selectable minimum level. Between the POR and BOR, complete voltage range coverage for execution protection can be implemented. 7.1.1 • • • • POWER-UP TIMER (PWRT) The Power-up Timer provides a nominal 64 ms timeout on POR or Brown-out Reset. The device is held in Reset as long as PWRT is active. The PWRT delay allows additional time for the VDD to rise to an acceptable level. The Power-up Timer is enabled by clearing the PWRTE bit in Configuration Word 1. The Power-up Timer starts after the release of the POR and BOR. For additional information, refer to Application Note AN607, “Power-up Trouble Shooting” (DS00607). TABLE 7-1: The Brown-out Reset module has four operating modes controlled by the BOREN bits in Configuration Word 1. The four operating modes are: BOR is always on BOR is off when in Sleep BOR is controlled by software BOR is always off Refer to Table 7-1 for more information. The Brown-out Reset voltage level is selectable by configuring the BORV bit in Configuration Word 2. A VDD noise rejection filter prevents the BOR from triggering on small events. If VDD falls below VBOR for a duration greater than parameter TBORDC, the device will reset. See Figure 7-2 for more information. BOR OPERATING MODES BOREN SBOREN Device Mode BOR Mode Device Operation Device Operation upon wake- up from upon release of POR Sleep 11 X X Active Waits for BOR ready(1) Awake Active 10 X Sleep Disabled 1 01 X 0 00 X X Waits for BOR ready Active Begins immediately Disabled Begins immediately Disabled Begins immediately Note 1: Even though this case specifically waits for the BOR, the BOR is already operating, so there is no delay in start-up. 7.2.1 BOR IS ALWAYS ON 7.2.3 BOR CONTROLLED BY SOFTWARE When the BOREN bits of Configuration Word 1 are set to ‘11’, the BOR is always on. The device start-up will be delayed until the BOR is ready and VDD is higher than the BOR threshold. When the BOREN bits of Configuration Word 1 are set to ‘01’, the BOR is controlled by the SBOREN bit of the BORCON register. The device start-up is not delayed by the BOR ready condition or the VDD level. BOR protection is active during Sleep. The BOR does not delay wake-up from Sleep. BOR protection begins as soon as the BOR circuit is ready. The status of the BOR circuit is reflected in the BORRDY bit of the BORCON register. 7.2.2 BOR IS OFF IN SLEEP When the BOREN bits of Configuration Word 1 are set to ‘10’, the BOR is on, except in Sleep. The device start-up will be delayed until the BOR is ready and VDD is higher than the BOR threshold. BOR protection is unchanged by Sleep. BOR protection is not active during Sleep. The device wake-up will be delayed until the BOR is ready. DS41391D-page 74  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 7-2: BROWN-OUT SITUATIONS VDD VBOR Internal Reset TPWRT(1) VDD VBOR Internal Reset < TPWRT TPWRT(1) VDD VBOR Internal Reset Note 1: TPWRT(1) TPWRT delay only if PWRTE bit is programmed to ‘0’. REGISTER 7-1: BORCON: BROWN-OUT RESET CONTROL REGISTER R/W-1/u U-0 U-0 U-0 U-0 U-0 U-0 R-q/u SBOREN — — — — — — BORRDY bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition bit 7 SBOREN: Software Brown-out Reset Enable bit If BOREN in Configuration Word 1  01: SBOREN is read/write, but has no effect on the BOR. If BOREN in Configuration Word 1 = 01: 1 = BOR Enabled 0 = BOR Disabled bit 6-1 Unimplemented: Read as ‘0’ bit 0 BORRDY: Brown-out Reset Circuit Ready Status bit 1 = The Brown-out Reset circuit is active 0 = The Brown-out Reset circuit is inactive  2011 Microchip Technology Inc. DS41391D-page 75 PIC16(L)F1826/27 7.3 MCLR 7.7 The MCLR is an optional external input that can reset the device. The MCLR function is controlled by the MCLRE bit of Configuration Word 1 and the LVP bit of Configuration Word 2 (Table 7-2). TABLE 7-2: MCLR CONFIGURATION MCLRE LVP MCLR 0 0 Disabled 1 0 Enabled x 1 Enabled 7.3.1 MCLR ENABLED When MCLR is enabled and the pin is held low, the device is held in Reset. The MCLR pin is connected to VDD through an internal weak pull-up. The device has a noise filter in the MCLR Reset path. The filter will detect and ignore small pulses. Note: 7.3.2 A Reset does not drive the MCLR pin low. MCLR DISABLED When MCLR is disabled, the pin functions as a general purpose input and the internal weak pull-up is under software control. See Section 12.2 “PORTA Registers” for more information. 7.4 Watchdog Timer (WDT) Reset The Watchdog Timer generates a Reset if the firmware does not issue a CLRWDT instruction within the time-out period. The TO and PD bits in the STATUS register are changed to indicate the WDT Reset. See Section 10.0 “Watchdog Timer” for more information. 7.5 Programming Mode Exit Upon exit of Programming mode, the device will behave as if a POR had just occurred. 7.8 Power-Up Timer The Power-up Timer optionally delays device execution after a BOR or POR event. This timer is typically used to allow VDD to stabilize before allowing the device to start running. The Power-up Timer is controlled by the PWRTE bit of Configuration Word 1. 7.9 Start-up Sequence Upon the release of a POR or BOR, the following must occur before the device will begin executing: 1. 2. 3. Power-up Timer runs to completion (if enabled). Oscillator start-up timer runs to completion (if required for oscillator source). MCLR must be released (if enabled). The total time-out will vary based on oscillator configuration and Power-up Timer configuration. See Section 5.0 “Oscillator Module (With Fail-Safe Clock Monitor)” for more information. The Power-up Timer and oscillator start-up timer run independently of MCLR Reset. If MCLR is kept low long enough, the Power-up Timer and oscillator startup timer will expire. Upon bringing MCLR high, the device will begin execution immediately (see Figure 73). This is useful for testing purposes or to synchronize more than one device operating in parallel. RESET Instruction A RESET instruction will cause a device Reset. The RI bit in the PCON register will be set to ‘0’. See Table 7-4 for default conditions after a RESET instruction has occurred. 7.6 Stack Overflow/Underflow Reset The device can reset when the Stack Overflows or Underflows. The STKOVF or STKUNF bits of the PCON register indicate the Reset condition. These Resets are enabled by setting the STVREN bit in Configuration Word 2. See Section 3.4.2 “Overflow/Underflow Reset”for more information. DS41391D-page 76  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 7-3: RESET START-UP SEQUENCE VDD Internal POR TPWRT Power-Up Timer MCLR TMCLR Internal RESET Oscillator Modes External Crystal TOST Oscillator Start-Up Timer Oscillator FOSC Internal Oscillator Oscillator FOSC External Clock (EC) CLKIN FOSC  2011 Microchip Technology Inc. DS41391D-page 77 PIC16(L)F1826/27 7.10 Determining the Cause of a Reset Upon any Reset, multiple bits in the STATUS and PCON register are updated to indicate the cause of the Reset. Table 7-3 and Table 7-4 show the Reset conditions of these registers. TABLE 7-3: RESET STATUS BITS AND THEIR SIGNIFICANCE STKOVF STKUNF RMCLR RI POR BOR TO PD Condition 0 0 1 1 0 x 1 1 Power-on Reset 0 0 1 1 0 x 0 x Illegal, TO is set on POR 0 0 1 1 0 x x 0 Illegal, PD is set on POR 0 0 1 1 u 0 1 1 Brown-out Reset u u u u u u 0 u WDT Reset u u u u u u 0 0 WDT Wake-up from Sleep u u u u u u 1 0 Interrupt Wake-up from Sleep u u 0 u u u u u MCLR Reset during normal operation u u 0 u u u 1 0 MCLR Reset during Sleep u u u 0 u u u u RESET Instruction Executed 1 u u u u u u u Stack Overflow Reset (STVREN = 1) u 1 u u u u u u Stack Underflow Reset (STVREN = 1) TABLE 7-4: RESET CONDITION FOR SPECIAL REGISTERS(2) Program Counter STATUS Register PCON Register Power-on Reset 0000h ---1 1000 00-- 110x MCLR Reset during normal operation 0000h ---u uuuu uu-- 0uuu MCLR Reset during Sleep 0000h ---1 0uuu uu-- 0uuu WDT Reset 0000h ---0 uuuu uu-- uuuu WDT Wake-up from Sleep PC + 1 ---0 0uuu uu-- uuuu Brown-out Reset 0000h ---1 1uuu 00-- 11u0 ---1 0uuu uu-- uuuu ---u uuuu uu-- u0uu Condition Interrupt Wake-up from Sleep RESET Instruction Executed PC + 1 (1) 0000h Stack Overflow Reset (STVREN = 1) 0000h ---u uuuu 1u-- uuuu Stack Underflow Reset (STVREN = 1) 0000h ---u uuuu u1-- uuuu Legend: u = unchanged, x = unknown, - = unimplemented bit, reads as ‘0’. Note 1: When the wake-up is due to an interrupt and Global Enable bit (GIE) is set, the return address is pushed on the stack and PC is loaded with the interrupt vector (0004h) after execution of PC + 1. 2: If a Status bit is not implemented, that bit will be read as ‘0’. DS41391D-page 78  2011 Microchip Technology Inc. PIC16(L)F1826/27 7.11 Power Control (PCON) Register The Power Control (PCON) register contains flag bits to differentiate between a: • • • • • • Power-on Reset (POR) Brown-out Reset (BOR) Reset Instruction Reset (RI) MCLR Reset (RMCLR) Stack Underflow Reset (STKUNF) Stack Overflow Reset (STKOVF) The PCON register bits are shown in Register 7-2. REGISTER 7-2: PCON: POWER CONTROL REGISTER R/W/HS-0/q R/W/HS-0/q U-0 U-0 R/W/HC-1/q R/W/HC-1/q R/W/HC-q/u R/W/HC-q/u STKOVF STKUNF — — RMCLR RI POR BOR bit 7 bit 0 Legend: HC = Bit is cleared by hardware HS = Bit is set by hardware R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -m/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition bit 7 STKOVF: Stack Overflow Flag bit 1 = A Stack Overflow occurred 0 = A Stack Overflow has not occurred or set to ‘0’ by firmware bit 6 STKUNF: Stack Underflow Flag bit 1 = A Stack Underflow occurred 0 = A Stack Underflow has not occurred or set to ‘0’ by firmware bit 5-4 Unimplemented: Read as ‘0’ bit 3 RMCLR: MCLR Reset Flag bit 1 = A MCLR Reset has not occurred or set to ‘1’ by firmware 0 = A MCLR Reset has occurred (set to ‘0’ in hardware when a MCLR Reset occurs) bit 2 RI: RESET Instruction Flag bit 1 = A RESET instruction has not been executed or set to ‘1’ by firmware 0 = A RESET instruction has been executed (set to ‘0’ in hardware upon executing a RESET instruction) bit 1 POR: Power-on Reset Status bit 1 = No Power-on Reset occurred 0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs) bit 0 BOR: Brown-out Reset Status bit 1 = No Brown-out Reset occurred 0 = A Brown-out Reset occurred (must be set in software after a Power-on Reset or Brown-out Reset occurs)  2011 Microchip Technology Inc. DS41391D-page 79 PIC16(L)F1826/27 TABLE 7-5: SUMMARY OF REGISTERS ASSOCIATED WITH RESETS Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page BORCON SBOREN — — — — — — BORRDY 75 PCON STKOVF STKUNF — — RMCLR RI POR BOR 79 STATUS — — — TO PD Z DC C 21 WDTCON — — WDTPS4 WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN 99 Legend: — = unimplemented bit, reads as ‘0’. Shaded cells are not used by Resets. Note 1: Other (non Power-up) Resets include MCLR Reset and Watchdog Timer Reset during normal operation. DS41391D-page 80  2011 Microchip Technology Inc. PIC16(L)F1826/27 8.0 INTERRUPTS The interrupt feature allows certain events to preempt normal program flow. Firmware is used to determine the source of the interrupt and act accordingly. Some interrupts can be configured to wake the MCU from Sleep mode. This chapter contains the following information for Interrupts: • • • • • Operation Interrupt Latency Interrupts During Sleep INT Pin Automatic Context Saving Many peripherals produce Interrupts. Refer to the corresponding chapters for details. A block diagram of the interrupt logic is shown in Figure 8-1. FIGURE 8-1: INTERRUPT LOGIC IOCBNx D Q4Q1 Q CK Edge Detect R RBx IOCBPx D Data bus = 0 or 1 Q Write IOCBFx CK D S Q To data bus IOCBFx CK IOCIE R Q2 From all other IOCBFx individual pin detectors Q1 Q2 Q3 Q4 Q4Q1 Q1 Q1 Q2 Q2 Q3 Q4 Q4Q1  2011 Microchip Technology Inc. IOC interrupt to CPU core Q3 Q4 Q4 Q4Q1 Q4Q1 DS41391D-page 81 PIC16(L)F1826/27 8.1 Operation Interrupts are disabled upon any device Reset. They are enabled by setting the following bits: • GIE bit of the INTCON register • Interrupt Enable bit(s) for the specific interrupt events) • PEIE bit of the INTCON register (if the Interrupt Enable bit of the interrupt event is contained in the PIEx registers) 8.2 Interrupt Latency Interrupt latency is defined as the time from when the interrupt event occurs to the time code execution at the interrupt vector begins. The latency for synchronous interrupts is 3 or 4 instruction cycles. For asynchronous interrupts, the latency is 3 to 5 instruction cycles, depending on when the interrupt occurs. See Figure 8-2 and Figure 8.3 for more details. The INTCON, PIRx registers record individual interrupts via interrupt flag bits. Interrupt flag bits will be set, regardless of the status of the GIE, PEIE and individual interrupt enable bits. The following events happen when an interrupt event occurs while the GIE bit is set: • Current prefetched instruction is flushed • GIE bit is cleared • Current Program Counter (PC) is pushed onto the stack • Critical registers are automatically saved to the shadow registers (See “Section 8.5 “Automatic Context Saving”.”) • PC is loaded with the interrupt vector 0004h The firmware within the Interrupt Service Routine (ISR) should determine the source of the interrupt by polling the interrupt flag bits. The interrupt flag bits must be cleared before exiting the ISR to avoid repeated interrupts. Because the GIE bit is cleared, any interrupt that occurs while executing the ISR will be recorded through its interrupt flag, but will not cause the processor to redirect to the interrupt vector. The RETFIE instruction exits the ISR by popping the previous address from the stack, restoring the saved context from the shadow registers and setting the GIE bit. For additional information on a specific interrupt’s operation, refer to its peripheral chapter. Note 1: Individual interrupt flag bits are set, regardless of the state of any other enable bits. 2: All interrupts will be ignored while the GIE bit is cleared. Any interrupt occurring while the GIE bit is clear will be serviced when the GIE bit is set again. DS41391D-page 82  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 8-2: INTERRUPT LATENCY OSC1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 CLKOUT Interrupt Sampled during Q1 Interrupt GIE PC Execute PC-1 PC 1 Cycle Instruction at PC PC+1 0004h 0005h Inst(PC) NOP NOP Inst(0004h) PC+1/FSR ADDR New PC/ PC+1 0004h 0005h Inst(PC) NOP NOP Inst(0004h) FSR ADDR PC+1 PC+2 0004h 0005h INST(PC) NOP NOP NOP Inst(0004h) Inst(0005h) FSR ADDR PC+1 0004h 0005h INST(PC) NOP NOP Inst(0004h) Interrupt GIE PC Execute PC-1 PC 2 Cycle Instruction at PC Interrupt GIE PC Execute PC-1 PC 3 Cycle Instruction at PC Interrupt GIE PC Execute PC-1 PC 3 Cycle Instruction at PC  2011 Microchip Technology Inc. PC+2 NOP NOP DS41391D-page 83 PIC16(L)F1826/27 FIGURE 8-3: INT PIN INTERRUPT TIMING Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 OSC1 CLKOUT (3) (4) INT pin (1) (1) INTF Interrupt Latency (2) (5) GIE INSTRUCTION FLOW PC Instruction Fetched Instruction Executed Note 1: PC Inst (PC) Inst (PC – 1) PC + 1 Inst (PC + 1) Inst (PC) PC + 1 — Dummy Cycle 0004h 0005h Inst (0004h) Inst (0005h) Dummy Cycle Inst (0004h) INTF flag is sampled here (every Q1). 2: Asynchronous interrupt latency = 3-5 TCY. Synchronous latency = 3-4 TCY, where TCY = instruction cycle time. Latency is the same whether Inst (PC) is a single cycle or a 2-cycle instruction. 3: CLKOUT not available in all Oscillator modes. 4: For minimum width of INT pulse, refer to AC specifications in Section 30.0 “Electrical Specifications””. 5: INTF is enabled to be set any time during the Q4-Q1 cycles. DS41391D-page 84  2011 Microchip Technology Inc. PIC16(L)F1826/27 8.3 Interrupts During Sleep Some interrupts can be used to wake from Sleep. To wake from Sleep, the peripheral must be able to operate without the system clock. The interrupt source must have the appropriate Interrupt Enable bit(s) set prior to entering Sleep. On waking from Sleep, if the GIE bit is also set, the processor will branch to the interrupt vector. Otherwise, the processor will continue executing instructions after the SLEEP instruction. The instruction directly after the SLEEP instruction will always be executed before branching to the ISR. Refer to Section 9.0 “PowerDown Mode (Sleep)” for more details. 8.4 INT Pin The INT pin can be used to generate an asynchronous edge-triggered interrupt. This interrupt is enabled by setting the INTE bit of the INTCON register. The INTEDG bit of the OPTION_REG register determines on which edge the interrupt will occur. When the INTEDG bit is set, the rising edge will cause the interrupt. When the INTEDG bit is clear, the falling edge will cause the interrupt. The INTF bit of the INTCON register will be set when a valid edge appears on the INT pin. If the GIE and INTE bits are also set, the processor will redirect program execution to the interrupt vector. 8.5 Automatic Context Saving Upon entering an interrupt, the return PC address is saved on the stack. Additionally, the following registers are automatically saved in the Shadow registers: • • • • • W register STATUS register (except for TO and PD) BSR register FSR registers PCLATH register Upon exiting the Interrupt Service Routine, these registers are automatically restored. Any modifications to these registers during the ISR will be lost. If modifications to any of these registers are desired, the corresponding Shadow register should be modified and the value will be restored when exiting the ISR. The Shadow registers are available in Bank 31 and are readable and writable. Depending on the user’s application, other registers may also need to be saved.  2011 Microchip Technology Inc. DS41391D-page 85 PIC16(L)F1826/27 8.6 Interrupt Control Registers Note: 8.6.1 INTCON REGISTER The INTCON register is a readable and writable register, that contains the various enable and flag bits for TMR0 register overflow, interrupt-on-change and external INT pin interrupts. REGISTER 8-1: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the Global Enable bit, GIE, of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. INTCON: INTERRUPT CONTROL REGISTER R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R-0/0 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF(1) bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 GIE: Global Interrupt Enable bit 1 = Enables all active interrupts 0 = Disables all interrupts bit 6 PEIE: Peripheral Interrupt Enable bit 1 = Enables all active peripheral interrupts 0 = Disables all peripheral interrupts bit 5 TMR0IE: Timer0 Overflow Interrupt Enable bit 1 = Enables the Timer0 interrupt 0 = Disables the Timer0 interrupt bit 4 INTE: INT External Interrupt Enable bit 1 = Enables the INT external interrupt 0 = Disables the INT external interrupt bit 3 IOCIE: Interrupt-on-Change Enable bit 1 = Enables the interrupt-on-change 0 = Disables the interrupt-on-change bit 2 TMR0IF: Timer0 Overflow Interrupt Flag bit 1 = TMR0 register has overflowed 0 = TMR0 register did not overflow bit 1 INTF: INT External Interrupt Flag bit 1 = The INT external interrupt occurred 0 = The INT external interrupt did not occur bit 0 IOCIF: Interrupt-on-Change Interrupt Flag bit(1) 1 = When at least one of the interrupt-on-change pins changed state 0 = None of the interrupt-on-change pins have changed state Note 1: The IOCIF Flag bit is read-only and cleared when all the Interrupt-on-Change flags in the IOCBF register have been cleared by software. DS41391D-page 86  2011 Microchip Technology Inc. PIC16(L)F1826/27 8.6.2 PIE1 REGISTER The PIE1 register contains the interrupt enable bits, as shown in Register 8-2. REGISTER 8-2: Note: Bit PEIE of the INTCON register must be set to enable any peripheral interrupt. PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 TMR1GIE: Timer1 Gate Interrupt Enable bit 1 = Enables the Timer1 Gate Acquisition interrupt 0 = Disables the Timer1 Gate Acquisition interrupt bit 6 ADIE: A/D Converter (ADC) Interrupt Enable bit 1 = Enables the ADC interrupt 0 = Disables the ADC interrupt bit 5 RCIE: USART Receive Interrupt Enable bit 1 = Enables the USART receive interrupt 0 = Disables the USART receive interrupt bit 4 TXIE: USART Transmit Interrupt Enable bit 1 = Enables the USART transmit interrupt 0 = Disables the USART transmit interrupt bit 3 SSP1IE: Synchronous Serial Port 1 (MSSP1) Interrupt Enable bit 1 = Enables the MSSP1 interrupt 0 = Disables the MSSP1 interrupt bit 2 CCP1IE: CCP1 Interrupt Enable bit 1 = Enables the CCP1 interrupt 0 = Disables the CCP1 interrupt bit 1 TMR2IE: TMR2 to PR2 Match Interrupt Enable bit 1 = Enables the Timer2 to PR2 match interrupt 0 = Disables the Timer2 to PR2 match interrupt bit 0 TMR1IE: Timer1 Overflow Interrupt Enable bit 1 = Enables the Timer1 overflow interrupt 0 = Disables the Timer1 overflow interrupt  2011 Microchip Technology Inc. DS41391D-page 87 PIC16(L)F1826/27 8.6.3 PIE2 REGISTER The PIE2 register contains the interrupt enable bits, as shown in Register 8-3. REGISTER 8-3: Note: Bit PEIE of the INTCON register must be set to enable any peripheral interrupt. PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 U-0 R/W-0/0 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(1) bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 OSFIE: Oscillator Fail Interrupt Enable bit 1 = Enables the Oscillator Fail interrupt 0 = Disables the Oscillator Fail interrupt bit 6 C2IE: Comparator C2 Interrupt Enable bit 1 = Enables the Comparator C2 interrupt 0 = Disables the Comparator C2 interrupt bit 5 C1IE: Comparator C1 Interrupt Enable bit 1 = Enables the Comparator C1 interrupt 0 = Disables the Comparator C1 interrupt bit 4 EEIE: EEPROM Write Completion Interrupt Enable bit 1 = Enables the EEPROM Write Completion interrupt 0 = Disables the EEPROM Write Completion interrupt bit 3 BCL1IE: MSSP1 Bus Collision Interrupt Enable bit 1 = Enables the MSSP1 Bus Collision Interrupt 0 = Disables the MSSP1 Bus Collision Interrupt bit 2-1 Unimplemented: Read as ‘0’ bit 0 CCP2IE: CCP2 Interrupt Enable bit 1 = Enables the CCP2 interrupt 0 = Disables the CCP2 interrupt Note 1: PIC16(L)F1827 only. DS41391D-page 88  2011 Microchip Technology Inc. PIC16(L)F1826/27 8.6.4 PIE3 REGISTER The PIE3 register contains the interrupt enable bits, as shown in Register 8-4. Note: Bit PEIE of the INTCON register must be set to enable any peripheral interrupt. PIE3: PERIPHERAL INTERRUPT ENABLE REGISTER 3(1) REGISTER 8-4: U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 R/W-0/0 U-0 — — CCP4IE CCP3IE TMR6IE — TMR4IE — bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 Unimplemented: Read as ‘0’ bit 5 CCP4IE: CCP4 Interrupt Enable bit 1 = Enables the CCP4 interrupt 0 = Disables the CCP4 interrupt bit 4 CCP3IE: CCP3 Interrupt Enable bit 1 = Enables the CCP3 interrupt 0 = Disables the CCP3 interrupt bit 3 TMR6IE: TMR6 to PR6 Match Interrupt Enable bit 1 = Enables the TMR6 to PR6 Match interrupt 0 = Disables the TMR6 to PR6 Match interrupt bit 2 Unimplemented: Read as ‘0’ bit 1 TMR4IE: TMR4 to PR4 Match Interrupt Enable bit 1 = Enables the TMR4 to PR4 Match interrupt 0 = Disables the TMR4 to PR4 Match interrupt bit 0 Unimplemented: Read as ‘0’ Note 1: This register is only available on PIC16(L)F1827.  2011 Microchip Technology Inc. DS41391D-page 89 PIC16(L)F1826/27 PIE4 REGISTER(1) 8.6.5 The PIE4 register contains the interrupt enable bits, as shown in Register 8-5. Note 1: The PIE4 register is available only on the PIC16(L)F1827 device. 2: Bit PEIE of the INTCON register must be set to enable any peripheral interrupt. PIE4: PERIPHERAL INTERRUPT ENABLE REGISTER 4(1) REGISTER 8-5: U-0 U-0 U-0 U-0 U-0 U-0 R/W-0/0 R/W-0/0 — — — — — — BCL2IE SSP2IE bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-2 Unimplemented: Read as ‘0’ bit 1 BCL2IE: MSSP2 Bus Collision Interrupt Enable bit 1 = Enables the MSSP2 Bus Collision Interrupt 0 = Disables the MSSP2 Bus Collision Interrupt bit 0 SSP2IE: Master Synchronous Serial Port 2 (MSSP2) Interrupt Enable bit 1 = Enables the MSSP2 interrupt 0 = Disables the MSSP2 interrupt Note 1: This register is only available on PIC16(L)F1827. DS41391D-page 90  2011 Microchip Technology Inc. PIC16(L)F1826/27 8.6.6 PIR1 REGISTER The PIR1 register contains the interrupt flag bits, as shown in Register 8-6. REGISTER 8-6: Note: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the Global Enable bit, GIE, of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1 R/W-0/0 R/W-0/0 R-0/0 R-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 TMR1GIF: Timer1 Gate Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 6 ADIF: A/D Converter Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 5 RCIF: USART Receive Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 4 TXIF: USART Transmit Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 3 SSP1IF: Synchronous Serial Port 1 (MSSP1) Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 2 CCP1IF: CCP1 Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 1 TMR2IF: Timer2 to PR2 Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 0 TMR1IF: Timer1 Overflow Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending  2011 Microchip Technology Inc. DS41391D-page 91 PIC16(L)F1826/27 8.6.7 PIR2 REGISTER The PIR2 register contains the interrupt flag bits, as shown in Register 8-7. REGISTER 8-7: Note: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the Global Enable bit, GIE, of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. PIR2: PERIPHERAL INTERRUPT REQUEST REGISTER 2 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 U-0 R/W-0/0 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF(1) bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 OSFIF: Oscillator Fail Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 6 C2IF: Comparator C2 Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 5 C1IF: Comparator C1 Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 4 EEIF: EEPROM Write Completion Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 3 BCL1IF: MSSP1 Bus Collision Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 2-1 Unimplemented: Read as ‘0’ bit 0 CCP2IF: CCP2 Interrupt Flag bit(1) 1 = Interrupt is pending 0 = Interrupt is not pending Note 1: PIC16(L)F1827 only. DS41391D-page 92  2011 Microchip Technology Inc. PIC16(L)F1826/27 8.6.8 PIR3 REGISTER The PIR3 register contains the interrupt flag bits, as shown in Register 8-8. Note: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the Global Enable bit, GIE, of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. PIR3: PERIPHERAL INTERRUPT REQUEST REGISTER 3(1) REGISTER 8-8: U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 R/W-0/0 U-0 — — CCP4IF CCP3IF TMR6IF — TMR4IF — bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 Unimplemented: Read as ‘0’ bit 5 CCP4IF: CCP4 Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 4 CCP3IF: CCP3 Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 3 TMR6IF: TMR6 to PR6 Match Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 2 Unimplemented: Read as ‘0’ bit 1 TMR4IF: TMR4 to PR4 Match Interrupt Flag bit 1 = Interrupt is pending 0 = Interrupt is not pending bit 0 Unimplemented: Read as ‘0’ Note 1: This register is only available on PIC16(L)F1827.  2011 Microchip Technology Inc. DS41391D-page 93 PIC16(L)F1826/27 PIR4 REGISTER(1) 8.6.9 The PIR4 register contains the interrupt flag bits, as shown in Register 8-9. Note 1: The PIR4 register is available only on the PIC16(L)F1827 device. 2: Interrupt flag bits are set when an interrupt condition occurs, regardless of the state of its corresponding enable bit or the Global Enable bit, GIE, of the INTCON register. User software should ensure the appropriate interrupt flag bits are clear prior to enabling an interrupt. PIR4: PERIPHERAL INTERRUPT REQUEST REGISTER 4(1) REGISTER 8-9: U-0 U-0 U-0 U-0 U-0 U-0 R/W/HS-0/0 R/W/HS-0/0 — — — — — — BCL2IF SSP2IF bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared HS = Bit is set by hardware bit 7-2 Unimplemented: Read as ‘0’ bit 1 BCL2IF: MSSP2 Bus Collision Interrupt Flag bit 1 = A Bus Collision was detected (must be cleared in software) 0 = No Bus collision was detected bit 0 SSP2IF: Master Synchronous Serial Port 2 (MSSP2) Interrupt Flag bit 1 = The Transmission/Reception/Bus Condition is complete (must be cleared in software) 0 = Waiting to Transmit/Receive/Bus Condition in progress Note 1: This register is only available on PIC16(L)F1827. TABLE 8-1: SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPTS Name Bit 7 INTCON Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 177 PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 PIE2 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(1) 88 (1) PIE3 — — CCP4IE CCP3IE TMR6IE — TMR4IE — 89 PIE4(1) — — — — — — BCL2IE SSP2IE 90 PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 91 PIR2 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF(1) 92 PIR3(1) — — CCP4IF CCP3IF TMR6IF — TMR4IF — 93 PIR4(1) — — — — — — BCL2IF SSP2IF 94 OPTION_REG Legend: Note 1: — = unimplemented locations read as ‘0’. Shaded cells are not used by Interrupts. PIC16(L)F1827 only. DS41391D-page 94  2011 Microchip Technology Inc. PIC16(L)F1826/27 9.0 POWER-DOWN MODE (SLEEP) 9.1 Wake-up from Sleep The Power-Down mode is entered by executing a SLEEP instruction. The device can wake-up from Sleep through one of the following events: Upon entering Sleep mode, the following conditions exist: 1. 2. 3. 4. 5. 6. 1. WDT will be cleared but keeps running, if enabled for operation during Sleep. 2. PD bit of the STATUS register is cleared. 3. TO bit of the STATUS register is set. 4. CPU clock is disabled. 5. 31 kHz LFINTOSC is unaffected and peripherals that operate from it may continue operation in Sleep. 6. Timer1 oscillator is unaffected and peripherals that operate from it may continue operation in Sleep. 7. ADC is unaffected, if the dedicated FRC clock is selected. 8. Capacitive Sensing oscillator is unaffected. 9. I/O ports maintain the status they had before SLEEP was executed (driving high, low or highimpedance). 10. Resets other than WDT are not affected by Sleep mode. Refer to individual chapters for more details on peripheral operation during Sleep. To minimize current consumption, the following conditions should be considered: • • • • • • I/O pins should not be floating External circuitry sinking current from I/O pins Internal circuitry sourcing current from I/O pins Current draw from pins with internal weak pull-ups Modules using 31 kHz LFINTOSC Modules using Timer1 oscillator External Reset input on MCLR pin, if enabled BOR Reset, if enabled POR Reset Watchdog Timer, if enabled Any external interrupt Interrupts by peripherals capable of running during Sleep (see individual peripheral for more information) The first three events will cause a device Reset. The last three events are considered a continuation of program execution. To determine whether a device Reset or wake-up event occurred, refer to Section 7.10 “Determining the Cause of a Reset”. When the SLEEP instruction is being executed, the next instruction (PC + 1) is prefetched. For the device to wake-up through an interrupt event, the corresponding interrupt enable bit must be enabled. Wake-up will occur regardless of the state of the GIE bit. If the GIE bit is disabled, the device continues execution at the instruction after the SLEEP instruction. If the GIE bit is enabled, the device executes the instruction after the SLEEP instruction, the device will then call the Interrupt Service Routine. In cases where the execution of the instruction following SLEEP is not desirable, the user should have a NOP after the SLEEP instruction. The WDT is cleared when the device wakes up from Sleep, regardless of the source of wake-up. I/O pins that are high-impedance inputs should be pulled to VDD or VSS externally to avoid switching currents caused by floating inputs. Examples of internal circuitry that might be sourcing current include modules such as the DAC and FVR modules. See Section 17.0 “Digital-to-Analog Converter (DAC) Module” and Section 14.0 “Fixed Voltage Reference (FVR)” for more information on these modules.  2011 Microchip Technology Inc. DS41391D-page 95 PIC16(L)F1826/27 9.1.1 WAKE-UP USING INTERRUPTS When global interrupts are disabled (GIE cleared) and any interrupt source has both its interrupt enable bit and interrupt flag bit set, one of the following will occur: • If the interrupt occurs before the execution of a SLEEP instruction - SLEEP instruction will execute as a NOP. - WDT and WDT prescaler will not be cleared - TO bit of the STATUS register will not be set - PD bit of the STATUS register will not be cleared. FIGURE 9-1: • If the interrupt occurs during or after the execution of a SLEEP instruction - SLEEP instruction will be completely executed - Device will immediately wake-up from Sleep - WDT and WDT prescaler will be cleared - TO bit of the STATUS register will be set - PD bit of the STATUS register will be cleared. Even if the flag bits were checked before executing a SLEEP instruction, it may be possible for flag bits to become set before the SLEEP instruction completes. To determine whether a SLEEP instruction executed, test the PD bit. If the PD bit is set, the SLEEP instruction was executed as a NOP. WAKE-UP FROM SLEEP THROUGH INTERRUPT Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 OSC1(1) TOST(3) CLKOUT(2) Interrupt flag Interrupt Latency (4) GIE bit (INTCON reg.) Processor in Sleep Instruction Flow PC PC Instruction Fetched Instruction Executed Note 1: 2: 3: 4: PC + 1 Inst(PC) = Sleep Inst(PC - 1) PC + 2 PC + 2 PC + 2 Inst(PC + 1) Inst(PC + 2) Sleep Inst(PC + 1) Dummy Cycle 0004h 0005h Inst(0004h) Inst(0005h) Dummy Cycle Inst(0004h) XT, HS or LP Oscillator mode assumed. CLKOUT is not available in XT, HS, or LP Oscillator modes, but shown here for timing reference. TOST = 1024 TOSC (drawing not to scale). This delay applies only to XT, HS or LP Oscillator modes. GIE = 1 assumed. In this case after wake-up, the processor calls the ISR at 0004h. If GIE = 0, execution will continue in-line. TABLE 9-1: SUMMARY OF REGISTERS ASSOCIATED WITH POWER-DOWN MODE Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 91 IOCBF IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0 134 IOCBN IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0 134 IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0 134 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 92 — IOCBP PIE1 OSFIE C2IE C1IE EEIE BCL1IE — — — — — — — BCL2IE SSP2IE PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 96 PIR2 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF(1) 97 PIR4(1) — — — — — — BCL2IF SSP2IF 99 STATUS — — — TO PD Z DC C 23 — — WDTPS4 WDTPS3 WDTPS2 WDTPS1 WDTPS0 SWDTEN 105 PIE2 PIE4(1) WDTCON Legend: Note 1: CCP2IE (1) 93 95 — = unimplemented, read as ‘0’. Shaded cells are not used in Power-down mode. PIC16(L)F1827 only. DS41391D-page 96  2011 Microchip Technology Inc. PIC16(L)F1826/27 10.0 WATCHDOG TIMER The Watchdog Timer is a system timer that generates a Reset if the firmware does not issue a CLRWDT instruction within the time-out period. The Watchdog Timer is typically used to recover the system from unexpected events. The WDT has the following features: • Independent clock source • Multiple operating modes - WDT is always on - WDT is off when in Sleep - WDT is controlled by software - WDT is always off • Configurable time-out period is from 1 ms to 256 seconds (typical) • Multiple Reset conditions • Operation during Sleep FIGURE 10-1: WATCHDOG TIMER BLOCK DIAGRAM WDTE = 01 SWDTEN WDTE = 11 LFINTOSC 23-bit Programmable Prescaler WDT WDT Time-out WDTE = 10 Sleep  2011 Microchip Technology Inc. WDTPS DS41391D-page 97 PIC16(L)F1826/27 10.1 Independent Clock Source 10.3 The WDT derives its time base from the 31 kHz LFINTOSC internal oscillator. Time intervals in this chapter are based on a nominal interval of 1 ms. See Section 30.0 “Electrical Specifications” for the LFINTOSC tolerances. 10.2 WDT IS ALWAYS ON When the WDTE bits of Configuration Word 1 are set to ‘11’, the WDT is always on. WDT protection is active during Sleep. 10.2.2 WDT protection is not active during Sleep. WDT CONTROLLED BY SOFTWARE When the WDTE bits of Configuration Word 1 are set to ‘01’, the WDT is controlled by the SWDTEN bit of the WDTCON register. WDT protection is unchanged Table 10-1 for more details. TABLE 10-1: by Sleep. See WDT OPERATING MODES WDTE SWDTEN Device Mode WDT Mode 11 X X Active Awake Active 10 X Sleep Disabled 1 X 01 0 00 TABLE 10-2: X X 10.4 Clearing the WDT • • • • • • • Any Reset CLRWDT instruction is executed Device enters Sleep Device wakes up from Sleep Oscillator fail event WDT is disabled Oscillator Start-up TImer (OST) is running See Table 10-2 for more information. WDT IS OFF IN SLEEP When the WDTE bits of Configuration Word 1 are set to ‘10’, the WDT is on, except in Sleep. 10.2.3 The WDTPS bits of the WDTCON register set the time-out period from 1 ms to 256 seconds (nominal). After a Reset, the default time-out period is 2 seconds. The WDT is cleared when any of the following conditions occur: WDT Operating Modes The Watchdog Timer module has four operating modes controlled by the WDTE bits in Configuration Word 1. See Table 10-1. 10.2.1 Time-Out Period 10.5 Operation During Sleep When the device enters Sleep, the WDT is cleared. If the WDT is enabled during Sleep, the WDT resumes counting. When the device exits Sleep, the WDT is cleared again. The WDT remains clear until the OST, if enabled, completes. See Section 5.0 “Oscillator Module (With Fail-Safe Clock Monitor)” for more information on the OST. When a WDT time-out occurs while the device is in Sleep, no Reset is generated. Instead, the device wakes up and resumes operation. The TO and PD bits in the STATUS register are changed to indicate the event. See Register 3-1 for more information. Active Disabled Disabled WDT CLEARING CONDITIONS Conditions WDT WDTE = 00 WDTE = 01 and SWDTEN = 0 WDTE = 10 and enter Sleep CLRWDT Command Cleared Oscillator Fail Detected Exit Sleep + System Clock = T1OSC, EXTRC, INTOSC, EXTCLK Exit Sleep + System Clock = XT, HS, LP Change INTOSC divider (IRCF bits) DS41391D-page 98 Cleared until the end of OST Unaffected  2011 Microchip Technology Inc. PIC16(L)F1826/27 10.6 Watchdog Control Register REGISTER 10-1: WDTCON: WATCHDOG TIMER CONTROL REGISTER U-0 U-0 — — R/W-0/0 R/W-1/1 R/W-0/0 R/W-1/1 R/W-1/1 WDTPS bit 7 R/W-0/0 SWDTEN bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -m/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 Unimplemented: Read as ‘0’ bit 5-1 WDTPS: Watchdog Timer Period Select bits(1) Bit Value = Prescale Rate 00000 = 1:32 (Interval 1 ms nominal) 00001 = 1:64 (Interval 2 ms nominal) 00010 = 1:128 (Interval 4 ms nominal) 00011 = 1:256 (Interval 8 ms nominal) 00100 = 1:512 (Interval 16 ms nominal) 00101 = 1:1024 (Interval 32 ms nominal) 00110 = 1:2048 (Interval 64 ms nominal) 00111 = 1:4096 (Interval 128 ms nominal) 01000 = 1:8192 (Interval 256 ms nominal) 01001 = 1:16384 (Interval 512 ms nominal) 01010 = 1:32768 (Interval 1s nominal) 01011 = 1:65536 (Interval 2s nominal) (Reset value) 01100 = 1:131072 (217) (Interval 4s nominal) 01101 = 1:262144 (218) (Interval 8s nominal) 01110 = 1:524288 (219) (Interval 16s nominal) 01111 = 1:1048576 (220) (Interval 32s nominal) 10000 = 1:2097152 (221) (Interval 64s nominal) 10001 = 1:4194304 (222) (Interval 128s nominal) 10010 = 1:8388608 (223) (Interval 256s nominal) 10011 = Reserved. Results in minimum interval (1:32) • • • 11111 = Reserved. Results in minimum interval (1:32) bit 0 Note 1: SWDTEN: Software Enable/Disable for Watchdog Timer bit If WDTE = 00: This bit is ignored. If WDTE = 01: 1 = WDT is turned on 0 = WDT is turned off If WDTE = 1x: This bit is ignored. Times are approximate. WDT time is based on 31 kHz LFINTOSC.  2011 Microchip Technology Inc. DS41391D-page 99 PIC16(L)F1826/27 TABLE 10-3: Name SUMMARY OF REGISTERS ASSOCIATED WITH WATCHDOG TIMER Bit 7 Bit 6 OSCCON — STATUS — — — — WDTCON Legend: CONFIG1 Legend: Bit 4 Bit 3 IRCF — Bit 2 — TO PD Bit 1 Bit 0 SCS Z DC WDTPS Register on Page 69 C 21 SWDTEN 99 x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by Watchdog Timer. TABLE 10-4: Name Bit 5 SUMMARY OF CONFIGURATION WORD WITH WATCHDOG TIMER Bits Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 13:8 — — FCMEN IESO CLKOUTEN 7:0 CP MCLRE PWRTE Bit 10/2 Bit 9/1 BOREN WDTE FOSC Bit 8/0 CPD Register on Page 44 — = unimplemented location, read as ‘0’. Shaded cells are not used by Watchdog Timer. DS41391D-page 100  2011 Microchip Technology Inc. PIC16(L)F1826/27 11.0 DATA EEPROM AND FLASH PROGRAM MEMORY CONTROL The Data EEPROM and Flash program memory are readable and writable during normal operation (full VDD range). These memories are not directly mapped in the register file space. Instead, they are indirectly addressed through the Special Function Registers (SFRs). There are six SFRs used to access these memories: • • • • • • EECON1 EECON2 EEDATL EEDATH EEADRL EEADRH When interfacing the data memory block, EEDATL holds the 8-bit data for read/write, and EEADRL holds the address of the EEDATL location being accessed. These devices have 256 bytes of data EEPROM with an address range from 0h to 0FFh. When accessing the program memory block, the EEDATH:EEDATL register pair forms a 2-byte word that holds the 14-bit data for read/write, and the EEADRL and EEADRH registers form a 2-byte word that holds the 15-bit address of the program memory location being read. The EEPROM data memory allows byte read and write. An EEPROM byte write automatically erases the location and writes the new data (erase before write). The write time is controlled by an on-chip timer. The write/erase voltages are generated by an on-chip charge pump rated to operate over the voltage range of the device for byte or word operations. Depending on the setting of the Flash Program Memory Self Write Enable bits WRT of the Configuration Word 2, the device may or may not be able to write certain blocks of the program memory. However, reads from the program memory are always allowed. 11.1 EEADRL and EEADRH Registers The EEADRH:EEADRL register pair can address up to a maximum of 256 bytes of data EEPROM or up to a maximum of 32K words of program memory. When selecting a program address value, the MSB of the address is written to the EEADRH register and the LSB is written to the EEADRL register. When selecting a EEPROM address value, only the LSB of the address is written to the EEADRL register. 11.1.1 EECON1 AND EECON2 REGISTERS EECON1 is the control register for EE memory accesses. Control bit EEPGD determines if the access will be a program or data memory access. When clear, any subsequent operations will operate on the EEPROM memory. When set, any subsequent operations will operate on the program memory. On Reset, EEPROM is selected by default. Control bits RD and WR initiate read and write, respectively. These bits cannot be cleared, only set, in software. They are cleared in hardware at completion of the read or write operation. The inability to clear the WR bit in software prevents the accidental, premature termination of a write operation. The WREN bit, when set, will allow a write operation to occur. On power-up, the WREN bit is clear. The WRERR bit is set when a write operation is interrupted by a Reset during normal operation. In these situations, following Reset, the user can check the WRERR bit and execute the appropriate error handling routine. Interrupt flag bit EEIF of the PIR2 register is set when write is complete. It must be cleared in the software. Reading EECON2 will read all ‘0’s. The EECON2 register is used exclusively in the data EEPROM write sequence. To enable writes, a specific pattern must be written to EECON2. When the device is code-protected, the device programmer can no longer access data or program memory. When code-protected, the CPU may continue to read and write the data EEPROM memory and Flash program memory.  2011 Microchip Technology Inc. DS41391D-page 101 PIC16(L)F1826/27 11.2 Using the Data EEPROM The data EEPROM is a high-endurance, byte addressable array that has been optimized for the storage of frequently changing information (e.g., program variables or other data that are updated often). When variables in one section change frequently, while variables in another section do not change, it is possible to exceed the total number of write cycles to the EEPROM without exceeding the total number of write cycles to a single byte. Refer to Section 30.0 “Electrical Specifications”. If this is the case, then a refresh of the array must be performed. For this reason, variables that change infrequently (such as constants, IDs, calibration, etc.) should be stored in Flash program memory. 11.2.1 READING THE DATA EEPROM MEMORY To read a data memory location, the user must write the address to the EEADRL register, clear the EEPGD and CFGS control bits of the EECON1 register, and then set control bit RD. The data is available at the very next cycle, in the EEDATL register; therefore, it can be read in the next instruction. EEDATL will hold this value until another read or until it is written to by the user (during a write operation). EXAMPLE 11-1: DATA EEPROM READ BANKSEL EEADRL ; MOVLW DATA_EE_ADDR ; MOVWF EEADRL ;Data Memory ;Address to read BCF EECON1, CFGS ;Deselect Config space BCF EECON1, EEPGD;Point to DATA memory BSF EECON1, RD ;EE Read MOVF EEDATL, W ;W = EEDATL Note: Data EEPROM can be read regardless of the setting of the CPD bit. 11.2.2 WRITING TO THE DATA EEPROM MEMORY To write an EEPROM data location, the user must first write the address to the EEADRL register and the data to the EEDATL register. Then the user must follow a specific sequence to initiate the write for each byte. The write will not initiate if the above sequence is not followed exactly (write 55h to EECON2, write AAh to EECON2, then set the WR bit) for each byte. Interrupts should be disabled during this code segment. Additionally, the WREN bit in EECON1 must be set to enable write. This mechanism prevents accidental writes to data EEPROM due to errant (unexpected) code execution (i.e., lost programs). The user should keep the WREN bit clear at all times, except when updating EEPROM. The WREN bit is not cleared by hardware. After a write sequence has been initiated, clearing the WREN bit will not affect this write cycle. The WR bit will be inhibited from being set unless the WREN bit is set. At the completion of the write cycle, the WR bit is cleared in hardware and the EE Write Complete Interrupt Flag bit (EEIF) is set. The user can either enable this interrupt or poll this bit. EEIF must be cleared by software. 11.2.3 PROTECTION AGAINST SPURIOUS WRITE There are conditions when the user may not want to write to the data EEPROM memory. To protect against spurious EEPROM writes, various mechanisms have been built-in. On power-up, WREN is cleared. Also, the Power-up Timer (64 ms duration) prevents EEPROM write. The write initiate sequence and the WREN bit together help prevent an accidental write during: • Brown-out • Power Glitch • Software Malfunction 11.2.4 DATA EEPROM OPERATION DURING CODE-PROTECT Data memory can be code-protected by programming the CPD bit in the Configuration Word 1 (Register 4-1) to ‘0’. When the data memory is code-protected, only the CPU is able to read and write data to the data EEPROM. It is recommended to code-protect the program memory when code-protecting data memory. This prevents anyone from replacing your program with a program that will access the contents of the data EEPROM. DS41391D-page 102  2011 Microchip Technology Inc. PIC16(L)F1826/27 Required Sequence EXAMPLE 11-2: DATA EEPROM WRITE BANKSEL MOVLW MOVWF MOVLW MOVWF BCF BCF BSF EEADRL DATA_EE_ADDR EEADRL DATA_EE_DATA EEDATL EECON1, CFGS EECON1, EEPGD EECON1, WREN ; ; ;Data Memory Address to write ; ;Data Memory Value to write ;Deselect Configuration space ;Point to DATA memory ;Enable writes BCF MOVLW MOVWF MOVLW MOVWF BSF BSF BCF BTFSC GOTO INTCON, 55h EECON2 0AAh EECON2 EECON1, INTCON, EECON1, EECON1, $-2 ;Disable INTs. ; ;Write 55h ; ;Write AAh ;Set WR bit to begin write ;Enable Interrupts ;Disable writes ;Wait for write to complete ;Done GIE WR GIE WREN WR  2011 Microchip Technology Inc. DS41391D-page 103 PIC16(L)F1826/27 FIGURE 11-1: FLASH PROGRAM MEMORY READ CYCLE EXECUTION Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 PC Flash ADDR Flash Data PC + 1 INSTR (PC) INSTR(PC - 1) executed here EEADRH,EEADRL INSTR (PC + 1) BSF PMCON1,RD executed here PC +3 PC+3 EEDATH,EEDATL INSTR(PC + 1) executed here PC + 5 PC + 4 INSTR (PC + 3) Forced NOP executed here INSTR (PC + 4) INSTR(PC + 3) executed here INSTR(PC + 4) executed here RD bit EEDATH EEDATL Register DS41391D-page 104  2011 Microchip Technology Inc. PIC16(L)F1826/27 11.3 Flash Program Memory Overview It is important to understand the Flash program memory structure for erase and programming operations. Flash Program memory is arranged in rows. A row consists of a fixed number of 14-bit program memory words. A row is the minimum block size that can be erased by user software. Flash program memory may only be written or erased if the destination address is in a segment of memory that is not write-protected, as defined in bits WRT of Configuration Word 2. After a row has been erased, the user can reprogram all or a portion of this row. Data to be written into the program memory row is written to 14-bit wide data write latches. These write latches are not directly accessible to the user, but may be loaded via sequential writes to the EEDATH:EEDATL register pair. Note: If the user wants to modify only a portion of a previously programmed row, then the contents of the entire row must be read and saved in RAM prior to the erase. The number of data write latches may not be equivalent to the number of row locations. During programming, user software may need to fill the set of write latches and initiate a programming operation multiple times in order to fully reprogram an erased row. For example, a device with a row size of 32 words and eight write latches will need to load the write latches with data and initiate a programming operation four times. 11.3.1 READING THE FLASH PROGRAM MEMORY To read a program memory location, the user must: 1. 2. 3. 4. Write the Least and Most Significant address bits to the EEADRH:EEADRL register pair. Clear the CFGS bit of the EECON1 register. Set the EEPGD control bit of the EECON1 register. Then, set control bit RD of the EECON1 register. Once the read control bit is set, the program memory Flash controller will use the second instruction cycle to read the data. This causes the second instruction immediately following the “BSF EECON1,RD” instruction to be ignored. The data is available in the very next cycle, in the EEDATH:EEDATL register pair; therefore, it can be read as two bytes in the following instructions. EEDATH:EEDATL register pair will hold this value until another read or until it is written to by the user. Note 1: The two instructions following a program memory read are required to be NOPs. This prevents the user from executing a two-cycle instruction on the next instruction after the RD bit is set. 2: Flash program memory can be read regardless of the setting of the CP bit. The size of a program memory row and the number of program memory write latches may vary by device. See Table 11-1 for details. TABLE 11-1: FLASH MEMORY ORGANIZATION BY DEVICE Device PIC16(L)F1826/27 Erase Block (Row) Size/ Boundary Number of Write Latches/ Boundary 32 words, EEADRL = 00000 32 words, EEADRL = 00000  2011 Microchip Technology Inc. DS41391D-page 105 PIC16(L)F1826/27 EXAMPLE 11-3: FLASH PROGRAM MEMORY READ * This code block will read 1 word of program * memory at the memory address: PROG_ADDR_HI : PROG_ADDR_LO * data will be returned in the variables; * PROG_DATA_HI, PROG_DATA_LO BANKSEL MOVLW MOVWF MOVLW MOVWL EEADRL PROG_ADDR_LO EEADRL PROG_ADDR_HI EEADRH ; Select Bank for EEPROM registers ; ; Store LSB of address ; ; Store MSB of address BCF BSF BCF BSF NOP NOP BSF EECON1,CFGS EECON1,EEPGD INTCON,GIE EECON1,RD INTCON,GIE ; ; ; ; ; ; ; Do not select Configuration Space Select Program Memory Disable interrupts Initiate read Ignored (Figure 11-1) Ignored (Figure 11-1) Restore interrupts MOVF MOVWF MOVF MOVWF EEDATL,W PROG_DATA_LO EEDATH,W PROG_DATA_HI ; ; ; ; Get LSB of word Store in user location Get MSB of word Store in user location DS41391D-page 106  2011 Microchip Technology Inc. PIC16(L)F1826/27 11.3.2 ERASING FLASH PROGRAM MEMORY While executing code, program memory can only be erased by rows. To erase a row: 1. 2. 3. 4. 5. 6. Load the EEADRH:EEADRL register pair with the address of new row to be erased. Clear the CFGS bit of the EECON1 register. Set the EEPGD, FREE, and WREN bits of the EECON1 register. Write 55h, then AAh, to EECON2 (Flash programming unlock sequence). Set control bit WR of the EECON1 register to begin the erase operation. Poll the FREE bit in the EECON1 register to determine when the row erase has completed. See Example 11-4. After the “BSF EECON1,WR” instruction, the processor requires two cycles to set up the erase operation. The user must place two NOP instructions after the WR bit is set. The processor will halt internal operations for the typical 2 ms erase time. This is not Sleep mode as the clocks and peripherals will continue to run. After the erase cycle, the processor will resume operation with the third instruction after the EECON1 write instruction. 11.3.3 WRITING TO FLASH PROGRAM MEMORY Program memory is programmed using the following steps: 1. 2. 3. 4. Load the starting address of the word(s) to be programmed. Load the write latches with data. Initiate a programming operation. Repeat steps 1 through 3 until all data is written. Before writing to program memory, the word(s) to be written must be erased or previously unwritten. Program memory can only be erased one row at a time. No automatic erase occurs upon the initiation of the write. Program memory can be written one or more words at a time. The maximum number of words written at one time is equal to the number of write latches. See Figure 11-2 (block writes to program memory with 32 write latches) for more details. The write latches are aligned to the address boundary defined by EEADRL as shown in Table 11-1. Write operations do not cross these boundaries. At the completion of a program memory write operation, the write latches are reset to contain 0x3FFF.  2011 Microchip Technology Inc. The following steps should be completed to load the write latches and program a block of program memory. These steps are divided into two parts. First, all write latches are loaded with data except for the last program memory location. Then, the last write latch is loaded and the programming sequence is initiated. A special unlock sequence is required to load a write latch with data or initiate a Flash programming operation. This unlock sequence should not be interrupted. 1. Set the EEPGD and WREN bits of the EECON1 register. 2. Clear the CFGS bit of the EECON1 register. 3. Set the LWLO bit of the EECON1 register. When the LWLO bit of the EECON1 register is ‘1’, the write sequence will only load the write latches and will not initiate the write to Flash program memory. 4. Load the EEADRH:EEADRL register pair with the address of the location to be written. 5. Load the EEDATH:EEDATL register pair with the program memory data to be written. 6. Write 55h, then AAh, to EECON2, then set the WR bit of the EECON1 register (Flash programming unlock sequence). The write latch is now loaded. 7. Increment the EEADRH:EEADRL register pair to point to the next location. 8. Repeat steps 5 through 7 until all but the last write latch has been loaded. 9. Clear the LWLO bit of the EECON1 register. When the LWLO bit of the EECON1 register is ‘0’, the write sequence will initiate the write to Flash program memory. 10. Load the EEDATH:EEDATL register pair with the program memory data to be written. 11. Write 55h, then AAh, to EECON2, then set the WR bit of the EECON1 register (Flash programming unlock sequence). The entire latch block is now written to Flash program memory. It is not necessary to load the entire write latch block with user program data. However, the entire write latch block will be written to program memory. An example of the complete write sequence for eight words is shown in Example 11-5. The initial address is loaded into the EEADRH:EEADRL register pair; the eight words of data are loaded using indirect addressing. DS41391D-page 107 PIC16(L)F1826/27 After the “BSF EECON1,WR” instruction, the processor requires two cycles to set up the write operation. The user must place two NOP instructions after the WR bit is set. The processor will halt internal operations for the typical 2 ms, only during the cycle in which the write takes place (i.e., the last word of the block write). This is not Sleep mode as the clocks and peripherals will continue to run. The processor does not stall when LWLO = 1, loading the write latches. After the write cycle, the processor will resume operation with the third instruction after the EECON1 write instruction. FIGURE 11-2: BLOCK WRITES TO FLASH PROGRAM MEMORY WITH 32 WRITE LATCHES 7 5 0 0 7 EEDATH EEDATA 6 8 Last word of block to be written First word of block to be written 14 EEADRL = 00000 14 EEADRL = 00001 Buffer Register 14 EEADRL = 00010 Buffer Register 14 EEADRL = 11111 Buffer Register Buffer Register Program Memory DS41391D-page 108  2011 Microchip Technology Inc. PIC16(L)F1826/27 EXAMPLE 11-4: ERASING ONE ROW OF PROGRAM MEMORY - Required Sequence ; This row erase routine assumes the following: ; 1. A valid address within the erase block is loaded in ADDRH:ADDRL ; 2. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM) BCF BANKSEL MOVF MOVWF MOVF MOVWF BSF BCF BSF BSF INTCON,GIE EEADRL ADDRL,W EEADRL ADDRH,W EEADRH EECON1,EEPGD EECON1,CFGS EECON1,FREE EECON1,WREN MOVLW MOVWF MOVLW MOVWF BSF NOP 55h EECON2 0AAh EECON2 EECON1,WR NOP ; Disable ints so required sequences will execute properly ; Load lower 8 bits of erase address boundary ; Load upper 6 bits of erase address boundary ; ; ; ; Point to program memory Not configuration space Specify an erase operation Enable writes ; ; ; ; ; ; ; ; Start of required sequence to initiate erase Write 55h Write AAh Set WR bit to begin erase Any instructions here are ignored as processor halts to begin erase sequence Processor will stop here and wait for erase complete. ; after erase processor continues with 3rd instruction BCF BSF EECON1,WREN INTCON,GIE  2011 Microchip Technology Inc. ; Disable writes ; Enable interrupts DS41391D-page 109 PIC16(L)F1826/27 EXAMPLE 11-5: ; ; ; ; ; ; ; WRITING TO FLASH PROGRAM MEMORY This write routine assumes the following: 1. The 16 bytes of data are loaded, starting at the address in DATA_ADDR 2. Each word of data to be written is made up of two adjacent bytes in DATA_ADDR, stored in little endian format 3. A valid starting address (the least significant bits = 000) is loaded in ADDRH:ADDRL 4. ADDRH and ADDRL are located in shared data memory 0x70 - 0x7F (common RAM) BCF BANKSEL MOVF MOVWF MOVF MOVWF MOVLW MOVWF MOVLW MOVWF BSF BCF BSF BSF INTCON,GIE EEADRH ADDRH,W EEADRH ADDRL,W EEADRL LOW DATA_ADDR FSR0L HIGH DATA_ADDR FSR0H EECON1,EEPGD EECON1,CFGS EECON1,WREN EECON1,LWLO ; ; ; ; ; ; ; ; ; ; ; ; ; ; Disable ints so required sequences will execute properly Bank 3 Load initial address MOVIW MOVWF MOVIW MOVWF FSR0++ EEDATL FSR0++ EEDATH ; Load first data byte into lower ; ; Load second data byte into upper ; MOVF XORLW ANDLW BTFSC GOTO EEADRL,W 0x07 0x07 STATUS,Z START_WRITE ; Check if lower bits of address are '000' ; Check if we're on the last of 8 addresses ; ; Exit if last of eight words, ; MOVLW MOVWF MOVLW MOVWF BSF NOP 55h EECON2 0AAh EECON2 EECON1,WR ; ; ; ; ; ; ; ; Load initial data address Load initial data address Point to program memory Not configuration space Enable writes Only Load Write Latches Required Sequence LOOP NOP Start of required write sequence: Write 55h Write AAh Set WR bit to begin write Any instructions here are ignored as processor halts to begin write sequence Processor will stop here and wait for write to complete. ; After write processor continues with 3rd instruction. INCF GOTO Required Sequence START_WRITE BCF MOVLW MOVWF MOVLW MOVWF BSF NOP EEADRL,F LOOP ; Still loading latches Increment address ; Write next latches EECON1,LWLO ; No more loading latches - Actually start Flash program ; memory write 55h EECON2 0AAh EECON2 EECON1,WR ; ; ; ; ; ; ; ; NOP BCF BSF DS41391D-page 110 EECON1,WREN INTCON,GIE Start of required write sequence: Write 55h Write AAh Set WR bit to begin write Any instructions here are ignored as processor halts to begin write sequence Processor will stop here and wait for write complete. ; after write processor continues with 3rd instruction ; Disable writes ; Enable interrupts  2011 Microchip Technology Inc. PIC16(L)F1826/27 11.4 Modifying Flash Program Memory When modifying existing data in a program memory row, and data within that row must be preserved, it must first be read and saved in a RAM image. Program memory is modified using the following steps: 1. 2. 3. 4. 5. 6. 7. 8. Load the starting address of the row to be modified. Read the existing data from the row into a RAM image. Modify the RAM image to contain the new data to be written into program memory. Load the starting address of the row to be rewritten. Erase the program memory row. Load the write latches with data from the RAM image. Initiate a programming operation. Repeat steps 6 and 7 as many times as required to reprogram the erased row. TABLE 11-2: 11.5 User ID, Device ID and Configuration Word Access Instead of accessing program memory or EEPROM data memory, the User ID’s, Device ID/Revision ID and Configuration Words can be accessed when CFGS = 1 in the EECON1 register. This is the region that would be pointed to by PC = 1, but not all addresses are accessible. Different access may exist for reads and writes. Refer to Table 11-2. When read access is initiated on an address outside the parameters listed in Table 11-2, the EEDATH:EEDATL register pair is cleared. USER ID, DEVICE ID AND CONFIGURATION WORD ACCESS (CFGS = 1) Address Function Read Access Write Access 8000h-8003h 8006h 8007h-8008h User IDs Device ID/Revision ID Configuration Words 1 and 2 Yes Yes Yes Yes No No EXAMPLE 11-3: CONFIGURATION WORD AND DEVICE ID ACCESS * This code block will read 1 word of program memory at the memory address: * PROG_ADDR_LO (must be 00h-08h) data will be returned in the variables; * PROG_DATA_HI, PROG_DATA_LO BANKSEL MOVLW MOVWF CLRF EEADRL PROG_ADDR_LO EEADRL EEADRH ; Select correct Bank ; ; Store LSB of address ; Clear MSB of address BSF BCF BSF NOP NOP BSF EECON1,CFGS INTCON,GIE EECON1,RD INTCON,GIE ; ; ; ; ; ; Select Configuration Space Disable interrupts Initiate read Executed (See Figure 11-1) Ignored (See Figure 11-1) Restore interrupts MOVF MOVWF MOVF MOVWF EEDATL,W PROG_DATA_LO EEDATH,W PROG_DATA_HI ; ; ; ; Get LSB of word Store in user location Get MSB of word Store in user location  2011 Microchip Technology Inc. DS41391D-page 111 PIC16(L)F1826/27 11.6 Write Verify Depending on the application, good programming practice may dictate that the value written to the data EEPROM or program memory should be verified (see Example 11-6) to the desired value to be written. Example 11-6 shows how to verify a write to EEPROM. EXAMPLE 11-6: EEPROM WRITE VERIFY BANKSEL EEDATL MOVF EEDATL, W BSF XORWF BTFSS GOTO : ; ;EEDATL not changed ;from previous write EECON1, RD ;YES, Read the ;value written EEDATL, W ; STATUS, Z ;Is data the same WRITE_ERR ;No, handle error ;Yes, continue DS41391D-page 112  2011 Microchip Technology Inc. PIC16(L)F1826/27 11.7 EEPROM and Flash Control Registers REGISTER 11-1: R/W-x/u EEDATL: EEPROM LOW BYTE DATA REGISTER R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u EEDAT bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 EEDAT: Read/write value for EEPROM data byte or Least Significant bits of program memory REGISTER 11-2: EEDATH: EEPROM DATA HIGH BYTE REGISTER U-0 U-0 — — R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u EEDAT bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 Unimplemented: Read as ‘0’ bit 5-0 EEDAT: Read/write value for Most Significant bits of program memory REGISTER 11-3: R/W-0/0 EEADRL: EEPROM ADDRESS REGISTER R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 EEADR bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 EEADR: Specifies the Least Significant bits for program memory address or EEPROM address  2011 Microchip Technology Inc. DS41391D-page 113 PIC16(L)F1826/27 REGISTER 11-4: U-1 EEADRH: EEPROM ADDRESS HIGH BYTE REGISTER R/W-0/0 R/W-0/0 R/W-0/0 — R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 EEADR bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 Unimplemented: Read as ‘1’ bit 6-0 EEADR: Specifies the Most Significant bits for program memory address or EEPROM address DS41391D-page 114  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 11-5: EECON1: EEPROM CONTROL 1 REGISTER R/W-0/0 R/W-0/0 R/W-0/0 R/W/HC-0/0 R/W-x/q R/W-0/0 R/S/HC-0/0 R/S/HC-0/0 EEPGD CFGS LWLO FREE WRERR WREN WR RD bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ S = Bit can only be set x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared HC = Bit is cleared by hardware bit 7 EEPGD: Flash Program/Data EEPROM Memory Select bit 1 = Accesses program space Flash memory 0 = Accesses data EEPROM memory bit 6 CFGS: Flash Program/Data EEPROM or Configuration Select bit 1 = Accesses Configuration, User ID and Device ID Registers 0 = Accesses Flash Program or data EEPROM Memory bit 5 LWLO: Load Write Latches Only bit If CFGS = 1 (Configuration space) OR CFGS = 0 and EEPGD = 1 (program Flash): 1 = The next WR command does not initiate a write; only the program memory latches are updated. 0 = The next WR command writes a value from EEDATH:EEDATL into program memory latches and initiates a write of all the data stored in the program memory latches. If CFGS = 0 and EEPGD = 0: (Accessing data EEPROM) LWLO is ignored. The next WR command initiates a write to the data EEPROM. bit 4 FREE: Program Flash Erase Enable bit If CFGS = 1 (Configuration space) OR CFGS = 0 and EEPGD = 1 (program Flash): 1 = Performs an erase operation on the next WR command (cleared by hardware after completion of erase). 0 = Performs a write operation on the next WR command. If EEPGD = 0 and CFGS = 0: (Accessing data EEPROM) FREE is ignored. The next WR command will initiate both a erase cycle and a write cycle. bit 3 WRERR: EEPROM Error Flag bit 1 = Condition indicates an improper program or erase sequence attempt or termination (bit is set automatically on any set attempt (write ‘1’) of the WR bit). 0 = The program or erase operation completed normally. bit 2 WREN: Program/Erase Enable bit 1 = Allows program/erase cycles 0 = Inhibits programming/erasing of program Flash and data EEPROM bit 1 WR: Write Control bit 1 = Initiates a program Flash or data EEPROM program/erase operation. The operation is self-timed and the bit is cleared by hardware once operation is complete. The WR bit can only be set (not cleared) in software. 0 = Program/erase operation to the Flash or data EEPROM is complete and inactive. bit 0 RD: Read Control bit 1 = Initiates an program Flash or data EEPROM read. Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared) in software. 0 = Does not initiate a program Flash or data EEPROM data read.  2011 Microchip Technology Inc. DS41391D-page 115 PIC16(L)F1826/27 REGISTER 11-6: W-0/0 EECON2: EEPROM CONTROL 2 REGISTER W-0/0 W-0/0 W-0/0 W-0/0 W-0/0 W-0/0 W-0/0 EEPROM Control Register 2 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ S = Bit can only be set x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 Data EEPROM Unlock Pattern bits To unlock writes, a 55h must be written first, followed by an AAh, before setting the WR bit of the EECON1 register. The value written to this register is used to unlock the writes. There are specific timing requirements on these writes. Refer to Section 11.2.2 “Writing to the Data EEPROM Memory” for more information. TABLE 11-3: SUMMARY OF REGISTERS ASSOCIATED WITH DATA EEPROM Name Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 EECON1 EEPGD CFGS LWLO FREE WRERR WREN WR RD Register on Page 115 EECON2 EEPROM Control Register 2 (not a physical register) 101* EEADRL 113 EEADRH EEDATL EEADRL7 EEADRL6 EEADRL5 EEADRL4 EEADRL3 EEADRL2 EEADRL1 EEADRL0 — EEADRH6 EEADRH5 EEADRH4 EEADRH3 EEADRH2 EEADRH1 EEADRH0 114 EEDATL7 EEDATL6 EEDATL5 EEDATL4 EEDATL3 EEDATL2 EEDALT1 EEDATL0 113 EEDATH — — INTCON GIE PEIE EEDATH5 EEDATH4 EEDATH3 EEDATH2 EEDATH1 EEDATH0 TMR0IE INTE IOCIE TMR0IF INTF IOCIF 91 PIE2 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE 93 PIR2 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF 97 113 Legend: — = unimplemented read as ‘0’. Shaded cells are not used by data EEPROM module. * Page provides register information. DS41391D-page 116  2011 Microchip Technology Inc. PIC16(L)F1826/27 12.0 I/O PORTS FIGURE 12-1: GENERIC I/O PORT OPERATION Depending on the device selected and peripherals enabled, there are two ports available. In general, when a peripheral is enabled, that pin may not be used as a general purpose I/O pin. Read LATx Each port has three registers for its operation. These registers are: • TRISx registers (data direction register) • PORTx registers (reads the levels on the pins of the device) • LATx registers (output latch) Some ports may have one or more of the following additional registers. These registers are: D Write LATx Write PORTx Q CK VDD Data Register Data Bus I/O pin Read PORTx • ANSELx (analog select) • WPUx (weak pull-up) To peripherals ANSELx PIC16(L)F1826 ● ● PIC16(L)F1827 ● ● EXAMPLE 12-1: PORTC Device PORTB PORT AVAILABILITY PER DEVICE PORTA TABLE 12-1: TRISx ; ; ; ; ● BANKSEL CLRF BANKSEL CLRF BANKSEL CLRF BANKSEL MOVLW MOVWF The Data Latch (LATx registers) is useful for read-modify-write operations on the value that the I/O pins are driving. A write operation to the LATx register has the same effect as a write to the corresponding PORTx register. A read of the LATx register reads of the values held in the I/O PORT latches, while a read of the PORTx register reads the actual I/O pin value. VSS INITIALIZING PORTA This code example illustrates initializing the PORTA register. The other ports are initialized in the same manner. PORTA PORTA LATA LATA ANSELA ANSELA TRISA B'00111000' TRISA ; ;Init PORTA ;Data Latch ; ; ;digital I/O ; ;Set RA as inputs ;and set RA as ;outputs Ports with analog functions also have an ANSELx register which can disable the digital input and save power. A simplified model of a generic I/O port, without the interfaces to other peripherals, is shown in Figure 12-1.  2011 Microchip Technology Inc. DS41391D-page 117 PIC16(L)F1826/27 12.1 Alternate Pin Function The Alternate Pin Function Control (APFCON0 and APFCON1) registers are used to steer specific peripheral input and output functions between different pins. The APFCON0 and APFCON1 registers are shown in Register 12-1 and Register 12-2. For this device family, the following functions can be moved between different pins. • • • • • • • • • RX/DT SDO1 SS1 (Slave Select 1) P2B CCP2/P2A P1D P1C CCP1/P1A TX/CK These bits have no effect on the values of any TRIS register. PORT and TRIS overrides will be routed to the correct pin. The unselected pin will be unaffected. DS41391D-page 118  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 12-1: APFCON0: ALTERNATE PIN FUNCTION CONTROL REGISTER 0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 RXDTSEL SDO1SEL SS1SEL P2BSEL(1) CCP2SEL(1) P1DSEL P1CSEL CCP1SEL bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 RXDTSEL: Pin Selection bit 0 = RX/DT function is on RB1 1 = RX/DT function is on RB2 bit 6 SDO1SEL: Pin Selection bit 0 = SDO1 function is on RB2 1 = SDO1 function is on RA6 bit 5 SS1SEL: Pin Selection bit 0 = SS1 function is on RB5 1 = SS1 function is on RA5 bit 4 P2BSEL: Pin Selection bit 0 = P2B function is on RB7 1 = P2B function is on RA6 bit 3 CCP2SEL: Pin Selection bit 0 = CCP2/P2A function is on RB6 1 = CCP2/P2A function is on RA7 bit 2 P1DSEL: Pin Selection bit 0 = P1D function is on RB7 1 = P1D function is on RA6 bit 1 P1CSEL: Pin Selection bit 0 = P1C function is on RB6 1 = P1C function is on RA7 bit 0 CCP1SEL: Pin Selection bit 0 = CCP1/P1A function is on RB3 1 = CCP1/P1A function is on RB0 Note 1: PIC16(L)F1827 only. REGISTER 12-2: APFCON1: ALTERNATE PIN FUNCTION CONTROL REGISTER 1 U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-0/0 — — — — — — — TXCKSEL bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-1 Unimplemented: Read as ‘0’ bit 0 TXCKSEL: Pin Selection bit 0 = TX/CK function is on RB2 1 = TX/CK function is on RB5  2011 Microchip Technology Inc. DS41391D-page 119 PIC16(L)F1826/27 12.2 PORTA Registers PORTA is a 8-bit wide, bidirectional port. The corresponding data direction register is TRISA (Register 12-4). Setting a TRISA bit (= 1) will make the corresponding PORTA pin an input (i.e., disable the output driver). Clearing a TRISA bit (= 0) will make the corresponding PORTA pin an output (i.e., enables output driver and puts the contents of the output latch on the selected pin). The exception is RA5, which is input only and its TRIS bit will always read as ‘1’. Example 12-1 shows how to initialize an I/O port. Reading the PORTA register (Register 12-3) reads the status of the pins, whereas writing to it will write to the PORT latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the port pins are read, this value is modified and then written to the PORT data latch (LATA). The TRISA register (Register 12-4) controls the PORTA pin output drivers, even when they are being used as analog inputs. The user should ensure the bits in the TRISA register are maintained set when using them as analog inputs. I/O pins configured as analog input always read ‘0’. 12.2.1 WEAK PULL-UPS Each of the PORTA pins has an individually configurable internal weak pull-up. Control bit WPUA enables or disables the pull-up (see Register 12-6). The weak pull-up is automatically turned off when the port pin is configured as an output. The pull-up is disabled on a Power-on Reset by the WPUEN bit of the OPTION register. 12.2.2 ANSELA REGISTER The ANSELA register (Register 12-7) is used to configure the Input mode of an I/O pin to analog. Setting the appropriate ANSELA bit high will cause all digital reads on the pin to be read as ‘0’ and allow analog functions on the pin to operate correctly. The state of the ANSELA bits has no effect on digital output functions. A pin with TRIS clear and ANSEL set will still operate as a digital output, but the Input mode will be analog. This can cause unexpected behavior when executing read-modify-write instructions on the affected port. Note: The ANSELA bits default to the Analog mode after Reset. To use any pins as digital general purpose or peripheral inputs, the corresponding ANSEL bits must be initialized to ‘0’ by user software. DS41391D-page 120  2011 Microchip Technology Inc. PIC16(L)F1826/27 12.2.3 PORTA FUNCTIONS AND OUTPUT PRIORITIES Each PORTA pin is multiplexed with other functions. The pins, their combined functions and their output priorities are shown in Table 12-2. When multiple outputs are enabled, the actual pin control goes to the peripheral with the highest priority. Analog input functions, such as ADC, comparator and CapSense inputs, are not shown in the priority lists. These inputs are active when the I/O pin is set for Analog mode using the ANSELx registers. Digital output functions may control the pin when it is in Analog mode with the priority shown in Table 12-2. TABLE 12-2: Pin Name Note 1: PORTA OUTPUT PRIORITY Function Priority(1) RA0 SDO2 (PIC16(L)F1827 only) RA0 RA1 SS2 (PIC16(L)F1827 only) RA1 RA2 DACOUT (DAC) RA2 RA3 SRQ (SR latch) CCP3 (PIC16(L)F1827 only) C1OUT (Comparator) RA3 RA4 SRNQ (SR latch) CCP4 (PIC16(L)F1827 only) T0CKI C2OUT (Comparator) RA4 RA5 Input only pin RA6 OSC2 (enabled by Configuration Word) CLKOUT CLKR SDO1 P1D P2B (PIC16(L)F1827 only) RA6 RA7 OSC1/CLKIN (enabled by Configuration Word) P1C CCP2 (PIC16(L)F1827 only) P2A (PIC16(L)F1827 only) RA7 Priority listed from highest to lowest. Each PORTA pin is multiplexed with other functions. The pins, their combined functions and their output priorities are briefly described here. For additional information, refer to the appropriate section in this data sheet. When multiple outputs are enabled, the actual pin control goes to the peripheral with the lowest number in the following lists.  2011 Microchip Technology Inc. DS41391D-page 121 PIC16(L)F1826/27 REGISTER 12-3: PORTA: PORTA REGISTER R/W-x/x R/W-x/x R-x/x R/W-x/x R/W-x/x R/W-x/x R/W-x/x R/W-x/x RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared RA: PORTA I/O Value bits(1) 1 = Port pin is > VIH 0 = Port pin is < VIL bit 7-0 Note 1: Writes to PORTA are actually written to corresponding LATA register. Reads from PORTA register is return of actual I/O pin values. REGISTER 12-4: TRISA: PORTA TRI-STATE REGISTER R/W-1/1 R/W-1/1 R-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 TRISA: PORTA Tri-State Control bit 1 = PORTA pin configured as an input (tri-stated) 0 = PORTA pin configured as an output bit 5 TRISA5: RA5 Port Tri-State Control bit This bit is always ‘1’ as RA5 is an input only bit 4-0 TRISA: PORTA Tri-State Control bit 1 = PORTA pin configured as an input (tri-stated) 0 = PORTA pin configured as an output REGISTER 12-5: LATA: PORTA DATA LATCH REGISTER R/W-x/u R/W-x/u U-0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u LATA7 LATA6 — LATA4 LATA3 LATA2 LATA1 LATA0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 LATA: RA Output Latch Value bits(1) bit 5 Unimplemented: Read as ‘0 bit 4-0 LATA: RA Output Latch Value bits(1) Note 1: Writes to PORTA are actually written to corresponding LATA register. Reads from PORTA register is return of actual I/O pin values. DS41391D-page 122  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 12-6: WPUA: WEAK PULL-UP PORTA REGISTER U-0 U-0 R/W-1/1 U-0 U-0 U-0 U-0 U-0 — — WPUA5 — — — — — bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 Unimplemented: Read as ‘0’ bit 5 WPUA5: Weak Pull-up RA5 Control bit If MCLRE in Configuration Word 1 = 0, MCLR is disabled): 1 = Weak Pull-up enabled(1) 0 = Weak Pull-up disabled If MCLRE in Configuration Word 1 = 1, MCLR is enabled): Weak Pull-up is always enabled. bit 4-0 Unimplemented: Read as ‘0’ Note 1: 2: Global WPUEN bit of the OPTION register must be cleared for individual pull-ups to be enabled. The weak pull-up device is automatically disabled if the pin is in configured as an output. REGISTER 12-7: ANSELA: PORTA ANALOG SELECT REGISTER U-0 U-0 U-0 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-5 Unimplemented: Read as ‘0’ bit 4-0 ANSA: Analog Select between Analog or Digital Function on pins RA, respectively 0 = Digital I/O. Pin is assigned to port or digital special function. 1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled. Note 1: When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to allow external control of the voltage on the pin.  2011 Microchip Technology Inc. DS41391D-page 123 PIC16(L)F1826/27 TABLE 12-3: SUMMARY OF REGISTERS ASSOCIATED WITH PORTA Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 123 LATA7 LATA6 — LATA4 LATA3 LATA2 LATA1 LATA0 122 WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 176 PORTA RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0 122 TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 WPUA — — WPUA5 — — — — — 123 Register on Page Name ANSELA LATA OPTION_REG Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA. TABLE 12-4: Name CONFIG1 Legend: SUMMARY OF CONFIGURATION WORD ASSOCIATED WITH PORTA Bits Bit -/7 Bit -/6 Bit 13/5 Bit 12/4 Bit 11/3 Bit 10/2 Bit 9/1 Bit 8/0 13:8 — — FCMEN IESO CLKOUTEN BOREN1 BOREN0 CPD 7:0 CP MCLRE PWRTE WDTE1 WDTE0 FOSC2 FOSC1 FOSC0 44 — = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA. DS41391D-page 124  2011 Microchip Technology Inc. PIC16(L)F1826/27 12.3 PORTB and TRISB Registers PORTB is an 8-bit wide, bidirectional port. The corresponding data direction register is TRISB (Register 12-9). Setting a TRISB bit (= 1) will make the corresponding PORTB pin an input (i.e., put the corresponding output driver in a High-Impedance mode). Clearing a TRISB bit (= 0) will make the corresponding PORTB pin an output (i.e., enable the output driver and put the contents of the output latch on the selected pin). Example 12-1 shows how to initialize an I/O port. Reading the PORTB register (Register 12-8) reads the status of the pins, whereas writing to it will write to the PORT latch. All write operations are read-modify-write operations. Therefore, a write to a port implies that the port pins are read, this value is modified and then written to the PORT data latch. The TRISB register (Register 12-9) controls the PORTB pin output drivers, even when they are being used as analog inputs. The user should ensure the bits in the TRISB register are maintained set when using them as analog inputs. I/O pins configured as analog input always read ‘0’. 12.3.1 12.3.3 ANSELB REGISTER The ANSELB register (Register 12-12) is used to configure the Input mode of an I/O pin to analog. Setting the appropriate ANSELB bit high will cause all digital reads on the pin to be read as ‘0’ and allow analog functions on the pin to operate correctly. The state of the ANSELB bits has no affect on digital output functions. A pin with TRIS clear and ANSELB set will still operate as a digital output, but the Input mode will be analog. This can cause unexpected behavior when executing read-modify-write instructions on the affected port. The TRISB register (Register 12-9) controls the PORTB pin output drivers, even when they are being used as analog inputs. The user should ensure the bits in the TRISB register are maintained set when using them as analog inputs. I/O pins configured as analog input always read ‘0’. Note: The ANSELB register must be initialized to configure an analog channel as a digital input. Pins configured as analog inputs will read ‘0’. INTERRUPT-ON-CHANGE All of the PORTB pins are individually configurable as an interrupt-on-change pin. Control bits IOCB enable or disable the interrupt function for each pin. The interrupt-on-change feature is disabled on a Power-on Reset. Reference Section 13.0 “Interrupt-On-Change” for more information. 12.3.2 WEAK PULL-UPS Each of the PORTB pins has an individually configurable internal weak pull-up. Control bits WPUB enable or disable each pull-up (see Register 12-11). Each weak pull-up is automatically turned off when the port pin is configured as an output. All pull-ups are disabled on a Power-on Reset by the WPUEN bit of the OPTION register.  2011 Microchip Technology Inc. DS41391D-page 125 PIC16(L)F1826/27 12.3.4 PORTB FUNCTIONS AND OUTPUT PRIORITIES Each PORTB pin is multiplexed with other functions. The pins, their combined functions and their output priorities are shown in Table 12-5. When multiple outputs are enabled, the actual pin control goes to the peripheral with the highest priority. Analog input and some digital input functions are not included in the list below. These input functions can remain active when the pin is configured as an output. Certain digital input functions, such as the EUSART RX signal, override other port functions and are included in the priority list. TABLE 12-5: Pin Name Function Priority(1) RB0 P1A RB0 RB1 SDA1 RX/DT RB1 RB2 SDA2 (PIC16(L)F1827 only) TX/CK RX/DT SDO1 RB2 RB3 MDOUT CCP1/P1A RB3 RB4 SCL1 SCK1 RB4 RB5 SCL2 (PIC16(L)F1827 only) TX/CK SCK2 (PIC16(L)F1827 only) P1B RB5 RB6 ICSPCLK (Programming) T1OSI P1C CCP2 (PIC16(L)F1827 only) P2A (PIC16(L)F1827 only) RB6 RB7 ICSPDAT (Programming) T1OSO P1D P2B (PIC16(L)F1827 only) RB7 Note 1: DS41391D-page 126 PORTB OUTPUT PRIORITY Priority listed from highest to lowest.  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 12-8: PORTB: PORTB REGISTER R/W-x/x R/W-x/x R/W-x/x R/W-x/x R/W-x/x R/W-x/x R/W-x/x R/W-x/x RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 RB: PORTB I/O Pin bit 1 = Port pin is > VIH 0 = Port pin is < VIL REGISTER 12-9: TRISB: PORTB TRI-STATE REGISTER R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 TRISB: PORTB Tri-State Control bit 1 = PORTB pin configured as an input (tri-stated) 0 = PORTB pin configured as an output REGISTER 12-10: LATB: PORTB DATA LATCH REGISTER R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 Note 1: LATB: PORTB Output Latch Value bits(1) Writes to PORTB are actually written to corresponding LATB register. Reads from PORTB register is return of actual I/O pin values.  2011 Microchip Technology Inc. DS41391D-page 127 PIC16(L)F1826/27 REGISTER 12-11: WPUB: WEAK PULL-UP PORTB REGISTER R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 Note 1: 2: WPUB: Weak Pull-up Register bits 1 = Pull-up enabled 0 = Pull-up disabled Global WPUEN bit of the OPTION register must be cleared for individual pull-ups to be enabled. The weak pull-up device is automatically disabled if the pin is in configured as an output. REGISTER 12-12: ANSELB: PORTB ANALOG SELECT REGISTER R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 U-0 ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-1 ANSB: Analog Select between Analog or Digital Function on Pins RB, respectively 0 = Digital I/O. Pin is assigned to port or digital special function. 1 = Analog input. Pin is assigned as analog input(1). Digital input buffer disabled. bit 0 Unimplemented: Read as ‘0’ Note 1: When setting a pin to an analog input, the corresponding TRIS bit must be set to Input mode in order to allow external control of the voltage on the pin. DS41391D-page 128  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 12-6: Name ANSELB LATB OPTION_REG SUMMARY OF REGISTERS ASSOCIATED WITH PORTB Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — 128 LATB7 LATB6 LATB5 LATB4 LATB3 LATB2 LATB1 LATB0 127 WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 176 PORTB RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 127 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 WPUB7 WPUB6 WPUB5 WPUB4 WPUB3 WPUB2 WPUB1 WPUB0 128 WPUB Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used by PORTB.  2011 Microchip Technology Inc. DS41391D-page 129 PIC16(L)F1826/27 NOTES: DS41391D-page 130  2011 Microchip Technology Inc. PIC16(L)F1826/27 13.0 INTERRUPT-ON-CHANGE The PORTB pins can be configured to operate as Interrupt-On-Change (IOC) pins. An interrupt can be generated by detecting a signal that has either a rising edge or a falling edge. Any individual PORTB pin can be configured to generate an interrupt. The interrupt-on-change module has the following features: • • • • Interrupt-on-Change enable (Master Switch) Individual pin configuration Rising and falling edge detection Individual pin interrupt flags Figure 13-1 is a block diagram of the IOC module. 13.1 Enabling the Module 13.3 Interrupt Flags The IOCBFx bits located in the IOCBF register are status flags that correspond to the Interrupt-on-change pins of the port. If an expected edge is detected on an appropriately enabled pin, then the status flag for that pin will be set, and an interrupt will be generated if the IOCIE bit is set. The IOCIF bit of the INTCON register reflects the status of all IOCBFx bits. 13.4 Clearing Interrupt Flags The individual status flags, (IOCBFx bits), can be cleared by resetting them to zero. If another edge is detected during this clearing operation, the associated status flag will be set at the end of the sequence, regardless of the value actually being written. To allow individual port pins to generate an interrupt, the IOCIE bit of the INTCON register must be set. If the IOCIE bit is disabled, the edge detection on the pin will still occur, but an interrupt will not be generated. In order to ensure that no detected edge is lost while clearing flags, only AND operations masking out known changed bits should be performed. The following sequence is an example of what should be performed. 13.2 Individual Pin Configuration EXAMPLE 13-1: For each port pin, a rising edge detector and a falling edge detector are present. To enable a pin to detect a rising edge, the associated IOCBPx bit of the IOCBP register is set. To enable a pin to detect a falling edge, the associated IOCBNx bit of the IOCBN register is set. MOVLW XORWF ANDWF A pin can be configured to detect rising and falling edges simultaneously by setting both the IOCBPx bit and the IOCBNx bit of the IOCBP and IOCBN registers, respectively. FIGURE 13-1: 13.5 0xff IOCBF, W IOCBF, F Operation in Sleep The interrupt-on-change interrupt sequence will wake the device from Sleep mode, if the IOCIE bit is set. If an edge is detected while in Sleep mode, the IOCBF register will be updated prior to the first instruction executed out of Sleep. INTERRUPT-ON-CHANGE BLOCK DIAGRAM IOCIE IOCBNx D Q IOCBFx From all other IOCBFx individual pin detectors CK R IOC Interrupt to CPU Core RBx IOCBPx D Q CK R Q2 Clock Cycle  2011 Microchip Technology Inc. DS41391D-page 131 PIC16(L)F1826/27 13.6 Interrupt-On-Change Registers REGISTER 13-1: IOCBP: INTERRUPT-ON-CHANGE POSITIVE EDGE REGISTER R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 IOCBP: Interrupt-on-Change Positive Edge Enable bits 1 = Interrupt-on-change enabled on the pin for a positive going edge. Associated Status bit and interrupt flag will be set upon detecting an edge. 0 = Interrupt-on-change disabled for the associated pin. REGISTER 13-2: IOCBN: INTERRUPT-ON-CHANGE NEGATIVE EDGE REGISTER R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 IOCBN: Interrupt-on-Change Negative Edge Enable bits 1 = Interrupt-on-change enabled on the pin for a negative going edge. Associated Status bit and interrupt flag will be set upon detecting an edge. 0 = Interrupt-on-change disabled for the associated pin. REGISTER 13-3: IOCBF: INTERRUPT-ON-CHANGE FLAG REGISTER R/W/HS-0/0 R/W/HS-0/0 IOCBF7 IOCBF6 R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0 IOCBF5 IOCBF4 IOCBF3 R/W/HS-0/0 R/W/HS-0/0 R/W/HS-0/0 IOCBF2 IOCBF1 IOCBF0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared HS - Bit is set in hardware bit 7-0 IOCBF: Interrupt-on-Change Flag bits 1 = An enabled change was detected on the associated pin. Set when IOCBPx = 1 and a rising edge was detected on RBx, or when IOCBNx = 1 and a falling edge was detected on RBx. 0 = No change was detected, or the user cleared the detected change. DS41391D-page 132  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 13-1: SUMMARY OF REGISTERS ASSOCIATED WITH INTERRUPT-ON-CHANGE Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page ANSELB ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — 128 INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 Name IOCBF IOCBF7 IOCBF6 IOCBF5 IOCBF4 IOCBF3 IOCBF2 IOCBF1 IOCBF0 132 IOCBN IOCBN7 IOCBN6 IOCBN5 IOCBN4 IOCBN3 IOCBN2 IOCBN1 IOCBN0 132 IOCBP IOCBP7 IOCBP6 IOCBP5 IOCBP4 IOCBP3 IOCBP2 IOCBP1 IOCBP0 132 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 Legend: — = unimplemented locations read as ‘0’. Shaded cells are not used by interrupt-on-change.  2011 Microchip Technology Inc. DS41391D-page 133 PIC16(L)F1826/27 NOTES: DS41391D-page 134  2011 Microchip Technology Inc. PIC16(L)F1826/27 14.0 FIXED VOLTAGE REFERENCE (FVR) 14.1 The output of the FVR supplied to the ADC, Comparators, and DAC and CPS is routed through two independent programmable gain amplifiers. Each amplifier can be configured to amplify the reference voltage by 1x, 2x or 4x, to produce the three possible voltage levels. The Fixed Voltage Reference, or FVR, is a stable voltage reference, independent of VDD, with 1.024V, 2.048V or 4.096V selectable output levels. The output of the FVR can be configured to supply a reference voltage to the following: • • • • • Independent Gain Amplifiers The ADFVR bits of the FVRCON register are used to enable and configure the gain amplifier settings for the reference supplied to the ADC module. Reference Section 16.0 “Analog-to-Digital Converter (ADC) Module” for additional information. ADC input channel ADC positive reference Comparator positive input Digital-to-Analog Converter (DAC) Capacitive Sensing (CPS) module The CDAFVR bits of the FVRCON register are used to enable and configure the gain amplifier settings for the reference supplied to the DAC and comparator module. Reference Section 16.0 “Digital-to-Analog Converter (DAC) Module” and Section 18.0 “Comparator Module” and Section 27.0 “Capacitive Sensing Module” for additional information. The FVR can be enabled by setting the FVREN bit of the FVRCON register. 14.2 FVR Stabilization Period When the Fixed Voltage Reference module is enabled, it requires time for the reference and amplifier circuits to stabilize. Once the circuits stabilize and are ready for use, the FVRRDY bit of the FVRCON register will be set. See Section 30.0 “Electrical Specifications” for the minimum delay requirement. FIGURE 14-1: VOLTAGE REFERENCE BLOCK DIAGRAM ADFVR CDAFVR 2 X1 X2 X4 FVR BUFFER1 (To ADC Module) X1 X2 X4 FVR BUFFER2 (To Comparators, DAC, CPS) 2 1.024V Fixed Reference FVREN + _ FVRRDY Any peripheral requiring the Fixed Reference (See Table 14-1)  2011 Microchip Technology Inc. DS41391D-page 135 PIC16(L)F1826/27 14.3 FVR Control Registers REGISTER 14-1: FVRCON: FIXED VOLTAGE REFERENCE CONTROL REGISTER R/W-0/0 R-q/q R/W-0/0 R/W-0/0 FVREN FVRRDY(1) Reserved Reserved R/W-0/0 R/W-0/0 R/W-0/0 CDAFVR R/W-0/0 ADFVR bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared q = Value depends on condition bit 7 FVREN: Fixed Voltage Reference Enable bit 0 = Fixed Voltage Reference is disabled 1 = Fixed Voltage Reference is enabled bit 6 FVRRDY: Fixed Voltage Reference Ready Flag bit(1) 0 = Fixed Voltage Reference output is not ready or not enabled 1 = Fixed Voltage Reference output is ready for use bit 5-4 Reserved: Read as ‘0’. Maintain these bits clear. bit 3-2 CDAFVR: Comparator and DAC Fixed Voltage Reference Selection bit 00 = Comparator and DAC Fixed Voltage Reference Peripheral output is off. 01 = Comparator and DAC Fixed Voltage Reference Peripheral output is 1x (1.024V) 10 = Comparator and DAC Fixed Voltage Reference Peripheral output is 2x (2.048V)(2) 11 = Comparator and DAC Fixed Voltage Reference Peripheral output is 4x (4.096V)(2) bit 1-0 ADFVR: ADC Fixed Voltage Reference Selection bit 00 = ADC Fixed Voltage Reference Peripheral output is off. 01 = ADC Fixed Voltage Reference Peripheral output is 1x (1.024V) 10 = ADC Fixed Voltage Reference Peripheral output is 2x (2.048V)(2) 11 = ADC Fixed Voltage Reference Peripheral output is 4x (4.096V)(2) Note 1: 2: FVRRDY is always ‘1’ on devices with LDO (PIC16F1826/27). Fixed Voltage Reference output cannot exceed VDD. TABLE 14-1: Name FVRCON Legend: SUMMARY OF REGISTERS ASSOCIATED WITH THE FVR MODULE Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on page FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 136 Shaded cells are unused by the FVR module. DS41391D-page 136  2011 Microchip Technology Inc. PIC16(L)F1826/27 15.0 TEMPERATURE INDICATOR MODULE FIGURE 15-1: This family of devices is equipped with a temperature circuit designed to measure the operating temperature of the silicon die. The circuit's range of operating temperature falls between of -40°C and +85°C. The output is a voltage that is proportional to the device temperature. The output of the temperature indicator is internally connected to the device ADC. VDD TSEN TSRNG The circuit may be used as a temperature threshold detector or a more accurate temperature indicator, depending on the level of calibration performed. A onepoint calibration allows the circuit to indicate a temperature closely surrounding that point. A two-point calibration allows the circuit to sense the entire range of temperature more accurately. Reference Application Note AN1333, “Use and Calibration of the Internal Temperature Indicator” (DS01333) for more details regarding the calibration process. 15.1 TEMPERATURE CIRCUIT DIAGRAM VOUT ADC MUX ADC n CHS bits (ADCON0 register) Circuit Operation Figure 15-1 shows a simplified block diagram of the temperature circuit. The proportional voltage output is achieved by measuring the forward voltage drop across multiple silicon junctions. Equation 15-1 describes the output characteristics of the temperature indicator. EQUATION 15-1: VOUT RANGES High Range: VOUT = VDD - 4VT Low Range: VOUT = VDD - 2VT 15.2 Minimum Operating VDD vs. Minimum Sensing Temperature When the temperature circuit is operated in low range, the device may be operated at any operating voltage that is within specifications. When the temperature circuit is operated in high range, the device operating voltage, VDD, must be high enough to ensure that the temperature circuit is correctly biased. Table 15-1 shows the recommended minimum VDD vs. range setting. TABLE 15-1: The temperature sense circuit is integrated with the Fixed Voltage Reference (FVR) module. See Section 14.0 “Fixed Voltage Reference (FVR)” for more information. The circuit is enabled by setting the TSEN bit of the FVRCON register. When disabled, the circuit draws no current. The circuit operates in either high or low range. The high range, selected by setting the TSRNG bit of the FVRCON register, provides a wider output voltage. This provides more resolution over the temperature range, but may be less consistent from part to part. This range requires a higher bias voltage to operate and thus, a higher VDD is needed. RECOMMENDED VDD VS. RANGE Min. VDD, TSRNG = 1 Min. VDD, TSRNG = 0 3.6V 1.8V 15.3 Temperature Output The output of the circuit is measured using the internal analog to digital converter. Channel 29 is reserved for the temperature circuit output. Refer to Section 16.0 “Analog-to-Digital Converter (ADC) Module” for detailed information. The low range is selected by clearing the TSRNG bit of the FVRCON register. The low range generates a lower voltage drop and thus, a lower bias voltage is needed to operate the circuit. The low range is provided for low voltage operation.  2011 Microchip Technology Inc. DS41391D-page 137 PIC16(L)F1826/27 NOTES: DS41391D-page 138  2011 Microchip Technology Inc. PIC16(L)F1826/27 16.0 The ADC can generate an interrupt upon completion of a conversion. This interrupt can be used to wake-up the device from Sleep. ANALOG-TO-DIGITAL CONVERTER (ADC) MODULE The Analog-to-Digital Converter (ADC) allows conversion of an analog input signal to a 10-bit binary representation of that signal. This device uses analog inputs, which are multiplexed into a single sample and hold circuit. The output of the sample and hold is connected to the input of the converter. The converter generates a 10-bit binary result via successive approximation and stores the conversion result into the ADC result registers (ADRESH:ADRESL register pair). Figure 16-1 shows the block diagram of the ADC. The ADC voltage reference is software selectable to be either internally generated or externally supplied. FIGURE 16-1: ADC BLOCK DIAGRAM ADNREF = 1 VREF- ADNREF = 0 VDD VSS ADPREF = 00 ADPREF = 11 VREF+ AN0 00000 AN1 00001 AN2 00010 AN3 00011 AN4 00100 AN5 00101 AN6 00110 AN7 00111 AN8 01000 AN9 01001 AN10 01010 AN11 01011 ADPREF = 10 ADC 10 GO/DONE ADFM 0 = Left Justify 1 = Right Justify 16 ADON Temp Indicator 11101 DAC 11110 FVR Buffer1 11111 VSS ADRESH ADRESL CHS(2) Note 1: 2: When ADON = 0, all multiplexer inputs are disconnected. See ADCON0 register (Register 16-1) for detailed analog channel selection per device.  2011 Microchip Technology Inc. DS41391D-page 139 PIC16(L)F1826/27 16.1 ADC Configuration When configuring and using the ADC the following functions must be considered: • • • • • • Port configuration Channel selection ADC voltage reference selection ADC conversion clock source Interrupt control Result formatting 16.1.1 PORT CONFIGURATION The ADC can be used to convert both analog and digital signals. When converting analog signals, the I/O pin should be configured for analog by setting the associated TRIS and ANSEL bits. Refer to Section 12.0 “I/O Ports” for more information. Note: 16.1.2 Analog voltages on any pin that is defined as a digital input may cause the input buffer to conduct excess current. CHANNEL SELECTION There are up to 15 channel selections available: • • • • AN pins Temperature Indicator DAC Output FVR (Fixed Voltage Reference) Output 16.1.4 CONVERSION CLOCK The source of the conversion clock is software selectable via the ADCS bits of the ADCON1 register. There are seven possible clock options: • • • • • • • FOSC/2 FOSC/4 FOSC/8 FOSC/16 FOSC/32 FOSC/64 FRC (dedicated internal oscillator) The time to complete one bit conversion is defined as TAD. One full 10-bit conversion requires 11.5 TAD periods as shown in Figure 16-2. For correct conversion, the appropriate TAD specification must be met. Refer to the A/D conversion requirements in Section 30.0 “Electrical Specifications”for more information. Table 16-1 gives examples of appropriate ADC clock selections. Note: Unless using the FRC, any changes in the system clock frequency will change the ADC clock frequency, which may adversely affect the ADC result. Refer to Section 14.0 “Fixed Voltage Reference (FVR)”and Section 15.0 “Temperature Indicator Module” for more information on these channel selections. The CHS bits of the ADCON0 register determine which channel is connected to the sample and hold circuit. When changing channels, a delay is required before starting the next conversion. Refer to Section 16.2 “ADC Operation” for more information. 16.1.3 ADC VOLTAGE REFERENCE The ADPREF bits of the ADCON1 register provides control of the positive voltage reference. The positive voltage reference can be: • • • • VREF+ pin VDD FVR 2.048V FVR 4.096V (Not available on LF devices) The ADNREF bits of the ADCON1 register provides control of the negative voltage reference. The negative voltage reference can be: • VREF- pin • VSS See Section 14.0 “Fixed Voltage Reference (FVR)” for more details on the fixed voltage reference. DS41391D-page 140  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 16-1: ADC CLOCK PERIOD (TAD) VS. DEVICE OPERATING FREQUENCIES ADC Clock Period (TAD) ADC Clock Source Device Frequency (FOSC) ADCS 32 MHz 20 MHz 16 MHz 8 MHz 4 MHz 1 MHz 000 62.5ns(2) 100 ns(2) 125 ns(2) 250 ns(2) 500 ns(2) 2.0 s FOSC/4 100 125 ns (2) (2) (2) (2) FOSC/8 001 0.5 s(2) 400 ns(2) 0.5 s(2) FOSC/16 101 800 ns 800 ns 010 1.0 s FOSC/64 110 FRC x11 FOSC/2 FOSC/32 Legend: Note 1: 2: 3: 4: 1.0 s 4.0 s 1.0 s 2.0 s 8.0 s(3) 1.0 s 2.0 s 4.0 s 16.0 s(3) 1.6 s 2.0 s 4.0 s 2.0 s 3.2 s 4.0 s 1.0-6.0 s(1,4) 1.0-6.0 s(1,4) 1.0-6.0 s(1,4) 200 ns 250 ns 500 ns 8.0 s (3) 8.0 s 16.0 s (3) 1.0-6.0 s(1,4) (3) 1.0-6.0 s(1,4) 32.0 s(3) 64.0 s(3) 1.0-6.0 s(1,4) Shaded cells are outside of recommended range. The FRC source has a typical TAD time of 1.6 s for VDD. These values violate the minimum required TAD time. For faster conversion times, the selection of another clock source is recommended. The ADC clock period (TAD) and total ADC conversion time can be minimized when the ADC clock is derived from the system clock FOSC. However, the FRC clock source must be used when conversions are to be performed with the device in Sleep mode. FIGURE 16-2: ANALOG-TO-DIGITAL CONVERSION TAD CYCLES TCY - TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11 b4 b1 b0 b6 b7 b2 b9 b8 b3 b5 Conversion starts Holding capacitor is disconnected from analog input (typically 100 ns) Set GO bit On the following cycle: ADRESH:ADRESL is loaded, GO bit is cleared, ADIF bit is set, holding capacitor is connected to analog input.  2011 Microchip Technology Inc. DS41391D-page 141 PIC16(L)F1826/27 16.1.5 INTERRUPTS 16.1.6 The ADC module allows for the ability to generate an interrupt upon completion of an Analog-to-Digital conversion. The ADC Interrupt Flag is the ADIF bit in the PIR1 register. The ADC Interrupt Enable is the ADIE bit in the PIE1 register. The ADIF bit must be cleared in software. RESULT FORMATTING The 10-bit A/D conversion result can be supplied in two formats, left justified or right justified. The ADFM bit of the ADCON1 register controls the output format. Figure 16-3 shows the two output formats. Note 1: The ADIF bit is set at the completion of every conversion, regardless of whether or not the ADC interrupt is enabled. 2: The ADC operates during Sleep only when the FRC oscillator is selected. This interrupt can be generated while the device is operating or while in Sleep. If the device is in Sleep, the interrupt will wake-up the device. Upon waking from Sleep, the next instruction following the SLEEP instruction is always executed. If the user is attempting to wake-up from Sleep and resume in-line code execution, the GIE and PEIE bits of the INTCON register must be disabled. If the GIE and PEIE bits of the INTCON register are enabled, execution will switch to the Interrupt Service Routine. FIGURE 16-3: 10-BIT A/D CONVERSION RESULT FORMAT ADRESH (ADFM = 0) ADRESL MSB LSB bit 7 bit 0 bit 7 10-bit A/D Result Unimplemented: Read as ‘0’ MSB (ADFM = 1) bit 7 Unimplemented: Read as ‘0’ DS41391D-page 142 bit 0 LSB bit 0 bit 7 bit 0 10-bit A/D Result  2011 Microchip Technology Inc. PIC16(L)F1826/27 16.2 16.2.1 ADC Operation STARTING A CONVERSION To enable the ADC module, the ADON bit of the ADCON0 register must be set to a ‘1’. Setting the GO/ DONE bit of the ADCON0 register to a ‘1’ will start the Analog-to-Digital conversion. Note: 16.2.2 The GO/DONE bit should not be set in the same instruction that turns on the ADC. Refer to Section 16.2.6 “A/D Conversion Procedure”. COMPLETION OF A CONVERSION When the conversion is complete, the ADC module will: • Clear the GO/DONE bit • Set the ADIF Interrupt Flag bit • Update the ADRESH and ADRESL registers with new conversion result 16.2.3 TERMINATING A CONVERSION If a conversion must be terminated before completion, the GO/DONE bit can be cleared in software. The ADRESH and ADRESL registers will be updated with the partially complete Analog-to-Digital conversion sample. Incomplete bits will match the last bit converted. Note: A device Reset forces all registers to their Reset state. Thus, the ADC module is turned off and any pending conversion is terminated. 16.2.4 ADC OPERATION DURING SLEEP The ADC module can operate during Sleep. This requires the ADC clock source to be set to the FRC option. When the FRC clock source is selected, the ADC waits one additional instruction before starting the conversion. This allows the SLEEP instruction to be executed, which can reduce system noise during the conversion. If the ADC interrupt is enabled, the device will wake-up from Sleep when the conversion completes. If the ADC interrupt is disabled, the ADC module is turned off after the conversion completes, although the ADON bit remains set. When the ADC clock source is something other than FRC, a SLEEP instruction causes the present conversion to be aborted and the ADC module is turned off, although the ADON bit remains set. 16.2.5 SPECIAL EVENT TRIGGER The Special Event Trigger of the CCPx/ECCPx module allows periodic ADC measurements without software intervention. When this trigger occurs, the GO/DONE bit is set by hardware and the Timer1 counter resets to zero. TABLE 16-2: SPECIAL EVENT TRIGGER Device CCPx/ECCPx PIC16(L)F1826 ECCP1 PIC16(L)F1827 CCP4 Using the Special Event Trigger does not assure proper ADC timing. It is the user’s responsibility to ensure that the ADC timing requirements are met. Refer to Section 24.0 “Capture/Compare/PWM Modules” for more information.  2011 Microchip Technology Inc. DS41391D-page 143 PIC16(L)F1826/27 16.2.6 A/D CONVERSION PROCEDURE This is an example procedure for using the ADC to perform an Analog-to-Digital conversion: 1. 2. 3. 4. 5. 6. 7. 8. Configure Port: • Disable pin output driver (Refer to the TRIS register) • Configure pin as analog (Refer to the ANSEL register) Configure the ADC module: • Select ADC conversion clock • Configure voltage reference • Select ADC input channel • Turn on ADC module Configure ADC interrupt (optional): • Clear ADC interrupt flag • Enable ADC interrupt • Enable peripheral interrupt • Enable global interrupt(1) Wait the required acquisition time(2). Start conversion by setting the GO/DONE bit. Wait for ADC conversion to complete by one of the following: • Polling the GO/DONE bit • Waiting for the ADC interrupt (interrupts enabled) Read ADC Result. Clear the ADC interrupt flag (required if interrupt is enabled). EXAMPLE 16-1: A/D CONVERSION ;This code block configures the ADC ;for polling, Vdd and Vss references, Frc ;clock and AN0 input. ; ;Conversion start & polling for completion ; are included. ; BANKSEL ADCON1 ; MOVLW B’11110000’ ;Right justify, Frc ;clock MOVWF ADCON1 ;Vdd and Vss Vref BANKSEL TRISA ; BSF TRISA,0 ;Set RA0 to input BANKSEL ANSEL ; BSF ANSEL,0 ;Set RA0 to analog BANKSEL ADCON0 ; MOVLW B’00000001’ ;Select channel AN0 MOVWF ADCON0 ;Turn ADC On CALL SampleTime ;Acquisiton delay BSF ADCON0,ADGO ;Start conversion BTFSC ADCON0,ADGO ;Is conversion done? GOTO $-1 ;No, test again BANKSEL ADRESH ; MOVF ADRESH,W ;Read upper 2 bits MOVWF RESULTHI ;store in GPR space BANKSEL ADRESL ; MOVF ADRESL,W ;Read lower 8 bits MOVWF RESULTLO ;Store in GPR space Note 1: The global interrupt can be disabled if the user is attempting to wake-up from Sleep and resume in-line code execution. 2: Refer to Section 16.4 “A/D Acquisition Requirements”. DS41391D-page 144  2011 Microchip Technology Inc. PIC16(L)F1826/27 16.3 ADC Register Definitions The following registers are used to control the operation of the ADC. REGISTER 16-1: U-0 ADCON0: A/D CONTROL REGISTER 0 R/W-0/0 R/W-0/0 — R/W-0/0 R/W-0/0 CHS R/W-0/0 R/W-0/0 R/W-0/0 GO/DONE ADON bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 Unimplemented: Read as ‘0’ bit 6-2 CHS: Analog Channel Select bits 00000 = AN0 00001 = AN1 00010 = AN2 00011 = AN3 00100 = AN4 00101 = AN5 00110 = AN6 00111 = AN7 01000 = AN8 01001 = AN9 01010 = AN10 01011 = AN11 01100 = Reserved. No channel connected. • • • 11101 = Temperature Indicator(3) 11110 = DAC output(1) 11111 = FVR (Fixed Voltage Reference) Buffer 1 Output(2) bit 1 GO/DONE: A/D Conversion Status bit 1 = A/D conversion cycle in progress. Setting this bit starts an A/D conversion cycle. This bit is automatically cleared by hardware when the A/D conversion has completed. 0 = A/D conversion completed/not in progress bit 0 ADON: ADC Enable bit 1 = ADC is enabled 0 = ADC is disabled and consumes no operating current Note 1: 2: 3: See Section 17.0 “Digital-to-Analog Converter (DAC) Module” for more information. See Section 14.0 “Fixed Voltage Reference (FVR)” for more information. See Section 15.0 “Temperature Indicator Module” for more information.  2011 Microchip Technology Inc. DS41391D-page 145 PIC16(L)F1826/27 REGISTER 16-2: R/W-0/0 ADCON1: A/D CONTROL REGISTER 1 R/W-0/0 ADFM R/W-0/0 R/W-0/0 ADCS U-0 R/W-0/0 — ADNREF R/W-0/0 R/W-0/0 ADPREF bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 ADFM: A/D Result Format Select bit 1 = Right justified. Six Most Significant bits of ADRESH are set to ‘0’ when the conversion result is loaded. 0 = Left justified. Six Least Significant bits of ADRESL are set to ‘0’ when the conversion result is loaded. bit 6-4 ADCS: A/D Conversion Clock Select bits 000 = FOSC/2 001 = FOSC/8 010 = FOSC/32 011 = FRC (clock supplied from a dedicated RC oscillator) 100 = FOSC/4 101 = FOSC/16 110 = FOSC/64 111 = FRC (clock supplied from a dedicated RC oscillator) bit 3 Unimplemented: Read as ‘0’ bit 2 ADNREF: A/D Negative Voltage Reference Configuration bit 0 = VREF- is connected to VSS 1 = VREF- is connected to external VREF- pin(1) bit 1-0 ADPREF: A/D Positive Voltage Reference Configuration bits 00 = VREF+ is connected to VDD 01 = Reserved 10 = VREF+ is connected to external VREF+ pin(1) 11 = VREF+ is connected to internal Fixed Voltage Reference (FVR) module(1) Note 1: When selecting the FVR or the VREF+ pin as the source of the positive reference, be aware that a minimum voltage specification exists. See Section 30.0 “Electrical Specifications” for details. DS41391D-page 146  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 16-3: R/W-x/u ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 0 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u ADRES bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 ADRES: ADC Result Register bits Upper 8 bits of 10-bit conversion result REGISTER 16-4: R/W-x/u ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 0 R/W-x/u ADRES R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u — — — — — — bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 ADRES: ADC Result Register bits Lower 2 bits of 10-bit conversion result bit 5-0 Reserved: Do not use.  2011 Microchip Technology Inc. DS41391D-page 147 PIC16(L)F1826/27 REGISTER 16-5: ADRESH: ADC RESULT REGISTER HIGH (ADRESH) ADFM = 1 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u — — — — — — R/W-x/u R/W-x/u ADRES bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-2 Reserved: Do not use. bit 1-0 ADRES: ADC Result Register bits Upper 2 bits of 10-bit conversion result REGISTER 16-6: R/W-x/u ADRESL: ADC RESULT REGISTER LOW (ADRESL) ADFM = 1 R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u R/W-x/u ADRES bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-0 ADRES: ADC Result Register bits Lower 8 bits of 10-bit conversion result DS41391D-page 148  2011 Microchip Technology Inc. PIC16(L)F1826/27 16.4 A/D Acquisition Requirements For the ADC to meet its specified accuracy, the charge holding capacitor (CHOLD) must be allowed to fully charge to the input channel voltage level. The Analog Input model is shown in Figure 16-4. The source impedance (RS) and the internal sampling switch (RSS) impedance directly affect the time required to charge the capacitor CHOLD. The sampling switch (RSS) impedance varies over the device voltage (VDD), refer to Figure 16-4. The maximum recommended impedance for analog sources is 10 k. As the EQUATION 16-1: Assumptions: source impedance is decreased, the acquisition time may be decreased. After the analog input channel is selected (or changed), an A/D acquisition must be done before the conversion can be started. To calculate the minimum acquisition time, Equation 16-1 may be used. This equation assumes that 1/2 LSb error is used (1,024 steps for the ADC). The 1/2 LSb error is the maximum error allowed for the ADC to meet its specified resolution. ACQUISITION TIME EXAMPLE Temperature = 50°C and external impedance of 10k  5.0V V DD T ACQ = Amplifier Settling Time + Hold Capacitor Charging Time + Temperature Coefficient = T AMP + T C + T COFF = 2µs + T C +   Temperature - 25°C   0.05µs/°C   The value for TC can be approximated with the following equations: 1  = V CHOLD V AP P LI ED  1 – -------------------------n+1   2 –1 ;[1] VCHOLD charged to within 1/2 lsb –TC ----------  RC V AP P LI ED  1 – e  = V CHOLD   ;[2] VCHOLD charge response to VAPPLIED – Tc ---------  1 RC  ;combining [1] and [2] V AP P LI ED  1 – e  = V A PP LIE D  1 – -------------------------n+1    2 –1 Note: Where n = number of bits of the ADC. Solving for TC: T C = – C HOLD  R IC + R SS + R S  ln(1/511) = – 10pF  1k  + 7k  + 10k   ln(0.001957) = 1.12 µs Therefore: T A CQ = 2µs + 1.12µs +   50°C- 25°C   0.05 µs/°C   = 4.42µs Note 1: The reference voltage (VREF) has no effect on the equation, since it cancels itself out. 2: The charge holding capacitor (CHOLD) is not discharged after each conversion. 3: The maximum recommended impedance for analog sources is 10 k. This is required to meet the pin leakage specification.  2011 Microchip Technology Inc. DS41391D-page 149 PIC16(L)F1826/27 FIGURE 16-4: ANALOG INPUT MODEL VDD Analog Input pin Rs VT  0.6V CPIN 5 pF VA RIC  1k Sampling Switch SS Rss I LEAKAGE(1) VT  0.6V CHOLD = 10 pF VSS/VREF- 6V 5V VDD 4V 3V 2V = Sample/Hold Capacitance = Input Capacitance Legend: CHOLD CPIN RSS I LEAKAGE = Leakage current at the pin due to various junctions = Interconnect Resistance RIC = Resistance of Sampling Switch RSS SS = Sampling Switch VT = Threshold Voltage Note 1: FIGURE 16-5: 5 6 7 8 9 10 11 Sampling Switch (k) Refer to Section 30.0 “Electrical Specifications”. ADC TRANSFER FUNCTION Full-Scale Range 3FFh 3FEh ADC Output Code 3FDh 3FCh 3FBh 03h 02h 01h 00h Analog Input Voltage 0.5 LSB VREF- DS41391D-page 150 Zero-Scale Transition 1.5 LSB Full-Scale Transition VREF+  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 16-3: Name SUMMARY OF REGISTERS ASSOCIATED WITH ADC Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page ADCON0 — CHS4 CHS3 CHS2 CHS1 CHS0 GO/DONE ADON 145 ADCON1 ADFM ADCS2 ADCS1 ADCS0 — ADNREF ADPREF1 ADPREF0 146 ADRESH A/D Result Register High 147, 148 ADRESL A/D Result Register Low 147, 148 ANSELA — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 123 ANSELB ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — 123 PxM1 PxM0 DCxB1 DCxB0 CCPxM3 CCPxM2 CCPxM1 CCPxM0 226 GIE PEIE TMR0IE INTE IOCE TMR0IF INTF IOCF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 91 TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 123 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 123 FVRCON FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 136 DACCON0 DACEN DACLPS DACOE — DACPSS1 DACPSS0 — DACNSS 156 — — — DACR4 DACR3 DACR2 DACR1 DACR0 156 CCPxCON INTCON DACCON1 Legend: — = unimplemented read as ‘0’. Shaded cells are not used for ADC module.  2011 Microchip Technology Inc. DS41391D-page 151 PIC16(L)F1826/27 NOTES: DS41391D-page 152  2011 Microchip Technology Inc. PIC16(L)F1826/27 17.0 DIGITAL-TO-ANALOG CONVERTER (DAC) MODULE The Digital-to-Analog Converter supplies a variable voltage reference, ratiometric with the input source, with 32 selectable output levels. The input of the DAC can be connected to: 17.1 Output Voltage Selection The DAC has 32 voltage level ranges. The 32 levels are set with the DACR bits of the DACCON1 register. The DAC output voltage is determined by the equations in Equation 17-1. • External VREF pins • VDD supply voltage • FVR (Fixed Voltage Reference) The output of the DAC can be configured to supply a reference voltage to the following: • • • • Comparator positive input ADC input channel DACOUT pin Capacitive Sensing module (CSM) The Digital-to-Analog Converter (DAC) can be enabled by setting the DACEN bit of the DACCON0 register. EQUATION 17-1: DAC OUTPUT VOLTAGE IF DACEN = 1 DACR  4:0  VOUT =   VSOURCE+ – VSOURCE-   ----------------------------+ VSOURCE5   2 IF DACEN = 0 and DACLPS = 1 and DACR[4:0] = 11111 V OUT = V SOURCE + IF DACEN = 0 and DACLPS = 0 and DACR[4:0] = 00000 V OUT = V SOURCE – VSOURCE+ = VDD, VREF, or FVR BUFFER 2 VSOURCE- = VSS 17.2 Ratiometric Output Level The DAC output value is derived using a resistor ladder with each end of the ladder tied to a positive and negative voltage reference input source. If the voltage of either input source fluctuates, a similar fluctuation will result in the DAC output value. The value of the individual resistors within the ladder can be found in Section 29.0 “Electrical Specifications”. 17.3 DAC Voltage Reference Output The DAC can be output to the DACOUT pin by setting the DACOE bit of the DACCON0 register to ‘1’. Selecting the DAC reference voltage for output on the DACOUT pin automatically overrides the digital output buffer and digital input threshold detector functions of that pin. Reading the DACOUT pin when it has been configured for DAC reference voltage output will always return a ‘0’. Due to the limited current drive capability, a buffer must be used on the DAC voltage reference output for external connections to DACOUT. Figure 17-2 shows an example buffering technique.  2011 Microchip Technology Inc. DS41391D-page 153 PIC16(L)F1826/27 FIGURE 17-1: DIGITAL-TO-ANALOG CONVERTER BLOCK DIAGRAM Digital-to-Analog Converter (DAC) FVR BUFFER2 VSOURCE+ VDD VREF+ R R 2 R DACEN DACLPS R R 32 Steps R 32-to-1 MUX DACPSS DACR 5 DAC (To Comparator and ADC Modules) R DACOUT R DACOE DACNSS VREF- VSOURCE- VSS FIGURE 17-2: VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE PIC® MCU DAC Module R Voltage Reference Output Impedance DS41391D-page 154 DACOUT + – Buffered DAC Output  2011 Microchip Technology Inc. PIC16(L)F1826/27 17.4 Low-Power Voltage State In order for the DAC module to consume the least amount of power, one of the two voltage reference input sources to the resistor ladder must be disconnected. Either the positive voltage source, (VSOURCE+), or the negative voltage source, (VSOURCE-) can be disabled. The negative voltage source is disabled by setting the DACLPS bit in the DACCON0 register. Clearing the DACLPS bit in the DACCON0 register disables the positive voltage source. 17.4.1 OUTPUT CLAMPED TO POSITIVE VOLTAGE SOURCE The DAC output voltage can be set to VSOURCE+ with the least amount of power consumption by performing the following: • Clearing the DACEN bit in the DACCON0 register. • Setting the DACLPS bit in the DACCON0 register. • Configuring the DACPSS bits to the proper positive source. • Configuring the DACR bits to ‘11111’ in the DACCON1 register. FIGURE 17-3: This is also the method used to output the voltage level from the FVR to an output pin. See Section 17.5 “Operation During Sleep” for more information. Reference Figure 17-3 for output clamping examples. 17.4.2 OUTPUT CLAMPED TO NEGATIVE VOLTAGE SOURCE The DAC output voltage can be set to VSOURCE- with the least amount of power consumption by performing the following: • Clearing the DACEN bit in the DACCON0 register. • Clearing the DACLPS bit in the DACCON0 register. • Configuring the DACNSS bits to the proper negative source. • Configuring the DACR bits to ‘00000’ in the DACCON1 register. This allows the comparator to detect a zero-crossing while not consuming additional current through the DAC module. Reference Figure 17-3 for output clamping examples. OUTPUT VOLTAGE CLAMPING EXAMPLES Output Clamped to Positive Voltage Source VSOURCE+ Output Clamped to Negative Voltage Source VSOURCE+ R R DACR = 11111 R DACEN = 0 DACLPS = 1 R DAC Voltage Ladder (see Figure 17-1) DACEN = 0 DACLPS = 0 R VSOURCE- 17.5 DAC Voltage Ladder (see Figure 17-1) R DACR = 00000 VSOURCE- Operation During Sleep When the device wakes up from Sleep through an interrupt or a Watchdog Timer time-out, the contents of the DACCON0 register are not affected. To minimize current consumption in Sleep mode, the voltage reference should be disabled. 17.6 Effects of a Reset A device Reset affects the following: • DAC is disabled. • DAC output voltage is removed from the DACOUT pin. • The DACR range select bits are cleared.  2011 Microchip Technology Inc. DS41391D-page 155 PIC16(L)F1826/27 17.7 DAC Control Registers REGISTER 17-1: DACCON0: VOLTAGE REFERENCE CONTROL REGISTER 0 R/W-0/0 R/W-0/0 R/W-0/0 U-0 DACEN DACLPS DACOE — R/W-0/0 R/W-0/0 DACPSS U-0 R/W-0/0 — DACNSS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 DACEN: DAC Enable bit 1 = DAC is enabled 0 = DAC is disabled bit 6 DACLPS: DAC Low-Power Voltage State Select bit 1 = DAC Positive reference source selected 0 = DAC Negative reference source selected bit 5 DACOE: DAC Voltage Output Enable bit 1 = DAC voltage level is also an output on the DACOUT pin 0 = DAC voltage level is disconnected from the DACOUT pin bit 4 Unimplemented: Read as ‘0’ bit 3-2 DACPSS: DAC Positive Source Select bits 00 = VDD 01 = VREF+ pin 10 = FVR Buffer2 output 11 = Reserved, do not use bit 1 Unimplemented: Read as ‘0’ bit 0 DACNSS: DAC Negative Source Select bits 1 = VREF0 = VSS REGISTER 17-2: DACCON1: VOLTAGE REFERENCE CONTROL REGISTER 1 U-0 U-0 U-0 — — — R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 DACR bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-5 Unimplemented: Read as ‘0’ bit 4-0 DACR: DAC Voltage Output Select bits TABLE 17-1: Name SUMMARY OF REGISTERS ASSOCIATED WITH THE DAC MODULE Bit 7 Bit 6 Bit 5 Bit 4 FVRCON FVREN FVRRDY Reserved DACCON0 DACEN DACLPS DACOE DACCON1 — — — Legend: Bit 0 Register on page ADFVR1 ADFVR0 138 — DACNSS 156 DACR1 DACR0 156 Bit 3 Bit 2 Bit 1 Reserved CDAFVR1 CDAFVR0 — DACPSS1 DACPSS0 DACR4 DACR3 DACR2 — = unimplemented, read as ‘0’. Shaded cells are unused with the DAC module. DS41391D-page 156  2011 Microchip Technology Inc. PIC16(L)F1826/27 18.0 SR LATCH The module consists of a single SR Latch with multiple Set and Reset inputs as well as separate latch outputs. The SR Latch module includes the following features: • • • • Programmable input selection SR Latch output is available externally Separate Q and Q outputs Firmware Set and Reset The SR Latch can be used in a variety of analog applications, including oscillator circuits, one-shot circuit, hysteretic controllers, and analog timing applications. 18.1 Latch Operation 18.2 Latch Output The SRQEN and SRNQEN bits of the SRCON0 register control the Q and Q latch outputs. Both of the SR Latch outputs may be directly output to an I/O pin at the same time. The applicable TRIS bit of the corresponding port must be cleared to enable the port pin output driver. 18.3 Effects of a Reset Upon any device Reset, the SR Latch output is not initialized to a known state. The user’s firmware is responsible for initializing the latch output before enabling the output pins. The latch is a Set-Reset Latch that does not depend on a clock source. Each of the Set and Reset inputs are active-high. The latch can be Set or Reset by: • • • • • Software control (SRPS and SRPR bits) Comparator C1 output (SYNCC1OUT) Comparator C2 output (SYNCC2OUT) SRI pin Programmable clock (SRCLK) The SRPS and the SRPR bits of the SRCON0 register may be used to set or reset the SR Latch, respectively. The latch is Reset-dominant. Therefore, if both Set and Reset inputs are high, the latch will go to the Reset state. Both the SRPS and SRPR bits are self resetting which means that a single write to either of the bits is all that is necessary to complete a latch Set or Reset operation. The output from Comparator C1 or C2 can be used as the Set or Reset inputs of the SR Latch. The output of either comparator can be synchronized to the Timer1 clock source. See Section 19.0 “Comparator Module” and Section 21.0 “Timer1 Module with Gate Control” for more information. An external source on the SRI pin can be used as the Set or Reset inputs of the SR Latch. An internal clock source is available that can periodically set or reset the SR Latch. The SRCLK bits in the SRCON0 register are used to select the clock source period. The SRSCKE and SRRCKE bits of the SRCON1 register enable the clock source to set or reset the SR Latch, respectively. Note: Enabling both the Set and Reset inputs from any one source at the same time may result in indeterminate operation, as the Reset dominance cannot be assured.  2011 Microchip Technology Inc. DS41391D-page 157 PIC16(L)F1826/27 FIGURE 18-1: SR LATCH SIMPLIFIED BLOCK DIAGRAM SRPS Pulse Gen(2) SRLEN SRQEN SRI S SRSPE SRCLK Q SRQ SRSCKE SYNCC2OUT(3) SRSC2E SYNCC1OUT(3) SRSC1E SRPR SR Latch(1) Pulse Gen(2) SRI SRRPE SRCLK SRRCKE SYNCC2OUT(3) SRRC2E R Q SRNQ SRLEN SRNQEN SYNCC1OUT(3) SRRC1E Note 1: 2: 3: DS41391D-page 158 If R = 1 and S = 1 simultaneously, Q = 0, Q = 1 Pulse generator causes a 1 Q-state pulse width. Name denotes the connection point at the comparator output.  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 18-1: SRCLK FREQUENCY TABLE SRCLK Divider FOSC = 32 MHz FOSC = 20 MHz FOSC = 16 MHz FOSC = 4 MHz FOSC = 1 MHz 111 512 110 256 62.5 kHz 39.0 kHz 31.3 kHz 7.81 kHz 1.95 kHz 125 kHz 78.1 kHz 62.5 kHz 15.6 kHz 3.90 kHz 101 100 128 250 kHz 156 kHz 125 kHz 31.25 kHz 7.81 kHz 64 500 kHz 313 kHz 250 kHz 62.5 kHz 15.6 kHz 011 32 1 MHz 625 kHz 500 kHz 125 kHz 31.3 kHz 010 16 2 MHz 1.25 MHz 1 MHz 250 kHz 62.5 kHz 001 8 4 MHz 2.5 MHz 2 MHz 500 kHz 125 kHz 000 4 8 MHz 5 MHz 4 MHz 1 MHz 250 kHz REGISTER 18-1: R/W-0/0 SRCON0: SR LATCH CONTROL 0 REGISTER R/W-0/0 SRLEN R/W-0/0 R/W-0/0 SRCLK R/W-0/0 R/W-0/0 R/S-0/0 R/S-0/0 SRQEN SRNQEN SRPS SRPR bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared S = Bit is set only bit 7 SRLEN: SR Latch Enable bit 1 = SR Latch is enabled 0 = SR Latch is disabled bit 6-4 SRCLK: SR Latch Clock Divider bits 000 = Generates a 1 FOSC wide pulse every 4th FOSC cycle clock 001 = Generates a 1 FOSC wide pulse every 8th FOSC cycle clock 010 = Generates a 1 FOSC wide pulse every 16th FOSC cycle clock 011 = Generates a 1 FOSC wide pulse every 32nd FOSC cycle clock 100 = Generates a 1 FOSC wide pulse every 64th FOSC cycle clock 101 = Generates a 1 FOSC wide pulse every 128th FOSC cycle clock 110 = Generates a 1 FOSC wide pulse every 256th FOSC cycle clock 111 = Generates a 1 FOSC wide pulse every 512th FOSC cycle clock bit 3 SRQEN: SR Latch Q Output Enable bit If SRLEN = 1: 1 = Q is present on the SRQ pin 0 = External Q output is disabled If SRLEN = 0: SR Latch is disabled bit 2 SRNQEN: SR Latch Q Output Enable bit If SRLEN = 1: 1 = Q is present on the SRnQ pin 0 = External Q output is disabled If SRLEN = 0: SR Latch is disabled bit 1 SRPS: Pulse Set Input of the SR Latch bit(1) 1 = Pulse set input for 1 Q-clock period 0 = No effect on set input. bit 0 SRPR: Pulse Reset Input of the SR Latch bit(1) 1 = Pulse reset input for 1 Q-clock period 0 = No effect on reset input. Note 1: Set only, always reads back ‘0’.  2011 Microchip Technology Inc. DS41391D-page 159 PIC16(L)F1826/27 REGISTER 18-2: SRCON1: SR LATCH CONTROL 1 REGISTER R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 SRSPE SRSCKE SRSC2E SRSC1E SRRPE SRRCKE SRRC2E SRRC1E bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 SRSPE: SR Latch Peripheral Set Enable bit 1 = SR Latch is set when the SRI pin is high. 0 = SRI pin has no effect on the set input of the SR Latch bit 6 SRSCKE: SR Latch Set Clock Enable bit 1 = Set input of SR Latch is pulsed with SRCLK 0 = SRCLK has no effect on the set input of the SR Latch bit 5 SRSC2E: SR Latch C2 Set Enable bit 1 = SR Latch is set when the C2 Comparator output is high 0 = C2 Comparator output has no effect on the set input of the SR Latch bit 4 SRSC1E: SR Latch C1 Set Enable bit 1 = SR Latch is set when the C1 Comparator output is high 0 = C1 Comparator output has no effect on the set input of the SR Latch bit 3 SRRPE: SR Latch Peripheral Reset Enable bit 1 = SR Latch is reset when the SRI pin is high. 0 = SRI pin has no effect on the reset input of the SR Latch bit 2 SRRCKE: SR Latch Reset Clock Enable bit 1 = Reset input of SR Latch is pulsed with SRCLK 0 = SRCLK has no effect on the reset input of the SR Latch bit 1 SRRC2E: SR Latch C2 Reset Enable bit 1 = SR Latch is reset when the C2 Comparator output is high 0 = C2 Comparator output has no effect on the reset input of the SR Latch bit 0 SRRC1E: SR Latch C1 Reset Enable bit 1 = SR Latch is reset when the C1 Comparator output is high 0 = C1 Comparator output has no effect on the reset input of the SR Latch DS41391D-page 160  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 18-2: Name ANSELA SUMMARY OF REGISTERS ASSOCIATED WITH SR LATCH MODULE Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 123 SRPS SRCON0 SRLEN SRCLK2 SRCLK1 SRCLK0 SRQEN SRNQEN SRCON1 SRSPE SRSCKE SRSC2E SRSC1E SRRPE SRRCKE SRRC2E TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 SRPR 159 SRRC1E 160 TRISA0 122 Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the SR latch module.  2011 Microchip Technology Inc. DS41391D-page 161 PIC16(L)F1826/27 NOTES: DS41391D-page 162  2011 Microchip Technology Inc. PIC16(L)F1826/27 19.0 COMPARATOR MODULE Comparators are used to interface analog circuits to a digital circuit by comparing two analog voltages and providing a digital indication of their relative magnitudes. Comparators are very useful mixed signal building blocks because they provide analog functionality independent of program execution. The analog comparator module includes the following features: • • • • • • • • • Independent comparator control Programmable input selection Comparator output is available internally/externally Programmable output polarity Interrupt-on-change Wake-up from Sleep Programmable Speed/Power optimization PWM shutdown Programmable and fixed voltage reference 19.1 Comparator Overview FIGURE 19-1: SINGLE COMPARATOR VIN+ + VIN- – Output VINVIN+ Output Note: The black areas of the output of the comparator represents the uncertainty due to input offsets and response time. A single comparator is shown in Figure 19-1 along with the relationship between the analog input levels and the digital output. When the analog voltage at VIN+ is less than the analog voltage at VIN-, the output of the comparator is a digital low level. When the analog voltage at VIN+ is greater than the analog voltage at VIN-, the output of the comparator is a digital high level.  2011 Microchip Technology Inc. DS41391D-page 163 PIC16(L)F1826/27 FIGURE 19-2: COMPARATOR 1 MODULE SIMPLIFIED BLOCK DIAGRAM CxNCH CxON(1) 2 CxINTP Interrupt det C12IN0- 0 C12IN1C12IN2- 1 MUX 2 (2) C12IN3- 3 Set CxIF det CXPOL CxVN D Cx(3) CxVP 0 MUX 1 (2) C1IN+ DAC FVR Buffer2 2 C12IN+ 3 CxINTN Interrupt CXOUT MCXOUT Q To Data Bus + EN Q1 CxHYS CxSP To ECCP PWM Logic CXSYNC CxON CXPCH 0 CXOE TRIS bit CXOUT 2 D (from Timer1) T1CLK Q 1 To Timer1 or SR Latch SYNCCXOUT Note 1: 2: 3: When CxON = 0, the Comparator will produce a ‘0’ at the output When CxON = 0, all multiplexer inputs are disconnected. Output of comparator can be frozen during debugging. DS41391D-page 164  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 19-3: COMPARATOR 2 MODULE SIMPLIFIED BLOCK DIAGRAM CxNCH CxON(1) 2 CxINTP Interrupt det C12IN0- 0 C12IN1- 1 MUX 2 (2) C12IN2C12IN3- 3 Set CxIF det CXPOL CxVN D Cx(3) CxVP C12IN+ DAC CxINTN Interrupt 0 MUX 1 (2) CXOUT MCXOUT Q To Data Bus + EN Q1 CxHYS CxSP To ECCP PWM Logic 2 FVR Buffer2 3 CXSYNC CxON VSS CXPCH 0 CXOE TRIS bit CXOUT 2 D (from Timer1) T1CLK Note 1: 2: 3: Q 1 To Timer1 or SR Latch SYNCCXOUT When CxON = 0, the Comparator will produce a ‘0’ at the output When CxON = 0, all multiplexer inputs are disconnected. Output of comparator can be frozen during debugging.  2011 Microchip Technology Inc. DS41391D-page 165 PIC16(L)F1826/27 19.2 Comparator Control Each comparator has 2 control registers: CMxCON0 and CMxCON1. The CMxCON0 registers (see Register 19-1) contain Control and Status bits for the following: • • • • • • Enable Output selection Output polarity Speed/Power selection Hysteresis enable Output synchronization The CMxCON1 registers (see Register 19-2) contain Control bits for the following: • • • • Interrupt enable Interrupt edge polarity Positive input channel selection Negative input channel selection 19.2.1 COMPARATOR ENABLE Setting the CxON bit of the CMxCON0 register enables the comparator for operation. Clearing the CxON bit disables the comparator resulting in minimum current consumption. 19.2.2 COMPARATOR OUTPUT SELECTION 19.2.3 COMPARATOR OUTPUT POLARITY Inverting the output of the comparator is functionally equivalent to swapping the comparator inputs. The polarity of the comparator output can be inverted by setting the CxPOL bit of the CMxCON0 register. Clearing the CxPOL bit results in a non-inverted output. Table 19-1 shows the output state versus input conditions, including polarity control. TABLE 19-1: COMPARATOR OUTPUT STATE VS. INPUT CONDITIONS Input Condition CxPOL CxOUT CxVN > CxVP 0 0 CxVN < CxVP 0 1 CxVN > CxVP 1 1 CxVN < CxVP 1 0 19.2.4 COMPARATOR SPEED/POWER SELECTION The trade-off between speed or power can be optimized during program execution with the CxSP control bit. The default state for this bit is ‘1’ which selects the normal speed mode. Device power consumption can be optimized at the cost of slower comparator propagation delay by clearing the CxSP bit to ‘0’. The output of the comparator can be monitored by reading either the CxOUT bit of the CMxCON0 register or the MCxOUT bit of the CMOUT register. In order to make the output available for an external connection, the following conditions must be true: • CxOE bit of the CMxCON0 register must be set • Corresponding TRIS bit must be cleared • CxON bit of the CMxCON0 register must be set Note 1: The CxOE bit of the CMxCON0 register overrides the PORT data latch. Setting the CxON bit of the CMxCON0 register has no impact on the port override. 2: The internal output of the comparator is latched with each instruction cycle. Unless otherwise specified, external outputs are not latched. DS41391D-page 166  2011 Microchip Technology Inc. PIC16(L)F1826/27 19.3 Comparator Hysteresis A selectable amount of separation voltage can be added to the input pins of each comparator to provide a hysteresis function to the overall operation. Hysteresis is enabled by setting the CxHYS bit of the CMxCON0 register. 19.5 Comparator Interrupt An interrupt can be generated upon a change in the output value of the comparator for each comparator, a rising edge detector and a Falling edge detector are present. See Section 29.0 “Electrical Specifications” for more information. When either edge detector is triggered and its associated enable bit is set (CxINTP and/or CxINTN bits of the CMxCON1 register), the Corresponding Interrupt Flag bit (CxIF bit of the PIR2 register) will be set. 19.4 To enable the interrupt, you must set the following bits: Timer1 Gate Operation The output resulting from a comparator operation can be used as a source for gate control of Timer1. See Section 21.6 “Timer1 Gate” for more information. This feature is useful for timing the duration or interval of an analog event. It is recommended that the comparator output be synchronized to Timer1. This ensures that Timer1 does not increment while a change in the comparator is occurring. 19.4.1 COMPARATOR OUTPUT SYNCHRONIZATION The output from either comparator, C1 or C2, can be synchronized with Timer1 by setting the CxSYNC bit of the CMxCON0 register. Once enabled, the comparator output is latched on the falling edge of the Timer1 source clock. If a prescaler is used with Timer1, the comparator output is latched after the prescaling function. To prevent a race condition, the comparator output is latched on the falling edge of the Timer1 clock source and Timer1 increments on the rising edge of its clock source. See the Comparator Block Diagrams (Figure 19-2 and Figure 19-3) and the Timer1 Block Diagram (Figure 21-1) for more information. • CxON, CxPOL and CxSP bits of the CMxCON0 register • CxIE bit of the PIE2 register • CxINTP bit of the CMxCON1 register (for a rising edge detection) • CxINTN bit of the CMxCON1 register (for a falling edge detection) • PEIE and GIE bits of the INTCON register The associated interrupt flag bit, CxIF bit of the PIR2 register, must be cleared in software. If another edge is detected while this flag is being cleared, the flag will still be set at the end of the sequence. Note: 19.6 Although a comparator is disabled, an interrupt can be generated by changing the output polarity with the CxPOL bit of the CMxCON0 register, or by switching the comparator on or off with the CxON bit of the CMxCON0 register. Comparator Positive Input Selection Configuring the CxPCH bits of the CMxCON1 register directs an internal voltage reference or an analog pin to the non-inverting input of the comparator: • • • • C1IN+ or C2IN+ analog pin DAC FVR (Fixed Voltage Reference) VSS (Ground) See Section 14.0 “Fixed Voltage Reference (FVR)” for more information on the Fixed Voltage Reference module. See Section 17.0 “Digital-to-Analog Converter (DAC) Module” for more information on the DAC input signal. Any time the comparator is disabled (CxON = 0), all comparator inputs are disabled.  2011 Microchip Technology Inc. DS41391D-page 167 PIC16(L)F1826/27 19.7 Comparator Negative Input Selection The CxNCH bits of the CMxCON0 register direct one of four analog pins to the comparator inverting input. Note: 19.8 To use CxIN+ and CxINx- pins as analog input, the appropriate bits must be set in the ANSEL register and the corresponding TRIS bits must also be set to disable the output drivers. Comparator Response Time The comparator output is indeterminate for a period of time after the change of an input source or the selection of a new reference voltage. This period is referred to as the response time. The response time of the comparator differs from the settling time of the voltage reference. Therefore, both of these times must be considered when determining the total response time to a comparator input change. See the Comparator and Voltage Reference Specifications in Section 29.0 “Electrical Specifications” for more details. 19.9 Interaction with ECCP Logic 19.10 Analog Input Connection Considerations A simplified circuit for an analog input is shown in Figure 19-4. Since the analog input pins share their connection with a digital input, they have reverse biased ESD protection diodes to VDD and VSS. The analog input, therefore, must be between VSS and VDD. If the input voltage deviates from this range by more than 0.6V in either direction, one of the diodes is forward biased and a latch-up may occur. A maximum source impedance of 10 k is recommended for the analog sources. Also, any external component connected to an analog input pin, such as a capacitor or a Zener diode, should have very little leakage current to minimize inaccuracies introduced. Note 1: When reading a PORT register, all pins configured as analog inputs will read as a ‘0’. Pins configured as digital inputs will convert as an analog input, according to the input specification. 2: Analog levels on any pin defined as a digital input, may cause the input buffer to consume more current than is specified. The C1 and C2 comparators can be used as general purpose comparators. Their outputs can be brought out to the C1OUT and C2OUT pins. When the ECCP Auto-Shutdown is active it can use one or both comparator signals. If auto-restart is also enabled, the comparators can be configured as a closed loop analog feedback to the ECCP, thereby, creating an analog controlled PWM. Note: When the comparator module is first initialized the output state is unknown. Upon initialization, the user should verify the output state of the comparator prior to relying on the result, primarily when using the result in connection with other peripheral features, such as the ECCP Auto-Shutdown mode. DS41391D-page 168  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 19-4: ANALOG INPUT MODEL VDD Rs < 10K Analog Input pin VT  0.6V RIC To Comparator CPIN 5 pF VA VT  0.6V ILEAKAGE(1) Vss Legend: CPIN = Input Capacitance ILEAKAGE = Leakage Current at the pin due to various junctions = Interconnect Resistance RIC = Source Impedance RS VA = Analog Voltage = Threshold Voltage VT Note 1: See Section 29.0 “Electrical Specifications”  2011 Microchip Technology Inc. DS41391D-page 169 PIC16(L)F1826/27 REGISTER 19-1: CMxCON0: COMPARATOR Cx CONTROL REGISTER 0 R/W-0/0 R-0/0 R/W-0/0 R/W-0/0 U-0 R/W-1/1 R/W-0/0 R/W-0/0 CxON CxOUT CxOE CxPOL — CxSP CxHYS CxSYNC bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 CxON: Comparator Enable bit 1 = Comparator is enabled and consumes no active power 0 = Comparator is disabled bit 6 CxOUT: Comparator Output bit If CxPOL = 1 (inverted polarity): 1 = CxVP < CxVN 0 = CxVP > CxVN If CxPOL = 0 (non-inverted polarity): 1 = CxVP > CxVN 0 = CxVP < CxVN bit 5 CxOE: Comparator Output Enable bit 1 = CxOUT is present on the CxOUT pin. Requires that the associated TRIS bit be cleared to actually drive the pin. Not affected by CxON. 0 = CxOUT is internal only bit 4 CxPOL: Comparator Output Polarity Select bit 1 = Comparator output is inverted 0 = Comparator output is not inverted bit 3 Unimplemented: Read as ‘0’ bit 2 CxSP: Comparator Speed/Power Select bit 1 = Comparator operates in normal power, higher speed mode 0 = Comparator operates in low-power, low-speed mode bit 1 CxHYS: Comparator Hysteresis Enable bit 1 = Comparator hysteresis enabled 0 = Comparator hysteresis disabled bit 0 CxSYNC: Comparator Output Synchronous Mode bit 1 = Comparator output to Timer1 and I/O pin is synchronous to changes on Timer1 clock source. Output updated on the falling edge of Timer1 clock source. 0 = Comparator output to Timer1 and I/O pin is asynchronous. DS41391D-page 170  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 19-2: CMxCON1: COMPARATOR Cx CONTROL REGISTER 1 R/W-0/0 R/W-0/0 CxINTP CxINTN R/W-0/0 R/W-0/0 CxPCH U-0 U-0 — — R/W-0/0 R/W-0/0 CxNCH bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 CxINTP: Comparator Interrupt on Positive Going Edge Enable bits 1 = The CxIF interrupt flag will be set upon a positive going edge of the CxOUT bit 0 = No interrupt flag will be set on a positive going edge of the CxOUT bit bit 6 CxINTN: Comparator Interrupt on Negative Going Edge Enable bits 1 = The CxIF interrupt flag will be set upon a negative going edge of the CxOUT bit 0 = No interrupt flag will be set on a negative going edge of the CxOUT bit bit 5-4 CxPCH: Comparator Positive Input Channel Select bits 00 = CxVP connects to CxIN+ pin 01 = CxVP connects to DAC Voltage Reference 10 = CxVP connects to FVR Voltage Reference For C1: 11 = CxVP connects to C12IN+ pin For C2: 11 = CxVP connects to VSS bit 3-2 Unimplemented: Read as ‘0’ bit 1-0 CxNCH: Comparator Negative Input Channel Select bits 00 = CxVN connects to C12IN0- pin 01 = CxVN connects to C12IN1- pin 10 = CxVN connects to C12IN2- pin 11 = CxVN connects to C12IN3- pin REGISTER 19-3: CMOUT: COMPARATOR OUTPUT REGISTER U-0 U-0 U-0 U-0 U-0 U-0 R-0/0 R-0/0 — — — — — — MC2OUT MC1OUT bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-2 Unimplemented: Read as ‘0’ bit 1 MC2OUT: Mirror Copy of C2OUT bit bit 0 MC1OUT: Mirror Copy of C1OUT bit  2011 Microchip Technology Inc. DS41391D-page 171 PIC16(L)F1826/27 TABLE 19-2: Name ANSELA SUMMARY OF REGISTERS ASSOCIATED WITH COMPARATOR MODULE Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 123 CMxCON0 CxON CxOUT CxOE CxPOL — CxSP CxHYS CxSYNC 170 CMxCON1 CxNTP CxINTN CxPCH1 CxPCH0 — — CxNCH1 CxNCH0 171 CMOUT DACCON0 — — — — — — MC2OUT MC1OUT 171 DACEN DACLPS DACOE — DACPSS1 DACPSS0 — DACNSS 156 — — — DACR4 DACR3 DACR2 DACR1 DACR0 156 FVRCON FVREN FVRRDY Reserved Reserved CDAFVR1 CDAFVR0 ADFVR1 ADFVR0 136 INTCON GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 DACCON1 LATA LATA7 LATA6 — LATA4 LATA3 LATA2 LATA1 LATA0 122 PIE2 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(1) 88 PIR2 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF(1) 92 RA7 RA6 RA5 RA4 RA3 RA2 RA1 RA0 122 TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 PORTA TRISA Legend: Note 1: — = unimplemented, read as ‘0’. Shaded cells are unused by the comparator module. PIC16(L)F1827 only. DS41391D-page 172  2011 Microchip Technology Inc. PIC16(L)F1826/27 20.0 20.1.2 TIMER0 MODULE In 8-Bit Counter mode, the Timer0 module will increment on every rising or falling edge of the T0CKI pin or the Capacitive Sensing Oscillator (CPSCLK) signal. The Timer0 module is an 8-bit timer/counter with the following features: • • • • • • 8-bit timer/counter register (TMR0) 8-bit prescaler (independent of Watchdog Timer) Programmable internal or external clock source Programmable external clock edge selection Interrupt on overflow TMR0 can be used to gate Timer1 8-Bit Counter mode using the T0CKI pin is selected by setting the TMR0CS bit in the OPTION_REG register to ‘1’ and resetting the T0XCS bit in the CPSCON0 register to ‘0’. 8-Bit Counter mode using the Capacitive Sensing Oscillator (CPSCLK) signal is selected by setting the TMR0CS bit in the OPTION_REG register to ‘1’ and setting the T0XCS bit in the CPSCON0 register to ‘1’. Figure 20-1 is a block diagram of the Timer0 module. 20.1 The rising or falling transition of the incrementing edge for either input source is determined by the TMR0SE bit in the OPTION_REG register. Timer0 Operation The Timer0 module can be used as either an 8-bit timer or an 8-bit counter. 20.1.1 8-BIT COUNTER MODE 8-BIT TIMER MODE The Timer0 module will increment every instruction cycle, if used without a prescaler. 8-Bit Timer mode is selected by clearing the TMR0CS bit of the OPTION_REG register. When TMR0 is written, the increment is inhibited for two instruction cycles immediately following the write. Note: The value written to the TMR0 register can be adjusted, in order to account for the two instruction cycle delay when TMR0 is written. FIGURE 20-1: BLOCK DIAGRAM OF THE TIMER0 FOSC/4 Data Bus 0 8 T0CKI 1 0 From CPSCLK Sync 2 TCY 1 TMR0 0 1 TMR0SE TMR0CS 8-bit Prescaler PSA T0XCS Set Flag bit TMR0IF on Overflow Overflow to Timer1 8 PS  2011 Microchip Technology Inc. DS41391D-page 173 PIC16(L)F1826/27 FIGURE 20-2: BLOCK DIAGRAM OF THE TIMER0 FOSC/4 Data Bus 0 8 T0CKI 1 Sync 2 TCY 1 TMR0 0 TMR0SE TMR0CS 8-bit Prescaler PSA Set Flag bit TMR0IF on Overflow Overflow to Timer1 8 PS DS41391D-page 174  2011 Microchip Technology Inc. PIC16(L)F1826/27 20.1.3 SOFTWARE PROGRAMMABLE PRESCALER A software programmable prescaler is available for exclusive use with Timer0. The prescaler is enabled by clearing the PSA bit of the OPTION_REG register. Note: The Watchdog Timer (WDT) uses its own independent prescaler. There are 8 prescaler options for the Timer0 module ranging from 1:2 to 1:256. The prescale values are selectable via the PS bits of the OPTION_REG register. In order to have a 1:1 prescaler value for the Timer0 module, the prescaler must be disabled by setting the PSA bit of the OPTION_REG register. The prescaler is not readable or writable. All instructions writing to the TMR0 register will clear the prescaler. 20.1.4 TIMER0 INTERRUPT Timer0 will generate an interrupt when the TMR0 register overflows from FFh to 00h. The TMR0IF interrupt flag bit of the INTCON register is set every time the TMR0 register overflows, regardless of whether or not the Timer0 interrupt is enabled. The TMR0IF bit can only be cleared in software. The Timer0 interrupt enable is the TMR0IE bit of the INTCON register. Note: 20.1.5 The Timer0 interrupt cannot wake the processor from Sleep since the timer is frozen during Sleep. 8-BIT COUNTER MODE SYNCHRONIZATION When in 8-Bit Counter mode, the incrementing edge on the T0CKI pin must be synchronized to the instruction clock. Synchronization can be accomplished by sampling the prescaler output on the Q2 and Q4 cycles of the instruction clock. The high and low periods of the external clocking source must meet the timing requirements as shown in Section 29.0 “Electrical Specifications”. 20.1.6 OPERATION DURING SLEEP Timer0 cannot operate while the processor is in Sleep mode. The contents of the TMR0 register will remain unchanged while the processor is in Sleep mode.  2011 Microchip Technology Inc. DS41391D-page 175 PIC16(L)F1826/27 20.2 Option and Timer0 Control Register REGISTER 20-1: OPTION_REG: OPTION REGISTER R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 WPUEN INTEDG TMR0CS TMR0SE PSA R/W-1/1 R/W-1/1 R/W-1/1 PS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 WPUEN: Weak Pull-up Enable bit 1 = All weak pull-ups are disabled (except MCLR, if it is enabled) 0 = Weak pull-ups are enabled by individual WPUx latch values bit 6 INTEDG: Interrupt Edge Select bit 1 = Interrupt on rising edge of INT pin 0 = Interrupt on falling edge of INT pin bit 5 TMR0CS: Timer0 Clock Source Select bit 1 = Transition on T0CKI pin 0 = Internal instruction cycle clock (FOSC/4) bit 4 TMR0SE: Timer0 Source Edge Select bit 1 = Increment on high-to-low transition on T0CKI pin 0 = Increment on low-to-high transition on T0CKI pin bit 3 PSA: Prescaler Assignment bit 1 = Prescaler is not assigned to the Timer0 module 0 = Prescaler is assigned to the Timer0 module bit 2-0 PS: Prescaler Rate Select bits TABLE 20-1: Name CPSCON0 000 001 010 011 100 101 110 111 1:2 1:4 1:8 1 : 16 1 : 32 1 : 64 1 : 128 1 : 256 Bit 7 Bit 6 Bit 5 Bit 4 CPSON — — — GIE PEIE TMR0IE INTE OPTION_REG WPUEN TMR0 Timer0 Rate SUMMARY OF REGISTERS ASSOCIATED WITH TIMER0 INTCON TRISA Bit Value INTEDG TMR0CS TMR0SE Bit 3 Bit 2 Bit 1 CPSRNG1 CPSRNG0 CPSOUT Bit 0 Register on Page T0XCS 318 IOCIE TMR0IF INTF IOCIF 86 PSA PS2 PS1 PS0 177 TRISA3 TRISA2 TRISA1 TRISA0 Timer0 Module Register TRISA7 TRISA6 TRISA5 173* TRISA4 122 Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by the Timer0 module. * Page provides register information. DS41391D-page 176  2011 Microchip Technology Inc. PIC16(L)F1826/27 21.0 • • • • TIMER1 MODULE WITH GATE CONTROL The Timer1 module is a 16-bit timer/counter with the following features: Figure 21-1 is a block diagram of the Timer1 module. • • • • • • • • 16-bit timer/counter register pair (TMR1H:TMR1L) Programmable internal or external clock source 2-bit prescaler Dedicated 32 kHz oscillator circuit Optionally synchronized comparator out Multiple Timer1 gate (count enable) sources Interrupt on overflow Wake-up on overflow (external clock, Asynchronous mode only) • Time base for the Capture/Compare function • Special Event Trigger (with CCP/ECCP) • Selectable Gate Source Polarity FIGURE 21-1: Gate Toggle mode Gate Single-pulse mode Gate Value Status Gate Event Interrupt TIMER1 BLOCK DIAGRAM T1GSS T1G T1GSPM 00 From Timer0 Overflow 01 Comparator 1 SYNCC1OUT 10 Comparator 2 SYNCC2OUT 11 0 T1G_IN T1GVAL 0 Single Pulse TMR1ON T1GPOL D Q CK R Q 1 Acq. Control 1 Q1 Data Bus D Q RD T1GCON EN Interrupt T1GGO/DONE Set TMR1GIF det T1GTM TMR1GE Set flag bit TMR1IF on Overflow TMR1ON To Comparator Module TMR1(2) TMR1H EN TMR1L Q D T1CLK Synchronized clock input 0 1 TMR1CS T1OSO OUT T1OSC T1OSI Cap. Sensing Oscillator T1SYNC 11 1 Synchronize(3) Prescaler 1, 2, 4, 8 det 10 EN 0 T1OSCEN (1) FOSC Internal Clock 01 FOSC/4 Internal Clock 00 2 T1CKPS FOSC/2 Internal Clock Sleep input T1CKI To Clock Switching Modules Note 1: ST Buffer is high speed type when using T1CKI. 2: Timer1 register increments on rising edge. 3: Synchronize does not operate while in Sleep.  2011 Microchip Technology Inc. DS41391D-page 177 PIC16(L)F1826/27 21.1 Timer1 Operation 21.2 The Timer1 module is a 16-bit incrementing counter which is accessed through the TMR1H:TMR1L register pair. Writes to TMR1H or TMR1L directly update the counter. The TMR1CS and T1OSCEN bits of the T1CON register are used to select the clock source for Timer1. Table 21-2 displays the clock source selections. 21.2.1 When used with an internal clock source, the module is a timer and increments on every instruction cycle. When used with an external clock source, the module can be used as either a timer or counter and increments on every selected edge of the external source. INTERNAL CLOCK SOURCE When the internal clock source is selected the TMR1H:TMR1L register pair will increment on multiples of FOSC as determined by the Timer1 prescaler. When the FOSC internal clock source is selected, the Timer1 register value will increment by four counts every instruction clock cycle. Due to this condition, a 2 LSB error in resolution will occur when reading the Timer1 value. To utilize the full resolution of Timer1, an asynchronous input signal must be used to gate the Timer1 clock input. Timer1 is enabled by configuring the TMR1ON and TMR1GE bits in the T1CON and T1GCON registers, respectively. Table 21-1 displays the Timer1 enable selections. TABLE 21-1: Clock Source Selection TIMER1 ENABLE SELECTIONS The following asynchronous sources may be used: • Asynchronous event on the T1G pin to Timer1 gate • C1 or C2 comparator input to Timer1 gate Timer1 Operation TMR1ON TMR1GE 0 0 Off 0 1 Off 21.2.2 1 0 Always On 1 1 Count Enabled When the external clock source is selected, the Timer1 module may work as a timer or a counter. EXTERNAL CLOCK SOURCE When enabled to count, Timer1 is incremented on the rising edge of the external clock input T1CKI or the capacitive sensing oscillator signal. Either of these external clock sources can be synchronized to the microcontroller system clock or they can run asynchronously. When used as a timer with a clock oscillator, an external 32.768 kHz crystal can be used in conjunction with the dedicated internal oscillator circuit. Note: In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge after any one or more of the following conditions: • • • • TABLE 21-2: Timer1 enabled after POR Write to TMR1H or TMR1L Timer1 is disabled Timer1 is disabled (TMR1ON = 0) when T1CKI is high then Timer1 is enabled (TMR1ON=1) when T1CKI is low. CLOCK SOURCE SELECTIONS TMR1CS1 TMR1CS0 T1OSCEN 0 0 x 0 1 x System Clock (FOSC) 1 0 0 External Clocking on T1CKI Pin 1 0 0 External Clocking on T1CKI Pin 1 1 x Capacitive Sensing Oscillator DS41391D-page 178 Clock Source Instruction Clock (FOSC/4)  2011 Microchip Technology Inc. PIC16(L)F1826/27 21.3 Timer1 Prescaler Timer1 has four prescaler options allowing 1, 2, 4 or 8 divisions of the clock input. The T1CKPS bits of the T1CON register control the prescale counter. The prescale counter is not directly readable or writable; however, the prescaler counter is cleared upon a write to TMR1H or TMR1L. 21.4 Timer1 Oscillator 21.5.1 READING AND WRITING TIMER1 IN ASYNCHRONOUS COUNTER MODE Reading TMR1H or TMR1L while the timer is running from an external asynchronous clock will ensure a valid read (taken care of in hardware). However, the user should keep in mind that reading the 16-bit timer in two 8-bit values itself, poses certain problems, since the timer may overflow between the reads. A dedicated low-power 32.768 kHz oscillator circuit is built-in between pins T1OSI (input) and T1OSO (amplifier output). This internal circuit is to be used in conjunction with an external 32.768 kHz crystal. For writes, it is recommended that the user simply stop the timer and write the desired values. A write contention may occur by writing to the timer registers, while the register is incrementing. This may produce an unpredictable value in the TMR1H:TMR1L register pair. The oscillator circuit is enabled by setting the T1OSCEN bit of the T1CON register. The oscillator will continue to run during Sleep. 21.6 Note: 21.5 The oscillator requires a start-up and stabilization time before use. Thus, T1OSCEN should be set and a suitable delay observed prior to using Timer1. A suitable delay similar to the OST delay can be implemented in software by clearing the TMR1IF bit then presetting the TMR1H:TMR1L register pair to FC00h. The TMR1IF flag will be set when 1024 clock cycles have elapsed, thereby indicating that the oscillator is running and reasonably stable. Timer1 Operation in Asynchronous Counter Mode If control bit T1SYNC of the T1CON register is set, the external clock input is not synchronized. The timer increments asynchronously to the internal phase clocks. If the external clock source is selected then the timer will continue to run during Sleep and can generate an interrupt on overflow, which will wake-up the processor. However, special precautions in software are needed to read/write the timer (see Section 21.5.1 “Reading and Writing Timer1 in Asynchronous Counter Mode”). Note: When switching from synchronous to asynchronous operation, it is possible to skip an increment. When switching from asynchronous to synchronous operation, it is possible to produce an additional increment.  2011 Microchip Technology Inc. Timer1 Gate Timer1 can be configured to count freely or the count can be enabled and disabled using Timer1 gate circuitry. This is also referred to as Timer1 gate enable. Timer1 gate can also be driven by multiple selectable sources. 21.6.1 TIMER1 GATE ENABLE The Timer1 Gate Enable mode is enabled by setting the TMR1GE bit of the T1GCON register. The polarity of the Timer1 Gate Enable mode is configured using the T1GPOL bit of the T1GCON register. When Timer1 Gate Enable mode is enabled, Timer1 will increment on the rising edge of the Timer1 clock source. When Timer1 Gate Enable mode is disabled, no incrementing will occur and Timer1 will hold the current count. See Figure 21-3 for timing details. TABLE 21-3: TIMER1 GATE ENABLE SELECTIONS T1CLK T1GPOL T1G Timer1 Operation  0 0 Counts  0 1 Holds Count  1 0 Holds Count  1 1 Counts DS41391D-page 179 PIC16(L)F1826/27 21.6.2 TIMER1 GATE SOURCE SELECTION The Timer1 gate source can be selected from one of four different sources. Source selection is controlled by the T1GSS bits of the T1GCON register. The polarity for each available source is also selectable. Polarity selection is controlled by the T1GPOL bit of the T1GCON register. TABLE 21-4: TIMER1 GATE SOURCES T1GSS Timer1 Gate Source 00 Timer1 Gate Pin 01 Overflow of Timer0 (TMR0 increments from FFh to 00h) 10 Comparator 1 Output SYNCC1OUT (optionally Timer1 synchronized output) 11 Comparator 2 Output SYNCC2OUT (optionally Timer1 synchronized output) 21.6.2.1 T1G Pin Gate Operation The T1G pin is one source for Timer1 gate control. It can be used to supply an external source to the Timer1 gate circuitry. 21.6.2.2 Timer0 Overflow Gate Operation When Timer0 increments from FFh to 00h, a low-to-high pulse will automatically be generated and internally supplied to the Timer1 gate circuitry. 21.6.2.3 Comparator C1 Gate Operation The output resulting from a Comparator 1 operation can be selected as a source for Timer1 gate control. The Comparator 1 output (SYNCC1OUT) can be synchronized to the Timer1 clock or left asynchronous. For more information see Section 19.4.1 “Comparator Output Synchronization”. 21.6.2.4 Comparator C2 Gate Operation The output resulting from a Comparator 2 operation can be selected as a source for Timer1 gate control. The Comparator 2 output (SYNCC2OUT) can be synchronized to the Timer1 clock or left asynchronous. For more information see Section 19.4.1 “Comparator Output Synchronization”. 21.6.3 TIMER1 GATE TOGGLE MODE When Timer1 Gate Toggle mode is enabled, it is possible to measure the full-cycle length of a Timer1 gate signal, as opposed to the duration of a single level pulse. The Timer1 gate source is routed through a flip-flop that changes state on every incrementing edge of the signal. See Figure 21-4 for timing details. Timer1 Gate Toggle mode is enabled by setting the T1GTM bit of the T1GCON register. When the T1GTM bit is cleared, the flip-flop is cleared and held clear. This is necessary in order to control which edge is measured. Note: 21.6.4 Enabling Toggle mode at the same time as changing the gate polarity may result in indeterminate operation. TIMER1 GATE SINGLE-PULSE MODE When Timer1 Gate Single-Pulse mode is enabled, it is possible to capture a single pulse gate event. Timer1 Gate Single-Pulse mode is first enabled by setting the T1GSPM bit in the T1GCON register. Next, the T1GGO/DONE bit in the T1GCON register must be set. The Timer1 will be fully enabled on the next incrementing edge. On the next trailing edge of the pulse, the T1GGO/DONE bit will automatically be cleared. No other gate events will be allowed to increment Timer1 until the T1GGO/DONE bit is once again set in software. See Figure 21-5 for timing details. If the Single Pulse Gate mode is disabled by clearing the T1GSPM bit in the T1GCON register, the T1GGO/DONE bit should also be cleared. Enabling the Toggle mode and the Single-Pulse mode simultaneously will permit both sections to work together. This allows the cycle times on the Timer1 gate source to be measured. See Figure 21-6 for timing details. 21.6.5 TIMER1 GATE VALUE STATUS When Timer1 Gate Value Status is utilized, it is possible to read the most current level of the gate control value. The value is stored in the T1GVAL bit in the T1GCON register. The T1GVAL bit is valid even when the Timer1 gate is not enabled (TMR1GE bit is cleared). 21.6.6 TIMER1 GATE EVENT INTERRUPT When Timer1 Gate Event Interrupt is enabled, it is possible to generate an interrupt upon the completion of a gate event. When the falling edge of T1GVAL occurs, the TMR1GIF flag bit in the PIR1 register will be set. If the TMR1GIE bit in the PIE1 register is set, then an interrupt will be recognized. The TMR1GIF flag bit operates even when the Timer1 gate is not enabled (TMR1GE bit is cleared). DS41391D-page 180  2011 Microchip Technology Inc. PIC16(L)F1826/27 21.7 Timer1 Interrupt The Timer1 register pair (TMR1H:TMR1L) increments to FFFFh and rolls over to 0000h. When Timer1 rolls over, the Timer1 interrupt flag bit of the PIR1 register is set. To enable the interrupt on rollover, you must set these bits: • • • • TMR1ON bit of the T1CON register TMR1IE bit of the PIE1 register PEIE bit of the INTCON register GIE bit of the INTCON register The interrupt is cleared by clearing the TMR1IF bit in the Interrupt Service Routine. The TMR1H:TMR1L register pair and the TMR1IF bit should be cleared before enabling interrupts. Note: 21.8 Timer1 Operation During Sleep Timer1 can only operate during Sleep when setup in Asynchronous Counter mode. In this mode, an external crystal or clock source can be used to increment the counter. To set up the timer to wake the device: • • • • • TMR1ON bit of the T1CON register must be set TMR1IE bit of the PIE1 register must be set PEIE bit of the INTCON register must be set T1SYNC bit of the T1CON register must be set TMR1CS bits of the T1CON register must be configured • T1OSCEN bit of the T1CON register must be configured The device will wake-up on an overflow and execute the next instructions. If the GIE bit of the INTCON register is set, the device will call the Interrupt Service Routine. 21.9 ECCP/CCP Capture/Compare Time Base The CCP modules use the TMR1H:TMR1L register pair as the time base when operating in Capture or Compare mode. In Capture mode, the value in the TMR1H:TMR1L register pair is copied into the CCPR1H:CCPR1L register pair on a configured event. In Compare mode, an event is triggered when the value CCPR1H:CCPR1L register pair matches the value in the TMR1H:TMR1L register pair. This event can be a Special Event Trigger. For more information, see “Capture/Compare/PWM Modules”. Section 24.0 21.10 ECCP/CCP Special Event Trigger When any of the CCP’s are configured to trigger a special event, the trigger will clear the TMR1H:TMR1L register pair. This special event does not cause a Timer1 interrupt. The CCP module may still be configured to generate a CCP interrupt. In this mode of operation, the CCPR1H:CCPR1L register pair becomes the period register for Timer1. Timer1 should be synchronized and FOSC/4 should be selected as the clock source in order to utilize the Special Event Trigger. Asynchronous operation of Timer1 can cause a Special Event Trigger to be missed. In the event that a write to TMR1H or TMR1L coincides with a Special Event Trigger from the CCP, the write will take precedence. For more information, see Section 16.2.5 “Special Event Trigger”. Timer1 oscillator will continue to operate in Sleep regardless of the T1SYNC bit setting. FIGURE 21-2: TIMER1 INCREMENTING EDGE T1CKI = 1 when TMR1 Enabled T1CKI = 0 when TMR1 Enabled Note 1: 2: Arrows indicate counter increments. In Counter mode, a falling edge must be registered by the counter prior to the first incrementing rising edge of the clock.  2011 Microchip Technology Inc. DS41391D-page 181 PIC16(L)F1826/27 FIGURE 21-3: TIMER1 GATE ENABLE MODE TMR1GE T1GPOL T1G_IN T1CKI T1GVAL Timer1 N FIGURE 21-4: N+1 N+2 N+3 N+4 TIMER1 GATE TOGGLE MODE TMR1GE T1GPOL T1GTM T1G_IN T1CKI T1GVAL Timer1 DS41391D-page 182 N N+1 N+2 N+3 N+4 N+5 N+6 N+7 N+8  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 21-5: TIMER1 GATE SINGLE-PULSE MODE TMR1GE T1GPOL T1GSPM T1GGO/ Cleared by hardware on falling edge of T1GVAL Set by software DONE Counting enabled on rising edge of T1G T1G_IN T1CKI T1GVAL Timer1 TMR1GIF N Cleared by software  2011 Microchip Technology Inc. N+1 N+2 Set by hardware on falling edge of T1GVAL Cleared by software DS41391D-page 183 PIC16(L)F1826/27 FIGURE 21-6: TIMER1 GATE SINGLE-PULSE AND TOGGLE COMBINED MODE TMR1GE T1GPOL T1GSPM T1GTM T1GGO/ Cleared by hardware on falling edge of T1GVAL Set by software DONE Counting enabled on rising edge of T1G T1G_IN T1CKI T1GVAL Timer1 TMR1GIF DS41391D-page 184 N Cleared by software N+1 N+2 N+3 N+4 Set by hardware on falling edge of T1GVAL Cleared by software  2011 Microchip Technology Inc. PIC16(L)F1826/27 21.11 Timer1 Control Register The Timer1 Control register (T1CON), shown in Register 21-1, is used to control Timer1 and select the various features of the Timer1 module. REGISTER 21-1: R/W-0/u T1CON: TIMER1 CONTROL REGISTER R/W-0/u R/W-0/u TMR1CS R/W-0/u T1CKPS R/W-0/u R/W-0/u U-0 R/W-0/u T1OSCEN T1SYNC — TMR1ON bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 TMR1CS: Timer1 Clock Source Select bits 11 = Timer1 clock source is Capacitive Sensing Oscillator (CAPOSC) 10 = Timer1 clock source is pin or oscillator: If T1OSCEN = 0: External clock from T1CKI pin (on the rising edge) If T1OSCEN = 1: Crystal oscillator on T1OSI/T1OSO pins 01 = Timer1 clock source is system clock (FOSC) 00 = Timer1 clock source is instruction clock (FOSC/4) bit 5-4 T1CKPS: Timer1 Input Clock Prescale Select bits 11 = 1:8 Prescale value 10 = 1:4 Prescale value 01 = 1:2 Prescale value 00 = 1:1 Prescale value bit 3 T1OSCEN: LP Oscillator Enable Control bit 1 = Dedicated Timer1 oscillator circuit enabled 0 = Dedicated Timer1 oscillator circuit disabled bit 2 T1SYNC: Timer1 External Clock Input Synchronization Control bit TMR1CS = 1X: 1 = Do not synchronize external clock input 0 = Synchronize external clock input with system clock (FOSC) TMR1CS = 0X: This bit is ignored. bit 1 Unimplemented: Read as ‘0’ bit 0 TMR1ON: Timer1 On bit 1 = Enables Timer1 0 = Stops Timer1 Clears Timer1 gate flip-flop  2011 Microchip Technology Inc. DS41391D-page 185 PIC16(L)F1826/27 21.12 Timer1 Gate Control Register The Timer1 Gate Control register (T1GCON), shown in Register 21-2, is used to control Timer1 gate. REGISTER 21-2: T1GCON: TIMER1 GATE CONTROL REGISTER R/W-0/u R/W-0/u R/W-0/u R/W-0/u R/W/HC-0/u R-x/x TMR1GE T1GPOL T1GTM T1GSPM T1GGO/ DONE T1GVAL R/W-0/u R/W-0/u T1GSS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared HC = Bit is cleared by hardware bit 7 TMR1GE: Timer1 Gate Enable bit If TMR1ON = 0: This bit is ignored If TMR1ON = 1: 1 = Timer1 counting is controlled by the Timer1 gate function 0 = Timer1 counts regardless of Timer1 gate function bit 6 T1GPOL: Timer1 Gate Polarity bit 1 = Timer1 gate is active-high (Timer1 counts when gate is high) 0 = Timer1 gate is active-low (Timer1 counts when gate is low) bit 5 T1GTM: Timer1 Gate Toggle Mode bit 1 = Timer1 Gate Toggle mode is enabled 0 = Timer1 Gate Toggle mode is disabled and toggle flip-flop is cleared Timer1 gate flip-flop toggles on every rising edge. bit 4 T1GSPM: Timer1 Gate Single-Pulse Mode bit 1 = Timer1 gate Single-Pulse mode is enabled and is controlling Timer1 gate 0 = Timer1 gate Single-Pulse mode is disabled bit 3 T1GGO/DONE: Timer1 Gate Single-Pulse Acquisition Status bit 1 = Timer1 gate single-pulse acquisition is ready, waiting for an edge 0 = Timer1 gate single-pulse acquisition has completed or has not been started bit 2 T1GVAL: Timer1 Gate Current State bit Indicates the current state of the Timer1 gate that could be provided to TMR1H:TMR1L. Unaffected by Timer1 Gate Enable (TMR1GE). bit 1-0 T1GSS: Timer1 Gate Source Select bits 00 = Timer1 gate pin 01 = Timer0 overflow output 10 = Comparator 1 optionally synchronized output (SYNCC1OUT) 11 = Comparator 2 optionally synchronized output (SYNCC2OUT) DS41391D-page 186  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 21-5: Name ANSELB CCP1CON SUMMARY OF REGISTERS ASSOCIATED WITH TIMER1 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — 128 PxM1 PxM0 DCxB1 DCxB0 CCPxM3 CCPxM2 CCPxM1 CCPxM0 226 86 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 91 RB7 RB6 RB5 RB4 RB3 RB2 RB1 RB0 127 INTCON PORTB TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 T1CON TMR1CS1 TMR1CS0 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC T1GCON TMR1GE T1GPOL T1GTM T1GSPM T1GGO/ DONE T1GVAL 177* 177* TRISB1 TRISB0 127 — TMR1ON 185 T1GSS1 T1GSS0 186 Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module. * Page provides register information.  2011 Microchip Technology Inc. DS41391D-page 187 PIC16(L)F1826/27 NOTES: DS41391D-page 188  2011 Microchip Technology Inc. PIC16(L)F1826/27 22.0 TIMER2/4/6 MODULES There are up to three identical Timer2-type modules available. To maintain pre-existing naming conventions, the Timers are called Timer2, Timer4 and Timer6 (also Timer2/4/6). Note: The ‘x’ variable used in this section is used to designate Timer2, Timer4, or Timer6. For example, TxCON references T2CON, T4CON, or T6CON. PRx references PR2, PR4, or PR6. The Timer2/4/6 modules incorporate the following features: • 8-bit Timer and Period registers (TMRx and PRx, respectively) • Readable and writable (both registers) • Software programmable prescaler (1:1, 1:4, 1:16, and 1:64) • Software programmable postscaler (1:1 to 1:16) • Interrupt on TMRx match with PRx, respectively • Optional use as the shift clock for the MSSPx modules (Timer2 only) See Figure 22-1 for a block diagram of Timer2/4/6. FIGURE 22-1: FOSC/4 TIMER2/4/6 BLOCK DIAGRAM Prescaler 1:1, 1:4, 1:16, 1:64 2 TMRx Comparator Reset EQ TMRx Output Postscaler 1:1 to 1:16 Sets Flag bit TMRxIF TxCKPS PRx 4 TxOUTPS  2011 Microchip Technology Inc. DS41391D-page 189 PIC16(L)F1826/27 22.1 Timer2/4/6 Operation The clock input to the Timer2/4/6 modules is the system instruction clock (FOSC/4). TMRx increments from 00h on each clock edge. A 4-bit counter/prescaler on the clock input allows direct input, divide-by-4 and divide-by-16 prescale options. These options are selected by the prescaler control bits, TxCKPS of the TxCON register. The value of TMRx is compared to that of the Period register, PRx, on each clock cycle. When the two values match, the comparator generates a match signal as the timer output. This signal also resets the value of TMRx to 00h on the next cycle and drives the output counter/postscaler (see Section 22.2 “Timer2/4/6 Interrupt”). 22.3 Timer2/4/6 Output The unscaled output of TMRx is available primarily to the CCP modules, where it is used as a time base for operations in PWM mode. Timer2 can be optionally used as the shift clock source for the MSSPx modules operating in SPI mode. Additional information is provided in Section 25.1 “Master SSPx (MSSPx) Module Overview” Timer2/4/6 Operation During Sleep The Timer2/4/6 timers cannot be operated while the processor is in Sleep mode. The contents of the TMRx and PRx registers will remain unchanged while the processor is in Sleep mode. The TMRx and PRx registers are both directly readable and writable. The TMRx register is cleared on any device Reset, whereas the PRx register initializes to FFh. Both the prescaler and postscaler counters are cleared on the following events: • • • • • • • • • a write to the TMRx register a write to the TxCON register Power-on Reset (POR) Brown-out Reset (BOR) MCLR Reset Watchdog Timer (WDT) Reset Stack Overflow Reset Stack Underflow Reset RESET Instruction Note: 22.2 TMRx is not cleared when TxCON is written. Timer2/4/6 Interrupt Timer2/4/6 can also generate an optional device interrupt. The Timer2/4/6 output signal (TMRx-to-PRx match) provides the input for the 4-bit counter/postscaler. This counter generates the TMRx match interrupt flag which is latched in TMRxIF of the PIRx register. The interrupt is enabled by setting the TMRx Match Interrupt Enable bit, TMRxIE of the PIEx register. A range of 16 postscale options (from 1:1 through 1:16 inclusive) can be selected with the postscaler control bits, TxOUTPS, of the TxCON register. DS41391D-page 190  2011 Microchip Technology Inc. PIC16(L)F1826/27 22.4 Timer2 Control Register REGISTER 22-1: U-0 TXCON: TIMER2/TIMER4/TIMER6 CONTROL REGISTER R/W-0/0 — R/W-0/0 R/W-0/0 R/W-0/0 TxOUTPS R/W-0/0 R/W-0/0 TMRxON bit 7 R/W-0/0 TxCKPS bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 Unimplemented: Read as ‘0’ bit 6-3 TxOUTPS: Timerx Output Postscaler Select bits 0000 = 1:1 Postscaler 0001 = 1:2 Postscaler 0010 = 1:3 Postscaler 0011 = 1:4 Postscaler 0100 = 1:5 Postscaler 0101 = 1:6 Postscaler 0110 = 1:7 Postscaler 0111 = 1:8 Postscaler 1000 = 1:9 Postscaler 1001 = 1:10 Postscaler 1010 = 1:11 Postscaler 1011 = 1:12 Postscaler 1100 = 1:13 Postscaler 1101 = 1:14 Postscaler 1110 = 1:15 Postscaler 1111 = 1:16 Postscaler bit 2 TMRxON: Timerx On bit 1 = Timerx is on 0 = Timerx is off bit 1-0 TxCKPS: Timer2-type Clock Prescale Select bits 00 = Prescaler is 1 01 = Prescaler is 4 10 = Prescaler is 16 11 = Prescaler is 64  2011 Microchip Technology Inc. DS41391D-page 191 PIC16(L)F1826/27 TABLE 22-1: SUMMARY OF REGISTERS ASSOCIATED WITH TIMER2/4/6 Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 91 PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 92 PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 96 PIE3(1) — — CCP4IE CCP3IE TMR6IE — TMR4IE — 94 PIR3(1) — — CCP4IF CCP3IF TMR6IF — TMR4IF — Name INTCON 98 PR2 Timer2 Module Period Register 189* PR4 Timer4 Module Period Register 189* PR6 Timer6 Module Period Register 189* T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 191 T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 191 T6CON — T6OUTPS3 T6OUTPS2 T6OUTPS1 T6OUTPS0 TMR6ON T6CKPS1 T6CKPS0 191 TMR2 Holding Register for the 8-bit TMR2 Time Base 189* TMR4 Holding Register for the 8-bit TMR4 Time Base(1) 189* TMR6 Holding Register for the 8-bit TMR6 Time Base(1) 189* Legend: * Note 1: — = unimplemented read as ‘0’. Shaded cells are not used for Timer2 module. Page provides register information. PIC16(L)F1827 only. DS41391D-page 192  2011 Microchip Technology Inc. PIC16(L)F1826/27 23.0 Using this method, the DSM can generate the following types of Key Modulation schemes: DATA SIGNAL MODULATOR The Data Signal Modulator (DSM) is a peripheral which allows the user to mix a data stream, also known as a modulator signal, with a carrier signal to produce a modulated output. • Frequency-Shift Keying (FSK) • Phase-Shift Keying (PSK) • On-Off Keying (OOK) Additionally, the following features are provided within the DSM module: Both the carrier and the modulator signals are supplied to the DSM module either internally, from the output of a peripheral, or externally through an input pin. • • • • • • • The modulated output signal is generated by performing a logical “AND” operation of both the carrier and modulator signals and then provided to the MDOUT pin. The carrier signal is comprised of two distinct and separate signals. A carrier high (CARH) signal and a carrier low (CARL) signal. During the time in which the modulator (MOD) signal is in a logic high state, the DSM mixes the carrier high signal with the modulator signal. When the modulator signal is in a logic low state, the DSM mixes the carrier low signal with the modulator signal. FIGURE 23-1: Carrier Synchronization Carrier Source Polarity Select Carrier Source Pin Disable Programmable Modulator Data Modulator Source Pin Disable Modulated Output Polarity Select Slew Rate Control Figure 23-1 shows a Simplified Block Diagram of the Data Signal Modulator peripheral. SIMPLIFIED BLOCK DIAGRAM OF THE DATA SIGNAL MODULATOR MDCH VSS MDCIN1 MDCIN2 CLKR CCP1 CCP2 CCP3 CCP4 Reserved No Channel Selected MDEN 0000 0001 0010 0011 0100 0101 CARH 0110 0111 1000 * * 1111 EN Data Signal Modulator MDCHPOL D SYNC MDMS MDBIT MDMIN CCP1 CCP2 CCP3 CCP4 Comparator C1 Comparator C2 MSSP1 SDO1 MSSP2 SDO2 EUSART Reserved No Channel Selected Q 0000 0001 0010 0011 0100 0101 0110 MOD 0111 1000 1001 1010 0011 * * 1111 1 0 MDCHSYNC MDOUT MDOPOL MDOE D SYNC MDCL VSS MDCIN1 MDCIN2 CLKR CCP1 CCP2 CCP3 CCP4 Reserved No Channel Selected Q 0000 0001 0010 0011 0100 0101 CARL 0110 0111 1000 * * 1111  2011 Microchip Technology Inc. 1 0 MDCLSYNC MDCLPOL DS41391D-page 193 PIC16(L)F1826/27 23.1 DSM Operation The DSM module can be enabled by setting the MDEN bit in the MDCON register. Clearing the MDEN bit in the MDCON register, disables the DSM module by automatically switching the carrier high and carrier low signals to the VSS signal source. The modulator signal source is also switched to the MDBIT in the MDCON register. This not only assures that the DSM module is inactive, but that it is also consuming the least amount of current. The values used to select the carrier high, carrier low, and modulator sources held by the Modulation Source, Modulation High Carrier, and Modulation Low Carrier control registers are not affected when the MDEN bit is cleared and the DSM module is disabled. The values inside these registers remain unchanged while the DSM is inactive. The sources for the carrier high, carrier low and modulator signals will once again be selected when the MDEN bit is set and the DSM module is again enabled and active. The modulated output signal can be disabled without shutting down the DSM module. The DSM module will remain active and continue to mix signals, but the output value will not be sent to the MDOUT pin. During the time that the output is disabled, the MDOUT pin will remain low. The modulated output can be disabled by clearing the MDOE bit in the MDCON register. 23.2 Modulator Signal Sources The modulator signal can be supplied from the following sources: • • • • • • • • • • • CCP1 Signal CCP2 Signal CCP3 Signal CCP4 Signal MSSP1 SDO1 Signal (SPI Mode Only) MSSP2 SDO2 Signal (SPI Mode Only) Comparator C1 Signal Comparator C2 Signal EUSART TX Signal External Signal on MDMIN1 pin MDBIT bit in the MDCON register 23.3 Carrier Signal Sources The carrier high signal and carrier low signal can be supplied from the following sources: • • • • • • • • CCP1 Signal CCP2 Signal CCP3 Signal CCP4 Signal Reference Clock Module Signal External Signal on MDCIN1 pin External Signal on MDCIN2 pin VSS The carrier high signal is selected by configuring the MDCH bits in the MDCARH register. The carrier low signal is selected by configuring the MDCL bits in the MDCARL register. 23.4 Carrier Synchronization During the time when the DSM switches between carrier high and carrier low signal sources, the carrier data in the modulated output signal can become truncated. To prevent this, the carrier signal can be synchronized to the modulator signal. When synchronization is enabled, the carrier pulse that is being mixed at the time of the transition is allowed to transition low before the DSM switches over to the next carrier source. Synchronization is enabled separately for the carrier high and carrier low signal sources. Synchronization for the carrier high signal can be enabled by setting the MDCHSYNC bit in the MDCARH register. Synchronization for the carrier low signal can be enabled by setting the MDCLSYNC bit in the MDCARL register. Figure 23-1 through Figure 23-5 show timing diagrams of using various synchronization methods. The modulator signal is selected by configuring the MDMS bits in the MDSRC register. DS41391D-page 194  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 23-2: ON OFF KEYING (OOK) SYNCHRONIZATION Carrier Low (CARL) Carrier High (CARH) Modulator (MOD) MDCHSYNC = 1 MDCLSYNC = 0 MDCHSYNC = 1 MDCLSYNC = 1 MDCHSYNC = 0 MDCLSYNC = 0 MDCHSYNC = 0 MDCLSYNC = 1 EXAMPLE 23-1: NO SYNCHRONIZATION (MDSHSYNC = 0, MDCLSYNC = 0) Carrier High (CARH) Carrier Low (CARL) Modulator (MOD) MDCHSYNC = 0 MDCLSYNC = 0 CARH Active Carrier State FIGURE 23-3: CARL CARH CARL CARRIER HIGH SYNCHRONIZATION (MDSHSYNC = 1, MDCLSYNC = 0) Carrier High (CARH) Carrier Low (CARL) Modulator (MOD) MDCHSYNC = 1 MDCLSYNC = 0 Active Carrier State CARH  2011 Microchip Technology Inc. both CARL CARH both CARL DS41391D-page 195 PIC16(L)F1826/27 FIGURE 23-4: CARRIER LOW SYNCHRONIZATION (MDSHSYNC = 0, MDCLSYNC = 1) Carrier High (CARH) Carrier Low (CARL) Modulator (MOD) MDCHSYNC = 0 MDCLSYNC = 1 Active Carrier State FIGURE 23-5: CARH CARL CARH CARL FULL SYNCHRONIZATION (MDSHSYNC = 1, MDCLSYNC = 1) Carrier High (CARH) Carrier Low (CARL) Falling edges used to sync Modulator (MOD) MDCHSYNC = 1 MDCLSYNC = 1 Active Carrier State DS41391D-page 196 CARH CARL CARH CARL  2011 Microchip Technology Inc. PIC16(L)F1826/27 23.5 Carrier Source Polarity Select The signal provided from any selected input source for the carrier high and carrier low signals can be inverted. Inverting the signal for the carrier high source is enabled by setting the MDCHPOL bit of the MDCARH register. Inverting the signal for the carrier low source is enabled by setting the MDCLPOL bit of the MDCARL register. 23.6 Carrier Source Pin Disable Some peripherals assert control over their corresponding output pin when they are enabled. For example, when the CCP1 module is enabled, the output of CCP1 is connected to the CCP1 pin. 23.11 Operation in Sleep Mode The DSM module is not affected by Sleep mode. The DSM can still operate during Sleep, if the Carrier and Modulator input sources are also still operable during Sleep. 23.12 Effects of a Reset Upon any device Reset, the data signal modulator module is disabled. The user's firmware is responsible for initializing the module before enabling the output. The registers are reset to their default values. This default connection to a pin can be disabled by setting the MDCHODIS bit in the MDCARH register for the carrier high source and the MDCLODIS bit in the MDCARL register for the carrier low source. 23.7 Programmable Modulator Data The MDBIT of the MDCON register can be selected as the source for the modulator signal. This gives the user the ability to program the value used for modulation. 23.8 Modulator Source Pin Disable The modulator source default connection to a pin can be disabled by setting the MDMSODIS bit in the MDSRC register. 23.9 Modulated Output Polarity The modulated output signal provided on the MDOUT pin can also be inverted. Inverting the modulated output signal is enabled by setting the MDOPOL bit of the MDCON register. 23.10 Slew Rate Control The slew rate limitation on the output port pin can be disabled. The slew rate limitation can be removed by clearing the MDSLR bit in the MDCON register.  2011 Microchip Technology Inc. DS41391D-page 197 PIC16(L)F1826/27 REGISTER 23-1: MDCON: MODULATION CONTROL REGISTER R/W-0/0 R/W-0/0 R/W-1/1 R/W-0/0 R-0/0 U-0 U-0 R/W-0/0 MDEN MDOE MDSLR MDOPOL MDOUT — — MDBIT bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 MDEN: Modulator Module Enable bit 1 = Modulator module is enabled and mixing input signals 0 = Modulator module is disabled and has no output bit 6 MDOE: Modulator Module Pin Output Enable bit 1 = Modulator pin output enabled 0 = Modulator pin output disabled bit 5 MDSLR: MDOUT Pin Slew Rate Limiting bit 1 = MDOUT pin slew rate limiting enabled 0 = MDOUT pin slew rate limiting disabled bit 4 MDOPOL: Modulator Output Polarity Select bit 1 = Modulator output signal is inverted 0 = Modulator output signal is not inverted bit 3 MDOUT: Modulator Output bit Displays the current output value of the modulator module.(1) bit 2-1 Unimplemented: Read as ‘0’ bit 0 MDBIT: Allows software to manually set modulation source input to module(2) 1 = Modulator uses High Carrier source 0 = Modulator uses Low Carrier source Note 1: 2: The modulated output frequency can be greater and asynchronous from the clock that updates this register bit, the bit value may not be valid for higher speed modulator or carrier signals. MDBIT must be selected as the modulation source in the MDSRC register for this operation. DS41391D-page 198  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 23-2: MDSRC: MODULATION SOURCE CONTROL REGISTER R/W-x/u U-0 U-0 U-0 MDMSODIS — — — R/W-x/u R/W-x/u R/W-x/u R/W-x/u MDMS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 MDMSODIS: Modulation Source Output Disable bit 1 = Output signal driving the peripheral output pin (selected by MDMS) is disabled 0 = Output signal driving the peripheral output pin (selected by MDMS) is enabled bit 6-4 Unimplemented: Read as ‘0’ bit 3-0 MDMS Modulation Source Selection bits 1111 = Reserved. No channel connected. 1110 = Reserved. No channel connected. 1101 = Reserved. No channel connected. 1100 = Reserved. No channel connected. 1011 = Reserved. No channel connected. 1010 = EUSART TX output 1001 = MSSP2 SDOx output 1000 = MSSP1 SDOx output 0111 = Comparator2 output 0110 = Comparator1 output 0101 = CCP4 output (PWM Output mode only) 0100 = CCP3 output (PWM Output mode only) 0011 = CCP2 output (PWM Output mode only) 0010 = CCP1 output (PWM Output mode only) 0001 = MDMIN port pin 0000 = MDBIT bit of MDCON register is modulation source Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not synchronized.  2011 Microchip Technology Inc. DS41391D-page 199 PIC16(L)F1826/27 REGISTER 23-3: MDCARH: MODULATION HIGH CARRIER CONTROL REGISTER R/W-x/u R/W-x/u R/W-x/u U-0 MDCHODIS MDCHPOL MDCHSYNC — R/W-x/u R/W-x/u R/W-x/u R/W-x/u MDCH bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 MDCHODIS: Modulator High Carrier Output Disable bit 1 = Output signal driving the peripheral output pin (selected by MDCH) is disabled 0 = Output signal driving the peripheral output pin (selected by MDCH) is enabled bit 6 MDCHPOL: Modulator High Carrier Polarity Select bit 1 = Selected high carrier signal is inverted 0 = Selected high carrier signal is not inverted bit 5 MDCHSYNC: Modulator High Carrier Synchronization Enable bit 1 = Modulator waits for a falling edge on the high time carrier signal before allowing a switch to the low time carrier 0 = Modulator Output is not synchronized to the high time carrier signal(1) bit 4 Unimplemented: Read as ‘0’ bit 3-0 MDCH Modulator Data High Carrier Selection bits (1) 1111 = Reserved. No channel connected. • • • 1000 = Reserved. No channel connected. 0111 = CCP4 output (PWM Output mode only) 0110 = CCP3 output (PWM Output mode only) 0101 = CCP2 output (PWM Output mode only) 0100 = CCP1 output (PWM Output mode only) 0011 = Reference Clock module signal 0010 = MDCIN2 port pin 0001 = MDCIN1 port pin 0000 = VSS Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not synchronized. DS41391D-page 200  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 23-4: MDCARL: MODULATION LOW CARRIER CONTROL REGISTER R/W-x/u R/W-x/u R/W-x/u U-0 MDCLODIS MDCLPOL MDCLSYNC — R/W-x/u R/W-x/u R/W-x/u R/W-x/u MDCL bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 MDCLODIS: Modulator Low Carrier Output Disable bit 1 = Output signal driving the peripheral output pin (selected by MDCL of the MDCARL register) is disabled 0 = Output signal driving the peripheral output pin (selected by MDCL of the MDCARL register) is enabled bit 6 MDCLPOL: Modulator Low Carrier Polarity Select bit 1 = Selected low carrier signal is inverted 0 = Selected low carrier signal is not inverted bit 5 MDCLSYNC: Modulator Low Carrier Synchronization Enable bit 1 = Modulator waits for a falling edge on the low time carrier signal before allowing a switch to the high time carrier 0 = Modulator Output is not synchronized to the low time carrier signal(1) bit 4 Unimplemented: Read as ‘0’ bit 3-0 MDCL Modulator Data High Carrier Selection bits (1) 1111 = Reserved. No channel connected. • • • 1000 = Reserved. No channel connected. 0111 = CCP4 output (PWM Output mode only) 0110 = CCP3 output (PWM Output mode only) 0101 = CCP2 output (PWM Output mode only) 0100 = CCP1 output (PWM Output mode only) 0011 = Reference Clock module signal 0010 = MDCIN2 port pin 0001 = MDCIN1 port pin 0000 = VSS Note 1: Narrowed carrier pulse widths or spurs may occur in the signal stream if the carrier is not synchronized. TABLE 23-1: Name SUMMARY OF REGISTERS ASSOCIATED WITH DATA SIGNAL MODULATOR MODE Bit 6 Bit 5 Bit 4 MDCARH MDCHODIS MDCHPOL MDCHSYNC — MDCH 200 MDCARL MDCLODIS MDCLPOL MDCLSYNC — MDCL 201 MDCON MDEN MDOE MDSLR MDOPOL MDSRC MDMSODIS Legend: — = unimplemented, read as ‘0’. Shaded cells are not used in the Data Signal Modulator mode. —  2011 Microchip Technology Inc. — — Bit 3 MDOUT Bit 2 — Bit 1 — Bit 0 Register on Page Bit 7 MDBIT MDMS 198 199 DS41391D-page 201 PIC16(L)F1826/27 NOTES: DS41391D-page 202  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.0 CAPTURE/COMPARE/PWM MODULES The Capture/Compare/PWM module is a peripheral which allows the user to time and control different events, and to generate Pulse-Width Modulation (PWM) signals. In Capture mode, the peripheral allows the timing of the duration of an event. The Compare mode allows the user to trigger an external event when a predetermined amount of time has expired. The PWM mode can generate Pulse-Width Modulated signals of varying frequency and duty cycle. Note 1: In devices with more than one CCP module, it is very important to pay close attention to the register names used. A number placed after the module acronym is used to distinguish between separate modules. For example, the CCP1CON and CCP2CON control the same operational aspects of two completely different CCP modules. 2: Throughout this section, generic references to a CCP module in any of its operating modes may be interpreted as being equally applicable to ECCP1, ECCP2, CCP3 and CCP4. Register names, module signals, I/O pins, and bit names may use the generic designator 'x' to indicate the use of a numeral to distinguish a particular module, when required. This family of devices contains two Enhanced Capture/Compare/PWM modules (ECCP1 and ECCP2) and two standard Capture/Compare/PWM modules (CCP3 and CCP4). The Capture and Compare functions are identical for all four CCP modules (ECCP1, ECCP2, CCP3 and CCP4). The only differences between CCP modules are in the Pulse-Width Modulation (PWM) function. The standard PWM function is identical in modules, CCP3 and CCP4. In CCP modules ECCP1 and ECCP2, the Enhanced PWM function has slight variations from one another. Full-Bridge ECCP modules have four available I/O pins while Half-Bridge ECCP modules only have two available I/O pins. See Table 24-1 for more information. TABLE 24-1: PWM RESOURCES Device Name ECCP1 ECCP2 CCP3 CCP4 PIC16(L)F1826 Enhanced PWM Full-Bridge Not Available Not Available Not Available PIC16(L)F1827 Enhanced PWM Full-Bridge Enhanced PWM Half-Bridge Standard PWM Standard PWM  2011 Microchip Technology Inc. DS41391D-page 203 PIC16(L)F1826/27 24.1 24.1.2 Capture Mode The Capture mode function described in this section is available and identical for CCP modules ECCP1, ECCP2, CCP3 and CCP4. Capture mode makes use of the 16-bit Timer1 resource. When an event occurs on the CCPx pin, the 16-bit CCPRxH:CCPRxL register pair captures and stores the 16-bit value of the TMR1H:TMR1L register pair, respectively. An event is defined as one of the following and is configured by the CCPxM bits of the CCPxCON register: • • • • Every falling edge Every rising edge Every 4th rising edge Every 16th rising edge When a capture is made, the Interrupt Request Flag bit CCPxIF of the PIRx register is set. The interrupt flag must be cleared in software. If another capture occurs before the value in the CCPRxH, CCPRxL register pair is read, the old captured value is overwritten by the new captured value. Figure 24-1 shows a simplified diagram of the Capture operation. 24.1.1 CCP PIN CONFIGURATION In Capture mode, the CCPx pin should be configured as an input by setting the associated TRIS control bit. Also, the CCPx pin function can be moved to alternative pins using the APFCON0 register. Refer to Section 12.1 “Alternate Pin Function” for more details. Note: If the CCPx pin is configured as an output, a write to the port can cause a capture condition. FIGURE 24-1: Prescaler  1, 4, 16 CAPTURE MODE OPERATION BLOCK DIAGRAM TIMER1 MODE RESOURCE Timer1 must be running in Timer mode or Synchronized Counter mode for the CCP module to use the capture feature. In Asynchronous Counter mode, the capture operation may not work. See Section 21.0 “Timer1 Module with Gate Control” for more information on configuring Timer1. 24.1.3 SOFTWARE INTERRUPT MODE When the Capture mode is changed, a false capture interrupt may be generated. The user should keep the CCPxIE interrupt enable bit of the PIEx register clear to avoid false interrupts. Additionally, the user should clear the CCPxIF interrupt flag bit of the PIRx register following any change in Operating mode. 24.1.4 CCP PRESCALER There are four prescaler settings specified by the CCPxM bits of the CCPxCON register. Whenever the CCP module is turned off, or the CCP module is not in Capture mode, the prescaler counter is cleared. Any Reset will clear the prescaler counter. Switching from one capture prescaler to another does not clear the prescaler and may generate a false interrupt. To avoid this unexpected operation, turn the module off by clearing the CCPxCON register before changing the prescaler. Equation 24-1 demonstrates the code to perform this function. EXAMPLE 24-1: CHANGING BETWEEN CAPTURE PRESCALERS BANKSEL CCPxCON CLRF MOVLW MOVWF ;Set Bank bits to point ;to CCPxCON CCPxCON ;Turn CCP module off NEW_CAPT_PS ;Load the W reg with ;the new prescaler ;move value and CCP ON CCPxCON ;Load CCPxCON with this ;value Set Flag bit CCPxIF (PIRx register) CCPx pin CCPRxH and Edge Detect CCPRxL Capture Enable TMR1H TMR1L CCPxM System Clock (FOSC) DS41391D-page 204  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.1.5 CAPTURE DURING SLEEP 24.1.6 Capture mode depends upon the Timer1 module for proper operation. There are two options for driving the Timer1 module in Capture mode. It can be driven by the instruction clock (FOSC/4), or by an external clock source. ALTERNATE PIN LOCATIONS This module incorporates I/O pins that can be moved to other locations with the use of the alternate pin function registers, APFCON0 and APFCON1. To determine which pins can be moved and what their default locations are upon a reset, see Section 12.1 “Alternate Pin Function” for more information. When Timer1 is clocked by FOSC/4, Timer1 will not increment during Sleep. When the device wakes from Sleep, Timer1 will continue from its previous state. Capture mode will operate during Sleep when Timer1 is clocked by an external clock source. TABLE 24-2: Name APFCON0 CCPxCON SUMMARY OF REGISTERS ASSOCIATED WITH CAPTURE Bit 7 Bit 6 RXDTSEL SDO1SEL PxM1(1) PxM0(1) Bit 5 Bit 4 Bit 3 SS1SEL P2BSEL(2) CCP2SEL(2) DCxB1 DCxB0 CCPxM3 CCPRxL Capture/Compare/PWM Register x Low Byte (LSB) CCPRxH Capture/Compare/PWM Register x High Byte (MSB) Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 CCPxM2 CCPxM1 CCPxM0 Bit 2 226 204* 204* CM1CON0 C1ON C1OUT C1OE C1POL — C1SP C1HYS C1SYNC 170 CM1CON1 C1INTP C1INTN C1PCH1 C1PCH0 — — C1NCH1 C1NCH0 171 CM2CON0 C2ON C2OUT C2OE C2POL — C2SP C2HYS C2SYNC 170 CM2CON1 C2INTP C2INTN C2PCH1 C2PCH0 — — C2NCH1 C2NCH0 171 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 PIE2 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(2) 88 — — CCP4IE CCP3IE TMR6IE — TMR4IE — 89 PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 91 PIR2 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF(2) 92 — — CCP4IF CCP3IF TMR6IF — TMR4IF — 93 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC — TMR1ON 185 T1GTM T1GSPM T1GGO/DONE T1GVAL T1GSS1 T1GSS0 186 INTCON PIE3(2) (2) PIR3 T1CON TMR1CS1 TMR1CS0 T1GCON TMR1GE T1GPOL TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register 177* TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register 177* TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by Capture mode. * Page provides register information. Note 1: Applies to ECCP modules only. 2: PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 205 PIC16(L)F1826/27 24.2 24.2.2 Compare Mode TIMER1 MODE RESOURCE The Compare mode function described in this section is available and identical for CCP modules ECCP1, ECCP2, CCP3 and CCP4. In Compare mode, Timer1 must be running in either Timer mode or Synchronized Counter mode. The compare operation may not work in Asynchronous Counter mode. Compare mode makes use of the 16-bit Timer1 resource. The 16-bit value of the CCPRxH:CCPRxL register pair is constantly compared against the 16-bit value of the TMR1H:TMR1L register pair. When a match occurs, one of the following events can occur: See Section 21.0 “Timer1 Module with Gate Control” for more information on configuring Timer1. • • • • • Toggle the CCPx output Set the CCPx output Clear the CCPx output Generate a Special Event Trigger Generate a Software Interrupt 24.2.3 The action on the pin is based on the value of the CCPxM control bits of the CCPxCON register. At the same time, the interrupt flag CCPxIF bit is set. All Compare modes can generate an interrupt. Figure 24-2 shows a simplified diagram of the Compare operation. FIGURE 24-2: COMPARE MODE OPERATION BLOCK DIAGRAM CCPxM Mode Select Q S R Output Logic Clocking Timer1 from the system clock (FOSC) should not be used in Compare mode. In order for Compare mode to recognize the trigger event on the CCPx pin, TImer1 must be clocked from the instruction clock (FOSC/4) or from an external clock source. SOFTWARE INTERRUPT MODE When Generate Software Interrupt mode is chosen (CCPxM = 1010), the CCPx module does not assert control of the CCPx pin (see the CCPxCON register). 24.2.4 SPECIAL EVENT TRIGGER When Special Event Trigger mode is chosen (CCPxM = 1011), the CCPx module does the following: • Resets Timer1 • Starts an ADC conversion if ADC is enabled The CCPx module does not assert control of the CCPx pin in this mode. Set CCPxIF Interrupt Flag (PIRx) 4 CCPRxH CCPRxL CCPx Pin Note: Match TRIS Output Enable Comparator TMR1H TMR1L Special Event Trigger The Special Event Trigger output of the CCP occurs immediately upon a match between the TMR1H, TMR1L register pair and the CCPRxH, CCPRxL register pair. The TMR1H, TMR1L register pair is not reset until the next rising edge of the Timer1 clock. The Special Event Trigger output starts an A/D conversion (if the A/D module is enabled). This allows the CCPRxH, CCPRxL register pair to effectively provide a 16-bit programmable period register for Timer1. TABLE 24-3: 24.2.1 SPECIAL EVENT TRIGGER CCP PIN CONFIGURATION Device CCPx/ECCPx The user must configure the CCPx pin as an output by clearing the associated TRIS bit. PIC16(L)F1826 ECCP1 PIC16(L)F1827 CCP4 Also, the CCPx pin function can be moved to alternative pins using the APFCON0 register. Refer to Section 12.1 “Alternate Pin Function” for more details. Note: Clearing the CCPxCON register will force the CCPx compare output latch to the default low level. This is not the PORT I/O data latch. DS41391D-page 206 Refer to Section 16.2.5 “Special Event Trigger” for more information. Note 1: The Special Event Trigger from the CCP module does not set interrupt flag bit TMR1IF of the PIR1 register. 2: Removing the match condition by changing the contents of the CCPRxH and CCPRxL register pair, between the clock edge that generates the Special Event Trigger and the clock edge that generates the Timer1 Reset, will preclude the Reset from occurring.  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.2.5 COMPARE DURING SLEEP 24.2.6 The Compare mode is dependent upon the system clock (FOSC) for proper operation. Since FOSC is shut down during Sleep mode, the Compare mode will not function properly during Sleep. TABLE 24-4: Name APFCON0 CCPxCON ALTERNATE PIN LOCATIONS This module incorporates I/O pins that can be moved to other locations with the use of the alternate pin function registers, APFCON0 and APFCON1. To determine which pins can be moved and what their default locations are upon a reset, see Section 12.1 “Alternate Pin Function” for more information. SUMMARY OF REGISTERS ASSOCIATED WITH COMPARE Bit 7 Bit 6 RXDTSEL SDO1SEL PxM1(1) PxM0(1) Bit 5 Bit 4 Bit 3 SS1SEL P2BSEL(2) CCP2SEL(2) DCxB1 DCxB0 CCPxM3 CCPRxL Capture/Compare/PWM Register x Low Byte (LSB) CCPRxH Capture/Compare/PWM Register x High Byte (MSB) Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 CCPxM2 CCPxM1 CCPxM0 Bit 2 226 204* 204* CM1CON0 C1ON C1OUT C1OE C1POL — C1SP C1HYS C1SYNC 170 CM1CON1 C1INTP C1INTN C1PCH1 C1PCH0 — — C1NCH1 C1NCH0 171 CM2CON0 C2ON C2OUT C2OE C2POL — C2SP C2HYS C2SYNC 170 CM2CON1 C2INTP C2INTN C2PCH1 C2PCH0 — — C2NCH1 C2NCH0 171 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 PIE2 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(2) 88 — — CCP4IE CCP3IE TMR6IE — TMR4IE — 89 PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 91 PIR2 OSFIF C2IF C1IF EEIF BCLIF — — CCP2IF(2) 92 — — CCP4IF CCP3IF TMR6IF — TMR4IF — 93 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC — TMR1ON 185 T1GTM T1GSPM T1GGO/DONE T1GVAL T1GSS1 T1GSS0 186 INTCON PIE3(2) (2) PIR3 T1CON TMR1CS1 TMR1CS0 T1GCON TMR1GE T1GPOL TMR1L Holding Register for the Least Significant Byte of the 16-bit TMR1 Register 177* TMR1H Holding Register for the Most Significant Byte of the 16-bit TMR1 Register 177* TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by Compare mode. * Page provides register information. Note 1: Applies to ECCP modules only. 2: PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 207 PIC16(L)F1826/27 24.3 PWM Overview Pulse-Width Modulation (PWM) is a scheme that provides power to a load by switching quickly between fully on and fully off states. The PWM signal resembles a square wave where the high portion of the signal is considered the on state and the low portion of the signal is considered the off state. The high portion, also known as the pulse width, can vary in time and is defined in steps. A larger number of steps applied, which lengthens the pulse width, also supplies more power to the load. Lowering the number of steps applied, which shortens the pulse width, supplies less power. The PWM period is defined as the duration of one complete cycle or the total amount of on and off time combined. PWM resolution defines the maximum number of steps that can be present in a single PWM period. A higher resolution allows for more precise control of the pulse width time and in turn the power that is applied to the load. FIGURE 24-3: Period Pulse Width 24.3.1 TMRx = 0 FIGURE 24-4: The standard PWM mode generates a Pulse-Width Modulation (PWM) signal on the CCPx pin with up to 10 bits of resolution. The period, duty cycle, and resolution are controlled by the following registers: • • • • SIMPLIFIED PWM BLOCK DIAGRAM CCPxCON Duty Cycle Registers CCPRxL CCPRxH(2) (Slave) CCPx R Comparator TMRx (1) Q S TRIS Comparator STANDARD PWM OPERATION The standard PWM function described in this section is available and identical for CCP modules ECCP1, ECCP2, CCP3 and CCP4. TMRx = PRx TMRx = CCPRxH:CCPxCON The term duty cycle describes the proportion of the on time to the off time and is expressed in percentages, where 0% is fully off and 100% is fully on. A lower duty cycle corresponds to less power applied and a higher duty cycle corresponds to more power applied. Figure 24-3 shows a typical waveform of the PWM signal. CCP PWM OUTPUT SIGNAL PRx Note 1: 2: Clear Timer, toggle CCPx pin and latch duty cycle The 8-bit timer TMRx register is concatenated with the 2-bit internal system clock (FOSC), or 2 bits of the prescaler, to create the 10-bit time base. In PWM mode, CCPRxH is a read-only register. PRx registers TxCON registers CCPRxL registers CCPxCON registers Figure 24-4 shows a simplified block diagram of PWM operation. Note 1: The corresponding TRIS bit must be cleared to enable the PWM output on the CCPx pin. 2: Clearing the CCPxCON register will relinquish control of the CCPx pin. DS41391D-page 208  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.3.2 SETUP FOR PWM OPERATION The following steps should be taken when configuring the CCP module for standard PWM operation: 1. 2. 3. 4. 5. 6. Disable the CCPx pin output driver by setting the associated TRIS bit. Load the PRx register with the PWM period value. Configure the CCP module for the PWM mode by loading the CCPxCON register with the appropriate values. Load the CCPRxL register and the DCxBx bits of the CCPxCON register, with the PWM duty cycle value. Configure and start Timer2/4/6: •Select the Timer2/4/6 resource to be used for PWM generation by setting the CxTSEL bits in the CCPTMRS register. •Clear the TMRxIF interrupt flag bit of the PIRx register. See Note below. •Configure the TxCKPS bits of the TxCON register with the Timer prescale value. •Enable the Timer by setting the TMRxON bit of the TxCON register. Enable PWM output pin: •Wait until the Timer overflows and the TMRxIF bit of the PIRx register is set. See Note below. •Enable the CCPx pin output driver by clearing the associated TRIS bit. Note: 24.3.3 In order to send a complete duty cycle and period on the first PWM output, the above steps must be included in the setup sequence. If it is not critical to start with a complete PWM signal on the first output, then step 6 may be ignored. TIMER2/4/6 TIMER RESOURCE The PWM standard mode makes use of one of the 8-bit Timer2/4/6 timer resources to specify the PWM period. When TMRx is equal to PRx, the following three events occur on the next increment cycle: • TMRx is cleared • The CCPx pin is set. (Exception: If the PWM duty cycle = 0%, the pin will not be set.) • The PWM duty cycle is latched from CCPRxL into CCPRxH. Note: 24.3.5 The Timer postscaler (see Section 22.1 “Timer2/4/6 Operation”) is not used in the determination of the PWM frequency. PWM DUTY CYCLE The PWM duty cycle is specified by writing a 10-bit value to multiple registers: CCPRxL register and DCxB bits of the CCPxCON register. The CCPRxL contains the eight MSbs and the DCxB bits of the CCPxCON register contain the two LSbs. CCPRxL and DCxB bits of the CCPxCON register can be written to at any time. The duty cycle value is not latched into CCPRxH until after the period completes (i.e., a match between PRx and TMRx registers occurs). While using the PWM, the CCPRxH register is read-only. Equation 24-2 is used to calculate the PWM pulse width. Equation 24-3 is used to calculate the PWM duty cycle ratio. EQUATION 24-2: PULSE WIDTH Pulse Width =  CCPRxL:CCPxCON   T OSC  (TMRx Prescale Value) EQUATION 24-3: DUTY CYCLE RATIO  CCPRxL:CCPxCON  Duty Cycle Ratio = ----------------------------------------------------------------------4  PRx + 1  Configuring the CxTSEL bits in the CCPTMRS register selects which Timer2/4/6 timer is used. The CCPRxH register and a 2-bit internal latch are used to double buffer the PWM duty cycle. This double buffering is essential for glitchless PWM operation. 24.3.4 The 8-bit timer TMRx register is concatenated with either the 2-bit internal system clock (FOSC), or 2 bits of the prescaler, to create the 10-bit time base. The system clock is used if the Timer2/4/6 prescaler is set to 1:1. PWM PERIOD The PWM period is specified by the PRx register of Timer2/4/6. The PWM period can be calculated using the formula of Equation 24-1. EQUATION 24-1: PWM PERIOD PWM Period =   PRx  + 1   4  T OSC  When the 10-bit time base matches the CCPRxH and 2-bit latch, then the CCPx pin is cleared (see Figure 24-4). (TMRx Prescale Value) Note 1: TOSC = 1/FOSC  2011 Microchip Technology Inc. DS41391D-page 209 PIC16(L)F1826/27 24.3.6 PWM RESOLUTION EQUATION 24-4: The resolution determines the number of available duty cycles for a given period. For example, a 10-bit resolution will result in 1024 discrete duty cycles, whereas an 8-bit resolution will result in 256 discrete duty cycles. The maximum PWM resolution is 10 bits when PRx is 255. The resolution is a function of the PRx register value as shown by Equation 24-4. TABLE 24-5: Timer Prescale (1, 4, 16) PRx Value Maximum Resolution (bits) Note: If the pulse width value is greater than the period the assigned PWM pin(s) will remain unchanged. 1.95 kHz 7.81 kHz 31.25 kHz 125 kHz 250 kHz 333.3 kHz 16 4 1 1 1 1 0xFF 0xFF 0xFF 0x3F 0x1F 0x17 10 10 10 8 7 6.6 EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 20 MHz) PWM Frequency Timer Prescale (1, 4, 16) PRx Value Maximum Resolution (bits) TABLE 24-7: log  4  PRx + 1   Resolution = ------------------------------------------ bits log  2  EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 32 MHz) PWM Frequency TABLE 24-6: PWM RESOLUTION 1.22 kHz 4.88 kHz 19.53 kHz 78.12 kHz 156.3 kHz 208.3 kHz 16 4 1 1 1 1 0xFF 0xFF 0xFF 0x3F 0x1F 0x17 10 10 10 8 7 6.6 EXAMPLE PWM FREQUENCIES AND RESOLUTIONS (FOSC = 8 MHz) PWM Frequency Timer Prescale (1, 4, 16) PRx Value Maximum Resolution (bits) DS41391D-page 210 1.22 kHz 4.90 kHz 19.61 kHz 76.92 kHz 153.85 kHz 200.0 kHz 16 4 1 1 1 1 0x65 0x65 0x65 0x19 0x0C 0x09 8 8 8 6 5 5  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.3.7 OPERATION IN SLEEP MODE 24.3.10 In Sleep mode, the TMRx register will not increment and the state of the module will not change. If the CCPx pin is driving a value, it will continue to drive that value. When the device wakes up, TMRx will continue from its previous state. 24.3.8 CHANGES IN SYSTEM CLOCK FREQUENCY ALTERNATE PIN LOCATIONS This module incorporates I/O pins that can be moved to other locations with the use of the alternate pin function registers, APFCON0 and APFCON1. To determine which pins can be moved and what their default locations are upon a reset, see Section 12.1 “Alternate Pin Function” for more information. The PWM frequency is derived from the system clock frequency. Any changes in the system clock frequency will result in changes to the PWM frequency. See Section 5.0 “Oscillator Module (With Fail-Safe Clock Monitor)” for additional details. 24.3.9 EFFECTS OF RESET Any Reset will force all ports to Input mode and the CCP registers to their Reset states. TABLE 24-8: Name SUMMARY OF REGISTERS ASSOCIATED WITH STANDARD PWM Bit 7 Bit 6 Bit 5 APFCON0 RXDTSEL SDO1SEL SS1SEL CCPxCON PxM1(1) PxM0(1) DCxB1 DCxB0 CCPxM3 CCPxAS CCPxASE CCPxAS2 CCPxAS1 CCPxAS0 PSSxAC1 CCPTMRS C4TSEL1 C4TSEL0 C3TSEL1 C3TSEL0 GIE PEIE TMR0IE INTE INTCON Bit 4 Bit 3 Register on Page Bit 1 Bit 0 P1DSEL P1CSEL CCP1SEL 119 CCPxM2 CCPxM1 CCPxM0 226 PSSxAC0 PSSxBD1 PSSxBD0 228 C2TSEL1 C2TSEL0 C1TSEL1 C1TSEL0 227 IOCIE TMR0IF INTF IOCIF P2BSEL(2) CCP2SEL(2) Bit 2 86 PR2 Timer2 Period Register 189* PR4 Timer4 Module Period Register 189* PR6 Timer6 Module Period Register 189* PSTRxCON — — — STRxSYNC STRxD STRxC STRxB STRxA 230 PWMxCON PxRSEN PxDC6 PxDC5 PxDC4 PxDC3 PxDC2 PxDC1 PxDC0 229 T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 191 T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 191 T6CON — T6OUTPS3 T6OUTPS2 T6OUTPS1 T6OUTPS0 TMR6ON T6CKPS1 T6CKPS0 191 TMR2 Holding Register for the 8-bit TMR2 Time Base 189* TMR4 Holding Register for the 8-bit TMR4 Time Base(1) 189* TMR6 Holding Register for the 8-bit TMR6 Time Base(1) TRISB TRISB7 TRISB6 TRISB5 TRISB4 189* TRISB3 TRISB2 TRISB1 TRISB0 127 Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by the PWM. * Page provides register information. Note 1: Applies to ECCP modules only. 2: PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 211 PIC16(L)F1826/27 24.4 To select an Enhanced PWM Output mode, the PxM bits of the CCPxCON register must be configured appropriately. PWM (Enhanced Mode) The enhanced PWM function described in this section is available for CCP modules ECCP1 and ECCP2, with any differences between modules noted. The PWM outputs are multiplexed with I/O pins and are designated PxA, PxB, PxC and PxD. The polarity of the PWM pins is configurable and is selected by setting the CCPxM bits in the CCPxCON register appropriately. The enhanced PWM mode generates a Pulse-Width Modulation (PWM) signal on up to four different output pins with up to 10 bits of resolution. The period, duty cycle, and resolution are controlled by the following registers: • • • • Figure 24-5 shows an example of a simplified block diagram of the Enhanced PWM module. Figure 24-9 shows the pin assignments for various Enhanced PWM modes. PRx registers TxCON registers CCPRxL registers CCPxCON registers Note 1: The corresponding TRIS bit must be cleared to enable the PWM output on the CCPx pin. The ECCP modules have the following additional PWM registers which control Auto-shutdown, Auto-restart, Dead-band Delay and PWM Steering modes: 2: Clearing the CCPxCON register will relinquish control of the CCPx pin. 3: Any pin not used in the enhanced PWM mode is available for alternate pin functions, if applicable. • CCPxAS registers • PSTRxCON registers • PWMxCON registers 4: To prevent the generation of an incomplete waveform when the PWM is first enabled, the ECCP module waits until the start of a new PWM period before generating a PWM signal. The enhanced PWM module can generate the following five PWM Output modes: • • • • • Single PWM Half-Bridge PWM Full-Bridge PWM, Forward Mode Full-Bridge PWM, Reverse Mode Single PWM with PWM Steering Mode FIGURE 24-5: EXAMPLE SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODE Duty Cycle Registers DCxB CCPxM 4 PxM 2 CCPRxL CCPx/PxA CCPx/PxA TRISx CCPRxH (Slave) PxB Comparator R Q Output Controller PxB TRISx PxC TMRx Comparator PRx Note 1: (1) PxC TRISx S PxD Clear Timer, toggle PWM pin and latch duty cycle PxD TRISx PWMxCON The 8-bit timer TMRx register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler to create the 10-bit time base. DS41391D-page 212  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 24-9: EXAMPLE PIN ASSIGNMENTS FOR VARIOUS PWM ENHANCED MODES ECCP Mode PxM CCPx/PxA PxB PxC PxD Single 00 Yes(1) Yes(1) Yes(1) Yes(1) Half-Bridge 10 Yes Yes No No Full-Bridge, Forward 01 Yes Yes Yes Yes Full-Bridge, Reverse 11 Yes Yes Yes Yes Note 1: PWM Steering enables outputs in Single mode. FIGURE 24-6: EXAMPLE PWM (ENHANCED MODE) OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE) Signal PxM PRX+1 Pulse Width 0 Period 00 (Single Output) PxA Modulated Delay Delay PxA Modulated 10 (Half-Bridge) PxB Modulated PxA Active 01 (Full-Bridge, Forward) PxB Inactive PxC Inactive PxD Modulated PxA Inactive 11 (Full-Bridge, Reverse) PxB Modulated PxC Active PxD Inactive Relationships: • Period = 4 * TOSC * (PRx + 1) * (TMRx Prescale Value) • Pulse Width = TOSC * (CCPRxL:CCPxCON) * (TMRx Prescale Value) • Delay = 4 * TOSC * (PWMxCON)  2011 Microchip Technology Inc. DS41391D-page 213 PIC16(L)F1826/27 FIGURE 24-7: EXAMPLE ENHANCED PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE) PxM Signal PRx+1 Pulse Width 0 Period 00 (Single Output) PxA Modulated PxA Modulated 10 (Half-Bridge) Delay Delay PxB Modulated PxA Active 01 (Full-Bridge, Forward) PxB Inactive PxC Inactive PxD Modulated PxA Inactive 11 (Full-Bridge, Reverse) PxB Modulated PxC Active PxD Inactive Relationships: • Period = 4 * TOSC * (PRx + 1) * (TMRx Prescale Value) • Pulse Width = TOSC * (CCPRxL:CCPxCON) * (TMRx Prescale Value) • Delay = 4 * TOSC * (PWMxCON) DS41391D-page 214  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.4.1 HALF-BRIDGE MODE In Half-Bridge mode, two pins are used as outputs to drive push-pull loads. The PWM output signal is output on the CCPx/PxA pin, while the complementary PWM output signal is output on the PxB pin (see Figure 24-9). This mode can be used for Half-Bridge applications, as shown in Figure 24-9, or for Full-Bridge applications, where four power switches are being modulated with two PWM signals. In Half-Bridge mode, the programmable dead-band delay can be used to prevent shoot-through current in Half-Bridge power devices. The value of the PDC bits of the PWMxCON register sets the number of instruction cycles before the output is driven active. If the value is greater than the duty cycle, the corresponding output remains inactive during the entire cycle. See Section 24.4.5 “Programmable Dead-Band Delay Mode” for more details of the dead-band delay operations. Since the PxA and PxB outputs are multiplexed with the PORT data latches, the associated TRIS bits must be cleared to configure PxA and PxB as outputs. FIGURE 24-8: Period Period Pulse Width PxA(2) td td PxB(2) (1) (1) (1) td = Dead-Band Delay Note 1: 2: FIGURE 24-9: EXAMPLE OF HALF-BRIDGE PWM OUTPUT At this time, the TMRx register is equal to the PRx register. Output signals are shown as active-high. EXAMPLE OF HALF-BRIDGE APPLICATIONS Standard Half-Bridge Circuit (“Push-Pull”) FET Driver + PxA Load FET Driver + PxB - Half-Bridge Output Driving a Full-Bridge Circuit V+ FET Driver FET Driver PxA FET Driver Load FET Driver PxB  2011 Microchip Technology Inc. DS41391D-page 215 PIC16(L)F1826/27 24.4.2 FULL-BRIDGE MODE In Full-Bridge mode, all four pins are used as outputs. An example of Full-Bridge application is shown in Figure 24-10. In the Forward mode, pin CCPx/PxA is driven to its active state, pin PxD is modulated, while PxB and PxC will be driven to their inactive state as shown in Figure 24-11. In the Reverse mode, PxC is driven to its active state, pin PxB is modulated, while PxA and PxD will be driven to their inactive state as shown Figure 24-11. PxA, PxB, PxC and PxD outputs are multiplexed with the PORT data latches. The associated TRIS bits must be cleared to configure the PxA, PxB, PxC and PxD pins as outputs. FIGURE 24-10: EXAMPLE OF FULL-BRIDGE APPLICATION V+ FET Driver QC QA FET Driver PxA Load PxB FET Driver PxC FET Driver QD QB VPxD DS41391D-page 216  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 24-11: EXAMPLE OF FULL-BRIDGE PWM OUTPUT Forward Mode Period PxA (2) Pulse Width PxB(2) PxC(2) PxD(2) (1) (1) Reverse Mode Period Pulse Width PxA(2) PxB(2) PxC(2) PxD(2) (1) Note 1: 2: (1) At this time, the TMRx register is equal to the PRx register. Output signal is shown as active-high.  2011 Microchip Technology Inc. DS41391D-page 217 PIC16(L)F1826/27 24.4.2.1 Direction Change in Full-Bridge Mode In the Full-Bridge mode, the PxM1 bit in the CCPxCON register allows users to control the forward/reverse direction. When the application firmware changes this direction control bit, the module will change to the new direction on the next PWM cycle. A direction change is initiated in software by changing the PxM1 bit of the CCPxCON register. The following sequence occurs four Timer cycles prior to the end of the current PWM period: • The modulated outputs (PxB and PxD) are placed in their inactive state. • The associated unmodulated outputs (PxA and PxC) are switched to drive in the opposite direction. • PWM modulation resumes at the beginning of the next period. See Figure 24-12 for an illustration of this sequence. The Full-Bridge mode does not provide dead-band delay. As one output is modulated at a time, dead-band delay is generally not required. There is a situation where dead-band delay is required. This situation occurs when both of the following conditions are true: 1. 2. The direction of the PWM output changes when the duty cycle of the output is at or near 100%. The turn off time of the power switch, including the power device and driver circuit, is greater than the turn on time. Figure 24-13 shows an example of the PWM direction changing from forward to reverse, at a near 100% duty cycle. In this example, at time t1, the output PxA and PxD become inactive, while output PxC becomes active. Since the turn off time of the power devices is longer than the turn on time, a shoot-through current will flow through power devices QC and QD (see Figure 24-10) for the duration of ‘t’. The same phenomenon will occur to power devices QA and QB for PWM direction change from reverse to forward. If changing PWM direction at high duty cycle is required for an application, two possible solutions for eliminating the shoot-through current are: 1. 2. Reduce PWM duty cycle for one PWM period before changing directions. Use switch drivers that can drive the switches off faster than they can drive them on. Other options to prevent shoot-through current may exist. FIGURE 24-12: EXAMPLE OF PWM DIRECTION CHANGE Period(1) Signal Period PxA (Active-High) PxB (Active-High) Pulse Width PxC (Active-High) (2) PxD (Active-High) Pulse Width Note 1: 2: The direction bit PxM1 of the CCPxCON register is written any time during the PWM cycle. When changing directions, the PxA and PxC signals switch before the end of the current PWM cycle. The modulated PxB and PxD signals are inactive at this time. The length of this time is four Timer counts. DS41391D-page 218  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 24-13: EXAMPLE OF PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE Forward Period t1 Reverse Period PxA PxB PW PxC PxD PW TON External Switch C TOFF External Switch D Potential Shoot-Through Current Note 1: T = TOFF – TON All signals are shown as active-high. 2: TON is the turn on delay of power switch QC and its driver. 3: TOFF is the turn off delay of power switch QD and its driver.  2011 Microchip Technology Inc. DS41391D-page 219 PIC16(L)F1826/27 24.4.3 ENHANCED PWM AUTO-SHUTDOWN MODE The PWM mode supports an Auto-Shutdown mode that will disable the PWM outputs when an external shutdown event occurs. Auto-Shutdown mode places the PWM output pins into a predetermined state. This mode is used to help prevent the PWM from damaging the application. Note 1: The auto-shutdown condition is a level-based signal, not an edge-based signal. As long as the level is present, the auto-shutdown will persist. 2: Writing to the CCPxASE bit of the CCPxAS register is disabled while an auto-shutdown condition persists. The auto-shutdown sources are selected using the CCPxAS bits of the CCPxAS register. A shutdown event may be generated by: 3: Once the auto-shutdown condition has been removed and the PWM restarted (either through firmware or auto-restart) the PWM signal will always restart at the beginning of the next PWM period. • A logic ‘0’ on the INT pin • A logic ‘1’ on a Comparator (Cx) output 4: Prior to an auto-shutdown event caused by a comparator output or INT pin event, a software shutdown can be triggered in firmware by setting the CCPxASE bit of the CCPxAS register to ‘1’. The Auto-Restart feature tracks the active status of a shutdown caused by a comparator output or INT pin event only. If it is enabled at this time, it will immediately clear this bit and restart the ECCP module at the beginning of the next PWM period. A shutdown condition is indicated by the CCPxASE (Auto-Shutdown Event Status) bit of the CCPxAS register. If the bit is a ‘0’, the PWM pins are operating normally. If the bit is a ‘1’, the PWM outputs are in the shutdown state. When a shutdown event occurs, two things happen: The CCPxASE bit is set to ‘1’. The CCPxASE will remain set until cleared in firmware or an auto-restart occurs (see Section 24.4.4 “Auto-Restart Mode”). The enabled PWM pins are asynchronously placed in their shutdown states. The PWM output pins are grouped into pairs [PxA/PxC] and [PxB/PxD]. The state of each pin pair is determined by the PSSxAC and PSSxBD bits of the CCPxAS register. Each pin pair may be placed into one of three states: • Drive logic ‘1’ • Drive logic ‘0’ • Tri-state (high-impedance) FIGURE 24-14: PWM AUTO-SHUTDOWN WITH FIRMWARE RESTART (PXRSEN = 0) Missing Pulse (Auto-Shutdown) Timer Overflow Timer Overflow Missing Pulse (CCPxASE not clear) Timer Overflow Timer Overflow Timer Overflow PWM Period PWM Activity Start of PWM Period Shutdown Event CCPxASE bit Shutdown Event Occurs DS41391D-page 220 Shutdown Event Clears PWM Resumes CCPxASE Cleared by Firmware  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.4.4 AUTO-RESTART MODE The Enhanced PWM can be configured to automatically restart the PWM signal once the auto-shutdown condition has been removed. Auto-restart is enabled by setting the PxRSEN bit in the PWMxCON register. FIGURE 24-15: If auto-restart is enabled, the CCPxASE bit will remain set as long as the auto-shutdown condition is active. When the auto-shutdown condition is removed, the CCPxASE bit will be cleared via hardware and normal operation will resume. PWM AUTO-SHUTDOWN WITH AUTO-RESTART (PXRSEN = 1) Missing Pulse (Auto-Shutdown) Timer Overflow Timer Overflow Missing Pulse (CCPxASE not clear) Timer Overflow Timer Overflow Timer Overflow PWM Period PWM Activity Start of PWM Period Shutdown Event CCPxASE bit PWM Resumes Shutdown Event Occurs Shutdown Event Clears  2011 Microchip Technology Inc. CCPxASE Cleared by Hardware DS41391D-page 221 PIC16(L)F1826/27 24.4.5 PROGRAMMABLE DEAD-BAND DELAY MODE FIGURE 24-16: In Half-Bridge applications where all power switches are modulated at the PWM frequency, the power switches normally require more time to turn off than to turn on. If both the upper and lower power switches are switched at the same time (one turned on, and the other turned off), both switches may be on for a short period of time until one switch completely turns off. During this brief interval, a very high current (shoot-through current) will flow through both power switches, shorting the bridge supply. To avoid this potentially destructive shoot-through current from flowing during switching, turning on either of the power switches is normally delayed to allow the other switch to completely turn off. Period Period Pulse Width PxA(2) td td PxB(2) (1) (1) (1) td = Dead-Band Delay Note 1: In Half-Bridge mode, a digitally programmable dead-band delay is available to avoid shoot-through current from destroying the bridge power switches. The delay occurs at the signal transition from the non-active state to the active state. See Figure 24-16 for illustration. The lower seven bits of the associated PWMxCON register (Register 24-4) sets the delay period in terms of microcontroller instruction cycles (TCY or 4 TOSC). FIGURE 24-17: EXAMPLE OF HALF-BRIDGE PWM OUTPUT 2: At this time, the TMRx register is equal to the PRx register. Output signals are shown as active-high. EXAMPLE OF HALF-BRIDGE APPLICATIONS V+ Standard Half-Bridge Circuit (“Push-Pull”) FET Driver + V - PxA Load FET Driver + V - PxB V- DS41391D-page 222  2011 Microchip Technology Inc. PIC16(L)F1826/27 24.4.6 PWM STEERING MODE In Single Output mode, PWM steering allows any of the PWM pins to be the modulated signal. Additionally, the same PWM signal can be simultaneously available on multiple pins. Once the Single Output mode is selected (CCPxM = 11 and PxM = 00 of the CCPxCON register), the user firmware can bring out the same PWM signal to one, two, three or four output pins by setting the appropriate STRx bits of the PSTRxCON register, as shown in Register 24-5. The associated TRIS bits must be set to output (‘0’) to enable the pin output driver in order to see the PWM signal on the pin. Note: While the PWM Steering mode is active, CCPxM bits of the CCPxCON register select the PWM output polarity for the Px pins. The PWM auto-shutdown operation also applies to PWM Steering mode as described in Section 24.4.3 “Enhanced PWM Auto-shutdown mode”. An auto-shutdown event will only affect pins that have PWM outputs enabled. FIGURE 24-18: SIMPLIFIED STEERING BLOCK DIAGRAM STRxA PxA Signal CCPxM1 1 PORT Data 0 PxA pin STRxB CCPxM0 1 PORT Data 0 STRxC CCPxM1 1 PORT Data 0 PORT Data PxB pin TRIS PxC pin TRIS STRxD CCPxM0 TRIS PxD pin 1 0 TRIS Note 1: Port outputs are configured as shown when the CCPxCON register bits PxM = 00 and CCPxM = 11. 2: Single PWM output requires setting at least one of the STRx bits.  2011 Microchip Technology Inc. DS41391D-page 223 PIC16(L)F1826/27 24.4.6.1 Steering Synchronization The STRxSYNC bit of the PSTRxCON register gives the user two selections of when the steering event will happen. When the STRxSYNC bit is ‘0’, the steering event will happen at the end of the instruction that writes to the PSTRxCON register. In this case, the output signal at the Px pins may be an incomplete PWM waveform. This operation is useful when the user firmware needs to immediately remove a PWM signal from the pin. When the STRxSYNC bit is ‘1’, the effective steering update will happen at the beginning of the next PWM period. In this case, steering on/off the PWM output will always produce a complete PWM waveform. configuration while the PWM pin output drivers are enable is not recommended since it may result in damage to the application circuits. The PxA, PxB, PxC and PxD output latches may not be in the proper states when the PWM module is initialized. Enabling the PWM pin output drivers at the same time as the Enhanced PWM modes may cause damage to the application circuit. The Enhanced PWM modes must be enabled in the proper Output mode and complete a full PWM cycle before enabling the PWM pin output drivers. The completion of a full PWM cycle is indicated by the TMRxIF bit of the PIRx register being set as the second PWM period begins. Note: Figures 24-19 and 24-20 illustrate the timing diagrams of the PWM steering depending on the STRxSYNC setting. 24.4.7 START-UP CONSIDERATIONS When any PWM mode is used, the application hardware must use the proper external pull-up and/or pull-down resistors on the PWM output pins. The CCPxM bits of the CCPxCON register allow the user to choose whether the PWM output signals are active-high or active-low for each pair of PWM output pins (PxA/PxC and PxB/PxD). The PWM output polarities must be selected before the PWM pin output drivers are enabled. Changing the polarity FIGURE 24-19: 24.4.8 When the microcontroller is released from Reset, all of the I/O pins are in the high-impedance state. The external circuits must keep the power switch devices in the Off state until the microcontroller drives the I/O pins with the proper signal levels or activates the PWM output(s). ALTERNATE PIN LOCATIONS This module incorporates I/O pins that can be moved to other locations with the use of the alternate pin function registers, APFCON0 and APFCON1. To determine which pins can be moved and what their default locations are upon a reset, see Section 12.1 “Alternate Pin Function” for more information. EXAMPLE OF STEERING EVENT AT END OF INSTRUCTION (STRxSYNC = 0) PWM Period PWM STRx P1 PORT Data PORT Data P1n = PWM FIGURE 24-20: EXAMPLE OF STEERING EVENT AT BEGINNING OF INSTRUCTION (STRxSYNC = 1) PWM STRx P1 PORT Data PORT Data P1n = PWM DS41391D-page 224  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 24-10: SUMMARY OF REGISTERS ASSOCIATED WITH ENHANCED PWM Name APFCON0 CCPxCON CCPxAS CCPTMRS Bit 7 Bit 6 Bit 5 RXDTSEL SDO1SEL SS1SEL (1) Bit 3 P2BSEL(2) CCP2SEL(2) DCxB PxM CCPxASE Bit 4 CCPxAS C4TSEL Bit 2 Bit 1 Bit 0 P1DSEL P1CSEL CCP1SEL CCPxM PSSxAC C3TSEL C2TSEL Register on Page 119 226 PSSxBD 228 C1TSEL 227 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF PIE1 TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 PIE2 OSFIE C2IE C1IE EEIE BCLIE — — CCP2IE 88 — — CCP4IE CCP3IE TMR6IE — TMR4IE — 89 PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 91 PIR2 OSFIF C2IF C1IF EEIF BCLIF — — CCP2IF 92 — — CCP4IF CCP3IF TMR6IF — TMR4IF — 93 INTCON PIE3(2) PIR3(2) 86 PR2 Timer2 Period Register 189* PR4 Timer4 Module Period Register 189* PR6 Timer6 Module Period Register PSTRxCON — PWMxCON PxRSEN — 189* — STRxSYNC STRxD STRxC STRxB STRxA PxDC 230 229 T2CON — T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0 191 T4CON — T4OUTPS3 T4OUTPS2 T4OUTPS1 T4OUTPS0 TMR4ON T4CKPS1 T4CKPS0 191 T6CON — T6OUTPS3 T6OUTPS2 T6OUTPS1 T6OUTPS0 TMR6ON T6CKPS1 T6CKPS0 191 TMR2 Holding Register for the 8-bit TMR2 Time Base 189* TMR4 Holding Register for the 8-bit TMR4 Time Base(1) 189* TMR6 Holding Register for the 8-bit TMR6 Time Base(1) 189* TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 Legend: — = Unimplemented location, read as ‘0’. Shaded cells are not used by the PWM. * Page provides register information. Note 1: Applies to ECCP modules only. 2: PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 225 PIC16(L)F1826/27 24.5 CCP Control Registers REGISTER 24-1: R/W-00 CCPxCON: CCPx CONTROL REGISTER R/W-0/0 R/W-0/0 PxM(1) R/W-0/0 R/W-0/0 DCxB R/W-0/0 R/W-0/0 R/W-0/0 CCPxM bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Reset ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 PxM: Enhanced PWM Output Configuration bits(1) Capture mode: Unused Compare mode: Unused If CCPxM = 00, 01, 10: xx = PxA assigned as Capture/Compare input; PxB, PxC, PxD assigned as port pins If CCPxM = 11: 00 = Single output; PxA modulated; PxB, PxC, PxD assigned as port pins 01 = Full-Bridge output forward; PxD modulated; PxA active; PxB, PxC inactive 10 = Half-Bridge output; PxA, PxB modulated with dead-band control; PxC, PxD assigned as port pins 11 = Full-Bridge output reverse; PxB modulated; PxC active; PxA, PxD inactive bit 5-4 DCxB: PWM Duty Cycle Least Significant bits Capture mode: Unused Compare mode: Unused PWM mode: These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPRxL. bit 3-0 CCPxM: ECCPx Mode Select bits 0000 =Capture/Compare/PWM off (resets ECCPx module) 0001 =Reserved 0010 =Compare mode: toggle output on match 0011 =Reserved 0100 =Capture mode: every falling edge 0101 =Capture mode: every rising edge 0110 =Capture mode: every 4th rising edge 0111 =Capture mode: every 16th rising edge 1000 =Compare mode: initialize ECCPx pin low; set output on compare match (set CCPxIF) 1001 =Compare mode: initialize ECCPx pin high; clear output on compare match (set CCPxIF) 1010 =Compare mode: generate software interrupt only; ECCPx pin reverts to I/O state 1011 =Compare mode: Special Event Trigger (ECCPx resets Timer, sets CCPxIF bit, starts A/D conversion if A/D module is enabled)(1) CCP Modules only: 11xx =PWM mode ECCP Modules only: 1100 =PWM mode: PxA, PxC active-high; PxB, PxD active-high 1101 =PWM mode: PxA, PxC active-high; PxB, PxD active-low 1110 =PWM mode: PxA, PxC active-low; PxB, PxD active-high 1111 =PWM mode: PxA, PxC active-low; PxB, PxD active-low Note 1: These bits are not implemented on CCP. DS41391D-page 226  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 24-2: R/W-0/0 CCPTMRS: PWM TIMER SELECTION CONTROL REGISTER R/W-0/0 C4TSEL R/W-0/0 R/W-0/0 R/W-0/0 C3TSEL R/W-0/0 R/W-0/0 C2TSEL bit 7 R/W-0/0 C1TSEL bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-6 C4TSEL: CCP4 Timer Selection 00 =CCP4 is based off Timer 2 in PWM Mode 01 =CCP4 is based off Timer 4 in PWM Mode 10 =CCP4 is based off Timer 6 in PWM Mode 11 =Reserved bit 5-4 C3TSEL: CCP3 Timer Selection 00 =CCP3 is based off Timer 2 in PWM Mode 01 =CCP3 is based off Timer 4 in PWM Mode 10 =CCP3 is based off Timer 6 in PWM Mode 11 =Reserved bit 3-2 C2TSEL: CCP2 Timer Selection 00 =CCP2 is based off Timer 2 in PWM Mode 01 =CCP2 is based off Timer 4 in PWM Mode 10 =CCP2 is based off Timer 6 in PWM Mode 11 =Reserved bit 1-0 C1TSEL: CCP1 Timer Selection 00 =CCP1 is based off Timer 2 in PWM Mode 01 =CCP1 is based off Timer 4 in PWM Mode 10 =CCP1 is based off Timer 6 in PWM Mode 11 =Reserved  2011 Microchip Technology Inc. DS41391D-page 227 PIC16(L)F1826/27 REGISTER 24-3: R/W-0/0 CCPxAS: CCPx AUTO-SHUTDOWN CONTROL REGISTER R/W-0/0 CCPxASE R/W-0/0 R/W-0/0 CCPxAS R/W-0/0 R/W-0/0 R/W-0/0 PSSxAC R/W-0/0 PSSxBD bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 CCPxASE: CCPx Auto-Shutdown Event Status bit 1 = A shutdown event has occurred; CCPx outputs are in shutdown state 0 = CCPx outputs are operating bit 6-4 CCxPAS: CCPx Auto-Shutdown Source Select bits 000 = Auto-shutdown is disabled 001 = Comparator C1 output high(1) 010 = Comparator C2 output high(1) 011 = Either Comparator C1 or C2 high(1) 100 = VIL on INT pin 101 = VIL on INT pin or Comparator C1 high(1) 110 = VIL on INT pin or Comparator C2 high(1) 111 =VIL on INT pin or Comparator C1 or Comparator C2 high(1) bit 3-2 PSSxAC: Pins PxA and PxC Shutdown State Control bits 00 = Drive pins PxA and PxC to ‘0’ 01 = Drive pins PxA and PxC to ‘1’ 1x = Pins PxA and PxC tri-state bit 1-0 PSSxBD: Pins PxB and PxD Shutdown State Control bits 00 = Drive pins PxB and PxD to ‘0’ 01 = Drive pins PxB and PxD to ‘1’ 1x = Pins PxB and PxD tri-state Note 1: If CxSYNC is enabled, the shutdown will be delayed by Timer1. DS41391D-page 228  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 24-4: R/W-0/0 PWMxCON: ENHANCED PWM CONTROL REGISTER R/W-0/0 R/W-0/0 R/W-0/0 PxRSEN R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 PxDC bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 PxRSEN: PWM Restart Enable bit 1 = Upon auto-shutdown, the CCPxASE bit clears automatically once the shutdown event goes away; the PWM restarts automatically 0 = Upon auto-shutdown, CCPxASE must be cleared in software to restart the PWM bit 6-0 PxDC: PWM Delay Count bits PxDCx =Number of FOSC/4 (4 * TOSC) cycles between the scheduled time when a PWM signal should transition active and the actual time it transitions active Note 1: Bit resets to ‘0’ with Two-Speed Start-up and LP, XT or HS selected as the Oscillator mode or Fail-Safe mode is enabled.  2011 Microchip Technology Inc. DS41391D-page 229 PIC16(L)F1826/27 PSTRxCON: PWM STEERING CONTROL REGISTER(1) REGISTER 24-5: U-0 U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-1/1 — — — STRxSYNC STRxD STRxC STRxB STRxA bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-5 Unimplemented: Read as ‘0’ bit 4 STRxSYNC: Steering Sync bit 1 = Output steering update occurs on next PWM period 0 = Output steering update occurs at the beginning of the instruction cycle boundary bit 3 STRxD: Steering Enable bit D 1 = PxD pin has the PWM waveform with polarity control from CCPxM 0 = PxD pin is assigned to port pin bit 2 STRxC: Steering Enable bit C 1 = PxC pin has the PWM waveform with polarity control from CCPxM 0 = PxC pin is assigned to port pin bit 1 STRxB: Steering Enable bit B 1 = PxB pin has the PWM waveform with polarity control from CCPxM 0 = PxB pin is assigned to port pin bit 0 STRxA: Steering Enable bit A 1 = PxA pin has the PWM waveform with polarity control from CCPxM 0 = PxA pin is assigned to port pin Note 1: The PWM Steering mode is available only when the CCPxCON register bits CCPxM = 11 and PxM = 00. DS41391D-page 230  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.0 MASTER SYNCHRONOUS SERIAL PORT (MSSP1 AND MSSP2) MODULE 25.1 Master SSPx (MSSPx) Module Overview The Master Synchronous Serial Port (MSSPx) module is a serial interface useful for communicating with other peripheral or microcontroller devices. These peripheral devices may be Serial EEPROMs, shift registers, display drivers, A/D converters, etc. The MSSPx module can operate in one of two modes: • Serial Peripheral Interface (SPI) • Inter-Integrated Circuit (I2C™) The SPI interface supports the following modes and features: • • • • • Master mode Slave mode Clock Parity Slave Select Synchronization (Slave mode only) Daisy-chain connection of slave devices Figure 25-1 is a block diagram of the SPI interface module. FIGURE 25-1: MSSPX BLOCK DIAGRAM (SPI MODE) Data Bus Read Write SSPxBUF Reg SDIx SSPxSR Reg SDOx bit 0 SSx SSx Control Enable Shift Clock 2 (CKP, CKE) Clock Select Edge Select SSPxM 4 SCKx Edge Select TRIS bit  2011 Microchip Technology Inc. ( TMR22Output ) Prescaler TOSC 4, 16, 64 Baud Rate Generator (SSPxADD) DS41391D-page 231 PIC16(L)F1826/27 The I2C interface supports the following modes and features: Master mode Slave mode Byte NACKing (Slave mode) Limited Multi-master support 7-bit and 10-bit addressing Start and Stop interrupts Interrupt masking Clock stretching Bus collision detection General call address matching Address masking Address Hold and Data Hold modes Selectable SDAx hold times Note 1: In devices with more than one MSSP module, it is very important to pay close attention to SSPxCONx register names. SSP1CON1 and SSP1CON2 registers control different operational aspects of the same module, while SSP1CON1 and SSP2CON1 control the same features for two different modules. 2: Throughout this section, generic references to an MSSP module in any of its operating modes may be interpreted as being equally applicable to MSSP1 or MSSP2. Register names, module I/O signals, and bit names may use the generic designator ‘x’ to indicate the use of a numeral to distinguish a particular module when required. Figure 25-2 is a block diagram of the I2C interface module in Master mode. Figure 25-3 is a diagram of the I2C interface module in Slave mode. MSSPX BLOCK DIAGRAM (I2C™ MASTER MODE) Internal data bus Read [SSPxM 3:0] Write SSPxBUF Baud rate generator (SSPxADD) Shift Clock SDAx SDAx in Receive Enable (RCEN) SCLx SCLx in Bus Collision DS41391D-page 232 LSb Start bit, Stop bit, Acknowledge Generate (SSPxCON2) Start bit detect, Stop bit detect Write collision detect Clock arbitration State counter for end of XMIT/RCV Address Match detect Clock Cntl SSPxSR MSb (Hold off clock source) FIGURE 25-2: Clock arbitrate/BCOL detect • • • • • • • • • • • • • The PIC16F1827 has two MSSP modules, MSSP1 and MSSP2, each module operating independently from the other. Set/Reset: S, P, SSPxSTAT, WCOL, SSPxOV Reset SEN, PEN (SSPxCON2) Set SSPxIF, BCLxIF  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 25-3: MSSPX BLOCK DIAGRAM (I2C™ SLAVE MODE) Internal Data Bus Read Write SSPxBUF Reg SCLx Shift Clock SSPxSR Reg SDAx MSb LSb SSPxMSK Reg Match Detect Addr Match SSPxADD Reg Start and Stop bit Detect  2011 Microchip Technology Inc. Set, Reset S, P bits (SSPxSTAT Reg) DS41391D-page 233 PIC16(L)F1826/27 25.2 SPI Mode Overview The Serial Peripheral Interface (SPI) bus is a synchronous serial data communication bus that operates in Full-Duplex mode. Devices communicate in a master/slave environment where the master device initiates the communication. A slave device is controlled through a Chip Select known as Slave Select. The SPI bus specifies four signal connections: • • • • Serial Clock (SCKx) Serial Data Out (SDOx) Serial Data In (SDIx) Slave Select (SSx) Figure 25-1 shows the block diagram of the MSSPx module when operating in SPI Mode. The SPI bus operates with a single master device and one or more slave devices. When multiple slave devices are used, an independent Slave Select connection is required from the master device to each slave device. Figure 25-4 shows a typical connection between a master device and multiple slave devices. The master selects only one slave at a time. Most slave devices have tri-state outputs so their output signal appears disconnected from the bus when they are not selected. Transmissions involve two shift registers, eight bits in size, one in the master and one in the slave. With either the master or the slave device, data is always shifted out one bit at a time, with the Most Significant bit (MSb) shifted out first. At the same time, a new Least Significant bit (LSb) is shifted into the same register. During each SPI clock cycle, a full-duplex data transmission occurs. This means that while the master device is sending out the MSb from its shift register (on its SDOx pin) and the slave device is reading this bit and saving it as the LSb of its shift register, that the slave device is also sending out the MSb from its shift register (on its SDOx pin) and the master device is reading this bit and saving it as the LSb of its shift register. After 8 bits have been shifted out, the master and slave have exchanged register values. If there is more data to exchange, the shift registers are loaded with new data and the process repeats itself. Whether the data is meaningful or not (dummy data), depends on the application software. This leads to three scenarios for data transmission: • Master sends useful data and slave sends dummy data. • Master sends useful data and slave sends useful data. • Master sends dummy data and slave sends useful data. Transmissions may involve any number of clock cycles. When there is no more data to be transmitted, the master stops sending the clock signal and it deselects the slave. Every slave device connected to the bus that has not been selected through its slave select line must disregard the clock and transmission signals and must not transmit out any data of its own. Figure 25-5 shows a typical connection between two processors configured as master and slave devices. Data is shifted out of both shift registers on the programmed clock edge and latched on the opposite edge of the clock. The master device transmits information out on its SDOx output pin which is connected to, and received by, the slave's SDIx input pin. The slave device transmits information out on its SDOx output pin, which is connected to, and received by, the master's SDIx input pin. To begin communication, the master device first sends out the clock signal. Both the master and the slave devices should be configured for the same clock polarity. The master device starts a transmission by sending out the MSb from its shift register. The slave device reads this bit from that same line and saves it into the LSb position of its shift register. DS41391D-page 234  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 25-4: SPI MASTER AND MULTIPLE SLAVE CONNECTION SPI Master SCKx SCKx SDOx SDIx SDIx SDOx General I/O General I/O SSx General I/O SCKx SDIx SDOx SPI Slave #1 SPI Slave #2 SSx SCKx SDIx SDOx SPI Slave #3 SSx 25.2.1 SPI MODE REGISTERS The MSSPx module has five registers for SPI mode operation. These are: • • • • • • MSSPx STATUS register (SSPxSTAT) MSSPx Control Register 1 (SSPxCON1) MSSPx Control Register 3 (SSPxCON3) MSSPx Data Buffer register (SSPxBUF) MSSPx Address register (SSPxADD) MSSPx Shift register (SSPxSR) (Not directly accessible) SSPxCON1 and SSPxSTAT are the control and STATUS registers in SPI mode operation. The SSPxCON1 register is readable and writable. The lower 6 bits of the SSPxSTAT are read-only. The upper two bits of the SSPxSTAT are read/write. In one SPI master mode, SSPxADD can be loaded with a value used in the Baud Rate Generator. More information on the Baud Rate Generator is available in Section 25.7 “Baud Rate Generator”. SSPxSR is the shift register used for shifting data in and out. SSPxBUF provides indirect access to the SSPxSR register. SSPxBUF is the buffer register to which data bytes are written, and from which data bytes are read. In receive operations, SSPxSR and SSPxBUF together create a buffered receiver. When SSPxSR receives a complete byte, it is transferred to SSPxBUF and the SSPxIF interrupt is set. During transmission, the SSPxBUF is not buffered. A write to SSPxBUF will write to both SSPxBUF and SSPxSR.  2011 Microchip Technology Inc. DS41391D-page 235 PIC16(L)F1826/27 25.2.2 SPI MODE OPERATION When initializing the SPI, several options need to be specified. This is done by programming the appropriate control bits (SSPxCON1 and SSPxSTAT). These control bits allow the following to be specified: • • • • Master mode (SCKx is the clock output) Slave mode (SCKx is the clock input) Clock Polarity (Idle state of SCKx) Data Input Sample Phase (middle or end of data output time) • Clock Edge (output data on rising/falling edge of SCKx) • Clock Rate (Master mode only) • Slave Select mode (Slave mode only) To enable the serial port, SSPx Enable bit, SSPxEN of the SSPxCON1 register, must be set. To reset or reconfigure SPI mode, clear the SSPxEN bit, re-initialize the SSPxCONx registers and then set the SSPxEN bit. This configures the SDIx, SDOx, SCKx and SSx pins as serial port pins. For the pins to behave as the serial port function, some must have their data direction bits (in the TRIS register) appropriately programmed as follows: • SDIx must have corresponding TRIS bit set • SDOx must have corresponding TRIS bit cleared • SCKx (Master mode) must have corresponding TRIS bit cleared • SCKx (Slave mode) must have corresponding TRIS bit set • SSx must have corresponding TRIS bit set FIGURE 25-5: Any serial port function that is not desired may be overridden by programming the corresponding data direction (TRIS) register to the opposite value. The MSSPx consists of a transmit/receive shift register (SSPxSR) and a buffer register (SSPxBUF). The SSPxSR shifts the data in and out of the device, MSb first. The SSPxBUF holds the data that was written to the SSPxSR until the received data is ready. Once the 8 bits of data have been received, that byte is moved to the SSPxBUF register. Then, the Buffer Full Detect bit, BF of the SSPxSTAT register, and the interrupt flag bit, SSPxIF, are set. This double-buffering of the received data (SSPxBUF) allows the next byte to start reception before reading the data that was just received. Any write to the SSPxBUF register during transmission/reception of data will be ignored and the write collision detect bit WCOL of the SSPxCON1 register, will be set. User software must clear the WCOL bit to allow the following write(s) to the SSPxBUF register to complete successfully. When the application software is expecting to receive valid data, the SSPxBUF should be read before the next byte of data to transfer is written to the SSPxBUF. The Buffer Full bit, BF of the SSPxSTAT register, indicates when SSPxBUF has been loaded with the received data (transmission is complete). When the SSPxBUF is read, the BF bit is cleared. This data may be irrelevant if the SPI is only a transmitter. Generally, the MSSPx interrupt is used to determine when the transmission/reception has completed. If the interrupt method is not going to be used, then software polling can be done to ensure that a write collision does not occur. SPI MASTER/SLAVE CONNECTION SPI Slave SSPxM = 010x SPI Master SSPxM = 00xx = 1010 SDOx SDIx Serial Input Buffer (BUF) LSb SCKx General I/O Processor 1 DS41391D-page 236 SDOx SDIx Shift Register (SSPxSR) MSb Serial Input Buffer (SSPxBUF) Serial Clock Slave Select (optional) Shift Register (SSPxSR) MSb LSb SCKx SSx Processor 2  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.2.3 SPI MASTER MODE The master can initiate the data transfer at any time because it controls the SCKx line. The master determines when the slave (Processor 2, Figure 25-5) is to broadcast data by the software protocol. In Master mode, the data is transmitted/received as soon as the SSPxBUF register is written to. If the SPI is only going to receive, the SDOx output could be disabled (programmed as an input). The SSPxSR register will continue to shift in the signal present on the SDIx pin at the programmed clock rate. As each byte is received, it will be loaded into the SSPxBUF register as if a normal received byte (interrupts and Status bits appropriately set). The clock polarity is selected by appropriately programming the CKP bit of the SSPxCON1 register and the CKE bit of the SSPxSTAT register. This then, would give waveforms for SPI communication as shown in Figure 25-6, Figure 25-8 and Figure 25-9, where the MSB is transmitted first. In Master mode, the SPI clock rate (bit rate) is user programmable to be one of the following: • • • • • FOSC/4 (or TCY) FOSC/16 (or 4 * TCY) FOSC/64 (or 16 * TCY) Timer2 output/2 Fosc/(4 * (SSPxADD + 1)) Figure 25-6 shows the waveforms for Master mode. When the CKE bit is set, the SDOx data is valid before there is a clock edge on SCKx. The change of the input sample is shown based on the state of the SMP bit. The time when the SSPxBUF is loaded with the received data is shown. FIGURE 25-6: SPI MODE WAVEFORM (MASTER MODE) Write to SSPxBUF SCKx (CKP = 0 CKE = 0) SCKx (CKP = 1 CKE = 0) 4 Clock Modes SCKx (CKP = 0 CKE = 1) SCKx (CKP = 1 CKE = 1) SDOx (CKE = 0) bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 SDOx (CKE = 1) bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 SDIx (SMP = 0) bit 0 bit 7 Input Sample (SMP = 0) SDIx (SMP = 1) bit 7 bit 0 Input Sample (SMP = 1) SSPxIF SSPxSR to SSPxBUF  2011 Microchip Technology Inc. DS41391D-page 237 PIC16(L)F1826/27 25.2.4 SPI SLAVE MODE In Slave mode, the data is transmitted and received as external clock pulses appear on SCKx. When the last bit is latched, the SSPxIF interrupt flag bit is set. Before enabling the module in SPI Slave mode, the clock line must match the proper Idle state. The clock line can be observed by reading the SCKx pin. The Idle state is determined by the CKP bit of the SSPxCON1 register. While in Slave mode, the external clock is supplied by the external clock source on the SCKx pin. This external clock must meet the minimum high and low times as specified in the electrical specifications. While in Sleep mode, the slave can transmit/receive data. The shift register is clocked from the SCKx pin input and when a byte is received, the device will generate an interrupt. If enabled, the device will wake-up from Sleep. 25.2.4.1 Daisy-Chain Configuration The SPI bus can sometimes be connected in a daisy-chain configuration. The first slave output is connected to the second slave input, the second slave output is connected to the third slave input, and so on. The final slave output is connected to the master input. Each slave sends out, during a second group of clock pulses, an exact copy of what was received during the first group of clock pulses. The whole chain acts as one large communication shift register. The daisy-chain feature only requires a single Slave Select line from the master device. Figure 25-7 shows the block diagram of a typical daisy-chain connection when operating in SPI Mode. In a daisy-chain configuration, only the most recent byte on the bus is required by the slave. Setting the BOEN bit of the SSPxCON3 register will enable writes to the SSPxBUF register, even if the previous byte has not been read. This allows the software to ignore data that may not apply to it. 25.2.5 SLAVE SELECT SYNCHRONIZATION The Slave Select can also be used to synchronize communication. The Slave Select line is held high until the master device is ready to communicate. When the Slave Select line is pulled low, the slave knows that a new transmission is starting. If the slave fails to receive the communication properly, it will be reset at the end of the transmission, when the Slave Select line returns to a high state. The slave is then ready to receive a new transmission when the Slave Select line is pulled low again. If the Slave Select line is not used, there is a risk that the slave will eventually become out of sync with the master. If the slave misses a bit, it will always be one bit off in future transmissions. Use of the Slave Select line allows the slave and master to align themselves at the beginning of each transmission. The SSx pin allows a Synchronous Slave mode. The SPI must be in Slave mode with SSx pin control enabled (SSPxCON1 = 0100). When the SSx pin is low, transmission and reception are enabled and the SDOx pin is driven. When the SSx pin goes high, the SDOx pin is no longer driven, even if in the middle of a transmitted byte and becomes a floating output. External pull-up/pull-down resistors may be desirable depending on the application. Note 1: When the SPI is in Slave mode with SSx pin control enabled (SSPxCON1 = 0100), the SPI module will reset if the SSx pin is set to VDD. 2: When the SPI is used in Slave mode with CKE set; the user must enable SSx pin control. 3: While operated in SPI Slave mode the SMP bit of the SSPxSTAT register must remain clear. When the SPI module resets, the bit counter is forced to ‘0’. This can be done by either forcing the SSx pin to a high level or clearing the SSPxEN bit. DS41391D-page 238  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 25-7: SPI DAISY-CHAIN CONNECTION SPI Master SCK SCK SDOx SDIx SDIx SDOx General I/O SPI Slave #1 SSx SCK SDIx SDOx SPI Slave #2 SSx SCK SDIx SDOx SPI Slave #3 SSx FIGURE 25-8: SLAVE SELECT SYNCHRONOUS WAVEFORM SSx SCKx (CKP = 0 CKE = 0) SCKx (CKP = 1 CKE = 0) Write to SSPxBUF Shift register SSPxSR and bit count are reset SSPxBUF to SSPxSR SDOx bit 7 bit 6 bit 7 SDIx bit 6 bit 0 bit 0 bit 7 bit 7 Input Sample SSPxIF Interrupt Flag SSPxSR to SSPxBUF  2011 Microchip Technology Inc. DS41391D-page 239 PIC16(L)F1826/27 FIGURE 25-9: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 0) SSx Optional SCKx (CKP = 0 CKE = 0) SCKx (CKP = 1 CKE = 0) Write to SSPxBUF Valid SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 SDIx bit 0 bit 7 Input Sample SSPxIF Interrupt Flag SSPxSR to SSPxBUF Write Collision detection active FIGURE 25-10: SPI MODE WAVEFORM (SLAVE MODE WITH CKE = 1) SSx Not Optional SCKx (CKP = 0 CKE = 1) SCKx (CKP = 1 CKE = 1) Write to SSPxBUF Valid SDOx bit 7 bit 6 bit 5 bit 4 bit 3 bit 2 bit 1 bit 0 SDIx bit 7 bit 0 Input Sample SSPxIF Interrupt Flag SSPxSR to SSPxBUF Write Collision detection active DS41391D-page 240  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.2.6 SPI OPERATION IN SLEEP MODE In SPI Master mode, module clocks may be operating at a different speed than when in full power mode; in the case of the Sleep mode, all clocks are halted. Special care must be taken by the user when the MSSPx clock is much faster than the system clock. In Slave mode, when MSSPx interrupts are enabled, after the master completes sending data, an MSSPx interrupt will wake the controller from Sleep. If an exit from Sleep mode is not desired, MSSPx interrupts should be disabled. TABLE 25-1: Name In SPI Master mode, when the Sleep mode is selected, all module clocks are halted and the transmission/reception will remain in that state until the device wakes. After the device returns to Run mode, the module will resume transmitting and receiving data. In SPI Slave mode, the SPI Transmit/Receive Shift register operates asynchronously to the device. This allows the device to be placed in Sleep mode and data to be shifted into the SPI Transmit/Receive Shift register. When all 8 bits have been received, the MSSPx interrupt flag bit will be set and if enabled, will wake the device. SUMMARY OF REGISTERS ASSOCIATED WITH SPI OPERATION Bit 2 Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 ANSA2 ANSA1 ANSA0 123 ANSB3 ANSB2 ANSB1 — 128 INTE IOCIE TMR0IF INTF IOCIF 86 RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 91 Bit 7 Bit 6 Bit 5 RXDTSEL SDO1SEL SS1SEL ANSELA — — — ANSA4 ANSA3 ANSELB ANSB7 ANSB6 ANSB5 ANSB4 INTCON GIE PEIE TMR0IE PIE1 TMR1GIE ADIE PIR1 TMR1GIF ADIF APFCON0 SSPxBUF Bit 4 Bit 3 P2BSEL(1) CCP2SEL(1) Synchronous Serial Port Receive Buffer/Transmit Register 235* SSPxCON1 WCOL SSPxOV SSPxEN CKP SSPxM3 SSPxM2 SSPxM1 SSPxM0 280 SSPxCON3 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN 282 SMP CKE D/A P S R/W UA BF 279 TRISA SSPxSTAT TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 Legend: * Note 1: — = Unimplemented location, read as ‘0’. Shaded cells are not used by the MSSPx in SPI mode. Page provides register information. PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 241 PIC16(L)F1826/27 25.3 I2C MODE OVERVIEW FIGURE 25-11: The Inter-Integrated Circuit Bus (I²C) is a multi-master serial data communication bus. Devices communicate in a master/slave environment where the master devices initiate the communication. A Slave device is controlled through addressing. VDD SCLx The I2C bus specifies two signal connections: • Serial Clock (SCLx) • Serial Data (SDAx) Figure 25-11 shows the block diagram of the MSSPx module when operating in I2C Mode. Both the SCLx and SDAx connections are bidirectional open-drain lines, each requiring pull-up resistors for the supply voltage. Pulling the line to ground is considered a logical zero and letting the line float is considered a logical one. Figure 25-11 shows a typical connection between two processors configured as master and slave devices. The I2C bus can operate with one or more master devices and one or more slave devices. There are four potential modes of operation for a given device: • Master Transmit mode (master is transmitting data to a slave) • Master Receive mode (master is receiving data from a slave) • Slave Transmit mode (slave is transmitting data to a master) • Slave Receive mode (slave is receiving data from the master) To begin communication, a master device starts out in Master Transmit mode. The master device sends out a Start bit followed by the address byte of the slave it intends to communicate with. This is followed by a single Read/Write bit, which determines whether the master intends to transmit to or receive data from the slave device. If the requested slave exists on the bus, it will respond with an Acknowledge bit, otherwise known as an ACK. The master then continues in either Transmit mode or Receive mode and the slave continues in the complement, either in Receive mode or Transmit mode, respectively. A Start bit is indicated by a high-to-low transition of the SDAx line while the SCLx line is held high. Address and data bytes are sent out, Most Significant bit (MSb) first. The Read/Write bit is sent out as a logical one when the master intends to read data from the slave, and is sent out as a logical zero when it intends to write data to the slave. DS41391D-page 242 I2C MASTER/ SLAVE CONNECTION SCLx VDD Master Slave SDAx SDAx The Acknowledge bit (ACK) is an active-low signal, which holds the SDAx line low to indicate to the transmitter that the slave device has received the transmitted data and is ready to receive more. The transition of a data bit is always performed while the SCLx line is held low. Transitions that occur while the SCLx line is held high are used to indicate Start and Stop bits. If the master intends to write to the slave, then it repeatedly sends out a byte of data, with the slave responding after each byte with an ACK bit. In this example, the master device is in Master Transmit mode and the slave is in Slave Receive mode. If the master intends to read from the slave, then it repeatedly receives a byte of data from the slave, and responds after each byte with an ACK bit. In this example, the master device is in Master Receive mode and the slave is Slave Transmit mode. On the last byte of data communicated, the master device may end the transmission by sending a Stop bit. If the master device is in Receive mode, it sends the Stop bit in place of the last ACK bit. A Stop bit is indicated by a low-to-high transition of the SDAx line while the SCLx line is held high. In some cases, the master may want to maintain control of the bus and re-initiate another transmission. If so, the master device may send another Start bit in place of the Stop bit or last ACK bit when it is in receive mode. The I2C bus specifies three message protocols; • Single message where a master writes data to a slave. • Single message where a master reads data from a slave. • Combined message where a master initiates a minimum of two writes, or two reads, or a combination of writes and reads, to one or more slaves.  2011 Microchip Technology Inc. PIC16(L)F1826/27 When one device is transmitting a logical one, or letting the line float, and a second device is transmitting a logical zero, or holding the line low, the first device can detect that the line is not a logical one. This detection, when used on the SCLx line, is called clock stretching. Clock stretching gives slave devices a mechanism to control the flow of data. When this detection is used on the SDAx line, it is called arbitration. Arbitration ensures that there is only one master device communicating at any single time. 25.3.1 CLOCK STRETCHING When a slave device has not completed processing data, it can delay the transfer of more data through the process of Clock Stretching. An addressed slave device may hold the SCLx clock line low after receiving or sending a bit, indicating that it is not yet ready to continue. The master that is communicating with the slave will attempt to raise the SCLx line in order to transfer the next bit, but will detect that the clock line has not yet been released. Because the SCLx connection is open-drain, the slave has the ability to hold that line low until it is ready to continue communicating. Clock stretching allows receivers that cannot keep up with a transmitter to control the flow of incoming data. 25.3.2 ARBITRATION Each master device must monitor the bus for Start and Stop bits. If the device detects that the bus is busy, it cannot begin a new message until the bus returns to an Idle state. However, two master devices may try to initiate a transmission on or about the same time. When this occurs, the process of arbitration begins. Each transmitter checks the level of the SDAx data line and compares it to the level that it expects to find. The first transmitter to observe that the two levels don't match, loses arbitration, and must stop transmitting on the SDAx line. For example, if one transmitter holds the SDAx line to a logical one (lets it float) and a second transmitter holds it to a logical zero (pulls it low), the result is that the SDAx line will be low. The first transmitter then observes that the level of the line is different than expected and concludes that another transmitter is communicating. The first transmitter to notice this difference is the one that loses arbitration and must stop driving the SDAx line. If this transmitter is also a master device, it also must stop driving the SCLx line. It then can monitor the lines for a Stop condition before trying to reissue its transmission. In the meantime, the other device that has not noticed any difference between the expected and actual levels on the SDAx line continues with it's original transmission. It can do so without any complications, because so far, the transmission appears exactly as expected with no other transmitter disturbing the message. Slave Transmit mode can also be arbitrated, when a master addresses multiple slaves, but this is less common. If two master devices are sending a message to two different slave devices at the address stage, the master sending the lower slave address always wins arbitration. When two master devices send messages to the same slave address, and addresses can sometimes refer to multiple slaves, the arbitration process must continue into the data stage. Arbitration usually occurs very rarely, but it is a necessary process for proper multi-master support.  2011 Microchip Technology Inc. DS41391D-page 243 PIC16(L)F1826/27 25.4 I2C MODE OPERATION All MSSPx I2C communication is byte oriented and shifted out MSb first. Six SFR registers and 2 interrupt flags interface the module with the PIC® microcontroller and user software. Two pins, SDAx and SCLx, are exercised by the module to communicate with other external I2C devices. 25.4.1 BYTE FORMAT All communication in I2C is done in 9-bit segments. A byte is sent from a Master to a Slave or vice-versa, followed by an Acknowledge bit sent back. After the 8th falling edge of the SCLx line, the device outputting data on the SDAx changes that pin to an input and reads in an acknowledge value on the next clock pulse. The clock signal, SCLx, is provided by the master. Data is valid to change while the SCLx signal is low, and sampled on the rising edge of the clock. Changes on the SDAx line while the SCLx line is high define special conditions on the bus, explained below. 25.4.2 DEFINITION OF I2C TERMINOLOGY There is language and terminology in the description of I2C communication that have definitions specific to I2C. That word usage is defined below and may be used in the rest of this document without explanation. This table was adapted from the Philips I2C specification. 25.4.3 SDAX AND SCLX PINS Selection of any I2C mode with the SSPxEN bit set, forces the SCLx and SDAx pins to be open-drain. These pins should be set by the user to inputs by setting the appropriate TRIS bits. Note: Data is tied to output zero when an I2C mode is enabled. 25.4.4 SDAX HOLD TIME The hold time of the SDAx pin is selected by the SDAHT bit of the SSPxCON3 register. Hold time is the time SDAx is held valid after the falling edge of SCLx. Setting the SDAHT bit selects a longer 300 ns minimum hold time and may help on buses with large capacitance. DS41391D-page 244 TABLE 25-2: TERM I2C BUS TERMS Description Transmitter The device which shifts data out onto the bus. Receiver The device which shifts data in from the bus. Master The device that initiates a transfer, generates clock signals and terminates a transfer. Slave The device addressed by the master. Multi-master A bus with more than one device that can initiate data transfers. Arbitration Procedure to ensure that only one master at a time controls the bus. Winning arbitration ensures that the message is not corrupted. Synchronization Procedure to synchronize the clocks of two or more devices on the bus. Idle No master is controlling the bus, and both SDAx and SCLx lines are high. Active Any time one or more master devices are controlling the bus. Slave device that has received a Addressed Slave matching address and is actively being clocked by a master. Matching Address byte that is clocked into a Address slave that matches the value stored in SSPxADD. Write Request Slave receives a matching address with R/W bit clear, and is ready to clock in data. Read Request Master sends an address byte with the R/W bit set, indicating that it wishes to clock data out of the Slave. This data is the next and all following bytes until a Restart or Stop. Clock Stretching When a device on the bus hold SCLx low to stall communication. Bus Collision Any time the SDAx line is sampled low by the module while it is outputting and expected high state.  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.4.5 25.4.7 START CONDITION The I2C specification defines a Start condition as a transition of SDAx from a high to a low state while SCLx line is high. A Start condition is always generated by the master and signifies the transition of the bus from an Idle to an Active state. Figure 25-10 shows wave forms for Start and Stop conditions. A Restart is valid any time that a Stop would be valid. A master can issue a Restart if it wishes to hold the bus after terminating the current transfer. A Restart has the same effect on the slave that a Start would, resetting all slave logic and preparing it to clock in an address. The master may want to address the same or another slave. A bus collision can occur on a Start condition if the module samples the SDAx line low before asserting it low. This does not conform to the I2C Specification that states no bus collision can occur on a Start. 25.4.6 RESTART CONDITION In 10-bit Addressing Slave mode a Restart is required for the master to clock data out of the addressed slave. Once a slave has been fully addressed, matching both high and low address bytes, the master can issue a Restart and the high address byte with the R/W bit set. The slave logic will then hold the clock and prepare to clock out data. STOP CONDITION A Stop condition is a transition of the SDAx line from low-to-high state while the SCLx line is high. After a full match with R/W clear in 10-bit mode, a prior match flag is set and maintained. Until a Stop condition, a high address with R/W clear, or high address match fails. Note: At least one SCLx low time must appear before a Stop is valid, therefore, if the SDAx line goes low then high again while the SCLx line stays high, only the Start condition is detected. 25.4.8 START/STOP CONDITION INTERRUPT MASKING The SCIE and PCIE bits of the SSPxCON3 register can enable the generation of an interrupt in Slave modes that do not typically support this function. Slave modes where interrupt on Start and Stop detect are already enabled, these bits will have no effect. FIGURE 25-12: I2C START AND STOP CONDITIONS SDAx SCLx S Start P Change of Change of Data Allowed Data Allowed Condition FIGURE 25-13: Stop Condition I2C RESTART CONDITION Sr Change of Change of Data Allowed Restart Data Allowed Condition  2011 Microchip Technology Inc. DS41391D-page 245 PIC16(L)F1826/27 25.4.9 ACKNOWLEDGE SEQUENCE The 9th SCLx pulse for any transferred byte in I2C is dedicated as an Acknowledge. It allows receiving devices to respond back to the transmitter by pulling the SDAx line low. The transmitter must release control of the line during this time to shift in the response. The Acknowledge (ACK) is an active-low signal, pulling the SDAx line low indicated to the transmitter that the device has received the transmitted data and is ready to receive more. The result of an ACK is placed in the ACKSTAT bit of the SSPxCON2 register. Slave software, when the AHEN and DHEN bits are set, allow the user to set the ACK value sent back to the transmitter. The ACKDT bit of the SSPxCON2 register is set/cleared to determine the response. Slave hardware will generate an ACK response if the AHEN and DHEN bits of the SSPxCON3 register are clear. There are certain conditions where an ACK will not be sent by the slave. If the BF bit of the SSPxSTAT register or the SSPxOV bit of the SSPxCON1 register are set when a byte is received. When the module is addressed, after the 8th falling edge of SCLx on the bus, the ACKTIM bit of the SSPxCON3 register is set. The ACKTIM bit indicates the acknowledge time of the active bus. The ACKTIM Status bit is only active when the AHEN bit or DHEN bit is enabled. 25.5 I2C SLAVE MODE OPERATION The MSSPx Slave mode operates in one of four modes selected in the SSPxM bits of SSPxCON1 register. The modes can be divided into 7-bit and 10-bit Addressing mode. 10-bit Addressing modes operate the same as 7-bit with some additional overhead for handling the larger addresses. Modes with Start and Stop bit interrupts operated the same as the other modes with SSPxIF additionally getting set upon detection of a Start, Restart, or Stop condition. 25.5.1 SLAVE MODE ADDRESSES The SSPxADD register (Register 25-6) contains the Slave mode address. The first byte received after a Start or Restart condition is compared against the value stored in this register. If the byte matches, the value is loaded into the SSPxBUF register and an interrupt is generated. If the value does not match, the module goes Idle and no indication is given to the software that anything happened. The SSPx Mask register (Register 25-5) affects the address matching process. See Section 25.5.9 “SSPx Mask Register” for more information. 25.5.1.1 I2C Slave 7-bit Addressing Mode In 7-bit Addressing mode, the LSb of the received data byte is ignored when determining if there is an address match. 25.5.1.2 I2C Slave 10-bit Addressing Mode In 10-bit Addressing mode, the first received byte is compared to the binary value of ‘1 1 1 1 0 A9 A8 0’. A9 and A8 are the two MSb of the 10-bit address and stored in bits 2 and 1 of the SSPxADD register. After the acknowledge of the high byte the UA bit is set and SCLx is held low until the user updates SSPxADD with the low address. The low address byte is clocked in and all 8 bits are compared to the low address value in SSPxADD. Even if there is not an address match; SSPxIF and UA are set, and SCLx is held low until SSPxADD is updated to receive a high byte again. When SSPxADD is updated the UA bit is cleared. This ensures the module is ready to receive the high address byte on the next communication. A high and low address match as a write request is required at the start of all 10-bit addressing communication. A transmission can be initiated by issuing a Restart once the slave is addressed, and clocking in the high address with the R/W bit set. The slave hardware will then acknowledge the read request and prepare to clock out data. This is only valid for a slave after it has received a complete high and low address byte match. DS41391D-page 246  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.5.2 SLAVE RECEPTION When the R/W bit of a matching received address byte is clear, the R/W bit of the SSPxSTAT register is cleared. The received address is loaded into the SSPxBUF register and acknowledged. When the overflow condition exists for a received address, then not Acknowledge is given. An overflow condition is defined as either bit BF of the SSPxSTAT register is set, or bit SSPxOV of the SSPxCON1 register is set. The BOEN bit of the SSPxCON3 register modifies this operation. For more information see Register 25-4. An MSSPx interrupt is generated for each transferred data byte. Flag bit, SSPxIF, must be cleared by software. When the SEN bit of the SSPxCON2 register is set, SCLx will be held low (clock stretch) following each received byte. The clock must be released by setting the CKP bit of the SSPxCON1 register, except sometimes in 10-bit mode. See Section 25.2.3 “SPI Master Mode” for more detail. 25.5.2.1 7-bit Addressing Reception This section describes a standard sequence of events for the MSSPx module configured as an I2C Slave in 7-bit Addressing mode. All decisions made by hardware or software and their effect on reception. Figure 25-13 and Figure 25-14 is used as a visual reference for this description. This is a step by step process of what typically must be done to accomplish I2C communication. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Start bit detected. S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled. Matching address with R/W bit clear is received. The slave pulls SDAx low sending an ACK to the master, and sets SSPxIF bit. Software clears the SSPxIF bit. Software reads received address from SSPxBUF clearing the BF flag. If SEN = 1; Slave software sets CKP bit to release the SCLx line. The master clocks out a data byte. Slave drives SDAx low sending an ACK to the master, and sets SSPxIF bit. Software clears SSPxIF. Software reads the received byte from SSPxBUF clearing BF. Steps 8-12 are repeated for all received bytes from the Master. Master sends Stop condition, setting P bit of SSPxSTAT, and the bus goes Idle.  2011 Microchip Technology Inc. 25.5.2.2 7-bit Reception with AHEN and DHEN Slave device reception with AHEN and DHEN set operate the same as without these options with extra interrupts and clock stretching added after the 8th falling edge of SCLx. These additional interrupts allow the slave software to decide whether it wants to ACK the receive address or data byte, rather than the hardware. This functionality adds support for PMBus™ that was not present on previous versions of this module. This list describes the steps that need to be taken by slave software to use these options for I2C communcation. Figure 25-15 displays a module using both address and data holding. Figure 25-16 includes the operation with the SEN bit of the SSPxCON2 register set. 1. S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled. 2. Matching address with R/W bit clear is clocked in. SSPxIF is set and CKP cleared after the 8th falling edge of SCLx. 3. Slave clears the SSPxIF. 4. Slave can look at the ACKTIM bit of the SSPxCON3 register to determine if the SSPxIF was after or before the ACK. 5. Slave reads the address value from SSPxBUF, clearing the BF flag. 6. Slave sets ACK value clocked out to the master by setting ACKDT. 7. Slave releases the clock by setting CKP. 8. SSPxIF is set after an ACK, not after a NACK. 9. If SEN = 1 the slave hardware will stretch the clock after the ACK. 10. Slave clears SSPxIF. Note: SSPxIF is still set after the 9th falling edge of SCLx even if there is no clock stretching and BF has been cleared. Only if NACK is sent to Master is SSPxIF not set 11. SSPxIF set and CKP cleared after 8th falling edge of SCLx for a received data byte. 12. Slave looks at ACKTIM bit of SSPxCON3 to determine the source of the interrupt. 13. Slave reads the received data from SSPxBUF clearing BF. 14. Steps 7-14 are the same for each received data byte. 15. Communication is ended by either the slave sending an ACK = 1, or the master sending a Stop condition. If a Stop is sent and Interrupt on Stop Detect is disabled, the slave will only know by polling the P bit of the SSTSTAT register. DS41391D-page 247 DS41391D-page 248 SSPxOV BF SSPxIF S 1 A7 2 A6 3 A5 4 A4 5 A3 6 A2 7 A1 8 9 ACK 1 D7 2 D6 4 D4 5 D3 6 D2 7 D1 SSPxBUF is read Cleared by software 3 D5 Receiving Data 8 9 2 D6 First byte of data is available in SSPxBUF 1 D0 ACK D7 4 D4 5 D3 6 D2 7 D1 8 D0 SSPxOV set because SSPxBUF is still full. ACK is not sent. Cleared by software 3 D5 Receiving Data From Slave to Master 9 P SSPxIF set on 9th falling edge of SCLx ACK = 1 FIGURE 25-14: SCLx SDAx Receiving Address Bus Master sends Stop condition PIC16(L)F1826/27 I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 0, DHEN = 0)  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. CKP SSPxOV BF SSPxIF 1 SCLx S A7 2 A6 3 A5 4 A4 5 A3 6 A2 7 A1 8 9 R/W=0 ACK SEN 2 D6 3 D5 4 D4 5 D3 6 D2 7 D1 8 D0 CKP is written to ‘1’ in software, releasing SCLx SSPxBUF is read Cleared by software Clock is held low until CKP is set to ‘1’ 1 D7 Receive Data 9 ACK SEN 3 D5 4 D4 5 D3 First byte of data is available in SSPxBUF 6 D2 7 D1 SSPxOV set because SSPxBUF is still full. ACK is not sent. Cleared by software 2 D6 CKP is written to 1 in software, releasing SCLx 1 D7 Receive Data 8 D0 9 ACK SCLx is not held low because ACK= 1 SSPxIF set on 9th falling edge of SCLx P FIGURE 25-15: SDAx Receive Address Bus Master sends Stop condition PIC16(L)F1826/27 I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 0, DHEN = 0) DS41391D-page 249 DS41391D-page 250 P S ACKTIM CKP ACKDT BF SSPxIF S Receiving Address 1 3 5 6 7 8 ACK the received byte Slave software clears ACKDT to Address is read from SSBUF If AHEN = 1: SSPxIF is set 4 ACKTIM set by hardware on 8th falling edge of SCLx When AHEN=1: CKP is cleared by hardware and SCLx is stretched 2 A7 A6 A5 A4 A3 A2 A1 Receiving Data 9 2 3 4 5 6 7 ACKTIM cleared by hardware in 9th rising edge of SCLx When DHEN=1: CKP is cleared by hardware on 8th falling edge of SCLx SSPxIF is set on 9th falling edge of SCLx, after ACK 1 8 ACK D7 D6 D5 D4 D3 D2 D1 D0 Received Data 1 2 4 5 6 ACKTIM set by hardware on 8th falling edge of SCLx CKP set by software, SCLx is released 8 Slave software sets ACKDT to not ACK 7 Cleared by software 3 D7 D6 D5 D4 D3 D2 D1 D0 Data is read from SSPxBUF 9 ACK 9 P No interrupt after not ACK from Slave ACK=1 Master sends Stop condition FIGURE 25-16: SCLx SDAx Master Releases SDAx to slave for ACK sequence PIC16(L)F1826/27 I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 1, DHEN = 1)  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. P S ACKTIM CKP ACKDT BF SSPxIF S Receiving Address 4 5 6 7 8 When AHEN = 1; on the 8th falling edge of SCLx of an address byte, CKP is cleared Slave software clears ACKDT to ACK the received byte Received address is loaded into SSPxBUF 2 3 ACKTIM is set by hardware on 8th falling edge of SCLx 1 A7 A6 A5 A4 A3 A2 A1 9 ACK Receive Data 2 3 4 5 6 7 8 ACKTIM is cleared by hardware on 9th rising edge of SCLx When DHEN = 1; on the 8th falling edge of SCLx of a received data byte, CKP is cleared Received data is available on SSPxBUF Cleared by software 1 D7 D6 D5 D4 D3 D2 D1 D0 9 ACK Receive Data 1 3 4 5 6 7 8 Set by software, release SCLx Slave sends not ACK SSPxBUF can be read any time before next byte is loaded 2 D7 D6 D5 D4 D3 D2 D1 D0 9 ACK CKP is not cleared if not ACK No interrupt after if not ACK from Slave P Master sends Stop condition FIGURE 25-17: SCLx SDAx R/W = 0 Master releases SDAx to slave for ACK sequence PIC16(L)F1826/27 I2C SLAVE, 7-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 1, DHEN = 1) DS41391D-page 251 PIC16(L)F1826/27 25.5.3 SLAVE TRANSMISSION 25.5.3.2 7-bit Transmission When the R/W bit of the incoming address byte is set and an address match occurs, the R/W bit of the SSPxSTAT register is set. The received address is loaded into the SSPxBUF register, and an ACK pulse is sent by the slave on the ninth bit. A master device can transmit a read request to a slave, and then clock data out of the slave. The list below outlines what software for a slave will need to do to accomplish a standard transmission. Figure 25-17 can be used as a reference to this list. Following the ACK, slave hardware clears the CKP bit and the SCLx pin is held low (see Section 25.5.6 “Clock Stretching” for more detail). By stretching the clock, the master will be unable to assert another clock pulse until the slave is done preparing the transmit data. 1. The transmit data must be loaded into the SSPxBUF register which also loads the SSPxSR register. Then the SCLx pin should be released by setting the CKP bit of the SSPxCON1 register. The eight data bits are shifted out on the falling edge of the SCLx input. This ensures that the SDAx signal is valid during the SCLx high time. The ACK pulse from the master-receiver is latched on the rising edge of the ninth SCLx input pulse. This ACK value is copied to the ACKSTAT bit of the SSPxCON2 register. If ACKSTAT is set (not ACK), then the data transfer is complete. In this case, when the not ACK is latched by the slave, the slave goes Idle and waits for another occurrence of the Start bit. If the SDAx line was low (ACK), the next transmit data must be loaded into the SSPxBUF register. Again, the SCLx pin must be released by setting bit CKP. An MSSPx interrupt is generated for each data transfer byte. The SSPxIF bit must be cleared by software and the SSPxSTAT register is used to determine the status of the byte. The SSPxIF bit is set on the falling edge of the ninth clock pulse. 25.5.3.1 Slave Mode Bus Collision A slave receives a Read request and begins shifting data out on the SDAx line. If a bus collision is detected and the SBCDE bit of the SSPxCON3 register is set, the BCLxIF bit of the PIRx register is set. Once a bus collision is detected, the slave goes Idle and waits to be addressed again. User software can use the BCLxIF bit to handle a slave bus collision. DS41391D-page 252 Master sends a Start condition on SDAx and SCLx. 2. S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled. 3. Matching address with R/W bit set is received by the Slave setting SSPxIF bit. 4. Slave hardware generates an ACK and sets SSPxIF. 5. SSPxIF bit is cleared by user. 6. Software reads the received address from SSPxBUF, clearing BF. 7. R/W is set so CKP was automatically cleared after the ACK. 8. The slave software loads the transmit data into SSPxBUF. 9. CKP bit is set releasing SCLx, allowing the master to clock the data out of the slave. 10. SSPxIF is set after the ACK response from the master is loaded into the ACKSTAT register. 11. SSPxIF bit is cleared. 12. The slave software checks the ACKSTAT bit to see if the master wants to clock out more data. Note 1: If the master ACKs the clock will be stretched. 2: ACKSTAT is the only bit updated on the rising edge of SCLx (9th) rather than the falling. 13. Steps 9-13 are repeated for each transmitted byte. 14. If the master sends a not ACK; the clock is not held, but SSPxIF is still set. 15. The master sends a Restart condition or a Stop. 16. The slave is no longer addressed.  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. P S D/A R/W ACKSTAT CKP BF SSPxIF S Receiving Address 1 2 5 6 7 8 Indicates an address has been received R/W is copied from the matching address byte 9 R/W = 1 Automatic ACK Received address is read from SSPxBUF 4 When R/W is set SCLx is always held low after 9th SCLx falling edge 3 A7 A6 A5 A4 A3 A2 A1 Transmitting Data Automatic 2 3 4 5 Set by software Data to transmit is loaded into SSPxBUF Cleared by software 1 6 7 8 9 D7 D6 D5 D4 D3 D2 D1 D0 ACK Transmitting Data 2 3 4 5 7 8 CKP is not held for not ACK 6 Masters not ACK is copied to ACKSTAT BF is automatically cleared after 8th falling edge of SCLx 1 D7 D6 D5 D4 D3 D2 D1 D0 9 ACK P FIGURE 25-18: SCLx SDAx Master sends Stop condition PIC16(L)F1826/27 I2C SLAVE, 7-BIT ADDRESS, TRANSMISSION (AHEN = 0) DS41391D-page 253 PIC16(L)F1826/27 25.5.3.3 7-bit Transmission with Address Hold Enabled Setting the AHEN bit of the SSPxCON3 register enables additional clock stretching and interrupt generation after the 8th falling edge of a received matching address. Once a matching address has been clocked in, CKP is cleared and the SSPxIF interrupt is set. Figure 25-18 displays a standard waveform of a 7-bit Address Slave Transmission with AHEN enabled. 1. 2. Bus starts Idle. Master sends Start condition; the S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled. 3. Master sends matching address with R/W bit set. After the 8th falling edge of the SCLx line the CKP bit is cleared and SSPxIF interrupt is generated. 4. Slave software clears SSPxIF. 5. Slave software reads ACKTIM bit of SSPxCON3 register, and R/W and D/A of the SSPxSTAT register to determine the source of the interrupt. 6. Slave reads the address value from the SSPxBUF register clearing the BF bit. 7. Slave software decides from this information if it wishes to ACK or not ACK and sets ACKDT bit of the SSPxCON2 register accordingly. 8. Slave sets the CKP bit releasing SCLx. 9. Master clocks in the ACK value from the slave. 10. Slave hardware automatically clears the CKP bit and sets SSPxIF after the ACK if the R/W bit is set. 11. Slave software clears SSPxIF. 12. Slave loads value to transmit to the master into SSPxBUF setting the BF bit. Note: SSPxBUF cannot be loaded until after the ACK. 13. Slave sets CKP bit releasing the clock. 14. Master clocks out the data from the slave and sends an ACK value on the 9th SCLx pulse. 15. Slave hardware copies the ACK value into the ACKSTAT bit of the SSPxCON2 register. 16. Steps 10-15 are repeated for each byte transmitted to the master from the slave. 17. If the master sends a not ACK the slave releases the bus allowing the master to send a Stop and end the communication. Note: Master must send a not ACK on the last byte to ensure that the slave releases the SCLx line to receive a Stop. DS41391D-page 254  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. D/A R/W ACKTIM CKP ACKSTAT ACKDT BF SSPxIF S Receiving Address 2 4 5 6 7 8 Slave clears ACKDT to ACK address ACKTIM is set on 8th falling edge of SCLx 9 ACK When R/W = 1; CKP is always cleared after ACK R/W = 1 Received address is read from SSPxBUF 3 When AHEN = 1; CKP is cleared by hardware after receiving matching address. 1 A7 A6 A5 A4 A3 A2 A1 3 4 5 6 Cleared by software 2 Set by software, releases SCLx Data to transmit is loaded into SSPxBUF 1 7 8 9 Transmitting Data Automatic D7 D6 D5 D4 D3 D2 D1 D0 ACK ACKTIM is cleared on 9th rising edge of SCLx Automatic Transmitting Data 1 3 4 5 6 7 after not ACK CKP not cleared Master’s ACK response is copied to SSPxSTAT BF is automatically cleared after 8th falling edge of SCLx 2 8 D7 D6 D5 D4 D3 D2 D1 D0 9 ACK P Master sends Stop condition FIGURE 25-19: SCLx SDAx Master releases SDAx to slave for ACK sequence PIC16(L)F1826/27 I2C SLAVE, 7-BIT ADDRESS, TRANSMISSION (AHEN = 1) DS41391D-page 255 PIC16(L)F1826/27 25.5.4 SLAVE MODE 10-BIT ADDRESS RECEPTION This section describes a standard sequence of events for the MSSPx module configured as an I2C Slave in 10-bit Addressing mode. Figure 25-19 is used as a visual reference for this description. This is a step by step process of what must be done by slave software to accomplish I2C communication. 1. 2. 3. 4. 5. 6. 7. 8. Bus starts Idle. Master sends Start condition; S bit of SSPxSTAT is set; SSPxIF is set if interrupt on Start detect is enabled. Master sends matching high address with R/W bit clear; UA bit of the SSPxSTAT register is set. Slave sends ACK and SSPxIF is set. Software clears the SSPxIF bit. Software reads received address from SSPxBUF clearing the BF flag. Slave loads low address into SSPxADD, releasing SCLx. Master sends matching low address byte to the Slave; UA bit is set. 25.5.5 10-BIT ADDRESSING WITH ADDRESS OR DATA HOLD Reception using 10-bit addressing with AHEN or DHEN set is the same as with 7-bit modes. The only difference is the need to update the SSPxADD register using the UA bit. All functionality, specifically when the CKP bit is cleared and SCLx line is held low are the same. Figure 25-20 can be used as a reference of a slave in 10-bit addressing with AHEN set. Figure 25-21 shows a standard waveform for a slave transmitter in 10-bit Addressing mode. Note: Updates to the SSPxADD register are not allowed until after the ACK sequence. 9. Slave sends ACK and SSPxIF is set. Note: If the low address does not match, SSPxIF and UA are still set so that the slave software can set SSPxADD back to the high address. BF is not set because there is no match. CKP is unaffected. 10. Slave clears SSPxIF. 11. Slave reads the received matching address from SSPxBUF clearing BF. 12. Slave loads high address into SSPxADD. 13. Master clocks a data byte to the slave and clocks out the slaves ACK on the 9th SCLx pulse; SSPxIF is set. 14. If SEN bit of SSPxCON2 is set, CKP is cleared by hardware and the clock is stretched. 15. Slave clears SSPxIF. 16. Slave reads the received byte from SSPxBUF clearing BF. 17. If SEN is set the slave sets CKP to release the SCLx. 18. Steps 13-17 repeat for each received byte. 19. Master sends Stop to end the transmission. DS41391D-page 256  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. CKP UA BF SSPxIF S 1 1 2 1 5 6 7 0 A9 A8 8 Set by hardware on 9th falling edge 4 1 When UA = 1; SCLx is held low 9 ACK If address matches SSPxADD it is loaded into SSPxBUF 3 1 Receive First Address Byte 1 3 4 5 6 7 8 Software updates SSPxADD and releases SCLx 2 9 A7 A6 A5 A4 A3 A2 A1 A0 ACK Receive Second Address Byte 1 3 4 5 6 7 8 9 1 3 4 5 6 7 Data is read from SSPxBUF SCLx is held low while CKP = 0 2 8 9 D7 D6 D5 D4 D3 D2 D1 D0 ACK Receive Data Set by software, When SEN = 1; releasing SCLx CKP is cleared after 9th falling edge of received byte Receive address is read from SSPxBUF Cleared by software 2 D7 D6 D5 D4 D3 D2 D1 D0 ACK Receive Data P FIGURE 25-20: SCLx SDAx Master sends Stop condition PIC16(L)F1826/27 I2C SLAVE, 10-BIT ADDRESS, RECEPTION (SEN = 1, AHEN = 0, DHEN = 0) DS41391D-page 257 DS41391D-page 258 ACKTIM CKP UA ACKDT BF 2 1 5 0 6 A9 7 A8 Set by hardware on 9th falling edge 4 1 ACKTIM is set by hardware on 8th falling edge of SCLx If when AHEN = 1; on the 8th falling edge of SCLx of an address byte, CKP is cleared Slave software clears ACKDT to ACK the received byte 3 1 8 R/W = 0 9 ACK UA 2 A6 3 A5 4 A4 5 A3 6 A2 7 A1 Update to SSPxADD is not allowed until 9th falling edge of SCLx SSPxBUF can be read anytime before the next received byte Cleared by software 1 A7 Receive Second Address Byte 8 A0 9 ACK UA 2 D6 3 D5 4 D4 6 D2 Set CKP with software releases SCLx 7 D1 Update of SSPxADD, clears UA and releases SCLx 5 D3 Receive Data Cleared by software 1 D7 8 9 2 Received data is read from SSPxBUF 1 D6 D5 Receive Data D0 ACK D7 FIGURE 25-21: SSPxIF 1 SCLx S 1 SDAx Receive First Address Byte PIC16(L)F1826/27 I2C SLAVE, 10-BIT ADDRESS, RECEPTION (SEN = 0, AHEN = 1, DHEN = 0)  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. D/A R/W ACKSTAT CKP UA BF SSPxIF 4 5 6 7 Set by hardware 3 Indicates an address has been received UA indicates SSPxADD must be updated SSPxBUF loaded with received address 2 8 9 1 SCLx S Receiving Address R/W = 0 1 1 1 1 0 A9 A8 ACK 1 3 4 5 6 7 8 After SSPxADD is updated, UA is cleared and SCLx is released Cleared by software 2 9 A7 A6 A5 A4 A3 A2 A1 A0 ACK Receiving Second Address Byte 1 4 5 6 7 8 Set by hardware 2 3 R/W is copied from the matching address byte When R/W = 1; CKP is cleared on 9th falling edge of SCLx High address is loaded back into SSPxADD Received address is read from SSPxBUF Sr 1 1 1 1 0 A9 A8 Receive First Address Byte 9 ACK 2 3 4 5 6 7 8 Masters not ACK is copied Set by software releases SCLx Data to transmit is loaded into SSPxBUF 1 D7 D6 D5 D4 D3 D2 D1 D0 Transmitting Data Byte 9 P Master sends Stop condition ACK = 1 Master sends not ACK FIGURE 25-22: SDAx Master sends Restart event PIC16(L)F1826/27 I2C SLAVE, 10-BIT ADDRESS, TRANSMISSION (SEN = 0, AHEN = 0, DHEN = 0) DS41391D-page 259 PIC16(L)F1826/27 25.5.6 CLOCK STRETCHING 25.5.6.2 Clock stretching occurs when a device on the bus holds the SCLx line low effectively pausing communication. The slave may stretch the clock to allow more time to handle data or prepare a response for the master device. A master device is not concerned with stretching as anytime it is active on the bus and not transferring data it is stretching. Any stretching done by a slave is invisible to the master software and handled by the hardware that generates SCLx. The CKP bit of the SSPxCON1 register is used to control stretching in software. Any time the CKP bit is cleared, the module will wait for the SCLx line to go low and then hold it. Setting CKP will release SCLx and allow more communication. 25.5.6.1 Normal Clock Stretching Following an ACK if the R/W bit of SSPxSTAT is set, a read request, the slave hardware will clear CKP. This allows the slave time to update SSPxBUF with data to transfer to the master. If the SEN bit of SSPxCON2 is set, the slave hardware will always stretch the clock after the ACK sequence. Once the slave is ready; CKP is set by software and communication resumes. Note 1: The BF bit has no effect on if the clock will be stretched or not. This is different than previous versions of the module that would not stretch the clock, clear CKP, if SSPxBUF was read before the 9th falling edge of SCLx. 2: Previous versions of the module did not stretch the clock for a transmission if SSPxBUF was loaded before the 9th falling edge of SCLx. It is now always cleared for read requests. FIGURE 25-23: 10-bit Addressing Mode In 10-bit Addressing mode, when the UA bit is set, the clock is always stretched. This is the only time the SCLx is stretched without CKP being cleared. SCLx is released immediately after a write to SSPxADD. Note: Previous versions of the module did not stretch the clock if the second address byte did not match. 25.5.6.3 Byte NACKing When AHEN bit of SSPxCON3 is set; CKP is cleared by hardware after the 8th falling edge of SCLx for a received matching address byte. When DHEN bit of SSPxCON3 is set; CKP is cleared after the 8th falling edge of SCLx for received data. Stretching after the 8th falling edge of SCLx allows the slave to look at the received address or data and decide if it wants to ACK the received data. 25.5.7 CLOCK SYNCHRONIZATION AND THE CKP BIT Any time the CKP bit is cleared, the module will wait for the SCLx line to go low and then hold it. However, clearing the CKP bit will not assert the SCLx output low until the SCLx output is already sampled low. Therefore, the CKP bit will not assert the SCLx line until an external I2C master device has already asserted the SCLx line. The SCLx output will remain low until the CKP bit is set and all other devices on the I2C bus have released SCLx. This ensures that a write to the CKP bit will not violate the minimum high time requirement for SCLx (see Figure 25-22). CLOCK SYNCHRONIZATION TIMING Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 SDAx DX ‚ – 1 DX SCLx CKP Master device asserts clock Master device releases clock WR SSPxCON1 DS41391D-page 260  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.5.8 GENERAL CALL ADDRESS SUPPORT In 10-bit Address mode, the UA bit will not be set on the reception of the general call address. The slave will prepare to receive the second byte as data, just as it would in 7-bit mode. The addressing procedure for the I2C bus is such that the first byte after the Start condition usually determines which device will be the slave addressed by the master device. The exception is the general call address which can address all devices. When this address is used, all devices should, in theory, respond with an acknowledge. If the AHEN bit of the SSPxCON3 register is set, just as with any other address reception, the slave hardware will stretch the clock after the 8th falling edge of SCLx. The slave must then set its ACKDT value and release the clock with communication progressing as it would normally. The general call address is a reserved address in the I2C protocol, defined as address 0x00. When the GCEN bit of the SSPxCON2 register is set, the slave module will automatically ACK the reception of this address regardless of the value stored in SSPxADD. After the slave clocks in an address of all zeros with the R/W bit clear, an interrupt is generated and slave software can read SSPxBUF and respond. Figure 25-23 shows a general call reception sequence. FIGURE 25-24: SLAVE MODE GENERAL CALL ADDRESS SEQUENCE Address is compared to General Call Address after ACK, set interrupt R/W = 0 ACK D7 General Call Address SDAx SCLx S 1 2 3 4 5 6 7 8 9 1 Receiving Data ACK D6 D5 D4 D3 D2 D1 D0 2 3 4 5 6 7 8 9 SSPxIF BF (SSPxSTAT) Cleared by software GCEN (SSPxCON2) SSPxBUF is read ’1’ 25.5.9 SSPX MASK REGISTER An SSPx Mask (SSPxMSK) register (Register 25-5) is available in I2C Slave mode as a mask for the value held in the SSPxSR register during an address comparison operation. A zero (‘0’) bit in the SSPxMSK register has the effect of making the corresponding bit of the received address a “don’t care”. This register is reset to all ‘1’s upon any Reset condition and, therefore, has no effect on standard SSPx operation until written with a mask value. The SSPx Mask register is active during: • 7-bit Address mode: address compare of A. • 10-bit Address mode: address compare of A only. The SSPx mask has no effect during the reception of the first (high) byte of the address.  2011 Microchip Technology Inc. DS41391D-page 261 PIC16(L)F1826/27 25.6 I2C MASTER MODE Master mode is enabled by setting and clearing the appropriate SSPxM bits in the SSPxCON1 register and by setting the SSPxEN bit. In Master mode, the SDAx and SCKx pins must be configured as inputs. The MSSP peripheral hardware will override the output driver TRIS controls when necessary to drive the pins low. Master mode of operation is supported by interrupt generation on the detection of the Start and Stop conditions. The Stop (P) and Start (S) bits are cleared from a Reset or when the MSSPx module is disabled. Control of the I 2C bus may be taken when the P bit is set, or the bus is Idle. In Firmware Controlled Master mode, user code conducts all I 2C bus operations based on Start and Stop bit condition detection. Start and Stop condition detection is the only active circuitry in this mode. All other communication is done by the user software directly manipulating the SDAx and SCLx lines. The following events will cause the SSPx Interrupt Flag bit, SSPxIF, to be set (SSPx interrupt, if enabled): • • • • • Start condition detected Stop condition detected Data transfer byte transmitted/received Acknowledge transmitted/received Repeated Start generated 25.6.1 I2C MASTER MODE OPERATION The master device generates all of the serial clock pulses and the Start and Stop conditions. A transfer is ended with a Stop condition or with a Repeated Start condition. Since the Repeated Start condition is also the beginning of the next serial transfer, the I2C bus will not be released. In Master Transmitter mode, serial data is output through SDAx, while SCLx outputs the serial clock. The first byte transmitted contains the slave address of the receiving device (7 bits) and the Read/Write (R/W) bit. In this case, the R/W bit will be logic ‘0’. Serial data is transmitted 8 bits at a time. After each byte is transmitted, an Acknowledge bit is received. Start and Stop conditions are output to indicate the beginning and the end of a serial transfer. In Master Receive mode, the first byte transmitted contains the slave address of the transmitting device (7 bits) and the R/W bit. In this case, the R/W bit will be logic ‘1’. Thus, the first byte transmitted is a 7-bit slave address followed by a ‘1’ to indicate the receive bit. Serial data is received via SDAx, while SCLx outputs the serial clock. Serial data is received 8 bits at a time. After each byte is received, an Acknowledge bit is transmitted. Start and Stop conditions indicate the beginning and end of transmission. A Baud Rate Generator is used to set the clock frequency output on SCLx. See Section 25.7 “Baud Rate Generator” for more detail. Note 1: The MSSPx module, when configured in I2C Master mode, does not allow queueing of events. For instance, the user is not allowed to initiate a Start condition and immediately write the SSPxBUF register to initiate transmission before the Start condition is complete. In this case, the SSPxBUF will not be written to and the WCOL bit will be set, indicating that a write to the SSPxBUF did not occur 2: When in Master mode, Start/Stop detection is masked and an interrupt is generated when the SEN/PEN bit is cleared and the generation is complete. DS41391D-page 262  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.6.2 CLOCK ARBITRATION Clock arbitration occurs when the master, during any receive, transmit or Repeated Start/Stop condition, releases the SCLx pin (SCLx allowed to float high). When the SCLx pin is allowed to float high, the Baud Rate Generator (BRG) is suspended from counting until the SCLx pin is actually sampled high. When the SCLx pin is sampled high, the Baud Rate Generator is reloaded with the contents of SSPxADD and begins counting. This ensures that the SCLx high time will always be at least one BRG rollover count in the event that the clock is held low by an external device (Figure 25-25). FIGURE 25-25: BAUD RATE GENERATOR TIMING WITH CLOCK ARBITRATION SDAx DX ‚ – 1 DX SCLx deasserted but slave holds SCLx low (clock arbitration) SCLx allowed to transition high SCLx BRG decrements on Q2 and Q4 cycles BRG Value 03h 02h 01h 00h (hold off) 03h 02h SCLx is sampled high, reload takes place and BRG starts its count BRG Reload 25.6.3 WCOL STATUS FLAG If the user writes the SSPxBUF when a Start, Restart, Stop, Receive or Transmit sequence is in progress, the WCOL is set and the contents of the buffer are unchanged (the write does not occur). Any time the WCOL bit is set it indicates that an action on SSPxBUF was attempted while the module was not Idle. Note: Because queueing of events is not allowed, writing to the lower 5 bits of SSPxCON2 is disabled until the Start condition is complete.  2011 Microchip Technology Inc. DS41391D-page 263 PIC16(L)F1826/27 25.6.4 I2C MASTER MODE START by hardware; the Baud Rate Generator is suspended, leaving the SDAx line held low and the Start condition is complete. CONDITION TIMING To initiate a Start condition, the user sets the Start Enable bit, SEN bit of the SSPxCON2 register. If the SDAx and SCLx pins are sampled high, the Baud Rate Generator is reloaded with the contents of SSPxADD and starts its count. If SCLx and SDAx are both sampled high when the Baud Rate Generator times out (TBRG), the SDAx pin is driven low. The action of the SDAx being driven low while SCLx is high is the Start condition and causes the S bit of the SSPxSTAT1 register to be set. Following this, the Baud Rate Generator is reloaded with the contents of SSPxADD and resumes its count. When the Baud Rate Generator times out (TBRG), the SEN bit of the SSPxCON2 register will be automatically cleared FIGURE 25-26: Note 1: If at the beginning of the Start condition, the SDAx and SCLx pins are already sampled low, or if during the Start condition, the SCLx line is sampled low before the SDAx line is driven low, a bus collision occurs, the Bus Collision Interrupt Flag, BCLxIF, is set, the Start condition is aborted and the I2C module is reset into its Idle state. 2: The Philips I2C Specification states that a bus collision cannot occur on a Start. FIRST START BIT TIMING Write to SEN bit occurs here Set S bit (SSPxSTAT) At completion of Start bit, hardware clears SEN bit and sets SSPxIF bit SDAx = 1, SCLx = 1 TBRG TBRG Write to SSPxBUF occurs here SDAx 1st bit 2nd bit TBRG SCLx S DS41391D-page 264 TBRG  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.6.5 I2C MASTER MODE REPEATED SSPxCON2 register will be automatically cleared and the Baud Rate Generator will not be reloaded, leaving the SDAx pin held low. As soon as a Start condition is detected on the SDAx and SCLx pins, the S bit of the SSPxSTAT register will be set. The SSPxIF bit will not be set until the Baud Rate Generator has timed out. START CONDITION TIMING A Repeated Start condition occurs when the RSEN bit of the SSPxCON2 register is programmed high and the Master state machine is no longer active. When the RSEN bit is set, the SCLx pin is asserted low. When the SCLx pin is sampled low, the Baud Rate Generator is loaded and begins counting. The SDAx pin is released (brought high) for one Baud Rate Generator count (TBRG). When the Baud Rate Generator times out, if SDAx is sampled high, the SCLx pin will be deasserted (brought high). When SCLx is sampled high, the Baud Rate Generator is reloaded and begins counting. SDAx and SCLx must be sampled high for one TBRG. This action is then followed by assertion of the SDAx pin (SDAx = 0) for one TBRG while SCLx is high. SCLx is asserted low. Following this, the RSEN bit of the FIGURE 25-27: Note 1: If RSEN is programmed while any other event is in progress, it will not take effect. 2: A bus collision during the Repeated Start condition occurs if: • SDAx is sampled low when SCLx goes from low-to-high. • SCLx goes low before SDAx is asserted low. This may indicate that another master is attempting to transmit a data ‘1’. REPEAT START CONDITION WAVEFORM S bit set by hardware Write to SSPxCON2 occurs here SDAx = 1, SCLx (no change) At completion of Start bit, hardware clears RSEN bit and sets SSPxIF SDAx = 1, SCLx = 1 TBRG TBRG TBRG 1st bit SDAx Write to SSPxBUF occurs here TBRG SCLx Sr TBRG Repeated Start  2011 Microchip Technology Inc. DS41391D-page 265 PIC16(L)F1826/27 25.6.6 I2C MASTER MODE TRANSMISSION Transmission of a data byte, a 7-bit address or the other half of a 10-bit address is accomplished by simply writing a value to the SSPxBUF register. This action will set the Buffer Full flag bit, BF and allow the Baud Rate Generator to begin counting and start the next transmission. Each bit of address/data will be shifted out onto the SDAx pin after the falling edge of SCLx is asserted. SCLx is held low for one Baud Rate Generator rollover count (TBRG). Data should be valid before SCLx is released high. When the SCLx pin is released high, it is held that way for TBRG. The data on the SDAx pin must remain stable for that duration and some hold time after the next falling edge of SCLx. After the eighth bit is shifted out (the falling edge of the eighth clock), the BF flag is cleared and the master releases SDAx. This allows the slave device being addressed to respond with an ACK bit during the ninth bit time if an address match occurred, or if data was received properly. The status of ACK is written into the ACKSTAT bit on the rising edge of the ninth clock. If the master receives an Acknowledge, the Acknowledge Status bit, ACKSTAT, is cleared. If not, the bit is set. After the ninth clock, the SSPxIF bit is set and the master clock (Baud Rate Generator) is suspended until the next data byte is loaded into the SSPxBUF, leaving SCLx low and SDAx unchanged (Figure 25-27). After the write to the SSPxBUF, each bit of the address will be shifted out on the falling edge of SCLx until all seven address bits and the R/W bit are completed. On the falling edge of the eighth clock, the master will release the SDAx pin, allowing the slave to respond with an Acknowledge. On the falling edge of the ninth clock, the master will sample the SDAx pin to see if the address was recognized by a slave. The status of the ACK bit is loaded into the ACKSTAT Status bit of the SSPxCON2 register. Following the falling edge of the ninth clock transmission of the address, the SSPxIF is set, the BF flag is cleared and the Baud Rate Generator is turned off until another write to the SSPxBUF takes place, holding SCLx low and allowing SDAx to float. 25.6.6.1 BF Status Flag 25.6.6.3 ACKSTAT Status Flag In Transmit mode, the ACKSTAT bit of the SSPxCON2 register is cleared when the slave has sent an Acknowledge (ACK = 0) and is set when the slave does not Acknowledge (ACK = 1). A slave sends an Acknowledge when it has recognized its address (including a general call), or when the slave has properly received its data. 25.6.6.4 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. Typical transmit sequence: The user generates a Start condition by setting the SEN bit of the SSPxCON2 register. SSPxIF is set by hardware on completion of the Start. SSPxIF is cleared by software. The MSSPx module will wait the required start time before any other operation takes place. The user loads the SSPxBUF with the slave address to transmit. Address is shifted out the SDAx pin until all 8 bits are transmitted. Transmission begins as soon as SSPxBUF is written to. The MSSPx module shifts in the ACK bit from the slave device and writes its value into the ACKSTAT bit of the SSPxCON2 register. The MSSPx module generates an interrupt at the end of the ninth clock cycle by setting the SSPxIF bit. The user loads the SSPxBUF with eight bits of data. Data is shifted out the SDAx pin until all 8 bits are transmitted. The MSSPx module shifts in the ACK bit from the slave device and writes its value into the ACKSTAT bit of the SSPxCON2 register. Steps 8-11 are repeated for all transmitted data bytes. The user generates a Stop or Restart condition by setting the PEN or RSEN bits of the SSPxCON2 register. Interrupt is generated once the Stop/Restart condition is complete. In Transmit mode, the BF bit of the SSPxSTAT register is set when the CPU writes to SSPxBUF and is cleared when all 8 bits are shifted out. 25.6.6.2 WCOL Status Flag If the user writes the SSPxBUF when a transmit is already in progress (i.e., SSPxSR is still shifting out a data byte), the WCOL is set and the contents of the buffer are unchanged (the write does not occur). WCOL must be cleared by software before the next transmission. DS41391D-page 266  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. S R/W PEN SEN BF (SSPxSTAT) SSPxIF SCLx SDAx A6 A5 A4 A3 A2 A1 3 4 5 Cleared by software 2 6 7 8 9 After Start condition, SEN cleared by hardware SSPxBUF written 1 D7 1 SCLx held low while CPU responds to SSPxIF ACK = 0 R/W = 0 SSPxBUF written with 7-bit address and R/W start transmit A7 Transmit Address to Slave 3 D5 4 D4 5 D3 6 D2 7 D1 8 D0 SSPxBUF is written by software Cleared by software service routine from SSPx interrupt 2 D6 Transmitting Data or Second Half of 10-bit Address P ACKSTAT in SSPxCON2 = 1 Cleared by software 9 ACK From slave, clear ACKSTAT bit SSPxCON2 FIGURE 25-28: SEN = 0 Write SSPxCON2 SEN = 1 Start condition begins PIC16(L)F1826/27 I2C MASTER MODE WAVEFORM (TRANSMISSION, 7 OR 10-BIT ADDRESS) DS41391D-page 267 PIC16(L)F1826/27 25.6.7 I2C MASTER MODE RECEPTION Master mode reception is enabled by programming the Receive Enable bit, RCEN bit of the SSPxCON2 register. Note: The MSSPx module must be in an Idle state before the RCEN bit is set or the RCEN bit will be disregarded. The Baud Rate Generator begins counting and on each rollover, the state of the SCLx pin changes (high-to-low/low-to-high) and data is shifted into the SSPxSR. After the falling edge of the eighth clock, the receive enable flag is automatically cleared, the contents of the SSPxSR are loaded into the SSPxBUF, the BF flag bit is set, the SSPxIF flag bit is set and the Baud Rate Generator is suspended from counting, holding SCLx low. The MSSPx is now in Idle state awaiting the next command. When the buffer is read by the CPU, the BF flag bit is automatically cleared. The user can then send an Acknowledge bit at the end of reception by setting the Acknowledge Sequence Enable, ACKEN bit of the SSPxCON2 register. 25.6.7.1 BF Status Flag 25.6.7.4 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. In receive operation, the BF bit is set when an address or data byte is loaded into SSPxBUF from SSPxSR. It is cleared when the SSPxBUF register is read. 11. 25.6.7.2 12. SSPxOV Status Flag In receive operation, the SSPxOV bit is set when 8 bits are received into the SSPxSR and the BF flag bit is already set from a previous reception. 13. 14. 25.6.7.3 15. WCOL Status Flag If the user writes the SSPxBUF when a receive is already in progress (i.e., SSPxSR is still shifting in a data byte), the WCOL bit is set and the contents of the buffer are unchanged (the write does not occur). DS41391D-page 268 Typical Receive Sequence: The user generates a Start condition by setting the SEN bit of the SSPxCON2 register. SSPxIF is set by hardware on completion of the Start. SSPxIF is cleared by software. User writes SSPxBUF with the slave address to transmit and the R/W bit set. Address is shifted out the SDAx pin until all 8 bits are transmitted. Transmission begins as soon as SSPxBUF is written to. The MSSPx module shifts in the ACK bit from the slave device and writes its value into the ACKSTAT bit of the SSPxCON2 register. The MSSPx module generates an interrupt at the end of the ninth clock cycle by setting the SSPxIF bit. User sets the RCEN bit of the SSPxCON2 register and the Master clocks in a byte from the slave. After the 8th falling edge of SCLx, SSPxIF and BF are set. Master clears SSPxIF and reads the received byte from SSPxUF, clears BF. Master sets ACK value sent to slave in ACKDT bit of the SSPxCON2 register and initiates the ACK by setting the ACKEN bit. Masters ACK is clocked out to the Slave and SSPxIF is set. User clears SSPxIF. Steps 8-13 are repeated for each received byte from the slave. Master sends a not ACK or Stop to end communication.  2011 Microchip Technology Inc.  2011 Microchip Technology Inc. S RCEN ACKEN SSPxOV BF (SSPxSTAT) SDAx = 0, SCLx = 1 while CPU responds to SSPxIF SSPxIF SCLx SDAx 1 A7 2 4 5 6 Cleared by software 3 A6 A5 A4 A3 A2 Transmit Address to Slave 7 8 9 ACK Receiving Data from Slave 2 3 5 6 7 8 D0 9 ACK Receiving Data from Slave 2 3 4 RCEN cleared automatically 5 6 7 Cleared by software Set SSPxIF interrupt at end of Acknowledge sequence Data shifted in on falling edge of CLK 1 ACK from Master SDAx = ACKDT = 0 Cleared in software Set SSPxIF at end of receive 9 ACK is not sent ACK RCEN cleared automatically P Set SSPxIF interrupt at end of Acknowledge sequence Bus master terminates transfer Set P bit (SSPxSTAT) and SSPxIF PEN bit = 1 written here SSPxOV is set because SSPxBUF is still full 8 D0 RCEN cleared automatically Set ACKEN, start Acknowledge sequence SDAx = ACKDT = 1 D7 D6 D5 D4 D3 D2 D1 Last bit is shifted into SSPxSR and contents are unloaded into SSPxBUF Cleared by software Set SSPxIF interrupt at end of receive 4 Cleared by software 1 D7 D6 D5 D4 D3 D2 D1 Master configured as a receiver by programming SSPxCON2 (RCEN = 1) A1 R/W RCEN = 1, start next receive ACK from Master SDAx = ACKDT = 0 FIGURE 25-29: RCEN cleared automatically Master configured as a receiver by programming SSPxCON2 (RCEN = 1) SEN = 0 Write to SSPxBUF occurs here, ACK from Slave start XMIT Write to SSPxCON2(SEN = 1), begin Start condition Write to SSPxCON2 to start Acknowledge sequence SDAx = ACKDT (SSPxCON2) = 0 PIC16(L)F1826/27 I2C MASTER MODE WAVEFORM (RECEPTION, 7-BIT ADDRESS) DS41391D-page 269 PIC16(L)F1826/27 25.6.8 ACKNOWLEDGE SEQUENCE TIMING 25.6.9 A Stop bit is asserted on the SDAx pin at the end of a receive/transmit by setting the Stop Sequence Enable bit, PEN bit of the SSPxCON2 register. At the end of a receive/transmit, the SCLx line is held low after the falling edge of the ninth clock. When the PEN bit is set, the master will assert the SDAx line low. When the SDAx line is sampled low, the Baud Rate Generator is reloaded and counts down to ‘0’. When the Baud Rate Generator times out, the SCLx pin will be brought high and one TBRG (Baud Rate Generator rollover count) later, the SDAx pin will be deasserted. When the SDAx pin is sampled high while SCLx is high, the P bit of the SSPxSTAT register is set. A TBRG later, the PEN bit is cleared and the SSPxIF bit is set (Figure 25-30). An Acknowledge sequence is enabled by setting the Acknowledge Sequence Enable bit, ACKEN bit of the SSPxCON2 register. When this bit is set, the SCLx pin is pulled low and the contents of the Acknowledge data bit are presented on the SDAx pin. If the user wishes to generate an Acknowledge, then the ACKDT bit should be cleared. If not, the user should set the ACKDT bit before starting an Acknowledge sequence. The Baud Rate Generator then counts for one rollover period (TBRG) and the SCLx pin is deasserted (pulled high). When the SCLx pin is sampled high (clock arbitration), the Baud Rate Generator counts for TBRG. The SCLx pin is then pulled low. Following this, the ACKEN bit is automatically cleared, the Baud Rate Generator is turned off and the MSSPx module then goes into Idle mode (Figure 25-29). 25.6.8.1 25.6.9.1 WCOL Status Flag If the user writes the SSPxBUF when a Stop sequence is in progress, then the WCOL bit is set and the contents of the buffer are unchanged (the write does not occur). WCOL Status Flag If the user writes the SSPxBUF when an Acknowledge sequence is in progress, then WCOL is set and the contents of the buffer are unchanged (the write does not occur). FIGURE 25-30: STOP CONDITION TIMING ACKNOWLEDGE SEQUENCE WAVEFORM Acknowledge sequence starts here, write to SSPxCON2 ACKEN = 1, ACKDT = 0 ACKEN automatically cleared TBRG TBRG SDAx SCLx D0 ACK 8 9 SSPxIF SSPxIF set at the end of receive Cleared in software Cleared in software SSPxIF set at the end of Acknowledge sequence Note: TBRG = one Baud Rate Generator period. DS41391D-page 270  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 25-31: STOP CONDITION RECEIVE OR TRANSMIT MODE SCLx = 1 for TBRG, followed by SDAx = 1 for TBRG after SDAx sampled high. P bit (SSPxSTAT) is set. Write to SSPxCON2, set PEN PEN bit (SSPxCON2) is cleared by hardware and the SSPxIF bit is set Falling edge of 9th clock TBRG SCLx SDAx ACK P TBRG TBRG TBRG SCLx brought high after TBRG SDAx asserted low before rising edge of clock to setup Stop condition Note: TBRG = one Baud Rate Generator period. 25.6.10 SLEEP OPERATION 2 While in Sleep mode, the I C slave module can receive addresses or data and when an address match or complete byte transfer occurs, wake the processor from Sleep (if the MSSPx interrupt is enabled). 25.6.11 EFFECTS OF A RESET A Reset disables the MSSPx module and terminates the current transfer. 25.6.12 MULTI-MASTER MODE In Multi-Master mode, the interrupt generation on the detection of the Start and Stop conditions allows the determination of when the bus is free. The Stop (P) and Start (S) bits are cleared from a Reset or when the MSSPx module is disabled. Control of the I 2C bus may be taken when the P bit of the SSPxSTAT register is set, or the bus is Idle, with both the S and P bits clear. When the bus is busy, enabling the SSPx interrupt will generate the interrupt when the Stop condition occurs. In multi-master operation, the SDAx line must be monitored for arbitration to see if the signal level is the expected output level. This check is performed by hardware with the result placed in the BCLxIF bit. The states where arbitration can be lost are: • • • • • Address Transfer Data Transfer A Start Condition A Repeated Start Condition An Acknowledge Condition 25.6.13 MULTI -MASTER COMMUNICATION, BUS COLLISION AND BUS ARBITRATION Multi-Master mode support is achieved by bus arbitration. When the master outputs address/data bits onto the SDAx pin, arbitration takes place when the master outputs a ‘1’ on SDAx, by letting SDAx float high and another master asserts a ‘0’. When the SCLx pin floats high, data should be stable. If the expected data on SDAx is a ‘1’ and the data sampled on the SDAx pin is ‘0’, then a bus collision has taken place. The master will set the Bus Collision Interrupt Flag, BCLxIF and reset the I2C port to its Idle state (Figure 25-31). If a transmit was in progress when the bus collision occurred, the transmission is halted, the BF flag is cleared, the SDAx and SCLx lines are deasserted and the SSPxBUF can be written to. When the user services the bus collision Interrupt Service Routine and if the I2C bus is free, the user can resume communication by asserting a Start condition. If a Start, Repeated Start, Stop or Acknowledge condition was in progress when the bus collision occurred, the condition is aborted, the SDAx and SCLx lines are deasserted and the respective control bits in the SSPxCON2 register are cleared. When the user services the bus collision Interrupt Service Routine and if the I2C bus is free, the user can resume communication by asserting a Start condition. The master will continue to monitor the SDAx and SCLx pins. If a Stop condition occurs, the SSPxIF bit will be set. A write to the SSPxBUF will start the transmission of data at the first data bit, regardless of where the transmitter left off when the bus collision occurred. In Multi-Master mode, the interrupt generation on the detection of Start and Stop conditions allows the determination of when the bus is free. Control of the I2C bus can be taken when the P bit is set in the SSPxSTAT register, or the bus is Idle and the S and P bits are cleared.  2011 Microchip Technology Inc. DS41391D-page 271 PIC16(L)F1826/27 FIGURE 25-32: BUS COLLISION TIMING FOR TRANSMIT AND ACKNOWLEDGE Data changes while SCLx = 0 SDAx line pulled low by another source SDAx released by master Sample SDAx. While SCLx is high, data does not match what is driven by the master. Bus collision has occurred. SDAx SCLx Set bus collision interrupt (BCLxIF) BCLxIF DS41391D-page 272  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.6.13.1 Bus Collision During a Start Condition During a Start condition, a bus collision occurs if: a) b) SDAx or SCLx are sampled low at the beginning of the Start condition (Figure 25-32). SCLx is sampled low before SDAx is asserted low (Figure 25-33). During a Start condition, both the SDAx and the SCLx pins are monitored. If the SDAx pin is sampled low during this count, the BRG is reset and the SDAx line is asserted early (Figure 25-34). If, however, a ‘1’ is sampled on the SDAx pin, the SDAx pin is asserted low at the end of the BRG count. The Baud Rate Generator is then reloaded and counts down to zero; if the SCLx pin is sampled as ‘0’ during this time, a bus collision does not occur. At the end of the BRG count, the SCLx pin is asserted low. Note: If the SDAx pin is already low, or the SCLx pin is already low, then all of the following occur: • the Start condition is aborted, • the BCLxIF flag is set and • the MSSPx module is reset to its Idle state (Figure 25-32). The Start condition begins with the SDAx and SCLx pins deasserted. When the SDAx pin is sampled high, the Baud Rate Generator is loaded and counts down. If the SCLx pin is sampled low while SDAx is high, a bus collision occurs because it is assumed that another master is attempting to drive a data ‘1’ during the Start condition. FIGURE 25-33: The reason that bus collision is not a factor during a Start condition is that no two bus masters can assert a Start condition at the exact same time. Therefore, one master will always assert SDAx before the other. This condition does not cause a bus collision because the two masters must be allowed to arbitrate the first address following the Start condition. If the address is the same, arbitration must be allowed to continue into the data portion, Repeated Start or Stop conditions. BUS COLLISION DURING START CONDITION (SDAX ONLY) SDAx goes low before the SEN bit is set. Set BCLxIF, S bit and SSPxIF set because SDAx = 0, SCLx = 1. SDAx SCLx Set SEN, enable Start condition if SDAx = 1, SCLx = 1 SEN cleared automatically because of bus collision. SSPx module reset into Idle state. SEN BCLxIF SDAx sampled low before Start condition. Set BCLxIF. S bit and SSPxIF set because SDAx = 0, SCLx = 1. SSPxIF and BCLxIF are cleared by software S SSPxIF SSPxIF and BCLxIF are cleared by software  2011 Microchip Technology Inc. DS41391D-page 273 PIC16(L)F1826/27 FIGURE 25-34: BUS COLLISION DURING START CONDITION (SCLX = 0) SDAx = 0, SCLx = 1 TBRG TBRG SDAx Set SEN, enable Start sequence if SDAx = 1, SCLx = 1 SCLx SCLx = 0 before SDAx = 0, bus collision occurs. Set BCLxIF. SEN SCLx = 0 before BRG time-out, bus collision occurs. Set BCLxIF. BCLxIF Interrupt cleared by software S ’0’ ’0’ SSPxIF ’0’ ’0’ FIGURE 25-35: BRG RESET DUE TO SDA ARBITRATION DURING START CONDITION SDAx = 0, SCLx = 1 Set S Less than TBRG SDAx SCLx TBRG SDAx pulled low by other master. Reset BRG and assert SDAx. S SCLx pulled low after BRG time-out SEN BCLxIF Set SSPxIF Set SEN, enable Start sequence if SDAx = 1, SCLx = 1 ’0’ S SSPxIF SDAx = 0, SCLx = 1, set SSPxIF DS41391D-page 274 Interrupts cleared by software  2011 Microchip Technology Inc. PIC16(L)F1826/27 25.6.13.2 Bus Collision During a Repeated Start Condition If SDAx is low, a bus collision has occurred (i.e., another master is attempting to transmit a data ‘0’, Figure 25-35). If SDAx is sampled high, the BRG is reloaded and begins counting. If SDAx goes from high-to-low before the BRG times out, no bus collision occurs because no two masters can assert SDAx at exactly the same time. During a Repeated Start condition, a bus collision occurs if: a) b) A low level is sampled on SDAx when SCLx goes from low level to high level. SCLx goes low before SDAx is asserted low, indicating that another master is attempting to transmit a data ‘1’. If SCLx goes from high-to-low before the BRG times out and SDAx has not already been asserted, a bus collision occurs. In this case, another master is attempting to transmit a data ‘1’ during the Repeated Start condition, see Figure 25-36. When the user releases SDAx and the pin is allowed to float high, the BRG is loaded with SSPxADD and counts down to zero. The SCLx pin is then deasserted and when sampled high, the SDAx pin is sampled. FIGURE 25-36: If, at the end of the BRG time-out, both SCLx and SDAx are still high, the SDAx pin is driven low and the BRG is reloaded and begins counting. At the end of the count, regardless of the status of the SCLx pin, the SCLx pin is driven low and the Repeated Start condition is complete. BUS COLLISION DURING A REPEATED START CONDITION (CASE 1) SDAx SCLx Sample SDAx when SCLx goes high. If SDAx = 0, set BCLxIF and release SDAx and SCLx. RSEN BCLxIF Cleared by software S ’0’ SSPxIF ’0’ FIGURE 25-37: BUS COLLISION DURING REPEATED START CONDITION (CASE 2) TBRG TBRG SDAx SCLx BCLxIF SCLx goes low before SDAx, set BCLxIF. Release SDAx and SCLx. Interrupt cleared by software RSEN S ’0’ SSPxIF  2011 Microchip Technology Inc. DS41391D-page 275 PIC16(L)F1826/27 25.6.13.3 Bus Collision During a Stop Condition The Stop condition begins with SDAx asserted low. When SDAx is sampled low, the SCLx pin is allowed to float. When the pin is sampled high (clock arbitration), the Baud Rate Generator is loaded with SSPxADD and counts down to 0. After the BRG times out, SDAx is sampled. If SDAx is sampled low, a bus collision has occurred. This is due to another master attempting to drive a data ‘0’ (Figure 25-37). If the SCLx pin is sampled low before SDAx is allowed to float high, a bus collision occurs. This is another case of another master attempting to drive a data ‘0’ (Figure 25-38). Bus collision occurs during a Stop condition if: a) b) After the SDAx pin has been deasserted and allowed to float high, SDAx is sampled low after the BRG has timed out. After the SCLx pin is deasserted, SCLx is sampled low before SDAx goes high. FIGURE 25-38: BUS COLLISION DURING A STOP CONDITION (CASE 1) TBRG TBRG SDAx sampled low after TBRG, set BCLxIF TBRG SDAx SDAx asserted low SCLx PEN BCLxIF P ’0’ SSPxIF ’0’ FIGURE 25-39: BUS COLLISION DURING A STOP CONDITION (CASE 2) TBRG TBRG TBRG SDAx Assert SDAx SCLx SCLx goes low before SDAx goes high, set BCLxIF PEN BCLxIF P ’0’ SSPxIF ’0’ DS41391D-page 276  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 25-3: SUMMARY OF REGISTERS ASSOCIATED WITH I2C™ OPERATION Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Reset Values on Page: GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 PIE2 OSFIE C2IE C1IE EEIE BCL1IE — — CCP2IE(1) 88 SSP2IE 90 91 Name INTCON PIE4 — — — — — — BCL2IE PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF PIR2 OSFIF C2IF C1IF EEIF BCL1IF — — CCP2IF(1) 92 PIR4(1) — — — — — — BCL2IF SSP2IF 94 TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 ADD7 ADD6 ADD5 ADD4 ADD3 ADD2 ADD1 ADD0 (1) SSPxADD SSPxBUF SSPxCON1 MSSPx Receive Buffer/Transmit Register WCOL SSPOV SSPEN CKP SSPxCON2 GCEN ACKSTAT ACKDT ACKEN SSPxCON3 ACKTIM PCIE SCIE BOEN MSK7 MSK6 MSK5 MSK4 SMP CKE D/A P SSPxMSK SSPxSTAT Legend: * Note 1: 283 235* SSPM3 SSPM2 SSPM1 SSPM0 280 RCEN PEN SDAHT SBCDE RSEN SEN 281 AHEN DHEN MSK3 282 MSK2 MSK1 MSK0 283 S R/W UA BF 279 — = unimplemented, read as ‘0’. Shaded cells are not used by the MSSP module in I2C™ mode. Page provides register information. PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 277 PIC16(L)F1826/27 25.7 BAUD RATE GENERATOR The MSSPx module has a Baud Rate Generator available for clock generation in both I2C and SPI Master modes. The Baud Rate Generator (BRG) reload value is placed in the SSPxADD register (Register 25-6). When a write occurs to SSPxBUF, the Baud Rate Generator will automatically begin counting down. Once the given operation is complete, the internal clock will automatically stop counting and the clock pin will remain in its last state. module clock line. The logic dictating when the reload signal is asserted depends on the mode the MSSPx is being operated in. Table 25-4 demonstrates clock rates based on instruction cycles and the BRG value loaded into SSPxADD. EQUATION 25-1: FOSC FCLOCK = ------------------------------------------------ SSPxADD + 1   4  An internal signal “Reload” in Figure 25-39 triggers the value from SSPxADD to be loaded into the BRG counter. This occurs twice for each oscillation of the FIGURE 25-40: BAUD RATE GENERATOR BLOCK DIAGRAM SSPxM SSPxM Reload SSPxADD Reload Control SCLx SSPxCLK BRG Down Counter FOSC/2 Note: Values of 0x00, 0x01 and 0x02 are not valid for SSPxADD when used as a Baud Rate Generator for I2C. This is an implementation limitation. TABLE 25-4: Note 1: MSSPX CLOCK RATE W/BRG FOSC FCY BRG Value FCLOCK (2 Rollovers of BRG) 32 MHz 8 MHz 13h 400 kHz(1) 32 MHz 8 MHz 19h 308 kHz 32 MHz 8 MHz 4Fh 100 kHz 16 MHz 4 MHz 09h 400 kHz(1) 16 MHz 4 MHz 0Ch 308 kHz 16 MHz 4 MHz 27h 100 kHz 4 MHz 1 MHz 09h 100 kHz 2C I2C specification (which applies to rates greater than The I interface does not conform to the 400 kHz 100 kHz) in all details, but may be used with care where higher rates are required by the application. DS41391D-page 278  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 25-1: SSPxSTAT: SSPx STATUS REGISTER R/W-0/0 R/W-0/0 R-0/0 R-0/0 R-0/0 R-0/0 R-0/0 R-0/0 SMP CKE D/A P S R/W UA BF bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 SMP: SPI Data Input Sample bit SPI Master mode: 1 = Input data sampled at end of data output time 0 = Input data sampled at middle of data output time SPI Slave mode: SMP must be cleared when SPI is used in Slave mode In I2 C Master or Slave mode: 1 = Slew rate control disabled for standard speed mode (100 kHz and 1 MHz) 0 = Slew rate control enabled for high speed mode (400 kHz) bit 6 CKE: SPI Clock Edge Select bit (SPI mode only) In SPI Master or Slave mode: 1 = Transmit occurs on transition from active to Idle clock state 0 = Transmit occurs on transition from Idle to active clock state In I2 C™ mode only: 1 = Enable input logic so that thresholds are compliant with SM bus™ specification 0 = Disable SM bus™ specific inputs bit 5 D/A: Data/Address bit (I2C mode only) 1 = Indicates that the last byte received or transmitted was data 0 = Indicates that the last byte received or transmitted was address bit 4 P: Stop bit (I2C mode only. This bit is cleared when the MSSPx module is disabled, SSPxEN is cleared.) 1 = Indicates that a Stop bit has been detected last (this bit is ‘0’ on Reset) 0 = Stop bit was not detected last bit 3 S: Start bit (I2C mode only. This bit is cleared when the MSSPx module is disabled, SSPxEN is cleared.) 1 = Indicates that a Start bit has been detected last (this bit is ‘0’ on Reset) 0 = Start bit was not detected last bit 2 R/W: Read/Write bit information (I2C mode only) This bit holds the R/W bit information following the last address match. This bit is only valid from the address match to the next Start bit, Stop bit, or not ACK bit. In I2 C Slave mode: 1 = Read 0 = Write In I2 C Master mode: 1 = Transmit is in progress 0 = Transmit is not in progress OR-ing this bit with SEN, RSEN, PEN, RCEN or ACKEN will indicate if the MSSPx is in Idle mode. bit 1 UA: Update Address bit (10-bit I2C mode only) 1 = Indicates that the user needs to update the address in the SSPxADD register 0 = Address does not need to be updated bit 0 BF: Buffer Full Status bit Receive (SPI and I2 C modes): 1 = Receive complete, SSPxBUF is full 0 = Receive not complete, SSPxBUF is empty Transmit (I2 C mode only): 1 = Data transmit in progress (does not include the ACK and Stop bits), SSPxBUF is full 0 = Data transmit complete (does not include the ACK and Stop bits), SSPxBUF is empty  2011 Microchip Technology Inc. DS41391D-page 279 PIC16(L)F1826/27 REGISTER 25-2: SSPxCON1: SSPx CONTROL REGISTER 1 R/C/HS-0/0 R/C/HS-0/0 R/W-0/0 R/W-0/0 WCOL SSPxOV SSPxEN CKP R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 SSPxM bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared HS = Bit is set by hardware C = User cleared bit 7 WCOL: Write Collision Detect bit Master mode: 1 = A write to the SSPxBUF register was attempted while the I2C conditions were not valid for a transmission to be started 0 = No collision Slave mode: 1 = The SSPxBUF register is written while it is still transmitting the previous word (must be cleared in software) 0 = No collision bit 6 SSPxOV: Receive Overflow Indicator bit(1) In SPI mode: 1 = A new byte is received while the SSPxBUF register is still holding the previous data. In case of overflow, the data in SSPxSR is lost. Overflow can only occur in Slave mode. In Slave mode, the user must read the SSPxBUF, even if only transmitting data, to avoid setting overflow. In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the SSPxBUF register (must be cleared in software). 0 = No overflow 2 In I C mode: 1 = A byte is received while the SSPxBUF register is still holding the previous byte. SSPxOV is a “don’t care” in Transmit mode (must be cleared in software). 0 = No overflow bit 5 SSPxEN: Synchronous Serial Port Enable bit In both modes, when enabled, these pins must be properly configured as input or output In SPI mode: 1 = Enables serial port and configures SCKx, SDOx, SDIx and SSx as the source of the serial port pins(2) 0 = Disables serial port and configures these pins as I/O port pins In I2C mode: 1 = Enables the serial port and configures the SDAx and SCLx pins as the source of the serial port pins(3) 0 = Disables serial port and configures these pins as I/O port pins bit 4 CKP: Clock Polarity Select bit In SPI mode: 1 = Idle state for clock is a high level 0 = Idle state for clock is a low level In I2C Slave mode: SCLx release control 1 = Enable clock 0 = Holds clock low (clock stretch). (Used to ensure data setup time.) In I2C Master mode: Unused in this mode bit 3-0 SSPxM: Synchronous Serial Port Mode Select bits 0000 = SPI Master mode, clock = FOSC/4 0001 = SPI Master mode, clock = FOSC/16 0010 = SPI Master mode, clock = FOSC/64 0011 = SPI Master mode, clock = TMR2 output/2 0100 = SPI Slave mode, clock = SCKx pin, SSx pin control enabled 0101 = SPI Slave mode, clock = SCKx pin, SSx pin control disabled, SSx can be used as I/O pin 0110 = I2C Slave mode, 7-bit address 0111 = I2C Slave mode, 10-bit address 1000 = I2C Master mode, clock = FOSC/(4 * (SSPxADD+1))(4) 1001 = Reserved 1010 = SPI Master mode, clock = FOSC/(4 * (SSPxADD+1))(5) 1011 = I2C firmware controlled Master mode (Slave idle) 1100 = Reserved 1101 = Reserved 1110 = I2C Slave mode, 7-bit address with Start and Stop bit interrupts enabled 1111 = I2C Slave mode, 10-bit address with Start and Stop bit interrupts enabled Note 1: 2: 3: 4: 5: In Master mode, the overflow bit is not set since each new reception (and transmission) is initiated by writing to the SSPxBUF register. When enabled, these pins must be properly configured as input or output. When enabled, the SDAx and SCLx pins must be configured as inputs. SSPxADD values of 0, 1 or 2 are not supported for I2C Mode. SSPxADD value of ‘0’ is not supported. Use SSPxM = 0000 instead. DS41391D-page 280  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 25-3: SSPxCON2: SSPx CONTROL REGISTER 2 R/W-0/0 R-0/0 R/W-0/0 R/S/HS-0/0 R/S/HS-0/0 R/S/HS-0/0 R/S/HS-0/0 R/W/HS-0/0 GCEN ACKSTAT ACKDT ACKEN RCEN PEN RSEN SEN bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared HC = Cleared by hardware S = User set bit 7 GCEN: General Call Enable bit (in I2C Slave mode only) 1 = Enable interrupt when a general call address (0x00 or 00h) is received in the SSPxSR 0 = General call address disabled bit 6 ACKSTAT: Acknowledge Status bit (in I2C mode only) 1 = Acknowledge was not received 0 = Acknowledge was received bit 5 ACKDT: Acknowledge Data bit (in I2C mode only) In Receive mode: Value transmitted when the user initiates an Acknowledge sequence at the end of a receive 1 = Not Acknowledge 0 = Acknowledge bit 4 ACKEN: Acknowledge Sequence Enable bit (in I2C Master mode only) In Master Receive mode: 1 = Initiate Acknowledge sequence on SDAx and SCLx pins, and transmit ACKDT data bit. Automatically cleared by hardware. 0 = Acknowledge sequence Idle bit 3 RCEN: Receive Enable bit (in I2C Master mode only) 1 = Enables Receive mode for I2C 0 = Receive Idle bit 2 PEN: Stop Condition Enable bit (in I2C Master mode only) SCKx Release Control: 1 = Initiate Stop condition on SDAx and SCLx pins. Automatically cleared by hardware. 0 = Stop condition Idle bit 1 RSEN: Repeated Start Condition Enabled bit (in I2C Master mode only) 1 = Initiate Repeated Start condition on SDAx and SCLx pins. Automatically cleared by hardware. 0 = Repeated Start condition Idle bit 0 SEN: Start Condition Enabled bit (in I2C Master mode only) In Master mode: 1 = Initiate Start condition on SDAx and SCLx pins. Automatically cleared by hardware. 0 = Start condition Idle In Slave mode: 1 = Clock stretching is enabled for both slave transmit and slave receive (stretch enabled) 0 = Clock stretching is disabled Note 1: For bits ACKEN, RCEN, PEN, RSEN, SEN: If the I2C module is not in the Idle mode, this bit may not be set (no spooling) and the SSPxBUF may not be written (or writes to the SSPxBUF are disabled).  2011 Microchip Technology Inc. DS41391D-page 281 PIC16(L)F1826/27 REGISTER 25-4: SSPxCON3: SSPx CONTROL REGISTER 3 R-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 ACKTIM PCIE SCIE BOEN SDAHT SBCDE AHEN DHEN bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 ACKTIM: Acknowledge Time Status bit (I2C mode only)(3) 1 = Indicates the I2C bus is in an Acknowledge sequence, set on 8TH falling edge of SCLx clock 0 = Not an Acknowledge sequence, cleared on 9TH rising edge of SCLx clock bit 6 PCIE: Stop Condition Interrupt Enable bit (I2C mode only) 1 = Enable interrupt on detection of Stop condition 0 = Stop detection interrupts are disabled(2) bit 5 SCIE: Start Condition Interrupt Enable bit (I2C mode only) 1 = Enable interrupt on detection of Start or Restart conditions 0 = Start detection interrupts are disabled(2) bit 4 BOEN: Buffer Overwrite Enable bit In SPI Slave mode:(1) 1 = SSPxBUF updates every time that a new data byte is shifted in ignoring the BF bit 0 = If new byte is received with BF bit of the SSPxSTAT register already set, SSPxOV bit of the SSPxCON1 register is set, and the buffer is not updated In I2C Master mode and SPI Master mode: This bit is ignored. In I2C Slave mode: 1 = SSPxBUF is updated and ACK is generated for a received address/data byte, ignoring the state of the SSPxOV bit only if the BF bit = 0. 0 = SSPxBUF is only updated when SSPxOV is clear bit 3 SDAHT: SDAx Hold Time Selection bit (I2C mode only) 1 = Minimum of 300 ns hold time on SDAx after the falling edge of SCLx 0 = Minimum of 100 ns hold time on SDAx after the falling edge of SCLx bit 2 SBCDE: Slave Mode Bus Collision Detect Enable bit (I2C Slave mode only) If on the rising edge of SCLx, SDAx is sampled low when the module is outputting a high state, the BCLxIF bit of the PIR2 register is set, and bus goes Idle 1 = Enable slave bus collision interrupts 0 = Slave bus collision interrupts are disabled bit 1 AHEN: Address Hold Enable bit (I2C Slave mode only) 1 = Following the 8th falling edge of SCLx for a matching received address byte; CKP bit of the SSPxCON1 register will be cleared and the SCLx will be held low. 0 = Address holding is disabled bit 0 DHEN: Data Hold Enable bit (I2C Slave mode only) 1 = Following the 8th falling edge of SCLx for a received data byte; slave hardware clears the CKP bit of the SSPxCON1 register and SCLx is held low. 0 = Data holding is disabled Note 1: 2: 3: For daisy-chained SPI operation; allows the user to ignore all but the last received byte. SSPxOV is still set when a new byte is received and BF = 1, but hardware continues to write the most recent byte to SSPxBUF. This bit has no effect in Slave modes that Start and Stop condition detection is explicitly listed as enabled. The ACKTIM Status bit is only active when the AHEN bit or DHEN bit is set. DS41391D-page 282  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 25-5: R/W-1/1 SSPxMSK: SSPx MASK REGISTER R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 R/W-1/1 MSK bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-1 MSK: Mask bits 1 = The received address bit n is compared to SSPxADD to detect I2C address match 0 = The received address bit n is not used to detect I2C address match bit 0 MSK: Mask bit for I2C Slave mode, 10-bit Address I2C Slave mode, 10-bit address (SSPxM = 0111 or 1111): 1 = The received address bit 0 is compared to SSPxADD to detect I2C address match 0 = The received address bit 0 is not used to detect I2C address match I2C Slave mode, 7-bit address, the bit is ignored REGISTER 25-6: R/W-0/0 SSPxADD: MSSPx ADDRESS AND BAUD RATE REGISTER (I2C MODE) R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 ADD bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared Master mode: bit 7-0 ADD: Baud Rate Clock Divider bits SCLx pin clock period = ((ADD + 1) *4)/FOSC 10-Bit Slave mode — Most Significant Address byte: bit 7-3 Not used: Unused for Most Significant Address byte. Bit state of this register is a “don’t care”. Bit pattern sent by master is fixed by I2C specification and must be equal to ‘11110’. However, those bits are compared by hardware and are not affected by the value in this register. bit 2-1 ADD: Two Most Significant bits of 10-bit address bit 0 Not used: Unused in this mode. Bit state is a “don’t care”. 10-Bit Slave mode — Least Significant Address byte: bit 7-0 ADD: Eight Least Significant bits of 10-bit address 7-Bit Slave mode: bit 7-1 ADD: 7-bit address bit 0 Not used: Unused in this mode. Bit state is a “don’t care”.  2011 Microchip Technology Inc. DS41391D-page 283 PIC16(L)F1826/27 NOTES: DS41391D-page 284  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.0 The EUSART module includes the following capabilities: ENHANCED UNIVERSAL SYNCHRONOUS ASYNCHRONOUS RECEIVER TRANSMITTER (EUSART) • • • • • • • • • • Full-duplex asynchronous transmit and receive Two-character input buffer One-character output buffer Programmable 8-bit or 9-bit character length Address detection in 9-bit mode Input buffer overrun error detection Received character framing error detection Half-duplex synchronous master Half-duplex synchronous slave Programmable clock polarity in synchronous modes • Sleep operation The Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) module is a serial I/O communications peripheral. It contains all the clock generators, shift registers and data buffers necessary to perform an input or output serial data transfer independent of device program execution. The EUSART, also known as a Serial Communications Interface (SCI), can be configured as a full-duplex asynchronous system or half-duplex synchronous system. Full-Duplex mode is useful for communications with peripheral systems, such as CRT terminals and personal computers. Half-Duplex Synchronous mode is intended for communications with peripheral devices, such as A/D or D/A integrated circuits, serial EEPROMs or other microcontrollers. These devices typically do not have internal clocks for baud rate generation and require the external clock signal provided by a master synchronous device. FIGURE 26-1: The EUSART module implements the following additional features, making it ideally suited for use in Local Interconnect Network (LIN) bus systems: • Automatic detection and calibration of the baud rate • Wake-up on Break reception • 13-bit Break character transmit Block diagrams of the EUSART transmitter and receiver are shown in Figure 26-1 and Figure 26-2. EUSART TRANSMIT BLOCK DIAGRAM Data Bus TXIE Interrupt TXIF TXREG Register 8 MSb TX/CK pin LSb (8) • • • 0 Pin Buffer and Control TRMT SPEN Transmit Shift Register (TSR) TXEN Baud Rate Generator FOSC TX9 n BRG16 +1 SPBRGH ÷n SPBRGL Multiplier x4 x16 x64 SYNC 1 X 0 0 0 BRGH X 1 1 0 0 BRG16 X 1 0 1 0  2011 Microchip Technology Inc. TX9D DS41391D-page 285 PIC16(L)F1826/27 FIGURE 26-2: EUSART RECEIVE BLOCK DIAGRAM SPEN CREN RX/DT pin Baud Rate Generator Data Recovery FOSC BRG16 SPBRGH SPBRGL Multiplier x4 x16 x64 SYNC 1 X 0 0 0 BRGH X 1 1 0 0 BRG16 X 1 0 1 0 Stop RCIDL RSR Register MSb Pin Buffer and Control +1 OERR (8) ••• 7 1 LSb 0 START RX9 ÷n n FERR RX9D RCREG Register 8 FIFO Data Bus RCIF RCIE Interrupt The operation of the EUSART module is controlled through three registers: • Transmit Status and Control (TXSTA) • Receive Status and Control (RCSTA) • Baud Rate Control (BAUDCON) These registers are detailed in Register 26-1, Register 26-2 and Register 26-3, respectively. When the receiver or transmitter section is not enabled then the corresponding RX or TX pin may be used for general purpose input and output. DS41391D-page 286  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.1 EUSART Asynchronous Mode The EUSART transmits and receives data using the standard non-return-to-zero (NRZ) format. NRZ is implemented with two levels: a VOH mark state which represents a ‘1’ data bit, and a VOL space state which represents a ‘0’ data bit. NRZ refers to the fact that consecutively transmitted data bits of the same value stay at the output level of that bit without returning to a neutral level between each bit transmission. An NRZ transmission port idles in the mark state. Each character transmission consists of one Start bit followed by eight or nine data bits and is always terminated by one or more Stop bits. The Start bit is always a space and the Stop bits are always marks. The most common data format is 8 bits. Each transmitted bit persists for a period of 1/(Baud Rate). An on-chip dedicated 8-bit/16-bit Baud Rate Generator is used to derive standard baud rate frequencies from the system oscillator. See Table 26-5 for examples of baud rate configurations. The EUSART transmits and receives the LSb first. The EUSART’s transmitter and receiver are functionally independent, but share the same data format and baud rate. Parity is not supported by the hardware, but can be implemented in software and stored as the ninth data bit. 26.1.1 EUSART ASYNCHRONOUS TRANSMITTER The EUSART transmitter block diagram is shown in Figure 26-1. The heart of the transmitter is the serial Transmit Shift Register (TSR), which is not directly accessible by software. The TSR obtains its data from the transmit buffer, which is the TXREG register. 26.1.1.1 Enabling the Transmitter The EUSART transmitter is enabled for asynchronous operations by configuring the following three control bits: • TXEN = 1 • SYNC = 0 • SPEN = 1 All other EUSART control bits are assumed to be in their default state. Setting the TXEN bit of the TXSTA register enables the transmitter circuitry of the EUSART. Clearing the SYNC bit of the TXSTA register configures the EUSART for asynchronous operation. Setting the SPEN bit of the RCSTA register enables the EUSART and automatically configures the TX/CK I/O pin as an output. If the TX/CK pin is shared with an analog peripheral, the analog I/O function must be disabled by clearing the corresponding ANSEL bit. Note: 26.1.1.2 Transmitting Data A transmission is initiated by writing a character to the TXREG register. If this is the first character, or the previous character has been completely flushed from the TSR, the data in the TXREG is immediately transferred to the TSR register. If the TSR still contains all or part of a previous character, the new character data is held in the TXREG until the Stop bit of the previous character has been transmitted. The pending character in the TXREG is then transferred to the TSR in one TCY immediately following the Stop bit transmission. The transmission of the Start bit, data bits and Stop bit sequence commences immediately following the transfer of the data to the TSR from the TXREG. 26.1.1.3 Transmit Data Polarity The polarity of the transmit data can be controlled with the SCKP bit of the BAUDCON register. The default state of this bit is ‘0’ which selects high true transmit idle and data bits. Setting the SCKP bit to ‘1’ will invert the transmit data resulting in low true idle and data bits. The SCKP bit controls transmit data polarity in Asynchronous mode only. In Synchronous mode, the SCKP bit has a different function. See Section 26.4.1.2 “Clock Polarity”. 26.1.1.4 Transmit Interrupt Flag The TXIF interrupt flag bit of the PIR1 register is set whenever the EUSART transmitter is enabled and no character is being held for transmission in the TXREG. In other words, the TXIF bit is only clear when the TSR is busy with a character and a new character has been queued for transmission in the TXREG. The TXIF flag bit is not cleared immediately upon writing TXREG. TXIF becomes valid in the second instruction cycle following the write execution. Polling TXIF immediately following the TXREG write will return invalid results. The TXIF bit is read-only, it cannot be set or cleared by software. The TXIF interrupt can be enabled by setting the TXIE interrupt enable bit of the PIE1 register. However, the TXIF flag bit will be set whenever the TXREG is empty, regardless of the state of TXIE enable bit. To use interrupts when transmitting data, set the TXIE bit only when there is more data to send. Clear the TXIE interrupt enable bit upon writing the last character of the transmission to the TXREG. The TXIF Transmitter Interrupt flag is set when the TXEN enable bit is set.  2011 Microchip Technology Inc. DS41391D-page 287 PIC16(L)F1826/27 26.1.1.5 TSR Status 26.1.1.7 The TRMT bit of the TXSTA register indicates the status of the TSR register. This is a read-only bit. The TRMT bit is set when the TSR register is empty and is cleared when a character is transferred to the TSR register from the TXREG. The TRMT bit remains clear until all bits have been shifted out of the TSR register. No interrupt logic is tied to this bit, so the user has to poll this bit to determine the TSR status. Note: 26.1.1.6 1. 2. 3. The TSR register is not mapped in data memory, so it is not available to the user. 4. 5. Transmitting 9-Bit Characters The EUSART supports 9-bit character transmissions. When the TX9 bit of the TXSTA register is set, the EUSART will shift 9 bits out for each character transmitted. The TX9D bit of the TXSTA register is the ninth, and Most Significant, data bit. When transmitting 9-bit data, the TX9D data bit must be written before writing the 8 Least Significant bits into the TXREG. All nine bits of data will be transferred to the TSR shift register immediately after the TXREG is written. A special 9-bit Address mode is available for use with multiple receivers. See Section 26.1.2.7 “Address Detection” for more information on the address mode. FIGURE 26-3: Write to TXREG BRG Output (Shift Clock) 8. Word 1 Start bit bit 0 bit 1 bit 7/8 Stop bit Word 1 TXIF bit (Transmit Buffer Reg. Empty Flag) FIGURE 26-4: 7. Initialize the SPBRGH, SPBRGL register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 26.3 “EUSART Baud Rate Generator (BRG)”). Enable the asynchronous serial port by clearing the SYNC bit and setting the SPEN bit. If 9-bit transmission is desired, set the TX9 control bit. A set ninth data bit will indicate that the 8 Least Significant data bits are an address when the receiver is set for address detection. Set SCKP bit if inverted transmit is desired. Enable the transmission by setting the TXEN control bit. This will cause the TXIF interrupt bit to be set. If interrupts are desired, set the TXIE interrupt enable bit of the PIE1 register. An interrupt will occur immediately provided that the GIE and PEIE bits of the INTCON register are also set. If 9-bit transmission is selected, the ninth bit should be loaded into the TX9D data bit. Load 8-bit data into the TXREG register. This will start the transmission. ASYNCHRONOUS TRANSMISSION TX/CK pin TRMT bit (Transmit Shift Reg. Empty Flag) 6. Asynchronous Transmission Set-up: 1 TCY Word 1 Transmit Shift Reg. ASYNCHRONOUS TRANSMISSION (BACK-TO-BACK) Write to TXREG BRG Output (Shift Clock) Word 1 TX/CK pin TXIF bit (Transmit Buffer Reg. Empty Flag) TRMT bit (Transmit Shift Reg. Empty Flag) Note: Word 2 Start bit bit 0 1 TCY bit 1 Word 1 bit 7/8 Stop bit Start bit bit 0 Word 2 1 TCY Word 1 Transmit Shift Reg. Word 2 Transmit Shift Reg. This timing diagram shows two consecutive transmissions. DS41391D-page 288  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 26-1: Name SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page APFCON0 RXDTSEL SDO1SEL SS1SEL P2BSEL(1) CCP2SEL(1) P1DSEL P1CSEL CCP1SEL 119 APFCON1 — — — — — — — TXCKSEL 119 BAUDCON ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN 296 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 91 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D INTCON RCSTA SPBRGL BRG SPBRGH TRISB TXREG TRISB6 TRISB5 297* TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 SYNC SENDB BRGH TRMT TX9D EUSART Transmit Data Register TXSTA CSRC Legend: Note BRG TRISB7 * 1: TX9 TXEN 295 297* 127 287* 294 — = unimplemented location, read as ‘0’. Shaded cells are not used for Asynchronous Transmission. Page provides register information. PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 289 PIC16(L)F1826/27 26.1.2 EUSART ASYNCHRONOUS RECEIVER The Asynchronous mode is typically used in RS-232 systems. The receiver block diagram is shown in Figure 26-2. The data is received on the RX/DT pin and drives the data recovery block. The data recovery block is actually a high-speed shifter operating at 16 times the baud rate, whereas the serial Receive Shift Register (RSR) operates at the bit rate. When all 8 or 9 bits of the character have been shifted in, they are immediately transferred to a two character First-In-First-Out (FIFO) memory. The FIFO buffering allows reception of two complete characters and the start of a third character before software must start servicing the EUSART receiver. The FIFO and RSR registers are not directly accessible by software. Access to the received data is via the RCREG register. 26.1.2.1 Enabling the Receiver The EUSART receiver is enabled for asynchronous operation by configuring the following three control bits: • CREN = 1 • SYNC = 0 • SPEN = 1 All other EUSART control bits are assumed to be in their default state. Setting the CREN bit of the RCSTA register enables the receiver circuitry of the EUSART. Clearing the SYNC bit of the TXSTA register configures the EUSART for asynchronous operation. Setting the SPEN bit of the RCSTA register enables the EUSART. The programmer must set the corresponding TRIS bit to configure the RX/DT I/O pin as an input. Note: If the RX/DT function is on an analog pin, the corresponding ANSEL bit must be cleared for the receiver to function. 26.1.2.2 Receiving Data The receiver data recovery circuit initiates character reception on the falling edge of the first bit. The first bit, also known as the Start bit, is always a zero. The data recovery circuit counts one-half bit time to the center of the Start bit and verifies that the bit is still a zero. If it is not a zero then the data recovery circuit aborts character reception, without generating an error, and resumes looking for the falling edge of the Start bit. If the Start bit zero verification succeeds then the data recovery circuit counts a full bit time to the center of the next bit. The bit is then sampled by a majority detect circuit and the resulting ‘0’ or ‘1’ is shifted into the RSR. This repeats until all data bits have been sampled and shifted into the RSR. One final bit time is measured and the level sampled. This is the Stop bit, which is always a ‘1’. If the data recovery circuit samples a ‘0’ in the Stop bit position then a framing error is set for this character, otherwise the framing error is cleared for this character. See Section 26.1.2.4 “Receive Framing Error” for more information on framing errors. Immediately after all data bits and the Stop bit have been received, the character in the RSR is transferred to the EUSART receive FIFO and the RCIF interrupt flag bit of the PIR1 register is set. The top character in the FIFO is transferred out of the FIFO by reading the RCREG register. Note: 26.1.2.3 If the receive FIFO is overrun, no additional characters will be received until the overrun condition is cleared. See Section 26.1.2.5 “Receive Overrun Error” for more information on overrun errors. Receive Interrupts The RCIF interrupt flag bit of the PIR1 register is set whenever the EUSART receiver is enabled and there is an unread character in the receive FIFO. The RCIF interrupt flag bit is read-only, it cannot be set or cleared by software. RCIF interrupts are enabled by setting all of the following bits: • RCIE interrupt enable bit of the PIE1 register • PEIE peripheral interrupt enable bit of the INTCON register • GIE global interrupt enable bit of the INTCON register The RCIF interrupt flag bit will be set when there is an unread character in the FIFO, regardless of the state of interrupt enable bits. DS41391D-page 290  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.1.2.4 Receive Framing Error Each character in the receive FIFO buffer has a corresponding framing error Status bit. A framing error indicates that a Stop bit was not seen at the expected time. The framing error status is accessed via the FERR bit of the RCSTA register. The FERR bit represents the status of the top unread character in the receive FIFO. Therefore, the FERR bit must be read before reading the RCREG. The FERR bit is read-only and only applies to the top unread character in the receive FIFO. A framing error (FERR = 1) does not preclude reception of additional characters. It is not necessary to clear the FERR bit. Reading the next character from the FIFO buffer will advance the FIFO to the next character and the next corresponding framing error. The FERR bit can be forced clear by clearing the SPEN bit of the RCSTA register which resets the EUSART. Clearing the CREN bit of the RCSTA register does not affect the FERR bit. A framing error by itself does not generate an interrupt. Note: 26.1.2.5 26.1.2.7 Address Detection A special Address Detection mode is available for use when multiple receivers share the same transmission line, such as in RS-485 systems. Address detection is enabled by setting the ADDEN bit of the RCSTA register. Address detection requires 9-bit character reception. When address detection is enabled, only characters with the ninth data bit set will be transferred to the receive FIFO buffer, thereby setting the RCIF interrupt bit. All other characters will be ignored. Upon receiving an address character, user software determines if the address matches its own. Upon address match, user software must disable address detection by clearing the ADDEN bit before the next Stop bit occurs. When user software detects the end of the message, determined by the message protocol used, software places the receiver back into the Address Detection mode by setting the ADDEN bit. If all receive characters in the receive FIFO have framing errors, repeated reads of the RCREG will not clear the FERR bit. Receive Overrun Error The receive FIFO buffer can hold two characters. An overrun error will be generated if a third character, in its entirety, is received before the FIFO is accessed. When this happens the OERR bit of the RCSTA register is set. The characters already in the FIFO buffer can be read but no additional characters will be received until the error is cleared. The error must be cleared by either clearing the CREN bit of the RCSTA register or by resetting the EUSART by clearing the SPEN bit of the RCSTA register. 26.1.2.6 Receiving 9-bit Characters The EUSART supports 9-bit character reception. When the RX9 bit of the RCSTA register is set the EUSART will shift 9 bits into the RSR for each character received. The RX9D bit of the RCSTA register is the ninth and Most Significant data bit of the top unread character in the receive FIFO. When reading 9-bit data from the receive FIFO buffer, the RX9D data bit must be read before reading the 8 Least Significant bits from the RCREG.  2011 Microchip Technology Inc. DS41391D-page 291 PIC16(L)F1826/27 26.1.2.8 Asynchronous Reception Set-up: 26.1.2.9 1. Initialize the SPBRGH, SPBRGL register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 26.3 “EUSART Baud Rate Generator (BRG)”). 2. Clear the ANSEL bit for the RX pin (if applicable). 3. Enable the serial port by setting the SPEN bit. The SYNC bit must be clear for asynchronous operation. 4. If interrupts are desired, set the RCIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. 5. If 9-bit reception is desired, set the RX9 bit. 6. Enable reception by setting the CREN bit. 7. The RCIF interrupt flag bit will be set when a character is transferred from the RSR to the receive buffer. An interrupt will be generated if the RCIE interrupt enable bit was also set. 8. Read the RCSTA register to get the error flags and, if 9-bit data reception is enabled, the ninth data bit. 9. Get the received 8 Least Significant data bits from the receive buffer by reading the RCREG register. 10. If an overrun occurred, clear the OERR flag by clearing the CREN receiver enable bit. FIGURE 26-5: Rcv Shift Reg Rcv Buffer Reg. RCIDL This mode would typically be used in RS-485 systems. To set up an Asynchronous Reception with Address Detect Enable: 1. Initialize the SPBRGH, SPBRGL register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 26.3 “EUSART Baud Rate Generator (BRG)”). 2. Clear the ANSEL bit for the RX pin (if applicable). 3. Enable the serial port by setting the SPEN bit. The SYNC bit must be clear for asynchronous operation. 4. If interrupts are desired, set the RCIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. 5. Enable 9-bit reception by setting the RX9 bit. 6. Enable address detection by setting the ADDEN bit. 7. Enable reception by setting the CREN bit. 8. The RCIF interrupt flag bit will be set when a character with the ninth bit set is transferred from the RSR to the receive buffer. An interrupt will be generated if the RCIE interrupt enable bit was also set. 9. Read the RCSTA register to get the error flags. The ninth data bit will always be set. 10. Get the received 8 Least Significant data bits from the receive buffer by reading the RCREG register. Software determines if this is the device’s address. 11. If an overrun occurred, clear the OERR flag by clearing the CREN receiver enable bit. 12. If the device has been addressed, clear the ADDEN bit to allow all received data into the receive buffer and generate interrupts. ASYNCHRONOUS RECEPTION Start bit bit 0 RX/DT pin 9-bit Address Detection Mode Set-up bit 1 bit 7/8 Stop bit Start bit Word 1 RCREG bit 0 bit 7/8 Stop bit Start bit bit 7/8 Stop bit Word 2 RCREG Read Rcv Buffer Reg. RCREG RCIF (Interrupt Flag) OERR bit CREN Note: This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after the third word, causing the OERR (overrun) bit to be set. DS41391D-page 292  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 26-2: Name APFCON0 SUMMARY OF REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION Bit 7 Bit 6 Bit 5 Bit 4 RXDTSEL SDO1SEL SS1SEL Bit 2 Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 Bit 3 P2BSEL(1) CCP2SEL(1) APFCON1 — — — — — — — TXCKSEL 119 BAUDCON ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN 296 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 INTCON TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF RCREG RCSTA EUSART Receive Data Register SPEN RX9 SREN SPBRGL TXSTA Legend: * Note 1: ADDEN FERR OERR RX9D BRG SPBRGH TRISB CREN 91 290* 295 297* BRG 297* TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 294 — = unimplemented location, read as ‘0’. Shaded cells are not used for Asynchronous Reception. Page provides register information. PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 293 PIC16(L)F1826/27 26.2 Clock Accuracy with Asynchronous Operation The factory calibrates the internal oscillator block output (INTOSC). However, the INTOSC frequency may drift as VDD or temperature changes, and this directly affects the asynchronous baud rate. Two methods may be used to adjust the baud rate clock, but both require a reference clock source of some kind. REGISTER 26-1: The first (preferred) method uses the OSCTUNE register to adjust the INTOSC output. Adjusting the value in the OSCTUNE register allows for fine resolution changes to the system clock source. See Section 5.2.2 “Internal Clock Sources” for more information. The other method adjusts the value in the Baud Rate Generator. This can be done automatically with the Auto-Baud Detect feature (see Section 26.3.1 “Auto-Baud Detect”). There may not be fine enough resolution when adjusting the Baud Rate Generator to compensate for a gradual change in the peripheral clock frequency. TXSTA: TRANSMIT STATUS AND CONTROL REGISTER R/W-/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R-1/1 R/W-0/0 CSRC TX9 TXEN(1) SYNC SENDB BRGH TRMT TX9D bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 CSRC: Clock Source Select bit Asynchronous mode: Don’t care Synchronous mode: 1 = Master mode (clock generated internally from BRG) 0 = Slave mode (clock from external source) bit 6 TX9: 9-bit Transmit Enable bit 1 = Selects 9-bit transmission 0 = Selects 8-bit transmission bit 5 TXEN: Transmit Enable bit(1) 1 = Transmit enabled 0 = Transmit disabled bit 4 SYNC: EUSART Mode Select bit 1 = Synchronous mode 0 = Asynchronous mode bit 3 SENDB: Send Break Character bit Asynchronous mode: 1 = Send Sync Break on next transmission (cleared by hardware upon completion) 0 = Sync Break transmission completed Synchronous mode: Don’t care bit 2 BRGH: High Baud Rate Select bit Asynchronous mode: 1 = High speed 0 = Low speed Synchronous mode: Unused in this mode bit 1 TRMT: Transmit Shift Register Status bit 1 = TSR empty 0 = TSR full bit 0 TX9D: Ninth bit of Transmit Data Can be address/data bit or a parity bit. Note 1: SREN/CREN overrides TXEN in Sync mode. DS41391D-page 294  2011 Microchip Technology Inc. PIC16(L)F1826/27 RCSTA: RECEIVE STATUS AND CONTROL REGISTER(1) REGISTER 26-2: R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 R-0/0 R-0/0 R-0/0 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 SPEN: Serial Port Enable bit 1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins) 0 = Serial port disabled (held in Reset) bit 6 RX9: 9-bit Receive Enable bit 1 = Selects 9-bit reception 0 = Selects 8-bit reception bit 5 SREN: Single Receive Enable bit Asynchronous mode: Don’t care Synchronous mode – Master: 1 = Enables single receive 0 = Disables single receive This bit is cleared after reception is complete. Synchronous mode – Slave Don’t care bit 4 CREN: Continuous Receive Enable bit Asynchronous mode: 1 = Enables receiver 0 = Disables receiver Synchronous mode: 1 = Enables continuous receive until enable bit CREN is cleared (CREN overrides SREN) 0 = Disables continuous receive bit 3 ADDEN: Address Detect Enable bit Asynchronous mode 9-bit (RX9 = 1): 1 = Enables address detection, enable interrupt and load the receive buffer when RSR is set 0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit Asynchronous mode 8-bit (RX9 = 0): Don’t care bit 2 FERR: Framing Error bit 1 = Framing error (can be updated by reading RCREG register and receive next valid byte) 0 = No framing error bit 1 OERR: Overrun Error bit 1 = Overrun error (can be cleared by clearing bit CREN) 0 = No overrun error bit 0 RX9D: Ninth bit of Received Data This can be address/data bit or a parity bit and must be calculated by user firmware.  2011 Microchip Technology Inc. DS41391D-page 295 PIC16(L)F1826/27 REGISTER 26-3: BAUDCON: BAUD RATE CONTROL REGISTER R-0/0 R-1/1 U-0 R/W-0/0 R/W-0/0 U-0 R/W-0/0 R/W-0/0 ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 ABDOVF: Auto-Baud Detect Overflow bit Asynchronous mode: 1 = Auto-baud timer overflowed 0 = Auto-baud timer did not overflow Synchronous mode: Don’t care bit 6 RCIDL: Receive Idle Flag bit Asynchronous mode: 1 = Receiver is Idle 0 = Start bit has been received and the receiver is receiving Synchronous mode: Don’t care bit 5 Unimplemented: Read as ‘0’ bit 4 SCKP: Synchronous Clock Polarity Select bit Asynchronous mode: 1 = Transmit inverted data to the TX/CK pin 0 = Transmit non-inverted data to the TX/CK pin Synchronous mode: 1 = Data is clocked on rising edge of the clock 0 = Data is clocked on falling edge of the clock bit 3 BRG16: 16-bit Baud Rate Generator bit 1 = 16-bit Baud Rate Generator is used 0 = 8-bit Baud Rate Generator is used bit 2 Unimplemented: Read as ‘0’ bit 1 WUE: Wake-up Enable bit Asynchronous mode: 1 = Receiver is waiting for a falling edge. No character will be received, byte RCIF will be set. WUE will automatically clear after RCIF is set. 0 = Receiver is operating normally Synchronous mode: Don’t care bit 0 ABDEN: Auto-Baud Detect Enable bit Asynchronous mode: 1 = Auto-Baud Detect mode is enabled (clears when auto-baud is complete) 0 = Auto-Baud Detect mode is disabled Synchronous mode: Don’t care DS41391D-page 296  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.3 EUSART Baud Rate Generator (BRG) The Baud Rate Generator (BRG) is an 8-bit or 16-bit timer that is dedicated to the support of both the asynchronous and synchronous EUSART operation. By default, the BRG operates in 8-bit mode. Setting the BRG16 bit of the BAUDCON register selects 16-bit mode. The SPBRGH, SPBRGL register pair determines the period of the free running baud rate timer. In Asynchronous mode the multiplier of the baud rate period is determined by both the BRGH bit of the TXSTA register and the BRG16 bit of the BAUDCON register. In Synchronous mode, the BRGH bit is ignored. Table 26-3 contains the formulas for determining the baud rate. Example 26-1 provides a sample calculation for determining the baud rate and baud rate error. Typical baud rates and error values for various asynchronous modes have been computed for your convenience and are shown in Table 26-3. It may be advantageous to use the high baud rate (BRGH = 1), or the 16-bit BRG (BRG16 = 1) to reduce the baud rate error. The 16-bit BRG mode is used to achieve slow baud rates for fast oscillator frequencies. EXAMPLE 26-1: CALCULATING BAUD RATE ERROR For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG: F OS C Desired Baud Rate = -----------------------------------------------------------------------64  [SPBRGH:SPBRGL] + 1  Solving for SPBRGH:SPBRGL: FOSC --------------------------------------------Desired Baud Rate X = --------------------------------------------- – 1 64 16000000 -----------------------9600 = ------------------------ – 1 64 =  25.042  = 25 16000000 Calculated Baud Rate = --------------------------64  25 + 1  = 9615 Calc. Baud Rate – Desired Baud Rate Error = -------------------------------------------------------------------------------------------Desired Baud Rate  9615 – 9600  = ---------------------------------- = 0.16% 9600 Writing a new value to the SPBRGH, SPBRGL register pair causes the BRG timer to be reset (or cleared). This ensures that the BRG does not wait for a timer overflow before outputting the new baud rate. If the system clock is changed during an active receive operation, a receive error or data loss may result. To avoid this problem, check the status of the RCIDL bit to make sure that the receive operation is Idle before changing the system clock.  2011 Microchip Technology Inc. DS41391D-page 297 PIC16(L)F1826/27 TABLE 26-3: BAUD RATE FORMULAS Configuration Bits BRG/EUSART Mode Baud Rate Formula 0 8-bit/Asynchronous FOSC/[64 (n+1)] 0 1 8-bit/Asynchronous 0 1 0 16-bit/Asynchronous 0 1 1 16-bit/Asynchronous 1 0 x 8-bit/Synchronous 1 x 16-bit/Synchronous SYNC BRG16 BRGH 0 0 0 1 Legend: Name BAUDCON SUMMARY OF REGISTERS ASSOCIATED WITH THE BAUD RATE GENERATOR Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN 296 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 295 SPBRGL BRG SPBRGH BRG TXSTA FOSC/[4 (n+1)] x = Don’t care, n = value of SPBRGH, SPBRGL register pair TABLE 26-4: RCSTA FOSC/[16 (n+1)] CSRC TX9 TXEN SYNC SENDB 297* 297* BRGH TRMT TX9D 294 Legend: — = unimplemented location, read as ‘0’. Shaded cells are not used for the Baud Rate Generator. * Page provides register information. DS41391D-page 298  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 26-5: BAUD RATES FOR ASYNCHRONOUS MODES SYNC = 0, BRGH = 0, BRG16 = 0 BAUD RATE FOSC = 32.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 20.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 18.432 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 11.0592 MHz Actual Rate % Error SPBRG value (decimal) 300 — — — — — — — — — — — — 1200 — — — 1221 1.73 255 1200 0.00 239 1200 0.00 143 2400 2404 0.16 207 2404 0.16 129 2400 0.00 119 2400 0.00 71 9600 9615 0.16 51 9470 -1.36 32 9600 0.00 29 9600 0.00 17 10417 10417 0.00 47 10417 0.00 29 10286 -1.26 27 10165 -2.42 16 19.2k 19.23k 0.16 25 19.53k 1.73 15 19.20k 0.00 14 19.20k 0.00 8 57.6k 55.55k -3.55 3 — — — 57.60k 0.00 7 57.60k 0.00 2 115.2k — — — — — — — — — — — — SYNC = 0, BRGH = 0, BRG16 = 0 BAUD RATE FOSC = 8.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 4.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 3.6864 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 1.000 MHz Actual Rate % Error SPBRG value (decimal) 300 — — — 300 0.16 207 300 0.00 191 300 0.16 51 1200 1202 0.16 103 1202 0.16 51 1200 0.00 47 1202 0.16 12 2400 2404 0.16 51 2404 0.16 25 2400 0.00 23 — — — 9600 9615 0.16 12 — — — 9600 0.00 5 — — — 10417 10417 0.00 11 10417 0.00 5 — — — — — — 19.2k — — — — — — 19.20k 0.00 2 — — — 57.6k — — — — — — 57.60k 0.00 0 — — — 115.2k — — — — — — — — — — — — SYNC = 0, BRGH = 1, BRG16 = 0 BAUD RATE FOSC = 32.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 20.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 18.432 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 11.0592 MHz Actual Rate % Error SPBRG value (decimal) 300 — — — — — — — — — — — — 1200 — — — — — — — — — — — — 2400 — — — — — — — — — — — — 9600 9615 0.16 207 9615 0.16 129 9600 0.00 119 9600 0.00 71 10417 10417 0.00 191 10417 0.00 119 10378 -0.37 110 10473 0.53 65 19.2k 19.23k 0.16 103 19.23k 0.16 64 19.20k 0.00 59 19.20k 0.00 35 57.6k 57.14k -0.79 34 56.82k -1.36 21 57.60k 0.00 19 57.60k 0.00 11 115.2k 117.64k 2.12 16 113.64k -1.36 10 115.2k 0.00 9 115.2k 0.00 5  2011 Microchip Technology Inc. DS41391D-page 299 PIC16(L)F1826/27 TABLE 26-5: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED) SYNC = 0, BRGH = 1, BRG16 = 0 BAUD RATE FOSC = 8.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 4.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 3.6864 MHz Actual Rate FOSC = 1.000 MHz % Error SPBRG value (decimal) Actual Rate % Error SPBRG value (decimal) 300 1200 — — — — — — — 1202 — 0.16 — 207 — 1200 — 0.00 — 191 300 1202 0.16 0.16 207 51 2400 2404 0.16 207 2404 0.16 103 2400 0.00 95 2404 0.16 25 — 9600 9615 0.16 51 9615 0.16 25 9600 0.00 23 — — 10417 10417 0.00 47 10417 0.00 23 10473 0.53 21 10417 0.00 5 19.2k 19231 0.16 25 19.23k 0.16 12 19.2k 0.00 11 — — — 57.6k 55556 -3.55 8 — — — 57.60k 0.00 3 — — — 115.2k — — — — — — 115.2k 0.00 1 — — — SYNC = 0, BRGH = 0, BRG16 = 1 BAUD RATE FOSC = 32.000 MHz Actual Rate FOSC = 20.000 MHz % Error SPBRG value (decimal) Actual Rate FOSC = 18.432 MHz % Error SPBRG value (decimal) Actual Rate FOSC = 11.0592 MHz % Error SPBRG value (decimal) Actual Rate % Error SPBRG value (decimal) 300 300.0 0.00 6666 300.0 -0.01 4166 300.0 0.00 3839 300.0 0.00 2303 1200 1200 -0.02 3332 1200 -0.03 1041 1200 0.00 959 1200 0.00 575 2400 2401 -0.04 832 2399 -0.03 520 2400 0.00 479 2400 0.00 287 71 9600 9615 0.16 207 9615 0.16 129 9600 0.00 119 9600 0.00 10417 10417 0.00 191 10417 0.00 119 10378 -0.37 110 10473 0.53 65 19.2k 19.23k 0.16 103 19.23k 0.16 64 19.20k 0.00 59 19.20k 0.00 35 57.6k 57.14k -0.79 34 56.818 -1.36 21 57.60k 0.00 19 57.60k 0.00 11 115.2k 117.6k 2.12 16 113.636 -1.36 10 115.2k 0.00 9 115.2k 0.00 5 SYNC = 0, BRGH = 0, BRG16 = 1 BAUD RATE FOSC = 8.000 MHz Actual Rate % Error SPBRG value (decimal) FOSC = 4.000 MHz Actual Rate FOSC = 3.6864 MHz % Error SPBRG value (decimal) Actual Rate FOSC = 1.000 MHz % Error SPBRG value (decimal) Actual Rate % Error SPBRG value (decimal) 300 299.9 -0.02 1666 300.1 0.04 832 300.0 0.00 767 300.5 0.16 207 1200 1199 -0.08 416 1202 0.16 207 1200 0.00 191 1202 0.16 51 2400 2404 0.16 207 2404 0.16 103 2400 0.00 95 2404 0.16 25 9600 9615 0.16 51 9615 0.16 25 9600 0.00 23 — — — 10417 10417 0.00 47 10417 0.00 23 10473 0.53 21 10417 0.00 5 19.2k 19.23k 0.16 25 19.23k 0.16 12 19.20k 0.00 11 — — — 57.6k 55556 -3.55 8 — — — 57.60k 0.00 3 — — — 115.2k — — — — — — 115.2k 0.00 1 — — — DS41391D-page 300  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 26-5: BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED) SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1 BAUD RATE FOSC = 32.000 MHz FOSC = 20.000 MHz FOSC = 18.432 MHz FOSC = 11.0592 MHz Actual Rate % Error SPBRG value (decimal) 300 1200 300.0 1200 0.00 0.00 26666 6666 300.0 1200 0.00 -0.01 16665 4166 300.0 1200 0.00 0.00 15359 3839 300.0 1200 0.00 0.00 9215 2303 2400 2400 0.01 3332 2400 0.02 2082 2400 0.00 1919 2400 0.00 1151 Actual Rate % Error SPBRG value (decimal) Actual Rate % Error SPBRG value (decimal) Actual Rate % Error SPBRG value (decimal) 9600 9604 0.04 832 9597 -0.03 520 9600 0.00 479 9600 0.00 287 10417 10417 0.00 767 10417 0.00 479 10425 0.08 441 10433 0.16 264 19.2k 19.18k -0.08 416 19.23k 0.16 259 19.20k 0.00 239 19.20k 0.00 143 57.6k 57.55k -0.08 138 57.47k -0.22 86 57.60k 0.00 79 57.60k 0.00 47 115.2k 115.9k 0.64 68 116.3k 0.94 42 115.2k 0.00 39 115.2k 0.00 23 SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1 BAUD RATE FOSC = 8.000 MHz Actual Rate FOSC = 4.000 MHz % Error SPBRG value (decimal) Actual Rate FOSC = 3.6864 MHz % Error SPBRG value (decimal) Actual Rate FOSC = 1.000 MHz % Error SPBRG value (decimal) Actual Rate % Error SPBRG value (decimal) 832 300 300.0 0.00 6666 300.0 0.01 3332 300.0 0.00 3071 300.1 0.04 1200 1200 -0.02 1666 1200 0.04 832 1200 0.00 767 1202 0.16 207 2400 2401 0.04 832 2398 0.08 416 2400 0.00 383 2404 0.16 103 9600 9615 0.16 207 9615 0.16 103 9600 0.00 95 9615 0.16 25 10417 10417 0 191 10417 0.00 95 10473 0.53 87 10417 0.00 23 19.2k 19.23k 0.16 103 19.23k 0.16 51 19.20k 0.00 47 19.23k 0.16 12 57.6k 57.14k -0.79 34 58.82k 2.12 16 57.60k 0.00 15 — — — 115.2k 117.6k 2.12 16 111.1k -3.55 8 115.2k 0.00 7 — — —  2011 Microchip Technology Inc. DS41391D-page 301 PIC16(L)F1826/27 26.3.1 AUTO-BAUD DETECT The EUSART module supports automatic detection and calibration of the baud rate. In the Auto-Baud Detect (ABD) mode, the clock to the BRG is reversed. Rather than the BRG clocking the incoming RX signal, the RX signal is timing the BRG. The Baud Rate Generator is used to time the period of a received 55h (ASCII “U”) which is the Sync character for the LIN bus. The unique feature of this character is that it has five rising edges including the Stop bit edge. Setting the ABDEN bit of the BAUDCON register starts the auto-baud calibration sequence (Figure 26-6). While the ABD sequence takes place, the EUSART state machine is held in Idle. On the first rising edge of the receive line, after the Start bit, the SPBRG begins counting up using the BRG counter clock as shown in Table 26-6. The fifth rising edge will occur on the RX pin at the end of the eighth bit period. At that time, an accumulated value totaling the proper BRG period is left in the SPBRGH, SPBRGL register pair, the ABDEN bit is automatically cleared and the RCIF interrupt flag is set. The value in the RCREG needs to be read to clear the RCIF interrupt. RCREG content should be discarded. When calibrating for modes that do not use the SPBRGH register the user can verify that the SPBRGL register did not overflow by checking for 00h in the SPBRGH register. The BRG auto-baud clock is determined by the BRG16 and BRGH bits as shown in Table 26-6. During ABD, both the SPBRGH and SPBRGL registers are used as a 16-bit counter, independent of the BRG16 bit setting. While calibrating the baud rate period, the SPBRGH FIGURE 26-6: Note 1: If the WUE bit is set with the ABDEN bit, auto-baud detection will occur on the byte following the Break character (see Section 26.3.3 “Auto-Wake-up on Break”). 2: It is up to the user to determine that the incoming character baud rate is within the range of the selected BRG clock source. Some combinations of oscillator frequency and EUSART baud rates are not possible. 3: During the auto-baud process, the auto-baud counter starts counting at 1. Upon completion of the auto-baud sequence, to achieve maximum accuracy, subtract 1 from the SPBRGH:SPBRGL register pair. TABLE 26-6: BRG COUNTER CLOCK RATES BRG16 BRGH BRG Base Clock BRG ABD Clock 0 0 FOSC/64 FOSC/512 0 1 FOSC/16 FOSC/128 1 0 FOSC/16 FOSC/128 1 FOSC/4 FOSC/32 1 Note: During the ABD sequence, SPBRGL and SPBRGH registers are both used as a 16-bit counter, independent of BRG16 setting. AUTOMATIC BAUD RATE CALIBRATION XXXXh BRG Value and SPBRGL registers are clocked at 1/8th the BRG base clock rate. The resulting byte measurement is the average bit time when clocked at full speed. RX pin 0000h 001Ch Start Edge #1 bit 1 bit 0 Edge #2 bit 3 bit 2 Edge #3 bit 5 bit 4 Edge #4 bit 7 bit 6 Edge #5 Stop bit BRG Clock Auto Cleared Set by User ABDEN bit RCIDL RCIF bit (Interrupt) Read RCREG SPBRGL XXh 1Ch SPBRGH XXh 00h Note 1: The ABD sequence requires the EUSART module to be configured in Asynchronous mode. DS41391D-page 302  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.3.2 AUTO-BAUD OVERFLOW During the course of automatic baud detection, the ABDOVF bit of the BAUDCON register will be set if the baud rate counter overflows before the fifth rising edge is detected on the RX pin. The ABDOVF bit indicates that the counter has exceeded the maximum count that can fit in the 16 bits of the SPBRGH:SPBRGL register pair. After the ABDOVF has been set, the counter continues to count until the fifth rising edge is detected on the RX pin. Upon detecting the fifth RX edge, the hardware will set the RCIF interrupt flag and clear the ABDEN bit of the BAUDCON register. The RCIF flag can be subsequently cleared by reading the RCREG register. The ABDOVF flag of the BAUDCON register can be cleared by software directly. To terminate the auto-baud process before the RCIF flag is set, clear the ABDEN bit then clear the ABDOVF bit of the BAUDCON register. The ABDOVF bit will remain set if the ABDEN bit is not cleared first. 26.3.3 AUTO-WAKE-UP ON BREAK During Sleep mode, all clocks to the EUSART are suspended. Because of this, the Baud Rate Generator is inactive and a proper character reception cannot be performed. The Auto-Wake-up feature allows the controller to wake-up due to activity on the RX/DT line. This feature is available only in Asynchronous mode. The Auto-Wake-up feature is enabled by setting the WUE bit of the BAUDCON register. Once set, the normal receive sequence on RX/DT is disabled, and the EUSART remains in an Idle state, monitoring for a wake-up event independent of the CPU mode. A wake-up event consists of a high-to-low transition on the RX/DT line. (This coincides with the start of a Sync Break or a wake-up signal character for the LIN protocol.) The EUSART module generates an RCIF interrupt coincident with the wake-up event. The interrupt is generated synchronously to the Q clocks in normal CPU operating modes (Figure 26-7), and asynchronously if the device is in Sleep mode (Figure 26-8). The interrupt condition is cleared by reading the RCREG register. 26.3.3.1 Special Considerations Break Character To avoid character errors or character fragments during a wake-up event, the wake-up character must be all zeros. When the wake-up is enabled the function works independent of the low time on the data stream. If the WUE bit is set and a valid non-zero character is received, the low time from the Start bit to the first rising edge will be interpreted as the wake-up event. The remaining bits in the character will be received as a fragmented character and subsequent characters can result in framing or overrun errors. Therefore, the initial character in the transmission must be all ‘0’s. This must be 10 or more bit times, 13-bit times recommended for LIN bus, or any number of bit times for standard RS-232 devices. Oscillator Start-up Time Oscillator start-up time must be considered, especially in applications using oscillators with longer start-up intervals (i.e., LP, XT or HS/PLL mode). The Sync Break (or wake-up signal) character must be of sufficient length, and be followed by a sufficient interval, to allow enough time for the selected oscillator to start and provide proper initialization of the EUSART. WUE Bit The wake-up event causes a receive interrupt by setting the RCIF bit. The WUE bit is cleared in hardware by a rising edge on RX/DT. The interrupt condition is then cleared in software by reading the RCREG register and discarding its contents. To ensure that no actual data is lost, check the RCIDL bit to verify that a receive operation is not in process before setting the WUE bit. If a receive operation is not occurring, the WUE bit may then be set just prior to entering the Sleep mode. The WUE bit is automatically cleared by the low-to-high transition on the RX line at the end of the Break. This signals to the user that the Break event is over. At this point, the EUSART module is in Idle mode waiting to receive the next character.  2011 Microchip Technology Inc. DS41391D-page 303 PIC16(L)F1826/27 FIGURE 26-7: AUTO-WAKE-UP BIT (WUE) TIMING DURING NORMAL OPERATION Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 OSC1 Auto Cleared Bit set by user WUE bit RX/DT Line RCIF Note 1: Cleared due to User Read of RCREG The EUSART remains in Idle while the WUE bit is set. FIGURE 26-8: AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP Q1Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 OSC1 Auto Cleared Bit Set by User WUE bit RX/DT Line Note 1 RCIF Sleep Command Executed Note 1: 2: Sleep Ends Cleared due to User Read of RCREG If the wake-up event requires long oscillator warm-up time, the automatic clearing of the WUE bit can occur while the stposc signal is still active. This sequence should not depend on the presence of Q clocks. The EUSART remains in Idle while the WUE bit is set. DS41391D-page 304  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.3.4 BREAK CHARACTER SEQUENCE The EUSART module has the capability of sending the special Break character sequences that are required by the LIN bus standard. A Break character consists of a Start bit, followed by 12 ‘0’ bits and a Stop bit. To send a Break character, set the SENDB and TXEN bits of the TXSTA register. The Break character transmission is then initiated by a write to the TXREG. The value of data written to TXREG will be ignored and all ‘0’s will be transmitted. The SENDB bit is automatically reset by hardware after the corresponding Stop bit is sent. This allows the user to preload the transmit FIFO with the next transmit byte following the Break character (typically, the Sync character in the LIN specification). The TRMT bit of the TXSTA register indicates when the transmit operation is active or Idle, just as it does during normal transmission. See Figure 26-9 for the timing of the Break character sequence. 26.3.4.1 Break and Sync Transmit Sequence The following sequence will start a message frame header made up of a Break, followed by an auto-baud Sync byte. This sequence is typical of a LIN bus master. 1. 2. 3. 4. 5. 26.3.5 RECEIVING A BREAK CHARACTER The Enhanced EUSART module can receive a Break character in two ways. The first method to detect a Break character uses the FERR bit of the RCSTA register and the Received data as indicated by RCREG. The Baud Rate Generator is assumed to have been initialized to the expected baud rate. A Break character has been received when; • RCIF bit is set • FERR bit is set • RCREG = 00h The second method uses the Auto-Wake-up feature described in Section 26.3.3 “Auto-Wake-up on Break”. By enabling this feature, the EUSART will sample the next two transitions on RX/DT, cause an RCIF interrupt, and receive the next data byte followed by another interrupt. Note that following a Break character, the user will typically want to enable the Auto-Baud Detect feature. For both methods, the user can set the ABDEN bit of the BAUDCON register before placing the EUSART in Sleep mode. Configure the EUSART for the desired mode. Set the TXEN and SENDB bits to enable the Break sequence. Load the TXREG with a dummy character to initiate transmission (the value is ignored). Write ‘55h’ to TXREG to load the Sync character into the transmit FIFO buffer. After the Break has been sent, the SENDB bit is reset by hardware and the Sync character is then transmitted. When the TXREG becomes empty, as indicated by the TXIF, the next data byte can be written to TXREG. FIGURE 26-9: Write to TXREG SEND BREAK CHARACTER SEQUENCE Dummy Write BRG Output (Shift Clock) TX (pin) Start bit bit 0 bit 1 bit 11 Stop bit Break TXIF bit (Transmit Interrupt Flag) TRMT bit (Transmit Shift Empty Flag) SENDB (send Break control bit)  2011 Microchip Technology Inc. SENDB Sampled Here Auto Cleared DS41391D-page 305 PIC16(L)F1826/27 26.4 EUSART Synchronous Mode Synchronous serial communications are typically used in systems with a single master and one or more slaves. The master device contains the necessary circuitry for baud rate generation and supplies the clock for all devices in the system. Slave devices can take advantage of the master clock by eliminating the internal clock generation circuitry. There are two signal lines in Synchronous mode: a bidirectional data line and a clock line. Slaves use the external clock supplied by the master to shift the serial data into and out of their respective receive and transmit shift registers. Since the data line is bidirectional, synchronous operation is half-duplex only. Half-duplex refers to the fact that master and slave devices can receive and transmit data but not both simultaneously. The EUSART can operate as either a master or slave device. Start and Stop bits are not used in synchronous transmissions. 26.4.1 SYNCHRONOUS MASTER MODE Clearing the SCKP bit sets the Idle state as low. When the SCKP bit is cleared, the data changes on the rising edge of each clock. 26.4.1.3 Data is transferred out of the device on the RX/DT pin. The RX/DT and TX/CK pin output drivers are automatically enabled when the EUSART is configured for synchronous master transmit operation. A transmission is initiated by writing a character to the TXREG register. If the TSR still contains all or part of a previous character the new character data is held in the TXREG until the last bit of the previous character has been transmitted. If this is the first character, or the previous character has been completely flushed from the TSR, the data in the TXREG is immediately transferred to the TSR. The transmission of the character commences immediately following the transfer of the data to the TSR from the TXREG. Each data bit changes on the leading edge of the master clock and remains valid until the subsequent leading clock edge. Note: The TSR register is not mapped in data memory, so it is not available to the user. 26.4.1.4 Synchronous Master Transmission Set-up: The following bits are used to configure the EUSART for Synchronous Master operation: • • • • • SYNC = 1 CSRC = 1 SREN = 0 (for transmit); SREN = 1 (for receive) CREN = 0 (for transmit); CREN = 1 (for receive) SPEN = 1 Setting the SYNC bit of the TXSTA register configures the device for synchronous operation. Setting the CSRC bit of the TXSTA register configures the device as a master. Clearing the SREN and CREN bits of the RCSTA register ensures that the device is in the Transmit mode, otherwise the device will be configured to receive. Setting the SPEN bit of the RCSTA register enables the EUSART. 26.4.1.1 26.4.1.2 1. 2. 3. 4. 5. 6. Master Clock Synchronous data transfers use a separate clock line, which is synchronous with the data. A device configured as a master transmits the clock on the TX/CK line. The TX/CK pin output driver is automatically enabled when the EUSART is configured for synchronous transmit or receive operation. Serial data bits change on the leading edge to ensure they are valid at the trailing edge of each clock. One clock cycle is generated for each data bit. Only as many clock cycles are generated as there are data bits. Synchronous Master Transmission 7. 8. Initialize the SPBRGH, SPBRGL register pair and the BRGH and BRG16 bits to achieve the desired baud rate (see Section 26.3 “EUSART Baud Rate Generator (BRG)”). Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC. Disable Receive mode by clearing bits SREN and CREN. Enable Transmit mode by setting the TXEN bit. If 9-bit transmission is desired, set the TX9 bit. If interrupts are desired, set the TXIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. If 9-bit transmission is selected, the ninth bit should be loaded in the TX9D bit. Start transmission by loading data to the TXREG register. Clock Polarity A clock polarity option is provided for Microwire compatibility. Clock polarity is selected with the SCKP bit of the BAUDCON register. Setting the SCKP bit sets the clock Idle state as high. When the SCKP bit is set, the data changes on the falling edge of each clock. DS41391D-page 306  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 26-10: SYNCHRONOUS TRANSMISSION RX/DT pin bit 0 bit 1 Word 1 bit 2 bit 7 bit 0 bit 1 Word 2 bit 7 TX/CK pin (SCKP = 0) TX/CK pin (SCKP = 1) Write to TXREG Reg Write Word 1 Write Word 2 TXIF bit (Interrupt Flag) TRMT bit TXEN bit Note: ‘1’ ‘1’ Sync Master mode, SPBRGL = 0, continuous transmission of two 8-bit words. FIGURE 26-11: SYNCHRONOUS TRANSMISSION (THROUGH TXEN) RX/DT pin bit 0 bit 1 bit 2 bit 6 bit 7 TX/CK pin Write to TXREG reg TXIF bit TRMT bit TXEN bit  2011 Microchip Technology Inc. DS41391D-page 307 PIC16(L)F1826/27 TABLE 26-7: Name APFCON0 SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION Bit 7 Bit 6 Bit 5 Bit 4 RXDTSEL SDO1SEL SS1SEL Bit 2 Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 Bit 3 P2BSEL(1) CCP2SEL(1) APFCON1 — — — — — — — TXCKSEL 119 BAUDCON ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN 296 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 91 SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 295 INTCON RCSTA SPBRGL BRG 297* SPBRGH BRG 297* TRISB TRISB7 TRISB6 TXREG TXSTA Legend: * Note 1: TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 EUSART Transmit Data Register CSRC TX9 TXEN SYNC SENDB 127 287* BRGH TRMT TX9D 294 — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Master Transmission. Page provides register information. PIC16(L)F1827 only. DS41391D-page 308  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.4.1.5 Synchronous Master Reception Data is received at the RX/DT pin. The RX/DT pin output driver is automatically disabled when the EUSART is configured for synchronous master receive operation. In Synchronous mode, reception is enabled by setting either the Single Receive Enable bit (SREN of the RCSTA register) or the Continuous Receive Enable bit (CREN of the RCSTA register). When SREN is set and CREN is clear, only as many clock cycles are generated as there are data bits in a single character. The SREN bit is automatically cleared at the completion of one character. When CREN is set, clocks are continuously generated until CREN is cleared. If CREN is cleared in the middle of a character the CK clock stops immediately and the partial character is discarded. If SREN and CREN are both set, then SREN is cleared at the completion of the first character and CREN takes precedence. To initiate reception, set either SREN or CREN. Data is sampled at the RX/DT pin on the trailing edge of the TX/CK clock pin and is shifted into the Receive Shift Register (RSR). When a complete character is received into the RSR, the RCIF bit is set and the character is automatically transferred to the two character receive FIFO. The Least Significant eight bits of the top character in the receive FIFO are available in RCREG. The RCIF bit remains set as long as there are unread characters in the receive FIFO. Note: 26.4.1.6 If the RX/DT function is on an analog pin, the corresponding ANSEL bit must be cleared for the receiver to function. Slave Clock Synchronous data transfers use a separate clock line, which is synchronous with the data. A device configured as a slave receives the clock on the TX/CK line. The TX/CK pin output driver is automatically disabled when the device is configured for synchronous slave transmit or receive operation. Serial data bits change on the leading edge to ensure they are valid at the trailing edge of each clock. One data bit is transferred for each clock cycle. Only as many clock cycles should be received as there are data bits. Note: 26.4.1.7 If the device is configured as a slave and the TX/CK function is on an analog pin, the corresponding ANSEL bit must be cleared. buffer can be read, however, no additional characters will be received until the error is cleared. The OERR bit can only be cleared by clearing the overrun condition. If the overrun error occurred when the SREN bit is set and CREN is clear then the error is cleared by reading RCREG. If the overrun occurred when the CREN bit is set then the error condition is cleared by either clearing the CREN bit of the RCSTA register or by clearing the SPEN bit which resets the EUSART. 26.4.1.8 Receiving 9-bit Characters The EUSART supports 9-bit character reception. When the RX9 bit of the RCSTA register is set the EUSART will shift 9-bits into the RSR for each character received. The RX9D bit of the RCSTA register is the ninth, and Most Significant, data bit of the top unread character in the receive FIFO. When reading 9-bit data from the receive FIFO buffer, the RX9D data bit must be read before reading the 8 Least Significant bits from the RCREG. 26.4.1.9 Synchronous Master Reception Set-up: 1. Initialize the SPBRGH, SPBRGL register pair for the appropriate baud rate. Set or clear the BRGH and BRG16 bits, as required, to achieve the desired baud rate. 2. Clear the ANSEL bit for the RX pin (if applicable). 3. Enable the synchronous master serial port by setting bits SYNC, SPEN and CSRC. 4. Ensure bits CREN and SREN are clear. 5. If interrupts are desired, set the RCIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. 6. If 9-bit reception is desired, set bit RX9. 7. Start reception by setting the SREN bit or for continuous reception, set the CREN bit. 8. Interrupt flag bit RCIF will be set when reception of a character is complete. An interrupt will be generated if the enable bit RCIE was set. 9. Read the RCSTA register to get the ninth bit (if enabled) and determine if any error occurred during reception. 10. Read the 8-bit received data by reading the RCREG register. 11. If an overrun error occurs, clear the error by either clearing the CREN bit of the RCSTA register or by clearing the SPEN bit which resets the EUSART. Receive Overrun Error The receive FIFO buffer can hold two characters. An overrun error will be generated if a third character, in its entirety, is received before RCREG is read to access the FIFO. When this happens the OERR bit of the RCSTA register is set. Previous data in the FIFO will not be overwritten. The two characters in the FIFO  2011 Microchip Technology Inc. DS41391D-page 309 PIC16(L)F1826/27 FIGURE 26-12: SYNCHRONOUS RECEPTION (MASTER MODE, SREN) RX/DT pin bit 0 bit 1 bit 2 bit 3 bit 4 bit 5 bit 6 bit 7 TX/CK pin (SCKP = 0) TX/CK pin (SCKP = 1) Write to bit SREN SREN bit CREN bit ‘0’ ‘0’ RCIF bit (Interrupt) Read RCREG Note: Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0. TABLE 26-8: Name SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION Bit 2 Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 — — TXCKSEL 119 BRG16 — WUE ABDEN 296 INTE IOCIE TMR0IF INTF IOCIF 86 RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 91 OERR RX9D Bit 7 Bit 6 Bit 5 APFCON0 RXDTSEL SDO1SEL SS1SEL APFCON1 — — — — — BAUDCON ABDOVF RCIDL — SCKP GIE PEIE TMR0IE PIE1 TMR1GIE ADIE PIR1 TMR1GIF ADIF SPEN RX9 SREN INTCON RCREG RCSTA Bit 4 Bit 3 P2BSEL(1) CCP2SEL(1) EUSART Receive Data Register CREN ADDEN 290* FERR 295 SPBRGL BRG 297* SPBRGH BRG 297* TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 TXSTA CSRC TX9 TXEN SYNC SENDB BRGH TRMT TX9D 294 Legend: * Note 1: — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Master Reception. Page provides register information. PIC16(L)F1827 only. DS41391D-page 310  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.4.2 SYNCHRONOUS SLAVE MODE The following bits are used to configure the EUSART for Synchronous slave operation: • • • • • SYNC = 1 CSRC = 0 SREN = 0 (for transmit); SREN = 1 (for receive) CREN = 0 (for transmit); CREN = 1 (for receive) SPEN = 1 1. 2. 3. 4. Setting the SYNC bit of the TXSTA register configures the device for synchronous operation. Clearing the CSRC bit of the TXSTA register configures the device as a slave. Clearing the SREN and CREN bits of the RCSTA register ensures that the device is in the Transmit mode, otherwise the device will be configured to receive. Setting the SPEN bit of the RCSTA register enables the EUSART. 26.4.2.1 If two words are written to the TXREG and then the SLEEP instruction is executed, the following will occur: 5. 26.4.2.2 1. EUSART Synchronous Slave Transmit The operation of the Synchronous Master and Slave modes are identical (see Section 26.4.1.3 “Synchronous Master Transmission”), except in the case of the Sleep mode. 2. 3. 4. 5. 6. 7. 8. TABLE 26-9: Name APFCON0 The first character will immediately transfer to the TSR register and transmit. The second word will remain in TXREG register. The TXIF bit will not be set. After the first character has been shifted out of TSR, the TXREG register will transfer the second character to the TSR and the TXIF bit will now be set. If the PEIE and TXIE bits are set, the interrupt will wake the device from Sleep and execute the next instruction. If the GIE bit is also set, the program will call the Interrupt Service Routine. Synchronous Slave Transmission Set-up: Set the SYNC and SPEN bits and clear the CSRC bit. Clear the ANSEL bit for the CK pin (if applicable). Clear the CREN and SREN bits. If interrupts are desired, set the TXIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. If 9-bit transmission is desired, set the TX9 bit. Enable transmission by setting the TXEN bit. If 9-bit transmission is selected, insert the Most Significant bit into the TX9D bit. Start transmission by writing the Least Significant 8 bits to the TXREG register. SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION Bit 7 Bit 6 Bit 5 Bit 4 RXDTSEL SDO1SEL SS1SEL Bit 2 Bit 1 Bit 0 Register on Page P1DSEL P1CSEL CCP1SEL 119 Bit 3 P2BSEL(1) CCP2SEL(1) APFCON1 — — — — — — — TXCKSEL 119 BAUDCON ABDOVF RCIDL — SCKP BRG16 — WUE ABDEN 296 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 PIE1 TMR1GIE ADIE RCIE TXIE SSPIE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSPIF CCP1IF TMR2IF TMR1IF 91 RCSTA SPEN RX9 SREN CREN ADDEN FERR OERR RX9D 295 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 INTCON TXREG TXSTA Legend: * Note 1: EUSART Transmit Data Register CSRC TX9 TXEN SYNC SENDB 127 287* BRGH TRMT TX9D 294 — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Slave Transmission. Page provides register information. PIC16(L)F1827 only.  2011 Microchip Technology Inc. DS41391D-page 311 PIC16(L)F1826/27 26.4.2.3 EUSART Synchronous Slave Reception 26.4.2.4 The operation of the Synchronous Master and Slave modes is identical (Section 26.4.1.5 “Synchronous Master Reception”), with the following exceptions: • Sleep • CREN bit is always set, therefore the receiver is never Idle • SREN bit, which is a “don’t care” in Slave mode 1. 2. 3. A character may be received while in Sleep mode by setting the CREN bit prior to entering Sleep. Once the word is received, the RSR register will transfer the data to the RCREG register. If the RCIE enable bit is set, the interrupt generated will wake the device from Sleep and execute the next instruction. If the GIE bit is also set, the program will branch to the interrupt vector. 4. 5. 6. 7. 8. 9. Synchronous Slave Reception Set-up: Set the SYNC and SPEN bits and clear the CSRC bit. Clear the ANSEL bit for both the CK and DT pins (if applicable). If interrupts are desired, set the RCIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. If 9-bit reception is desired, set the RX9 bit. Set the CREN bit to enable reception. The RCIF bit will be set when reception is complete. An interrupt will be generated if the RCIE bit was set. If 9-bit mode is enabled, retrieve the Most Significant bit from the RX9D bit of the RCSTA register. Retrieve the 8 Least Significant bits from the receive FIFO by reading the RCREG register. If an overrun error occurs, clear the error by either clearing the CREN bit of the RCSTA register or by clearing the SPEN bit which resets the EUSART. TABLE 26-10: SUMMARY OF REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION Name Register on Page P1CSEL CCP1SEL 119 — TXCKSEL 119 — WUE ABDEN 296 TMR0IF INTF IOCIF 86 CCP1IE TMR2IE TMR1IE 87 CCP1IF TMR2IF TMR1IF 91 FERR OERR RX9D TRISB3 TRISB2 TRISB1 TRISB0 127 SENDB BRGH TRMT TX9D 294 Bit 6 Bit 5 APFCON0 RXDTSEL SDO1SEL SS1SEL APFCON1 — — — — — BAUDCON ABDOVF RCIDL — SCKP GIE PEIE TMR0IE INTE PIE1 TMR1GIE ADIE RCIE PIR1 TMR1GIF ADIF RCIF RCSTA SPEN RX9 SREN CREN ADDEN TRISB TRISB7 TRISB6 TRISB5 TRISB4 TXSTA CSRC TX9 TXEN SYNC INTCON RCREG Legend: * Note 1: Bit 4 Bit 0 Bit 7 Bit 3 Bit 2 Bit 1 P1DSEL — BRG16 IOCIE TXIE SSPIE TXIF SSPIF P2BSEL(1) CCP2SEL(1) EUSART Receive Data Register 290* 295 — = unimplemented location, read as ‘0’. Shaded cells are not used for Synchronous Slave Reception. Page provides register information. PIC16(L)F1827 only. DS41391D-page 312  2011 Microchip Technology Inc. PIC16(L)F1826/27 26.5 EUSART Operation During Sleep The EUSART will remain active during Sleep only in the Synchronous Slave mode. All other modes require the system clock and therefore cannot generate the necessary signals to run the Transmit or Receive Shift registers during Sleep. Synchronous Slave mode uses an externally generated clock to run the Transmit and Receive Shift registers. 26.5.1 SYNCHRONOUS RECEIVE DURING SLEEP To receive during Sleep, all the following conditions must be met before entering Sleep mode: • RCSTA and TXSTA Control registers must be configured for Synchronous Slave Reception (see Section 26.4.2.4 “Synchronous Slave Reception Set-up:”). • If interrupts are desired, set the RCIE bit of the PIE1 register and the GIE and PEIE bits of the INTCON register. • The RCIF interrupt flag must be cleared by reading RCREG to unload any pending characters in the receive buffer. Upon entering Sleep mode, the device will be ready to accept data and clocks on the RX/DT and TX/CK pins, respectively. When the data word has been completely clocked in by the external device, the RCIF interrupt flag bit of the PIR1 register will be set. Thereby, waking the processor from Sleep. Upon waking from Sleep, the instruction following the SLEEP instruction will be executed. If the GIE global interrupt enable bit of the INTCON register is also set, then the Interrupt Service Routine at address 004h will be called.  2011 Microchip Technology Inc. 26.5.2 SYNCHRONOUS TRANSMIT DURING SLEEP To transmit during Sleep, all the following conditions must be met before entering Sleep mode: • RCSTA and TXSTA Control registers must be configured for Synchronous Slave Transmission (see Section 26.4.2.2 “Synchronous Slave Transmission Set-up:”). • The TXIF interrupt flag must be cleared by writing the output data to the TXREG, thereby filling the TSR and transmit buffer. • If interrupts are desired, set the TXIE bit of the PIE1 register and the PEIE bit of the INTCON register. • Interrupt enable bits TXIE of the PIE1 register and PEIE of the INTCON register must set. Upon entering Sleep mode, the device will be ready to accept clocks on TX/CK pin and transmit data on the RX/DT pin. When the data word in the TSR has been completely clocked out by the external device, the pending byte in the TXREG will transfer to the TSR and the TXIF flag will be set. Thereby, waking the processor from Sleep. At this point, the TXREG is available to accept another character for transmission, which will clear the TXIF flag. Upon waking from Sleep, the instruction following the SLEEP instruction will be executed. If the Global Interrupt Enable (GIE) bit is also set then the Interrupt Service Routine at address 0004h will be called. 26.5.3 ALTERNATE PIN LOCATIONS This module incorporates I/O pins that can be moved to other locations with the use of the alternate pin function registers, APFCON0 and APFCON1. To determine which pins can be moved and what their default locations are upon a reset, see Section 12.1 “Alternate Pin Function” for more information. DS41391D-page 313 PIC16(L)F1826/27 NOTES: DS41391D-page 314  2011 Microchip Technology Inc. PIC16(L)F1826/27 27.0 CAPACITIVE SENSING MODULE The capacitive sensing module allows for an interaction with an end user without a mechanical interface. In a typical application, the capacitive sensing module is attached to a pad on a Printed Circuit Board (PCB), which is electrically isolated from the end user. When the end user places their finger over the PCB pad, a capacitive load is added, causing a frequency shift in the capacitive sensing module. The capacitive sensing module requires software and at least one timer resource to determine the change in frequency. Key features of this module include: • • • • • Analog MUX for monitoring multiple inputs Capacitive sensing oscillator Multiple timer resources Software control Operation during Sleep FIGURE 27-1: CAPACITIVE SENSING BLOCK DIAGRAM Timer0 Module T0CKI Set TMR0IF TMR0CS T0XCS FOSC/4 0 0 TMR0 Overflow 1 1 CPSCH CPSON(1) CPS0 CPS1 CPS2 Timer1 Module CPSON CPS3 CPS4 CPS5 CPS6 CPS7 T1CS FOSC Capacitive Sensing Oscillator CPSOSC CPS8 CPSCLK CPSOUT CPSRNG CPS9 FOSC/4 T1OSC/ T1CKI Note 1: TMR1H:TMR1L T1GSEL T1G CPS10 SYNCC1OUT SYNCC2OUT CPS11 EN Timer1 Gate Control Logic If CPSON = 0, disabling capacitive sensing, no channel is selected.  2011 Microchip Technology Inc. DS41391D-page 315 PIC16(L)F1826/27 27.1 Analog MUX 27.4.1 TIMER0 The capacitive sensing module can monitor up to 12 inputs. The capacitive sensing inputs are defined as CPS. To determine if a frequency change has occurred the user must: To select Timer0 as the timer resource for the capacitive sensing module: • Select the appropriate CPS pin by setting the CPSCH bits of the CPSCON1 register • Set the corresponding ANSEL bit • Set the corresponding TRIS bit • Run the software algorithm When Timer0 is chosen as the timer resource, the capacitive sensing oscillator will be the clock source for Timer0. Refer to Section 20.0 “Timer0 Module” for additional information. Selection of the CPSx pin while the module is enabled will cause the capacitive sensing oscillator to be on the CPSx pin. Failure to set the corresponding ANSEL and TRIS bits can cause the capacitive sensing oscillator to stop, leading to false frequency readings. 27.2 Capacitive Sensing Oscillator The capacitive sensing oscillator consists of a constant current source and a constant current sink, to produce a triangle waveform. The CPSOUT bit of the CPSCON0 register shows the status of the capacitive sensing oscillator, whether it is a sinking or sourcing current. The oscillator is designed to drive a capacitive load (single PCB pad) and at the same time, be a clock source to either Timer0 or Timer1. The oscillator has three different current settings as defined by CPSRNG of the CPSCON0 register. The different current settings for the oscillator serve two purposes: • Maximize the number of counts in a timer for a fixed time base • Maximize the count differential in the timer during a change in frequency 27.3 • Set the T0XCS bit of the CPSCON0 register • Clear the TMR0CS bit of the OPTION register 27.4.2 TIMER1 To select Timer1 as the timer resource for the capacitive sensing module, set the TMR1CS of the T1CON register to ‘11’. When Timer1 is chosen as the timer resource, the capacitive sensing oscillator will be the clock source for Timer1. Because the Timer1 module has a gate control, developing a time base for the frequency measurement can be simplified by using the Timer0 overflow flag. It is recommend that the Timer0 overflow flag, in conjunction with the Toggle mode of the Timer1 gate, be used to develop the fixed time base required by the software portion of the capacitive sensing module. Refer to Section 21.6.3 “Timer1 Gate Toggle Mode” for additional information. TABLE 27-1: TIMER1 ENABLE FUNCTION TMR1ON TMR1GE Timer1 Operation 0 0 Off 0 1 Off 1 0 On 1 1 Count Enabled by input Timer resources To measure the change in frequency of the capacitive sensing oscillator, a fixed time base is required. For the period of the fixed time base, the capacitive sensing oscillator is used to clock either Timer0 or Timer1. The frequency of the capacitive sensing oscillator is equal to the number of counts in the timer divided by the period of the fixed time base. 27.4 Fixed Time Base To measure the frequency of the capacitive sensing oscillator, a fixed time base is required. Any timer resource or software loop can be used to establish the fixed time base. It is up to the end user to determine the method in which the fixed time base is generated. Note: The fixed time base can not be generated by the timer resource that the capacitive sensing oscillator is clocking. DS41391D-page 316  2011 Microchip Technology Inc. PIC16(L)F1826/27 27.5 Software Control The software portion of the capacitive sensing module is required to determine the change in frequency of the capacitive sensing oscillator. This is accomplished by the following: • Setting a fixed time base to acquire counts on Timer0 or Timer1 • Establishing the nominal frequency for the capacitive sensing oscillator • Establishing the reduced frequency for the capacitive sensing oscillator due to an additional capacitive load • Set the frequency threshold 27.5.1 • Remove any extra capacitive load on the selected CPSx pin • At the start of the fixed time base, clear the timer resource • At the end of the fixed time base save the value in the timer resource The value of the timer resource is the number of oscillations of the capacitive sensing oscillator for the given time base. The frequency of the capacitive sensing oscillator is equal to the number of counts on in the timer divided by the period of the fixed time base. FREQUENCY THRESHOLD The frequency threshold should be placed midway between the value of nominal frequency and the reduced frequency of the capacitive sensing oscillator. Refer to Application Note AN1103, “Software Handling for Capacitive Sensing” (DS01103) for more detailed information on the software required for capacitive sensing module. Note: For more information on general capacitive sensing refer to Application Notes: • AN1101, “Introduction to Capacitive Sensing” (DS01101) • AN1102, “Layout and Physical Design Guidelines for Capacitive Sensing” (DS01102) NOMINAL FREQUENCY (NO CAPACITIVE LOAD) To determine the nominal frequency of the capacitive sensing oscillator: 27.5.2 27.5.3 27.6 Operation during Sleep The capacitive sensing oscillator will continue to run as long as the module is enabled, independent of the part being in Sleep. In order for the software to determine if a frequency change has occurred, the part must be awake. However, the part does not have to be awake when the timer resource is acquiring counts. Note: Timer0 does not operate when in Sleep, and therefore cannot be used for capacitive sense measurements in Sleep. REDUCED FREQUENCY (ADDITIONAL CAPACITIVE LOAD) The extra capacitive load will cause the frequency of the capacitive sensing oscillator to decrease. To determine the reduced frequency of the capacitive sensing oscillator: • Add a typical capacitive load on the selected CPSx pin • Use the same fixed time base as the nominal frequency measurement • At the start of the fixed time base, clear the timer resource • At the end of the fixed time base save the value in the timer resource The value of the timer resource is the number of oscillations of the capacitive sensing oscillator with an additional capacitive load. The frequency of the capacitive sensing oscillator is equal to the number of counts on in the timer divided by the period of the fixed time base. This frequency should be less than the value obtained during the nominal frequency measurement.  2011 Microchip Technology Inc. DS41391D-page 317 PIC16(L)F1826/27 REGISTER 27-1: CPSCON0: CAPACITIVE SENSING CONTROL REGISTER 0 R/W-0/0 U-0 U-0 U-0 R/W-0/0 R/W-0/0 R-0/0 R/W-0/0 CPSON — — — CPSRNG1 CPSRNG0 CPSOUT T0XCS bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7 CPSON: Capacitive Sensing Module Enable bit 1 = Capacitive sensing module is enabled 0 = Capacitive sensing module is disabled bit 6-4 Unimplemented: Read as ‘0’ bit 3-2 CPSRNG: Capacitive Sensing Oscillator Range bits 00 = Oscillator is off 01 = Oscillator is in low range. Charge/discharge current is nominally 0.1 µA. 10 = Oscillator is in medium range. Charge/discharge current is nominally 1.2 µA. 11 = Oscillator is in high range. Charge/discharge current is nominally 18 µA. bit 1 CPSOUT: Capacitive Sensing Oscillator Status bit 1 = Oscillator is sourcing current (Current flowing out the pin) 0 = Oscillator is sinking current (Current flowing into the pin) bit 0 T0XCS: Timer0 External Clock Source Select bit If TMR0CS = 1 The T0XCS bit controls which clock external to the core/Timer0 module supplies Timer0: 1 = Timer0 clock source is the capacitive sensing oscillator 0 = Timer0 clock source is the T0CKI pin If TMR0CS = 0 Timer0 clock source is controlled by the core/Timer0 module and is FOSC/4 DS41391D-page 318  2011 Microchip Technology Inc. PIC16(L)F1826/27 REGISTER 27-2: CPSCON1: CAPACITIVE SENSING CONTROL REGISTER 1 U-0 U-0 U-0 U-0 R/W-0/0 R/W-0/0 R/W-0/0 R/W-0/0 — — — — CPSCH3 CPSCH2 CPSCH1 CPSCH0 bit 7 bit 0 Legend: R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’ u = Bit is unchanged x = Bit is unknown -n/n = Value at POR and BOR/Value at all other Resets ‘1’ = Bit is set ‘0’ = Bit is cleared bit 7-4 Unimplemented: Read as ‘0’ bit 3-0 CPSCH: Capacitive Sensing Channel Select bits If CPSON = 0: These bits are ignored. No channel is selected. If CPSON = 1: 0000 = channel 0, (CPS0) 0001 = channel 1, (CPS1) 0010 = channel 2, (CPS2) 0011 = channel 3, (CPS3) 0100 = channel 4, (CPS4) 0101 = channel 5, (CPS5) 0110 = channel 6, (CPS6) 0111 = channel 7, (CPS7) 1000 = channel 8, (CPS8) 1001 = channel 9, (CPS9) 1010 = channel 10, (CPS10) 1011 = channel 11, (CPS11) 1100 = Reserved. Do not use. 1101 = Reserved. Do not use. 1110 = Reserved. Do not use. 1111 = Reserved. Do not use. TABLE 27-2: Name SUMMARY OF REGISTERS ASSOCIATED WITH CAPACITIVE SENSING Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Register on Page 123 ANSELA — — — ANSA4 ANSA3 ANSA2 ANSA1 ANSA0 ANSELB ANSB7 ANSB6 ANSB5 ANSB4 ANSB3 ANSB2 ANSB1 — 128 CPSCON0 CPSON — — — CPSOUT T0XCS 318 319 CPSRNG1 CPSRNG0 — — — — CPSCH3 CPSCH2 CPSCH1 CPSCH0 GIE PEIE TMR0IE INTE IOCIE TMR0IF INTF IOCIF 86 WPUEN INTEDG TMR0CS TMR0SE PSA PS2 PS1 PS0 176 PIE1 TMR1GIE ADIE RCIE TXIE SSP1IE CCP1IE TMR2IE TMR1IE 87 PIR1 TMR1GIF ADIF RCIF TXIF SSP1IF CCP1IF TMR2IF TMR1IF 91 T1CON TMR1CS1 TMR1CS0 T1CKPS1 T1CKPS0 T1OSCEN T1SYNC — TMR1ON 185 TxCON — TxOUTPS3 TxOUTPS2 TxOUTPS1 TxOUTPS0 TMRxON TxCKPS1 TxCKPS0 185 TRISA TRISA7 TRISA6 TRISA5 TRISA4 TRISA3 TRISA2 TRISA1 TRISA0 122 TRISB TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 127 CPSCON1 INTCON OPTION_REG Legend: — = Unimplemented locations, read as ‘0’. Shaded cells are not used by the capacitive sensing module.  2011 Microchip Technology Inc. DS41391D-page 319 PIC16(L)F1826/27 NOTES: DS41391D-page 320  2011 Microchip Technology Inc. PIC16(L)F1826/27 28.0 IN-CIRCUIT SERIAL PROGRAMMING™ (ICSP™) ICSP™ programming allows customers to manufacture circuit boards with unprogrammed devices. Programming can be done after the assembly process allowing the device to be programmed with the most recent firmware or a custom firmware. Five pins are needed for ICSP™ programming: • ICSPCLK • ICSPDAT • MCLR/VPP • VDD • VSS In Program/Verify mode the Program Memory, User IDs and the Configuration Words are programmed through serial communications. The ICSPDAT pin is a bidirectional I/O used for transferring the serial data and the ICSPCLK pin is the clock input. For more information on ICSP™ refer to the “PIC16(L)F182X/PIC12(L)F1822 Memory Programming Specification” (DS41390). 28.1 High-Voltage Programming Entry Mode The device is placed into High-Voltage Programming Entry mode by holding the ICSPCLK and ICSPDAT pins low then raising the voltage on MCLR/VPP to VIHH. Some programmers produce VPP greater than VIHH (9.0V), an external circuit is required to limit the VPP voltage. See Figure 28-1 for example circuit. FIGURE 28-1: VPP LIMITER EXAMPLE CIRCUIT RJ11-6PIN 6 5 4 3 2 1 1 VPP 2 VDD 3 VSS 4 ICSP_DATA 5 ICSP_CLOCK 6 NC RJ11-6PIN ® To MPLAB ICD 2 R1 To Target Board 270 Ohm LM431BCMX 1 2 A K 3 A U1 6 A NC 4 7 A NC 5 R2 VREF 8 10k 1% Note: R3 24k 1% The ICD 2 produces a VPP voltage greater than the maximum VPP specification of the PIC16(L)F1826/27.  2011 Microchip Technology Inc. DS41391D-page 321 PIC16(L)F1826/27 28.2 FIGURE 28-2: Low-Voltage Programming Entry Mode The Low-Voltage Programming Entry mode allows the PIC16(L)F1826/27 devices to be programmed using VDD only, without high voltage. When the LVP bit of Configuration Word 2 is set to ‘1’, the low-voltage ICSP programming entry is enabled. To disable the Low-Voltage ICSP mode, the LVP bit must be programmed to ‘0’. VDD Entry into the Low-Voltage Programming Entry mode requires the following steps: 1. 2. ICSPDAT NC 2 4 6 ICSPCLK 1 3 5 VPP/MCLR MCLR is brought to VIL. A 32-bit key sequence is presented on ICSPDAT, while clocking ICSPCLK. VSS Target PC Board Bottom Side Pin Description* 1 = VPP/MCLR Once the key sequence is complete, MCLR must be held at VIL for as long as Program/Verify mode is to be maintained. 2 = VDD Target 3 = VSS (ground) 4 = ICSPDAT If low-voltage programming is enabled (LVP = 1), the MCLR Reset function is automatically enabled and cannot be disabled. See Section 7.3 “MCLR” for more information. 5 = ICSPCLK 6 = No Connect The LVP bit can only be reprogrammed to ‘0’ by using the High-Voltage Programming mode. 28.3 ICD RJ-11 STYLE CONNECTOR INTERFACE Another connector often found in use with the PICkit™ programmers is a standard 6-pin header with 0.1 inch spacing. Refer to Figure 28-3. Common Programming Interfaces Connection to a target device is typically done through an ICSP™ header. A commonly found connector on development tools is the RJ-11 in the 6P6C (6 pin, 6 connector) configuration. See Figure 28-2. FIGURE 28-3: PICkit™ STYLE CONNECTOR INTERFACE Pin 1 Indicator Pin Description* 1 2 3 4 5 6 1 = VPP/MCLR 2 = VDD Target 3 = VSS (ground) 4 = ICSPDAT 5 = ICSPCLK 6 = No Connect * DS41391D-page 322 The 6-pin header (0.100" spacing) accepts 0.025" square pins.  2011 Microchip Technology Inc. PIC16(L)F1826/27 For additional interface recommendations, refer to your specific device programmer manual prior to PCB design. It is recommended that isolation devices be used to separate the programming pins from other circuitry. The type of isolation is highly dependent on the specific application and may include devices such as resistors, diodes, or even jumpers. See Figure 28-4 for more information. FIGURE 28-4: TYPICAL CONNECTION FOR ICSP™ PROGRAMMING External Programming Signals Device to be Programmed VDD VDD VDD VPP MCLR/VPP VSS VSS Data ICSPDAT Clock ICSPCLK * * * To Normal Connections * Isolation devices (as required).  2011 Microchip Technology Inc. DS41391D-page 323 PIC16(L)F1826/27 NOTES: DS41391D-page 324  2011 Microchip Technology Inc. PIC16(L)F1826/27 29.0 INSTRUCTION SET SUMMARY 29.1 Read-Modify-Write Operations • Byte Oriented • Bit Oriented • Literal and Control Any instruction that specifies a file register as part of the instruction performs a Read-Modify-Write (R-M-W) operation. The register is read, the data is modified, and the result is stored according to either the instruction, or the destination designator ‘d’. A read operation is performed on a register even if the instruction writes to that register. The literal and control category contains the most varied instruction word format. TABLE 29-1: Each PIC16 instruction is a 14-bit word containing the operation code (opcode) and all required operands. The op codes are broken into three broad categories. Table 29-3 lists the instructions recognized by the MPASMTM assembler. All instructions are executed within a single instruction cycle, with the following exceptions, which may take two or three cycles: • Subroutine takes two cycles (CALL, CALLW) • Returns from interrupts or subroutines take two cycles (RETURN, RETLW, RETFIE) • Program branching takes two cycles (GOTO, BRA, BRW, BTFSS, BTFSC, DECFSZ, INCSFZ) • One additional instruction cycle will be used when any instruction references an indirect file register and the file select register is pointing to program memory. One instruction cycle consists of 4 oscillator cycles; for an oscillator frequency of 4 MHz, this gives a nominal instruction execution rate of 1 MHz. All instruction examples use the format ‘0xhh’ to represent a hexadecimal number, where ‘h’ signifies a hexadecimal digit. OPCODE FIELD DESCRIPTIONS Field f Description Register file address (0x00 to 0x7F) W Working register (accumulator) b Bit address within an 8-bit file register k Literal field, constant data or label x Don’t care location (= 0 or 1). The assembler will generate code with x = 0. It is the recommended form of use for compatibility with all Microchip software tools. d Destination select; d = 0: store result in W, d = 1: store result in file register f. Default is d = 1. n FSR or INDF number. (0-1) mm Pre-post increment-decrement mode selection TABLE 29-2: ABBREVIATION DESCRIPTIONS Field Program Counter TO Time-out bit C DC Z PD  2011 Microchip Technology Inc. Description PC Carry bit Digit carry bit Zero bit Power-down bit DS41391D-page 325 PIC16(L)F1826/27 FIGURE 29-1: GENERAL FORMAT FOR INSTRUCTIONS Byte-oriented file register operations 13 8 7 6 OPCODE d f (FILE #) 0 d = 0 for destination W d = 1 for destination f f = 7-bit file register address Bit-oriented file register operations 13 10 9 7 6 OPCODE b (BIT #) f (FILE #) 0 b = 3-bit bit address f = 7-bit file register address Literal and control operations General 13 OPCODE 8 7 0 k (literal) k = 8-bit immediate value CALL and GOTO instructions only 13 11 10 OPCODE 0 k (literal) k = 11-bit immediate value MOVLP instruction only 13 OPCODE 7 6 0 k (literal) k = 7-bit immediate value MOVLB instruction only 13 OPCODE 5 4 0 k (literal) k = 5-bit immediate value BRA instruction only 13 OPCODE 9 8 0 k (literal) k = 9-bit immediate value FSR Offset instructions 13 OPCODE 7 6 n 5 0 k (literal) n = appropriate FSR k = 6-bit immediate value FSR Increment instructions 13 OPCODE 3 2 1 0 n m (mode) n = appropriate FSR m = 2-bit mode value OPCODE only 13 0 OPCODE DS41391D-page 326  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 29-3: PIC16(L)F1826/27 ENHANCED INSTRUCTION SET 14-Bit Opcode Mnemonic, Operands Description Cycles MSb LSb Status Affected Notes BYTE-ORIENTED FILE REGISTER OPERATIONS ADDWF ADDWFC ANDWF ASRF LSLF LSRF CLRF CLRW COMF DECF INCF IORWF MOVF MOVWF RLF RRF SUBWF SUBWFB SWAPF XORWF f, d f, d f, d f, d f, d f, d f – f, d f, d f, d f, d f, d f f, d f, d f, d f, d f, d f, d Add W and f Add with Carry W and f AND W with f Arithmetic Right Shift Logical Left Shift Logical Right Shift Clear f Clear W Complement f Decrement f Increment f Inclusive OR W with f Move f Move W to f Rotate Left f through Carry Rotate Right f through Carry Subtract W from f Subtract with Borrow W from f Swap nibbles in f Exclusive OR W with f 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 00 11 00 11 11 11 00 00 00 00 00 00 00 00 00 00 00 11 00 00 0111 1101 0101 0111 0101 0110 0001 0001 1001 0011 1010 0100 1000 0000 1101 1100 0010 1011 1110 0110 dfff dfff dfff dfff dfff dfff lfff 0000 dfff dfff dfff dfff dfff 1fff dfff dfff dfff dfff dfff dfff ffff ffff ffff ffff ffff ffff ffff 00xx ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff C, DC, Z C, DC, Z Z C, Z C, Z C, Z Z Z Z Z Z Z Z C C C, DC, Z C, DC, Z Z 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 BYTE ORIENTED SKIP OPERATIONS DECFSZ INCFSZ f, d f, d Decrement f, Skip if 0 Increment f, Skip if 0 BCF BSF f, b f, b Bit Clear f Bit Set f 1(2) 1(2) 00 00 1, 2 1, 2 1011 dfff ffff 1111 dfff ffff BIT-ORIENTED FILE REGISTER OPERATIONS 1 1 01 01 00bb bfff ffff 01bb bfff ffff 2 2 1, 2 1, 2 BIT-ORIENTED SKIP OPERATIONS BTFSC BTFSS f, b f, b Bit Test f, Skip if Clear Bit Test f, Skip if Set 1 (2) 1 (2) 01 01 10bb bfff ffff 11bb bfff ffff 1 1 1 1 1 1 1 1 11 11 11 00 11 11 11 11 1110 1001 1000 0000 0001 0000 1100 1010 LITERAL OPERATIONS ADDLW ANDLW IORLW MOVLB MOVLP MOVLW SUBLW XORLW k k k k k k k k Add literal and W AND literal with W Inclusive OR literal with W Move literal to BSR Move literal to PCLATH Move literal to W Subtract W from literal Exclusive OR literal with W kkkk kkkk kkkk 001k 1kkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk kkkk C, DC, Z Z Z C, DC, Z Z Note 1:If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP. 2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require one additional instruction cycle.  2011 Microchip Technology Inc. DS41391D-page 327 PIC16(L)F1826/27 TABLE 29-3: PIC16(L)F1826/27 ENHANCED INSTRUCTION SET (CONTINUED) Mnemonic, Operands 14-Bit Opcode Description Cycles MSb LSb Status Affected Notes CONTROL OPERATIONS BRA BRW CALL CALLW GOTO RETFIE RETLW RETURN k – k – k k k – Relative Branch Relative Branch with W Call Subroutine Call Subroutine with W Go to address Return from interrupt Return with literal in W Return from Subroutine CLRWDT NOP OPTION RESET SLEEP TRIS – – – – – f Clear Watchdog Timer No Operation Load OPTION_REG register with W Software device Reset Go into Standby mode Load TRIS register with W ADDFSR MOVIW n, k n mm MOVWI k[n] n mm Add Literal k to FSRn Move Indirect FSRn to W with pre/post inc/dec modifier, mm Move INDFn to W, Indexed Indirect. Move W to Indirect FSRn with pre/post inc/dec modifier, mm Move W to INDFn, Indexed Indirect. 2 2 2 2 2 2 2 2 11 00 10 00 10 00 11 00 001k 0000 0kkk 0000 1kkk 0000 0100 0000 kkkk 0000 kkkk 0000 kkkk 0000 kkkk 0000 kkkk 1011 kkkk 1010 kkkk 1001 kkkk 1000 00 00 00 00 00 00 0000 0000 0000 0000 0000 0000 0110 0000 0110 0000 0110 0110 0100 TO, PD 0000 0010 0001 0011 TO, PD 0fff INHERENT OPERATIONS 1 1 1 1 1 1 C-COMPILER OPTIMIZED k[n] 1 1 11 00 0001 0nkk kkkk 0000 0001 0nmm Z 2, 3 1 1 11 00 1111 0nkk kkkk Z 0000 0001 1nmm 2 2, 3 1 11 1111 1nkk kkkk 2 Note 1:If the Program Counter (PC) is modified, or a conditional test is true, the instruction requires two cycles. The second cycle is executed as a NOP. 2: If this instruction addresses an INDF register and the MSb of the corresponding FSR is set, this instruction will require one additional instruction cycle. 3: See Table in the MOVIW and MOVWI instruction descriptions. DS41391D-page 328  2011 Microchip Technology Inc. PIC16(L)F1826/27 29.2 Instruction Descriptions ADDFSR Add Literal to FSRn ANDLW AND literal with W Syntax: [ label ] ADDFSR FSRn, k Syntax: [ label ] ANDLW Operands: -32  k  31 n  [ 0, 1] Operands: 0  k  255 Operation: (W) .AND. (k)  (W) Operation: FSR(n) + k  FSR(n) Status Affected: Z Status Affected: None Description: Description: The signed 6-bit literal ‘k’ is added to the contents of the FSRnH:FSRnL register pair. The contents of W register are AND’ed with the eight-bit literal ‘k’. The result is placed in the W register. AND W with f k FSRn is limited to the range 0000h FFFFh. Moving beyond these bounds will cause the FSR to wrap around. ADDLW Add literal and W ANDWF Syntax: [ label ] ADDLW Syntax: [ label ] ANDWF Operands: 0  f  127 d 0,1 Operation: (W) .AND. (f)  (destination) k Operands: 0  k  255 Operation: (W) + k  (W) Status Affected: C, DC, Z Description: The contents of the W register are added to the eight-bit literal ‘k’ and the result is placed in the W register. ADDWF Add W and f f,d Status Affected: Z Description: AND the W register with register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. ASRF Arithmetic Right Shift Syntax: [ label ] ADDWF Syntax: [ label ] ASRF Operands: 0  f  127 d 0,1 Operands: 0  f  127 d [0,1] Operation: (W) + (f)  (destination) Operation: (f) dest (f)  dest, (f)  C, f,d Status Affected: C, DC, Z Description: Add the contents of the W register with register ‘f’. If ‘d’ is ‘0’, the result is stored in the W register. If ‘d’ is ‘1’, the result is stored back in register ‘f’. ADDWFC ADD W and CARRY bit to f Syntax: [ label ] ADDWFC Operands: 0  f  127 d [0,1] Operation: (W) + (f) + (C)  dest Status Affected: C, DC, Z Description: Add W, the Carry flag and data memory location ‘f’. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is placed in data memory location ‘f’.  2011 Microchip Technology Inc. f {,d} Status Affected: C, Z Description: The contents of register ‘f’ are shifted one bit to the right through the Carry flag. The MSb remains unchanged. If ‘d’ is ‘0’, the result is placed in W. If ‘d’ is ‘1’, the result is stored back in register ‘f’. register f C f {,d} DS41391D-page 329 PIC16(L)F1826/27 BCF Bit Clear f Syntax: [ label ] BCF BTFSC f,b Bit Test f, Skip if Clear Syntax: [ label ] BTFSC f,b 0  f  127 0b7 Operands: 0  f  127 0b7 Operands: Operation: 0  (f) Operation: skip if (f) = 0 Status Affected: None Status Affected: None Description: Bit ‘b’ in register ‘f’ is cleared. Description: If bit ‘b’ in register ‘f’ is ‘1’, the next instruction is executed. If bit ‘b’, in register ‘f’, is ‘0’, the next instruction is discarded, and a NOP is executed instead, making this a 2-cycle instruction. BRA Relative Branch BTFSS Bit Test f, Skip if Set Syntax: [ label ] BRA label [ label ] BRA $+k Syntax: [ label ] BTFSS f,b Operands: 0  f  127 0b VDD)....................................................................................................... 20 mA Maximum output current sunk by any I/O pin.................................................................................................... 25 mA Maximum output current sourced by any I/O pin .............................................................................................. 25 mA Note 1: Power dissipation is calculated as follows: PDIS = VDD x {IDD –  IOH} +  {(VDD – VOH) x IOH} + (VOl x IOL). † NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress rating only and functional operation of the device at those or any other conditions above those indicated in the operation listings of this specification is not implied. Exposure above maximum rating conditions for extended periods may affect device reliability.  2011 Microchip Technology Inc. DS41391D-page 339 PIC16(L)F1826/27 PIC16F1826/27 VOLTAGE FREQUENCY GRAPH, -40°C  TA +125°C FIGURE 30-1: Vdd (V) 5.5 2.5 1.8 0 4 10 16 32 Frequency (MHz) Note 1: The shaded region indicates the permissible combinations of voltage and frequency. 2: Refer to Table 30-1 for each Oscillator mode’s supported frequencies. PIC16LF1826/27 VOLTAGE FREQUENCY GRAPH, -40°C  TA +125°C Vdd (V) FIGURE 30-2: 3.6 2.5 1.8 0 4 10 16 32 Frequency (MHz) Note 1: The shaded region indicates the permissible combinations of voltage and frequency. 2: Refer to Table 30-1 for each Oscillator mode’s supported frequencies. DS41391D-page 340  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 30-3: HFINTOSC FREQUENCY ACCURACY OVER DEVICE VDD AND TEMPERATURE 125 ± 5% Temperature (°C) 85 ± 3% 60 25 ± 2% 0 -20 -40 1.8 ± 5% 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 VDD (V)  2011 Microchip Technology Inc. DS41391D-page 341 PIC16(L)F1826/27 30.1 DC Characteristics: PIC16(L)F1826/27-I/E (Industrial, Extended) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param. No. D001 Sym. VDD D001 D002* VDR D002* Characteristic Min. Typ† Max. Units Conditions PIC16LF1826/27 1.8 2.5 — — 3.6 3.6 V V FOSC  16 MHz: FOSC  32 MHz (NOTE 2) PIC16F1826/27 1.8 2.5 — — 5.5 5.5 V V FOSC  16 MHz: FOSC  32 MHz (NOTE 2) Supply Voltage RAM Data Retention Voltage(1) PIC16LF1826/27 1.5 — — V Device in Sleep mode PIC16F1826/27 1.7 — — V Device in Sleep mode — 1.6 — V VPOR* Power-on Reset Release Voltage VPORR* Power-on Reset Rearm Voltage PIC16LF1826/27 — 0.8 — V Device in Sleep mode PIC16F1826/27 — 1.7 — V Device in Sleep mode D003 VADFVR Fixed Voltage Reference Voltage for ADC -8 -8 -8 — — — 6 6 6 % 1.024V, VDD  2.5V 2.048V, VDD  2.5V 4.096V, VDD  4.75 D003A VCDAFVR Fixed Voltage Reference Voltage for Comparator and DAC -11 -11 -11 — — — 7 7 7 % 1.024V, VDD  2.5V 2.048V, VDD  2.5V 4.096V, VDD  4.75 D004* SVDD VDD Rise Rate to ensure internal Power-on Reset signal 0.05 — — V/ms See Section 7.1 “Power-on Reset (POR)” for details. * † Note These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. 1: This is the limit to which VDD can be lowered in Sleep mode without losing RAM data. 2: PLL required for 32 MHz operation. DS41391D-page 342  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 30-4: POR AND POR REARM WITH SLOW RISING VDD VDD VPOR VPORR VSS NPOR POR REARM VSS TVLOW(2) Note 1: 2: 3: TPOR(3) When NPOR is low, the device is held in Reset. TPOR 1 s typical. TVLOW 2.7 s typical.  2011 Microchip Technology Inc. DS41391D-page 343 PIC16(L)F1826/27 30.2 DC Characteristics: PIC16(L)F1826/27-I/E (Industrial, Extended) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param No. Device Characteristics Conditions Min. Typ† Max. Units VDD Note Supply Current (IDD)(1, 2) — 7.0 13 A 1.8 — 9.0 16 A 3.0 — 7.0 17 A 1.8 — 9.0 18 A 3.0 — 24 40 A 1.8 — 30 48 A 3.0 — 32 55 A 5.0 — 24 43 A 1.8 — 30 50 A 3.0 — 32 60 A 5.0 — 110 200 A 1.8 — 200 400 A 3.0 — 160 210 A 1.8 — 210 400 A 3.0 — 250 450 A 5.0 D012 — 290 475 A 1.8 — 600 900 A 3.0 D012 — 380 570 A 1.8 — 650 880 A 3.0 — 680 1100 A 5.0 — 40 80 A 1.8 — 70 120 A 3.0 — 60 120 A 1.8 — 80 180 A 3.0 — 93 200 A 5.0 D010 D010 D011 D011 D013 D013 * † Note 1: 2: 3: 4: 5: FOSC = 32 kHz LP Oscillator mode, -40°C  TA  +85°C FOSC = 32 kHz LP Oscillator mode, -40°C  TA  +125°C FOSC = 32 kHz LP Oscillator mode -40°C  TA  +85°C FOSC = 32 kHz LP Oscillator mode -40°C  TA  +125°C FOSC = 1 MHz XT Oscillator mode FOSC = 1 MHz XT Oscillator mode FOSC = 4 MHz XT Oscillator mode FOSC = 4 MHz XT Oscillator mode FOSC = 500 kHz EC Oscillator mode, Low-power mode FOSC = 500 kHz EC Oscillator mode Low-power mode These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins as inputs, pulled to VDD; MCLR = VDD; WDT disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 8 MHz internal RC oscillator with 4x PLL enabled. 8 MHz crystal oscillator with 4x PLL enabled. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k. DS41391D-page 344  2011 Microchip Technology Inc. PIC16(L)F1826/27 30.2 DC Characteristics: PIC16(L)F1826/27-I/E (Industrial, Extended) (Continued) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param No. Device Characteristics Conditions Min. Typ† Max. Units VDD Note Supply Current (IDD)(1, 2) — 260 475 A 1.8 — 550 800 A 3.0 — 375 655 A 1.8 — 600 800 A 3.0 — 650 930 A 5.0 D015 — 3.6 10 A 1.8 — 7.0 15 A 3.0 D015 — 21 42 A 1.8 — 27 55 A 3.0 — 28 60 A 5.0 — 110 210 A 1.8 — 150 250 A 3.0 — 150 250 A 1.8 — 210 345 A 3.0 — 270 425 A 5.0 D017* — 0.8 1.5 mA 1.8 — 1.3 2.4 mA 3.0 D017* — 1.0 2.0 mA 1.8 — 1.5 2.6 mA 3.0 — 1.7 2.8 mA 5.0 — 1.2 2.5 mA 1.8 — 2.5 3.75 mA 3.0 — 1.7 2.23 mA 1.8 — 2.7 4.3 mA 3.0 — 3.0 4.6 mA 5.0 D014 D014 D016 D016 D018 D018 * † Note 1: 2: 3: 4: 5: FOSC = 4 MHz EC Oscillator mode, Medium-power mode FOSC = 4 MHz EC Oscillator mode Medium-power mode FOSC = 31 kHz LFINTOSC mode FOSC = 31 kHz LFINTOSC mode FOSC = 500 kHz MFINTOSC mode FOSC = 500 kHz MFINTOSC mode FOSC = 8 MHz HFINTOSC mode FOSC = 8 MHz HFINTOSC mode FOSC = 16 MHz HFINTOSC mode FOSC = 16 MHz HFINTOSC mode These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins as inputs, pulled to VDD; MCLR = VDD; WDT disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 8 MHz internal RC oscillator with 4x PLL enabled. 8 MHz crystal oscillator with 4x PLL enabled. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k.  2011 Microchip Technology Inc. DS41391D-page 345 PIC16(L)F1826/27 30.2 DC Characteristics: PIC16(L)F1826/27-I/E (Industrial, Extended) (Continued) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param No. Device Characteristics Conditions Min. Typ† Max. Units VDD Note Supply Current (IDD)(1, 2) D019 D019 D020 D020 D021 D021 * † Note 1: 2: 3: 4: 5: — 4.0 7.3 mA 3.0 — 4.4 7.5 mA 3.6 — 4.2 7.3 mA 3.0 — 4.6 7.5 mA 5.0 — 4.0 6.0 mA 3.0 — 4.7 7.0 mA 3.6 — 4.2 6.8 mA 3.0 — 4.9 7.6 mA 5.0 — 410 0.65 mA 1.8 — 710 1.25 mA 3.0 — 430 0.695 mA 1.8 — 730 1.3 mA 3.0 — 860 1.35 mA 5.0 FOSC = 32 MHz HFINTOSC mode (Note 3) FOSC = 32 MHz HFINTOSC mode (Note 3) FOSC = 32 MHz HS Oscillator mode (Note 4) FOSC = 32 MHz HS Oscillator mode (Note 4) FOSC = 4 MHz EXTRC mode (Note 5) FOSC = 4 MHz EXTRC mode (Note 5) These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. The test conditions for all IDD measurements in active operation mode are: OSC1 = external square wave, from rail-to-rail; all I/O pins as inputs, pulled to VDD; MCLR = VDD; WDT disabled. The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O pin loading and switching rate, oscillator type, internal code execution pattern and temperature, also have an impact on the current consumption. 8 MHz internal RC oscillator with 4x PLL enabled. 8 MHz crystal oscillator with 4x PLL enabled. For RC oscillator configurations, current through REXT is not included. The current through the resistor can be extended by the formula IR = VDD/2REXT (mA) with REXT in k. DS41391D-page 346  2011 Microchip Technology Inc. PIC16(L)F1826/27 30.3 DC Characteristics: PIC16(L)F1826/27-I/E (Power-Down) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param No. Device Characteristics Power-down Base Current Min. Typ† Conditions Max. +85°C Max. +125°C Units A VDD D022 — 0.02 1.0 4.0 — 0.03 1.1 7.0 A 3.0 D022 — 15 35 50 A 1.8 — 18 40 60 A 3.0 — 19 45 70 A 5.0 — 0.5 1.1 5.0 A 1.8 — 0.8 2.0 8.0 A 3.0 — 16 35 50 A 1.8 — 19 40 60 A 3.0 D023 D023 D023A D023A Note (IPD)(2) 1.8 — 20 45 70 A 5.0 — 8.5 23 32 A 1.8 — 8.5 26 40 A 3.0 — 32 62 66 A 1.8 — 39 70 80 A 3.0 WDT, BOR, FVR, and T1OSC disabled, all Peripherals Inactive WDT, BOR, FVR, and T1OSC disabled, all Peripherals Inactive LPWDT Current (Note 1) LPWDT Current (Note 1) FVR current (Note 1) FVR current (Note 1) — 70 110 120 A 5.0 D024 — 8.1 14 20 A 3.0 BOR Current (Note 1) D024 — 34 57 70 A 3.0 BOR Current (Note 1) — 67 100 115 A 5.0 D025 — 0.6 1.5 5.0 A 1.8 — 0.8 2.5 8.0 A 3.0 D025 — 16 35 50 A 1.8 — 21 40 60 A 3.0 — 25 45 70 A 5.0 — 0.1 1.1 5.0 A 1.8 — 0.1 2.0 8.0 A 3.0 — 16 35 50 A 1.8 — 21 40 60 A 3.0 — 25 45 70 A 5.0 D026 D026 * † Note 1: 2: 3: T1OSC Current (Note 1) T1OSC Current (Note 1) A/D Current (Note 1, Note 3), no conversion in progress A/D Current (Note 1, Note 3), no conversion in progress These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral  current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins set to inputs state and tied to VDD. A/D oscillator source is FRC.  2011 Microchip Technology Inc. DS41391D-page 347 PIC16(L)F1826/27 30.3 DC Characteristics: PIC16(L)F1826/27-I/E (Power-Down) (Continued) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param No. Device Characteristics Min. Power-down Base Current (IPD) D026A* D026A* Typ† Conditions Max. +85°C Max. +125°C Units VDD — 250 — — A 1.8 — 250 — — A 3.0 — 280 — — A 1.8 — 280 — — A 3.0 — 280 — — A 5.0 D027 — 3.5 6 8 A 1.8 — 7 10 14 A 3.0 D027 — 4.3 36 38 A 1.8 — 5.8 39 42 A 3.0 — 6.3 42 45 A 5.0 — 4.2 8 10 A 1.8 — 6 12 15 A 3.0 — 7.4 38 40 A 1.8 — 9.7 42 43 A 3.0 D027A D027A D027B D027B D028 D028 D028A D028A * † Note 1: 2: 3: Note (2) — 10.4 46 48 A 5.0 — 6 10 15 A 1.8 — 10 14 20 A 3.0 — 17 44 50 A 1.8 — 41 68 80 A 3.0 — 50 78 90 A 5.0 — 6.9 11 15 A 1.8 — 7.0 13 16 A 3.0 — 24 45 60 A 1.8 — 24.5 60 70 A 3.0 — 25 65 75 A 5.0 — 7.0 12 16 A 1.8 — 7.2 14 17 A 3.0 — 24 45 60 A 1.8 — 24.5 60 70 A 3.0 — 25 65 75 A 5.0 A/D Current (Note 1, Note 3), conversion in progress A/D Current (Note 1, Note 3), conversion in progress Cap Sense Low Power Oscillator mode (Note 1) Cap Sense Low Power Oscillator mode (Note 1) Cap Sense Medium Power Oscillator mode (Note 1) Cap Sense Medium Power Oscillator mode (Note 1) Cap Sense High Power Oscillator mode (Note 1) Cap Sense High Power Oscillator mode (Note 1) Comparator Current, Low Power mode, one comparator enabled (Note 1) Comparator Current, Low Power mode, one comparator enabled (Note 1) Comparator Current, Low Power mode, two comparators enabled (Note 1) Comparator Current, Low Power mode, two comparators enabled (Note 1) These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral  current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins set to inputs state and tied to VDD. A/D oscillator source is FRC. DS41391D-page 348  2011 Microchip Technology Inc. PIC16(L)F1826/27 30.3 DC Characteristics: PIC16(L)F1826/27-I/E (Power-Down) (Continued) PIC16LF1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended PIC16F1826/27 Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Param No. Device Characteristics Min. Power-down Base Current (IPD) D028B D028B D028C D028C * † Note 1: 2: 3: Typ† Conditions Max. +85°C Max. +125°C Units VDD Note Comparator Current, High Power mode, one comparator enabled (Note 1) (2) — 24 32 40 A 1.8 — 25 35 45 A 3.0 — 36 60 80 A 1.8 — 37 63 87 A 3.0 — 38 65 90 A 5.0 — 40 80 90 A 1.8 — 41 83 95 A 3.0 — 43 86 100 A 1.8 — 44 90 105 A 3.0 — 45 95 110 A 5.0 Comparator Current, High Power mode, one comparator enabled (Note 1) Comparator Current, High Power mode, two comparators enabled Comparator Current, High Power mode, two comparators enabled (Note 1) These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. The peripheral current is the sum of the base IDD or IPD and the additional current consumed when this peripheral is enabled. The peripheral  current can be determined by subtracting the base IDD or IPD current from this limit. Max values should be used when calculating total current consumption. The power-down current in Sleep mode does not depend on the oscillator type. Power-down current is measured with the part in Sleep mode, with all I/O pins set to inputs state and tied to VDD. A/D oscillator source is FRC.  2011 Microchip Technology Inc. DS41391D-page 349 PIC16(L)F1826/27 30.4 DC Characteristics: PIC16(L)F1826/27-I/E DC CHARACTERISTICS Param No. Sym. VIL Characteristic Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +85°C for industrial -40°C  TA  +125°C for extended Min. Typ† Max. Units — — with Schmitt Trigger buffer with I2C™ levels Conditions — 0.8 V 4.5V  VDD  5.5V — 0.15 VDD V 1.8V  VDD  4.5V — — 0.2 VDD V 2.0V  VDD  5.5V — — 0.3 VDD V Input Low Voltage I/O PORT: D030 with TTL buffer D030A D031 D032 D033 VIH 2.7V  VDD  5.5V with SMBus™ levels — — 0.8 V MCLR, OSC1 (RC mode)(1) — — 0.2 VDD V OSC1 (HS mode) — — 0.3 VDD V — — 2.0 — — V 4.5V  VDD 5.5V 0.25 VDD + 0.8 — — V 1.8V  VDD  4.5V with Schmitt Trigger buffer 0.8 VDD — — V 2.0V  VDD  5.5V with I2C™ levels 0.7 VDD — — V Input High Voltage I/O ports: D040 with TTL buffer D040A D041 with SMBus™ levels 2.7V  VDD  5.5V 2.1 — — V D042 MCLR 0.8 VDD — — V D043A OSC1 (HS mode) 0.7 VDD — — V D043B OSC1 (RC mode) 0.9 VDD — — V (Note 1) IIL Input Leakage Current(2) D060 I/O ports — ±5 ± 100 nA ±5 ± 1000 nA VSS  VPIN  VDD, Pin at highimpedance at 85°C 125°C D061 MCLR(3) — ± 50 ± 200 nA VSS  VPIN  VDD at 85°C 25 25 100 140 200 300 A VDD = 3.3V, VPIN = VSS VDD = 5.0V, VPIN = VSS — — 0.6 V IOL = 8mA, VDD = 5V IOL = 6mA, VDD = 3.3V IOL = 1.8mA, VDD = 1.8V VDD - 0.7 — — V IOH = 3.5mA, VDD = 5V IOH = 3mA, VDD = 3.3V IOH = 1mA, VDD = 1.8V — — 15 pF — — 50 pF IPUR Weak Pull-up Current D070* VOL D080 Output Low Voltage(4) I/O ports VOH D090 Output High Voltage(4) I/O ports Capacitive Loading Specs on Output Pins D101* COSC2 OSC2 pin D101A* CIO * † Note 1: 2: 3: 4: All I/O pins In XT, HS and LP modes when external clock is used to drive OSC1 These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. In RC oscillator configuration, the OSC1/CLKIN pin is a Schmitt Trigger input. It is not recommended to use an external clock in RC mode. Negative current is defined as current sourced by the pin. The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified levels represent normal operating conditions. Higher leakage current may be measured at different input voltages. Including OSC2 in CLKOUT mode. DS41391D-page 350  2011 Microchip Technology Inc. PIC16(L)F1826/27 30.5 Memory Programming Requirements Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +125°C DC CHARACTERISTICS Param No. Sym. Characteristic Min. Typ† Max. Units Conditions Program Memory Programming Specifications D110 VIHH Voltage on MCLR/VPP/RA5 pin 8.0 — 9.0 V D111 IDDP Supply Current during Programming — — 10 mA VDD for Bulk Erase 2.7 — VDD max. V D112 D113 VPEW VDD for Write or Row Erase VDD min. — VDD max. V D114 IPPPGM Current on MCLR/VPP during Erase/ Write — — 1.0 mA D115 IDDPGM Current on VDD during Erase/Write — 5.0 mA D116 ED Byte Endurance D117 VDRW VDD for Read/Write D118 TDEW (Note 3, Note 4) Data EEPROM Memory 100K — — E/W VDD min. — VDD max. V Erase/Write Cycle Time — 4.0 5.0 ms D119 TRETD Characteristic Retention — 40 — Year Provided no other specifications are violated D120 TREF 1M 10M — E/W -40°C to +85°C D121 EP Cell Endurance 10K — — E/W -40C to +85C (Note 1) D122 VPR VDD for Read VDD min. — VDD max. V D123 TIW Self-timed Write Cycle Time — 2 2.5 ms D124 TRETD Characteristic Retention — 40 — Year Number of Total Erase/Write Cycles before Refresh(2) -40C to +85C Program Flash Memory Provided no other specifications are violated † Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Self-write and Block Erase. 2: Refer to Section 11.2 “Using the Data EEPROM” for a more detailed discussion on data EEPROM endurance. 3: Required only if single-supply programming is disabled. 4: The MPLAB ICD 2 does not support variable VPP output. Circuitry to limit the ICD 2 VPP voltage must be placed between the ICD 2 and target system when programming or debugging with the ICD 2.  2011 Microchip Technology Inc. DS41391D-page 351 PIC16(L)F1826/27 30.6 Thermal Considerations Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +125°C Param No. TH01 TH02 TH03 TH04 TH05 Sym. Characteristic Typ. Units JA Thermal Resistance Junction to Ambient 65.5 C/W 18-pin PDIP package 76 C/W 18-pin SOIC package 89.3 C/W 20-pin SSOP package TBD C/W 28-pin UQFN 4x4mm package 31.1 C/W 28-pin QFN 6x6mm package 29.5 C/W 18-pin PDIP package 23.5 C/W 18-pin SOIC package 31.1 C/W 20-pin SSOP package TBD C/W 28-pin UQFN 4x4mm package 5 C/W 28-pin QFN 6x6mm package 150 C JC TJMAX PD Thermal Resistance Junction to Case Maximum Junction Temperature Power Dissipation PINTERNAL Internal Power Dissipation Conditions — W PD = PINTERNAL + PI/O — W PINTERNAL = IDD x VDD(1) TH06 PI/O I/O Power Dissipation — W PI/O =  (IOL * VOL) +  (IOH * (VDD - VOH)) TH07 PDER Derated Power — W PDER = PDMAX (TJ - TA)/JA(2) Legend: TBD = To Be Determined Note 1: IDD is current to run the chip alone without driving any load on the output pins. 2: TA = Ambient Temperature 3: TJ = Junction Temperature DS41391D-page 352  2011 Microchip Technology Inc. PIC16(L)F1826/27 30.7 Timing Parameter Symbology The timing parameter symbols have been created with one of the following formats: 1. TppS2ppS 2. TppS T F Frequency Lowercase letters (pp) and their meanings: pp cc CCP1 ck CLKOUT cs CS di SDIx do SDO dt Data in io I/O PORT mc MCLR Uppercase letters and their meanings: S F Fall H High I Invalid (High-impedance) L Low FIGURE 30-5: T Time osc rd rw sc ss t0 t1 wr OSC1 RD RD or WR SCKx SS T0CKI T1CKI WR P R V Z Period Rise Valid High-impedance LOAD CONDITIONS Load Condition Pin Cl Vss Legend: CL = 50 pF for all pins, 15 pF for OSC2 output  2011 Microchip Technology Inc. DS41391D-page 353 PIC16(L)F1826/27 30.8 AC Characteristics: PIC16(L)F1826/27-I/E FIGURE 30-6: CLOCK TIMING Q4 Q1 Q2 Q3 Q4 Q1 OSC1/CLKIN OS02 OS04 OS04 OS03 OSC2/CLKOUT (LP,XT,HS Modes) OSC2/CLKOUT (CLKOUT Mode) TABLE 30-1: CLOCK OSCILLATOR TIMING REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +125°C Param No. OS01 Sym. FOSC Characteristic External CLKIN Frequency(1) Oscillator Frequency(1) OS02 TOSC External CLKIN Period(1) Oscillator Period(1) OS03 TCY Instruction Cycle Time(1) OS04* TosH, TosL External CLKIN High, External CLKIN Low TosR, TosF External CLKIN Rise, External CLKIN Fall OS05* Min. Typ† Max. Units Conditions DC — 0.5 MHz EC Oscillator mode (low) DC — 4 MHz EC Oscillator mode (medium) DC — 20 MHz EC Oscillator mode (high) — 32.768 — kHz LP Oscillator mode 0.1 — 4 MHz XT Oscillator mode 1 — 4 MHz HS Oscillator mode 1 — 20 MHz HS Oscillator mode, VDD > 2.7V DC — 4 MHz 27 —  s 250 —  ns XT Oscillator mode 50 —  ns HS Oscillator mode EC Oscillator mode RC Oscillator mode, VDD > 2.0V LP Oscillator mode 50 —  ns — 30.5 — s LP Oscillator mode 250 — 10,000 ns XT Oscillator mode 50 — 1,000 ns HS Oscillator mode 250 — — ns RC Oscillator mode 200 TCY — DC ns TCY = FOSC/4 2 — — s LP oscillator 100 — — ns XT oscillator 20 — — ns HS oscillator 0 —  ns LP oscillator 0 —  ns XT oscillator 0 —  ns HS oscillator * † These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at “min” values with an external clock applied to OSC1 pin. When an external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices. DS41391D-page 354  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-2: OSCILLATOR PARAMETERS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C TA +125°C Param No. OS08 Sym. HFOSC OS08A MFOSC Freq. Tolerance Min. Typ† Max. Units Internal Calibrated HFINTOSC Frequency(2) 2% — 16.0 — MHz 0°C  TA  +60°C, VDD  2.5V 3% — 16.0 — MHz 60°C  TA  +85°C, VDD  2.5V 5% — 16.0 — MHz -40°C  TA  +125°C Internal Calibrated MFINTOSC Frequency(2) 2% — 500 — kHz 0°C  TA  +60°C, VDD  2.5V 3% — 500 — kHz 60°C  TA  +85°C, VDD  2.5V 5% — 500 — kHz -40°C  TA  +125°C -40°C  TA  +125°C Characteristic OS09 LFOSC Internal LFINTOSC Frequency — — 31 — kHz OS10* TIOSC ST HFINTOSC Wake-up from Sleep Start-up Time — — 3.2 8 s — — 24 35 s MFINTOSC Wake-up from Sleep Start-up Time Conditions * † These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at “min” values with an external clock applied to the OSC1 pin. When an external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices. 2: To ensure these oscillator frequency tolerances, VDD and VSS must be capacitively decoupled as close to the device as possible. 0.1 F and 0.01 F values in parallel are recommended. 3: By design. TABLE 30-3: Param No. Sym. F10 PLL CLOCK TIMING SPECIFICATIONS (VDD = 2.7V TO 5.5V) Min. Typ† Max. Units FOSC Oscillator Frequency Range 4 — 8 MHz F11 FSYS On-Chip VCO System Frequency 16 — 32 MHz F12 TRC PLL Start-up Time (Lock Time) — — 2 ms CLK CLKOUT Stability (Jitter) -0.25% — +0.25% % F13* Characteristic Conditions * These parameters are characterized but not tested. † Data in “Typ” column is at 3V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested.  2011 Microchip Technology Inc. DS41391D-page 355 PIC16(L)F1826/27 FIGURE 30-7: Cycle CLKOUT AND I/O TIMING Write Fetch Q1 Q4 Read Execute Q2 Q3 FOSC OS12 OS11 OS20 OS21 CLKOUT OS19 OS16 OS13 OS18 OS17 I/O pin (Input) OS14 OS15 I/O pin (Output) New Value Old Value OS18, OS19 DS41391D-page 356  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-4: CLKOUT AND I/O TIMING PARAMETERS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C TA +125°C Param No. Sym. Characteristic FOSC to CLKOUT (1) OS11 TosH2ckL OS12 TosH2ckH FOSC to CLKOUT (1) (1) OS13 TckL2ioV CLKOUT to Port out valid OS14 OS15 OS16 TioV2ckH TosH2ioV TosH2ioI OS17 TioV2osH OS18 TioR Port input valid before CLKOUT(1) Fosc (Q1 cycle) to Port out valid Fosc (Q2 cycle) to Port input invalid (I/O in hold time) Port input valid to Fosc(Q2 cycle) (I/O in setup time) Port output rise time(2) OS19 TioF Port output fall time(2) OS20* Tinp OS21* Tioc Min. Typ† Max. Units Conditions — — 70 ns VDD = 3.3-5.0V — — 72 ns VDD = 3.3-5.0V — — 20 ns TOSC + 200 ns — 50 — 50 — — 70* — ns ns ns 20 — — ns — — — — 25 25 40 15 28 15 — — 72 32 55 30 — — ns INT pin input high or low time Interrupt-on-change new input level time * These parameters are characterized but not tested. † Data in “Typ” column is at 3.0V, 25C unless otherwise stated. Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC. 2: Includes OSC2 in CLKOUT mode. FIGURE 30-8: ns VDD = 3.3-5.0V VDD = 3.3-5.0V VDD = 1.8V VDD = 3.3-5.0V VDD = 1.8V VDD = 3.3-5.0V ns ns RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP TIMER TIMING Vdd MCLR 30 Internal POR PWRT Time-out 33 32 OSC Start-Up Time Internal Reset(1) Watchdog Timer Reset(1) 34 31 34 I/O pins Note 1: Asserted low.  2011 Microchip Technology Inc. DS41391D-page 357 PIC16(L)F1826/27 FIGURE 30-9: BROWN-OUT RESET TIMING AND CHARACTERISTICS Vdd VBOR and VHYST VBOR (Device in Brown-out Reset) (Device not in Brown-out Rese 37 Reset (due to BOR) 33(1) Note 1: 64 ms delay only if PWRTE bit in the Configuration Word 1 is programmed to ‘0’. 2 ms delay if PWRTE = 0 and VREGEN = 1. DS41391D-page 358  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-5: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER AND BROWN-OUT RESET PARAMETERS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C TA +125°C Param No. Sym. Characteristic Min. Typ† Max. Units Conditions 2 — — s 10 16 27 ms Oscillator Start-up Timer Period(1), (2) — 1024 — TPWRT Power-up Timer Period, PWRTE = 0 40 65 140 ms 34* TIOZ I/O high-impedance from MCLR Low or Watchdog Timer Reset — — 2.0 s 35 VBOR Brown-out Reset Voltage 2.38 1.80 2.5 1.9 2.73 2.11 V 36* VHYST Brown-out Reset Hysteresis 0 25 50 mV -40°C to +85°C 37* TBORDC Brown-out Reset DC Response Time 0 3 35 s VDD  VBOR 30 TMCL 31 TWDTLP Low-Power Watchdog Timer Time-out Period (No Prescaler) 32 TOST 33* * † Note 1: 2: 3: 4: MCLR Pulse Width (low) VDD = 3.3V-5V 1:16 Prescaler used Tosc (Note 3) BORV=2.5V BORV=1.9V These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Instruction cycle period (TCY) equals four times the input oscillator time base period. All specified values are based on characterization data for that particular oscillator type under standard operating conditions with the device executing code. Exceeding these specified limits may result in an unstable oscillator operation and/or higher than expected current consumption. All devices are tested to operate at “min” values with an external clock applied to the OSC1 pin. When an external clock input is used, the “max” cycle time limit is “DC” (no clock) for all devices. By design. Period of the slower clock. To ensure these voltage tolerances, VDD and VSS must be capacitively decoupled as close to the device as possible. 0.1 F and 0.01 F values in parallel are recommended. FIGURE 30-10: TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS T0CKI 40 41 42 T1CKI 45 46 47 49 TMR0 or TMR1  2011 Microchip Technology Inc. DS41391D-page 359 PIC16(L)F1826/27 TABLE 30-6: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C TA +125°C Param No. 40* Sym. Characteristic TT0H T0CKI High Pulse Width Min. No Prescaler TT0L T0CKI Low Pulse Width No Prescaler TT0P T0CKI Period 45* TT1H T1CKI High Synchronous, No Prescaler Time Synchronous, with Prescaler — — ns — — ns 0.5 TCY + 20 — — ns 10 — — ns Greater of: 20 or TCY + 40 N — — ns 0.5 TCY + 20 — — ns 15 — — ns Asynchronous TT1L 46* T1CKI Low Time 30 — — ns Synchronous, No Prescaler 0.5 TCY + 20 — — ns Synchronous, with Prescaler 15 — — ns Asynchronous 30 — — ns Greater of: 30 or TCY + 40 N — — ns 47* TT1P T1CKI Input Synchronous Period 48 FT1 Timer1 Oscillator Input Frequency Range (oscillator enabled by setting bit T1OSCEN) 49* TCKEZTMR1 Delay from External Clock Edge to Timer Increment Asynchronous * † Units 10 With Prescaler 42* Max. 0.5 TCY + 20 With Prescaler 41* Typ† 60 — — ns 32.4 32.768 33.1 kHz 2 TOSC — 7 TOSC — Conditions N = prescale value (2, 4, ..., 256) Timers in Sync mode These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. FIGURE 30-11: CAPTURE/COMPARE/PWM TIMINGS (CCP) CCPx (Capture mode) CC01 CC02 CC03 Note: Refer to Figure 30.5 for load conditions. TABLE 30-7: CAPTURE/COMPARE/PWM REQUIREMENTS (CCP) Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C  TA  +125°C Param Sym. No. CC01* TccL CC02* TccH CC03* TccP * † Characteristic CCPx Input Low Time CCPx Input High Time CCPx Input Period Min. Typ† Max. Units No Prescaler 0.5TCY + 20 — — ns With Prescaler 20 — — ns No Prescaler 0.5TCY + 20 — — ns With Prescaler 20 — — ns 3TCY + 40 N — — ns Conditions N = prescale value (1, 4 or 16) These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. DS41391D-page 360  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-8: PIC16(L)F1826/27 A/D CONVERTER (ADC) CHARACTERISTICS: Standard Operating Conditions (unless otherwise stated) Operating temperature Tested at +25°C Param Sym. No. Characteristic Min. Typ† Max. Units Conditions AD01 NR Resolution — — 10 AD02 EIL Integral Error — — ±1.7 AD03 EDL Differential Error — — ±1 AD04 EOFF Offset Error — — ±2.5 LSb VREF = 3.0V AD05 EGN LSb VREF = 3.0V AD06 VREF Reference Voltage(3) AD07 VAIN AD08 ZAIN * † Note 1: 2: 3: 4: 5: Gain Error bit LSb VREF = 3.0V LSb No missing codes VREF = 3.0V — — ±2.0 — — VDD V Full-Scale Range — — VREF V Recommended Impedance of Analog Voltage Source — — 10 VREF = (VREF+ minus VREF-) (NOTE 5) k Can go higher if external 0.01F capacitor is present on input pin. These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Total Absolute Error includes integral, differential, offset and gain errors. The A/D conversion result never decreases with an increase in the input voltage and has no missing codes. ADC VREF is from external VREF, VDD pin or FVR, whichever is selected as reference input. When ADC is off, it will not consume any current other than leakage current. The power-down current specification includes any such leakage from the ADC module. FVR voltage selected must be 2.048V or 4.096V. TABLE 30-9: PIC16(L)F1826/27 A/D CONVERSION REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating temperature -40°C  TA  +125°C Param No. Sym. AD130* TAD AD131 TCNV AD132* TACQ Characteristic Min. Typ† Max. Units Conditions A/D Clock Period 1.0 — 9.0 s TOSC-based A/D Internal RC Oscillator Period 1.0 2.5 6.0 s ADCS = 11 (ADRC mode) Conversion Time (not including Acquisition Time)(1) — 11 — TAD Set GO/DONE bit to conversion complete Acquisition Time — 5.0 — s * † These parameters are characterized but not tested. Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. Note 1: The ADRES register may be read on the following TCY cycle.  2011 Microchip Technology Inc. DS41391D-page 361 PIC16(L)F1826/27 FIGURE 30-12: PIC16(L)F1826/27 A/D CONVERSION TIMING (NORMAL MODE) BSF ADCON0, GO AD134 1 Tcy (TOSC/2(1)) AD131 Q4 AD130 A/D CLK 7 A/D Data 6 5 4 3 2 1 0 NEW_DATA OLD_DATA ADRES 1 Tcy ADIF GO DONE Sampling Stopped AD132 Sample Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. FIGURE 30-13: PIC16(L)F1826/27 A/D CONVERSION TIMING (SLEEP MODE) BSF ADCON0, GO AD134 (TOSC/2 + TCY(1)) 1 Tcy AD131 Q4 AD130 A/D CLK 7 A/D Data 6 5 4 OLD_DATA ADRES 2 1 0 NEW_DATA 1 Tcy ADIF GO Sample 3 DONE AD132 Sampling Stopped Note 1: If the A/D clock source is selected as RC, a time of TCY is added before the A/D clock starts. This allows the SLEEP instruction to be executed. DS41391D-page 362  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-10: COMPARATOR SPECIFICATIONS Operating Conditions: 1.8V < VDD < 5.5V, -40°C < TA < +125°C (unless otherwise stated). Param No. Sym. Characteristics Min. Typ. Max. Units CM01 Vioff Input Offset Voltage — ±7.5 ±60 mV CM02 Vicm Input Common Mode Voltage 0 — VDD V CM03* CMRR Common Mode Rejection Ratio — 50 — dB Response Time Rising Edge — 400 800 ns CM04A CM04B CM04C Tresp CM04D High Power Mode High Power Mode Response Time Falling Edge — 200 400 ns High Power Mode Response Time Rising Edge — 1200 — ns Low Power Mode Response Time Falling Edge — 550 — ns CM05* Tmc2ov Comparator Mode Change to Output Valid — — 10 s CM06 Chyster Comparator Hysteresis — 65 — mV * Comments Hysteresis ON These parameters are characterized but not tested. TABLE 30-11: DIGITAL-TO-ANALOG CONVERTER (DAC) SPECIFICATIONS Operating Conditions: 1.8V < VDD < 5.5V, -40°C < TA < +125°C (unless otherwise stated). Param No. Sym. Characteristics Min. Typ. Max. Units VDD/32 — V CLSB Step Size — DAC02* CACC Absolute Accuracy — —  1/2 LSb DAC03* CR Unit Resistor Value (R) — 5000 —  CST Time(1) — — 10 s DAC01* DAC04* * Note 1: Settling Comments These parameters are characterized but not tested. Settling time measured while DACR transitions from ‘0000’ to ‘1111’.  2011 Microchip Technology Inc. DS41391D-page 363 PIC16(L)F1826/27 FIGURE 30-14: USART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING CK US121 US121 DT US122 US120 Note: Refer to Figure 30-5 for load conditions. TABLE 30-12: USART SYNCHRONOUS TRANSMISSION REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C TA +125°C Param. No. Symbol Characteristic Min. Max. Units US120 TCKH2DTV SYNC XMIT (Master and Slave) Clock high to data-out valid 3.0-5.5V — 80 ns 1.8-5.5V — 100 ns US121 TCKRF Clock out rise time and fall time (Master mode) 3.0-5.5V — 45 ns 1.8-5.5V — 50 ns Data-out rise time and fall time 3.0-5.5V — 45 ns 1.8-5.5V — 50 ns US122 TDTRF FIGURE 30-15: Conditions USART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING CK US125 DT US126 Note: Refer to Figure 30-5 for load conditions. TABLE 30-13: USART SYNCHRONOUS RECEIVE REQUIREMENTS Standard Operating Conditions (unless otherwise stated) Operating Temperature -40°C TA +125°C Param. No. Symbol Characteristic US125 TDTV2CKL SYNC RCV (Master and Slave) Data-hold before CK  (DT hold time) US126 TCKL2DTL DS41391D-page 364 Data-hold after CK  (DT hold time) Min. Max. Units 10 — ns 15 — ns Conditions  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 30-16: SPI MASTER MODE TIMING (CKE = 0, SMP = 0) SSx SP70 SCKx (CKP = 0) SP71 SP72 SP78 SP79 SP79 SP78 SCKx (CKP = 1) SP80 bit 6 - - - - - -1 MSb SDOx LSb SP75, SP76 SDIx MSb In bit 6 - - - -1 LSb In SP74 SP73 Note: Refer to Figure 30-5 for load conditions. FIGURE 30-17: SPI MASTER MODE TIMING (CKE = 1, SMP = 1) SSx SP81 SCKx (CKP = 0) SP71 SP72 SP79 SP73 SCKx (CKP = 1) SP80 SDOx MSb bit 6 - - - - - -1 SP78 LSb SP75, SP76 SDIx MSb In bit 6 - - - -1 LSb In SP74 Note: Refer to Figure 30-5 for load conditions.  2011 Microchip Technology Inc. DS41391D-page 365 PIC16(L)F1826/27 FIGURE 30-18: SPI SLAVE MODE TIMING (CKE = 0) SSx SP70 SCKx (CKP = 0) SP83 SP71 SP72 SP78 SP79 SP79 SP78 SCKx (CKP = 1) SP80 MSb SDOx LSb bit 6 - - - - - -1 SP77 SP75, SP76 SDIx MSb In bit 6 - - - -1 LSb In SP74 SP73 Note: Refer to Figure 30-5 for load conditions. FIGURE 30-19: SSx SPI SLAVE MODE TIMING (CKE = 1) SP82 SP70 SP83 SCKx (CKP = 0) SP71 SP72 SCKx (CKP = 1) SP80 SDOx MSb bit 6 - - - - - -1 LSb SP77 SP75, SP76 SDIx MSb In bit 6 - - - -1 LSb In SP74 Note: Refer to Figure 30-5 for load conditions. DS41391D-page 366  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-14: SPI MODE REQUIREMENTS Param No. Symbol Characteristic Min. Typ† Max. Units Conditions SP70* TSSL2SCH, SSx to SCKx or SCKx input TSSL2SCL TCY — — ns SP71* TSCH SCKx input high time (Slave mode) TCY + 20 — — ns SP72* TSCL SCKx input low time (Slave mode) TCY + 20 — — ns SP73* TDIV2SCH, Setup time of SDIx data input to SCKx edge TDIV2SCL 100 — — ns SP74* TSCH2DIL, TSCL2DIL Hold time of SDIx data input to SCKx edge 100 — — ns SP75* TDOR SDO data output rise time — 10 25 ns SP76* TDOF SDOx data output fall time 3.0-5.5V 1.8-5.5V — 25 50 ns — 10 25 ns SP77* TSSH2DOZ SSx to SDOx output high-impedance 10 — 50 ns SP78* TSCR SCKx output rise time (Master mode) — 10 25 ns SP79* TSCF SCKx output fall time (Master mode) 3.0-5.5V — 25 50 ns — 10 25 ns 3.0-5.5V — — 50 ns 1.8-5.5V — — 145 ns SP81* TDOV2SCH, SDOx data output setup to SCKx edge TDOV2SCL Tcy — — ns SP82* TSSL2DOV — — 50 ns 1.5TCY + 40 — — ns SP80* TSCH2DOV, SDOx data output valid after TSCL2DOV SCKx edge 1.8-5.5V SDOx data output valid after SS edge SP83* TSCH2SSH, SSx after SCKx edge TSCL2SSH * These parameters are characterized but not tested. † Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. FIGURE 30-20: I2C™ BUS START/STOP BITS TIMING SCLx SP93 SP91 SP90 SP92 SDAx Start Condition Stop Condition Note: Refer to Figure 30-5 for load conditions.  2011 Microchip Technology Inc. DS41391D-page 367 PIC16(L)F1826/27 FIGURE 30-21: I2C™ BUS DATA TIMING SP103 SCLx SP100 SP90 SP102 SP101 SP106 SP107 SP92 SP91 SDAx In SP110 SP109 SP109 SDAx Out Note: Refer to Figure 30-5 for load conditions. TABLE 30-15: I2C™ BUS START/STOP BITS REQUIREMENTS Param No. Symbol Characteristic SP90* TSU:STA SP91* THD:STA SP92* TSU:STO SP93 THD:STO Stop condition Start condition Typ 4700 — Max. Units — Setup time 400 kHz mode 600 — — Start condition 100 kHz mode 4000 — — Hold time 400 kHz mode 600 — — Stop condition 100 kHz mode 4700 — — Setup time Hold time * 100 kHz mode Min. 400 kHz mode 600 — — 100 kHz mode 4000 — — 400 kHz mode 600 — — Conditions ns Only relevant for Repeated Start condition ns After this period, the first clock pulse is generated ns ns These parameters are characterized but not tested. DS41391D-page 368  2011 Microchip Technology Inc. PIC16(L)F1826/27 TABLE 30-16: I2C™ BUS DATA REQUIREMENTS Param. No. Symbol SP100* THIGH SP101* TLOW SP102* TR SP103* TF SP106* THD:DAT SP107* TSU:DAT SP109* TAA SP110* SP111 * Note 1: 2: TBUF CB Characteristic Clock high time Min. Max. Units Conditions 100 kHz mode 4.0 — s Device must operate at a minimum of 1.5 MHz 400 kHz mode 0.6 — s Device must operate at a minimum of 10 MHz SSPx module 1.5TCY — — 100 kHz mode 4.7 — s Device must operate at a minimum of 1.5 MHz 400 kHz mode 1.3 — s Device must operate at a minimum of 10 MHz SSPx module 1.5TCY — — 100 kHz mode — 1000 ns 400 kHz mode 20 + 0.1CB 300 ns SDAx and SCLx fall 100 kHz mode time 400 kHz mode — 250 ns 20 + 0.1CB 250 ns Clock low time SDAx and SCLx rise time Data input hold time 100 kHz mode 0 — ns 400 kHz mode 0 0.9 s Data input setup time 100 kHz mode 250 — ns 400 kHz mode 100 — ns Output valid from clock 100 kHz mode — 3500 ns 400 kHz mode — — ns Bus free time 100 kHz mode 4.7 — s 400 kHz mode 1.3 — s — 400 pF Bus capacitive loading CB is specified to be from 10-400 pF CB is specified to be from 10-400 pF (Note 2) (Note 1) Time the bus must be free before a new transmission can start These parameters are characterized but not tested. As a transmitter, the device must provide this internal minimum delay time to bridge the undefined region (min. 300 ns) of the falling edge of SCLx to avoid unintended generation of Start or Stop conditions. A Fast mode (400 kHz) I2C™ bus device can be used in a Standard mode (100 kHz) I2C bus system, but the requirement TSU:DAT 250 ns must then be met. This will automatically be the case if the device does not stretch the low period of the SCLx signal. If such a device does stretch the low period of the SCLx signal, it must output the next data bit to the SDAx line TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the Standard mode I2C bus specification), before the SCLx line is released.  2011 Microchip Technology Inc. DS41391D-page 369 PIC16(L)F1826/27 TABLE 30-17: CAP SENSE OSCILLATOR SPECIFICATIONS Param. No. CS01 CS02 Symbol ISRC ISNK Characteristic Current Source Current Sink CS03 VCTH Cap Threshold CS04 VCTL Cap Threshold CS05 VCHYST CAP HYSTERESIS (VCTH - VCTL) Min. Typ† Max. Units -3 -8 -15 A Medium -0.8 -1.5 -3 A Low -0.1 -0.3 -0.4 A High High 2.5 7.5 14 A Medium 0.6 1.5 2.9 A Low 0.1 0.25 0.6 A — 0.8 — mV — 0.4 — mV High 350 525 725 mV Medium 250 375 500 mV Low 175 300 425 mV Conditions * These parameters are characterized but not tested. † Data in “Typ” column is at 3.0V, 25°C unless otherwise stated. These parameters are for design guidance only and are not tested. FIGURE 30-22: CAP SENSE OSCILLATOR VCTH VCTL ISRC Enabled DS41391D-page 370 ISNK Enabled  2011 Microchip Technology Inc. PIC16(L)F1826/27 31.0 DC AND AC CHARACTERISTICS GRAPHS AND CHARTS The graphs and tables provided in this section are for design guidance and are not tested. In some graphs or tables, the data presented are outside specified operating range (i.e., outside specified VDD range). This is for information only and devices are ensured to operate properly only within the specified range. Note: The graphs and tables provided following this note are a statistical summary based on a limited number of samples and are provided for informational purposes only. The performance characteristics listed herein are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified operating range (e.g., outside specified power supply range) and therefore, outside the warranted range. “Typical” represents the mean of the distribution at 25C. “Maximum” or “minimum” represents (mean + 3) or (mean - 3) respectively, where  is a standard deviation, over each temperature range. FIGURE 31-1: VOH VS. IOH OVER TEMPERATURE (VDD = 5.0V) 6 Max: Maximum + 3 Min: Minimum - 3 5 VOH (V) 4 3 Min. 125°C 2 Max. -40°C Typ. 25°C 1 0 0 -2.5 -5 -7.5 -10 -12.5 -15 -17.5 -20 -22.5 -25 -27.5 -30 IOH (mA) FIGURE 31-2: VOL VS. IOL OVER TEMPERATURE (VDD = 5.0V) 5 Typ. 25°C Max. 125°C Min. -40°C 4 VOL (V) 3 2 1 0 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 IOL (mA)  2011 Microchip Technology Inc. DS41391D-page 371 PIC16(L)F1826/27 FIGURE 31-3: VOH VS. IOH OVER TEMPERATURE (VDD = 3.0V) 3.5 Max: Maximum + 3 Min: Minimum - 3 Hysterisis (mV) 3 VOH (V) 2.5 2 Min 125°C Max -40°C Typ 25°C 1.5 1 0.5 0 0 -2.5 -5 -7.5 -10 -12.5 -15 IOH (mA) FIGURE 31-4: 3 VOL VS. IOL OVER TEMPERATURE (VDD = 3.0V) Max: Maximum + 3 Min: Minimum - 3 2.5 VOL (V) 2 Typ 25°C Max 125°C Min -40°C 1.5 1 0.5 0 0 5 10 15 20 25 30 IOL (mA) DS41391D-page 372  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 31-5: VOH VS. IOH OVER TEMPERATURE (VDD = 1.8V) 2 Max: Maximum + 3 Min: Minimum - 3 1.8 1.6 Max -40°C VOH (V) 1.4 1.2 Typ 25°C 1 Min 125°C 0.8 0.6 0.4 0.2 0 0 -0.5 -1 -1.5 -2 -2.5 -3 -3.5 -4 -4.5 -5 IOH (mA) FIGURE 31-6: 1.8 VOL VS. IOL OVER TEMPERATURE (VDD = 1.8V) Max: Maximum + 3 Min: Minimum - 3 1.6 Typ 25°C Max 125°C Min -40°C 1.4 VOL (V) 1.2 1 0.8 0.6 0.4 0.2 0 0 1 2 3 4 5 6 7 8 9 10 IOL (mA)  2011 Microchip Technology Inc. DS41391D-page 373 PIC16(L)F1826/27 FIGURE 31-7: 2.100 PIC16(L)F1826/27 RESET VOLTAGE (BOR = 1.9V) Max: High Power + 3 Min: Low Power - 3 2.050 Voltage (V) 2.000 Max 1.950 1.900 Min 1.850 1.800 -40°C 25°C 85°C 125°C Temperature FIGURE 31-8: 2.650 PIC16(L)F1826/27 RESET VOLTAGE (BOR = 1.9V) Max: High Power + 3 Min: Low Power - 3 Max 2.600 Voltage (V) 2.550 2.500 Min 2.450 2.400 2.350 -40°C 25°C 85°C 125°C Temperature DS41391D-page 374  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 31-9: 1.7 PIC16(L)F1826/27 POR RELEASE Max: High Power + 3 Min: Power+- 3  Max:Low Maximum 3s 1.68 Release Voltage (V) 1.66 Max 1.64 1.62 Typical 1.6 1.58 1.56 Min 1.54 1.52 1.5 -40°C 25°C 85°C 125°C Temperature (Celsius) FIGURE 31-10: 90 PIC16(L)F1826/27 COMPARATOR HYSTERISIS, HIGH-POWER MODE Max: Maximum + 3 Min: Minimum - 3 80 Max 125°C Hysterisis (mV) 70 60 50 Typical 25°C 40 30 20 10 Min -40°C 0 1.8 3 3.6 5.5 VDD (Volts)  2011 Microchip Technology Inc. DS41391D-page 375 PIC16(L)F1826/27 FIGURE 31-11: PIC16(L)F1826/27 COMPARATOR HYSTERISIS, LOW-POWER MODE 16 Max: Maximum + 3 Min: Minimum - 3 Max 125°C 14 Hysterisis (mV) 12 10 Typical 25°C 8 6 4 Min -40°C 2 0 1.8 5.5 VDD (Volts) FIGURE 31-12: PIC16(L)F1826/27 COMPARATOR OFFSET, HIGH-POWER MODE (VDD = 5.5V) 60 Max: Maximum + 3 Min: Minimum - 3 40 Offset (mV) 20 Max 0 Typical -20 Min -40 -60 0.2 1 1.8 2.6 3.4 4.2 5 Common Mode Voltage (Volts) DS41391D-page 376  2011 Microchip Technology Inc. PIC16(L)F1826/27 FIGURE 31-13: 350 PIC16(L)F1826/27 COMPARATOR RESPONSE TIME, HIGH-POWER MODE Max: High Power + 3 Max:Low Maximum 3s Min: Power + - 3 300 Max Time (nSeconds) 250 200 150 Typ 100 50 0 1.8 2 2.5 3 3.6 5.5 VDD (Volts) FIGURE 31-14: TYPICAL COMPARATOR RESPONSE TIME OVER TEMP, HIGH-POWER MODE 170 -40°C 165 Time (nSeconds) 160 25°C 155 85°C 150 125°C 145 140 135 1.8 2 2.5 3 3.6 5.5 VDD (Volts)  2011 Microchip Technology Inc. DS41391D-page 377 PIC16(L)F1826/27 NOTES: DS41391D-page 378  2011 Microchip Technology Inc. PIC16(L)F1826/27 32.0 DEVELOPMENT SUPPORT The PIC® microcontrollers and dsPIC® digital signal controllers are supported with a full range of software and hardware development tools: • Integrated Development Environment - MPLAB® IDE Software • Compilers/Assemblers/Linkers - MPLAB C Compiler for Various Device Families - HI-TECH C for Various Device Families - MPASMTM Assembler - MPLINKTM Object Linker/ MPLIBTM Object Librarian - MPLAB Assembler/Linker/Librarian for Various Device Families • Simulators - MPLAB SIM Software Simulator • Emulators - MPLAB REAL ICE™ In-Circuit Emulator • In-Circuit Debuggers - MPLAB ICD 3 - PICkit™ 3 Debug Express • Device Programmers - PICkit™ 2 Programmer - MPLAB PM3 Device Programmer • Low-Cost Demonstration/Development Boards, Evaluation Kits, and Starter Kits 32.1 MPLAB Integrated Development Environment Software The MPLAB IDE software brings an ease of software development previously unseen in the 8/16/32-bit microcontroller market. The MPLAB IDE is a Windows® operating system-based application that contains: • A single graphical interface to all debugging tools - Simulator - Programmer (sold separately) - In-Circuit Emulator (sold separately) - In-Circuit Debugger (sold separately) • A full-featured editor with color-coded context • A multiple project manager • Customizable data windows with direct edit of contents • High-level source code debugging • Mouse over variable inspection • Drag and drop variables from source to watch windows • Extensive on-line help • Integration of select third party tools, such as IAR C Compilers The MPLAB IDE allows you to: • Edit your source files (either C or assembly) • One-touch compile or assemble, and download to emulator and simulator tools (automatically updates all project information) • Debug using: - Source files (C or assembly) - Mixed C and assembly - Machine code MPLAB IDE supports multiple debugging tools in a single development paradigm, from the cost-effective simulators, through low-cost in-circuit debuggers, to full-featured emulators. This eliminates the learning curve when upgrading to tools with increased flexibility and power.  2011 Microchip Technology Inc. DS41391D-page 379 PIC16(L)F1826/27 32.2 MPLAB C Compilers for Various Device Families The MPLAB C Compiler code development systems are complete ANSI C compilers for Microchip’s PIC18, PIC24 and PIC32 families of microcontrollers and the dsPIC30 and dsPIC33 families of digital signal controllers. These compilers provide powerful integration capabilities, superior code optimization and ease of use. For easy source level debugging, the compilers provide symbol information that is optimized to the MPLAB IDE debugger. 32.3 HI-TECH C for Various Device Families The HI-TECH C Compiler code development systems are complete ANSI C compilers for Microchip’s PIC family of microcontrollers and the dsPIC family of digital signal controllers. These compilers provide powerful integration capabilities, omniscient code generation and ease of use. For easy source level debugging, the compilers provide symbol information that is optimized to the MPLAB IDE debugger. The compilers include a macro assembler, linker, preprocessor, and one-step driver, and can run on multiple platforms. 32.4 MPASM Assembler The MPASM Assembler is a full-featured, universal macro assembler for PIC10/12/16/18 MCUs. The MPASM Assembler generates relocatable object files for the MPLINK Object Linker, Intel® standard HEX files, MAP files to detail memory usage and symbol reference, absolute LST files that contain source lines and generated machine code and COFF files for debugging. The MPASM Assembler features include: 32.5 MPLINK Object Linker/ MPLIB Object Librarian The MPLINK Object Linker combines relocatable objects created by the MPASM Assembler and the MPLAB C18 C Compiler. It can link relocatable objects from precompiled libraries, using directives from a linker script. The MPLIB Object Librarian manages the creation and modification of library files of precompiled code. When a routine from a library is called from a source file, only the modules that contain that routine will be linked in with the application. This allows large libraries to be used efficiently in many different applications. The object linker/library features include: • Efficient linking of single libraries instead of many smaller files • Enhanced code maintainability by grouping related modules together • Flexible creation of libraries with easy module listing, replacement, deletion and extraction 32.6 MPLAB Assembler, Linker and Librarian for Various Device Families MPLAB Assembler produces relocatable machine code from symbolic assembly language for PIC24, PIC32 and dsPIC devices. MPLAB C Compiler uses the assembler to produce its object file. The assembler generates relocatable object files that can then be archived or linked with other relocatable object files and archives to create an executable file. Notable features of the assembler include: • • • • • • Support for the entire device instruction set Support for fixed-point and floating-point data Command line interface Rich directive set Flexible macro language MPLAB IDE compatibility • Integration into MPLAB IDE projects • User-defined macros to streamline assembly code • Conditional assembly for multi-purpose source files • Directives that allow complete control over the assembly process DS41391D-page 380  2011 Microchip Technology Inc. PIC16(L)F1826/27 32.7 MPLAB SIM Software Simulator The MPLAB SIM Software Simulator allows code development in a PC-hosted environment by simulating the PIC MCUs and dsPIC® DSCs on an instruction level. On any given instruction, the data areas can be examined or modified and stimuli can be applied from a comprehensive stimulus controller. Registers can be logged to files for further run-time analysis. The trace buffer and logic analyzer display extend the power of the simulator to record and track program execution, actions on I/O, most peripherals and internal registers. The MPLAB SIM Software Simulator fully supports symbolic debugging using the MPLAB C Compilers, and the MPASM and MPLAB Assemblers. The software simulator offers the flexibility to develop and debug code outside of the hardware laboratory environment, making it an excellent, economical software development tool. 32.8 MPLAB REAL ICE In-Circuit Emulator System MPLAB REAL ICE In-Circuit Emulator System is Microchip’s next generation high-speed emulator for Microchip Flash DSC and MCU devices. It debugs and programs PIC® Flash MCUs and dsPIC® Flash DSCs with the easy-to-use, powerful graphical user interface of the MPLAB Integrated Development Environment (IDE), included with each kit. The emulator is connected to the design engineer’s PC using a high-speed USB 2.0 interface and is connected to the target with either a connector compatible with incircuit debugger systems (RJ11) or with the new highspeed, noise tolerant, Low-Voltage Differential Signal (LVDS) interconnection (CAT5). The emulator is field upgradable through future firmware downloads in MPLAB IDE. In upcoming releases of MPLAB IDE, new devices will be supported, and new features will be added. MPLAB REAL ICE offers significant advantages over competitive emulators including low-cost, full-speed emulation, run-time variable watches, trace analysis, complex breakpoints, a ruggedized probe interface and long (up to three meters) interconnection cables.  2011 Microchip Technology Inc. 32.9 MPLAB ICD 3 In-Circuit Debugger System MPLAB ICD 3 In-Circuit Debugger System is Microchip's most cost effective high-speed hardware debugger/programmer for Microchip Flash Digital Signal Controller (DSC) and microcontroller (MCU) devices. It debugs and programs PIC® Flash microcontrollers and dsPIC® DSCs with the powerful, yet easyto-use graphical user interface of MPLAB Integrated Development Environment (IDE). The MPLAB ICD 3 In-Circuit Debugger probe is connected to the design engineer's PC using a high-speed USB 2.0 interface and is connected to the target with a connector compatible with the MPLAB ICD 2 or MPLAB REAL ICE systems (RJ-11). MPLAB ICD 3 supports all MPLAB ICD 2 headers. 32.10 PICkit 3 In-Circuit Debugger/ Programmer and PICkit 3 Debug Express The MPLAB PICkit 3 allows debugging and programming of PIC® and dsPIC® Flash microcontrollers at a most affordable price point using the powerful graphical user interface of the MPLAB Integrated Development Environment (IDE). The MPLAB PICkit 3 is connected to the design engineer's PC using a full speed USB interface and can be connected to the target via an Microchip debug (RJ-11) connector (compatible with MPLAB ICD 3 and MPLAB REAL ICE). The connector uses two device I/O pins and the reset line to implement in-circuit debugging and In-Circuit Serial Programming™. The PICkit 3 Debug Express include the PICkit 3, demo board and microcontroller, hookup cables and CDROM with user’s guide, lessons, tutorial, compiler and MPLAB IDE software. DS41391D-page 381 PIC16(L)F1826/27 32.11 PICkit 2 Development Programmer/Debugger and PICkit 2 Debug Express 32.13 Demonstration/Development Boards, Evaluation Kits, and Starter Kits The PICkit™ 2 Development Programmer/Debugger is a low-cost development tool with an easy to use interface for programming and debugging Microchip’s Flash families of microcontrollers. The full featured Windows® programming interface supports baseline (PIC10F, PIC12F5xx, PIC16F5xx), midrange (PIC12F6xx, PIC16F), PIC18F, PIC24, dsPIC30, dsPIC33, and PIC32 families of 8-bit, 16-bit, and 32-bit microcontrollers, and many Microchip Serial EEPROM products. With Microchip’s powerful MPLAB Integrated Development Environment (IDE) the PICkit™ 2 enables in-circuit debugging on most PIC® microcontrollers. In-Circuit-Debugging runs, halts and single steps the program while the PIC microcontroller is embedded in the application. When halted at a breakpoint, the file registers can be examined and modified. A wide variety of demonstration, development and evaluation boards for various PIC MCUs and dsPIC DSCs allows quick application development on fully functional systems. Most boards include prototyping areas for adding custom circuitry and provide application firmware and source code for examination and modification. The PICkit 2 Debug Express include the PICkit 2, demo board and microcontroller, hookup cables and CDROM with user’s guide, lessons, tutorial, compiler and MPLAB IDE software. 32.12 MPLAB PM3 Device Programmer The MPLAB PM3 Device Programmer is a universal, CE compliant device programmer with programmable voltage verification at VDDMIN and VDDMAX for maximum reliability. It features a large LCD display (128 x 64) for menus and error messages and a modular, detachable socket assembly to support various package types. The ICSP™ cable assembly is included as a standard item. In Stand-Alone mode, the MPLAB PM3 Device Programmer can read, verify and program PIC devices without a PC connection. It can also set code protection in this mode. The MPLAB PM3 connects to the host PC via an RS-232 or USB cable. The MPLAB PM3 has high-speed communications and optimized algorithms for quick programming of large memory devices and incorporates an MMC card for file storage and data applications. DS41391D-page 382 The boards support a variety of features, including LEDs, temperature sensors, switches, speakers, RS-232 interfaces, LCD displays, potentiometers and additional EEPROM memory. The demonstration and development boards can be used in teaching environments, for prototyping custom circuits and for learning about various microcontroller applications. In addition to the PICDEM™ and dsPICDEM™ demonstration/development board series of circuits, Microchip has a line of evaluation kits and demonstration software for analog filter design, KEELOQ® security ICs, CAN, IrDA®, PowerSmart battery management, SEEVAL® evaluation system, Sigma-Delta ADC, flow rate sensing, plus many more. Also available are starter kits that contain everything needed to experience the specified device. This usually includes a single application and debug capability, all on one board. Check the Microchip web page (www.microchip.com) for the complete list of demonstration, development and evaluation kits.  2011 Microchip Technology Inc. PIC16(L)F1826/27 33.0 PACKAGING INFORMATION 33.1 Package Marking Information 18-Lead PDIP Example XXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXX YYWWNNN 18-Lead SOIC (.300”) XXXXXXXXXXXX XXXXXXXXXXXX XXXXXXXXXXXX PIC16F1826-I/P 1110017 Example PIC16C1826-I /SO 1110017 YYWWNNN 20-Lead SSOP Example XXXXXXXXXXX XXXXXXXXXXX YYWWNNN 28-Lead QFN/UQFN XXXXXXXX XXXXXXXX YYWWNNN Legend: XX...X Y YY WW NNN e3 * Note: * PIC16F1827 -I/SS 1110017 Example 16F1827 /ML 1110017 Customer-specific information Year code (last digit of calendar year) Year code (last 2 digits of calendar year) Week code (week of January 1 is week ‘01’) Alphanumeric traceability code Pb-free JEDEC designator for Matte Tin (Sn) This package is Pb-free. The Pb-free JEDEC designator ( e3 ) can be found on the outer packaging for this package. In the event the full Microchip part number cannot be marked on one line, it will be carried over to the next line, thus limiting the number of available characters for customer-specific information. Standard PICmicro® device marking consists of Microchip part number, year code, week code and traceability code. For PICmicro device marking beyond this, certain price adders apply. Please check with your Microchip Sales Office. For QTP devices, any special marking adders are included in QTP price.  2011 Microchip Technology Inc. DS41391D-page 383 PIC16(L)F1826/27 33.2 Package Details The following sections give the technical details of the packages. /HDG3ODVWLF'XDO,Q/LQH3±PLO%RG\>3',3@ 1RWH )RUWKHPRVWFXUUHQWSDFNDJHGUDZLQJVSOHDVHVHHWKH0LFURFKLS3DFNDJLQJ6SHFLILFDWLRQORFDWHGDW KWWSZZZPLFURFKLSFRPSDFNDJLQJ  N NOTE 1 E1 1 2 3 D E A2 A L c A1 b1 b e eB 8QLWV 'LPHQVLRQ/LPLWV 1XPEHURI3LQV ,1&+(6 0,1 1 120 0$;  3LWFK H 7RSWR6HDWLQJ3ODQH $ ± ±  0ROGHG3DFNDJH7KLFNQHVV $    %DVHWR6HDWLQJ3ODQH $  ± ± 6KRXOGHUWR6KRXOGHU:LGWK (    0ROGHG3DFNDJH:LGWK (    2YHUDOO/HQJWK '    7LSWR6HDWLQJ3ODQH /    /HDG7KLFNQHVV F    E    E    H% ± ± 8SSHU/HDG:LGWK /RZHU/HDG:LGWK 2YHUDOO5RZ6SDFLQJ† %6&  1RWHV  3LQYLVXDOLQGH[IHDWXUHPD\YDU\EXWPXVWEHORFDWHGZLWKLQWKHKDWFKHGDUHD  †6LJQLILFDQW&KDUDFWHULVWLF  'LPHQVLRQV'DQG(GRQRWLQFOXGHPROGIODVKRUSURWUXVLRQV0ROGIODVKRUSURWUXVLRQVVKDOOQRWH[FHHGSHUVLGH  'LPHQVLRQLQJDQGWROHUDQFLQJSHU$60(6623@ 1RWH )RUWKHPRVWFXUUHQWSDFNDJHGUDZLQJVSOHDVHVHHWKH0LFURFKLS3DFNDJLQJ6SHFLILFDWLRQORFDWHGDW KWWSZZZPLFURFKLSFRPSDFNDJLQJ D N E E1 NOTE 1 1 2 e b c A2 A φ A1 L1 8QLWV 'LPHQVLRQ/LPLWV 1XPEHURI3LQV L 0,//,0(7(56 0,1 1 120 0$;  3LWFK H 2YHUDOO+HLJKW $ ± %6& ±  0ROGHG3DFNDJH7KLFNQHVV $    6WDQGRII $  ± ± 2YHUDOO:LGWK (    0ROGHG3DFNDJH:LGWK (    2YHUDOO/HQJWK '    )RRW/HQJWK /    )RRWSULQW / 5() /HDG7KLFNQHVV F  ± )RRW$QJOH  ƒ ƒ  ƒ /HDG:LGWK E  ±  1RWHV  3LQYLVXDOLQGH[IHDWXUHPD\YDU\EXWPXVWEHORFDWHGZLWKLQWKHKDWFKHGDUHD  'LPHQVLRQV'DQG(GRQRWLQFOXGHPROGIODVKRUSURWUXVLRQV0ROGIODVKRUSURWUXVLRQVVKDOOQRWH[FHHGPPSHUVLGH  'LPHQVLRQLQJDQGWROHUDQFLQJSHU$60(4)1@ ZLWKPP&RQWDFW/HQJWK 1RWH )RUWKHPRVWFXUUHQWSDFNDJHGUDZLQJVSOHDVHVHHWKH0LFURFKLS3DFNDJLQJ6SHFLILFDWLRQORFDWHGDW KWWSZZZPLFURFKLSFRPSDFNDJLQJ  2011 Microchip Technology Inc. DS41391D-page 389 PIC16(L)F1826/27 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging DS41391D-page 390  2011 Microchip Technology Inc. PIC16(L)F1826/27 Note: For the most current package drawings, please see the Microchip Packaging Specification located at http://www.microchip.com/packaging  2011 Microchip Technology Inc. DS41391D-page 391 PIC16(L)F1826/27 NOTES: DS41391D-page 392  2011 Microchip Technology Inc. PIC16(L)F1826/27 APPENDIX A: DATA SHEET REVISION HISTORY Revision A APPENDIX B: MIGRATING FROM OTHER PIC® DEVICES This section provides comparisons when migrating devices to the from other similar PIC® PIC16(L)F1826/27 family of devices. Original release (06/2009) Revision B (08/09) Revised Tables 5-3, 6-2, 12-2, 12-3; Updated Electrical Specifications; Added UQFN Package; Added SOIC and QFN Land Patterns; Updated Product ID section. Revision C (06/10) Updated Electrical Specification Enhanced Core Golden Chapters. and Revision D (04/11) Added Char Data to release Final data sheet. included B.1 PIC16F648A to PIC16(L)F1827 TABLE B-1: FEATURE COMPARISON Feature Max. Operating Speed 20 MHz 32 MHz Max. Program Memory (Words) 4K 4K Max. SRAM (Bytes) 256 384 Max. EEPROM (Bytes) 256 256 A/D Resolution 10-bit 10-bit Timers (8/16-bit) 2/1 4/1 Brown-out Reset Y Y Internal Pull-ups RB RB, RA5 Interrupt-on-Change RB RB, Edge Selectable Comparator 2 2 1/0 0/2 Extended WDT N Y Software Control Option of WDT/BOR N Y 48 kHz or 4 MHz 31 kHz 32 MHz Clock Switching Y Y Capacitive Sensing N Y AUSART/EUSART INTOSC Frequencies CCP/ECCP  2011 Microchip Technology Inc. PIC16F648A PIC16(L)F1827 2/0 2/2 Enhanced PIC16 CPU N Y MSSPx/SSPx 0 2/0 Reference Clock N Y Data Signal Modulator N Y SR Latch N Y Voltage Reference N Y DAC Y Y DS41391D-page 393 PIC16(L)F1826/27 NOTES: DS41391D-page 394  2011 Microchip Technology Inc. PIC16(L)F1826/27 INDEX A A/D Specifications............................................................ 361 Absolute Maximum Ratings .............................................. 339 AC Characteristics Industrial and Extended ............................................ 354 Load Conditions ........................................................ 353 ACKSTAT ......................................................................... 266 ACKSTAT Status Flag ...................................................... 266 ADC .................................................................................. 139 Acquisition Requirements ......................................... 149 Associated registers.................................................. 151 Block Diagram........................................................... 139 Calculating Acquisition Time..................................... 149 Channel Selection..................................................... 140 Configuration............................................................. 140 Configuring Interrupt ................................................. 144 Conversion Clock...................................................... 140 Conversion Procedure .............................................. 144 Internal Sampling Switch (RSS) IMPEDANCE .............. 149 Interrupts................................................................... 142 Operation .................................................................. 143 Operation During Sleep ............................................ 143 Port Configuration ..................................................... 140 Reference Voltage (VREF)......................................... 140 Source Impedance.................................................... 149 Special Event Trigger................................................ 143 Starting an A/D Conversion ...................................... 142 ADCON0 Register....................................................... 28, 145 ADCON1 Register....................................................... 28, 146 ADDFSR ........................................................................... 329 ADDWFC .......................................................................... 329 ADRESH Register............................................................... 28 ADRESH Register (ADFM = 0) ......................................... 147 ADRESH Register (ADFM = 1) ......................................... 148 ADRESL Register (ADFM = 0).......................................... 147 ADRESL Register (ADFM = 1).......................................... 148 Alternate Pin Function....................................................... 118 Analog-to-Digital Converter. See ADC ANSELA Register ............................................................. 123 ANSELB Register ............................................................. 128 APFCON0 Register........................................................... 119 APFCON1 Register........................................................... 119 Assembler MPASM Assembler................................................... 380 Automatic Context Saving................................................... 85 B Bank 10 ............................................................................... 33 Bank 11 ............................................................................... 33 Bank 12 ......................................................................... 33, 34 Bank 13 ......................................................................... 33, 34 Bank 14 ............................................................................... 33 Bank 15 ............................................................................... 33 Bank 16 ............................................................................... 33 Bank 17 ............................................................................... 33 Bank 18 ............................................................................... 33 Bank 19 ............................................................................... 33 Bank 20 ............................................................................... 33 Bank 21 ............................................................................... 33 Bank 22 ............................................................................... 33 Bank 23 ............................................................................... 34 Bank 31 ............................................................................... 35  2011 Microchip Technology Inc. Bank 6 ................................................................................ 31 Bank 7 ................................................................................ 31 Bank 8 ................................................................................ 32 Bank 9 ................................................................................ 33 BAUDCON Register ......................................................... 296 BF ............................................................................. 266, 268 BF Status Flag .......................................................... 266, 268 Block Diagram Capacitive Sensing................................................... 315 Block Diagrams (CCP) Capture Mode Operation ............................... 204 ADC .......................................................................... 139 ADC Transfer Function............................................. 150 Analog Input Model........................................... 150, 169 CCP PWM ................................................................ 208 Clock Source .............................................................. 52 Comparator............................................................... 164 Compare................................................................... 206 Crystal Operation.................................................. 54, 55 Digital-to-Analog Converter (DAC) ........................... 154 EUSART Receive ..................................................... 286 EUSART Transmit .................................................... 285 External RC Mode ...................................................... 55 Fail-Safe Clock Monitor (FSCM)................................. 63 Generic I/O Port........................................................ 117 Interrupt Logic............................................................. 81 On-Chip Reset Circuit................................................. 73 PIC16F/LF1826/27 ..................................................... 10 PIC16F193X/LF193X ................................................. 16 PWM (Enhanced) ..................................................... 212 Resonator Operation .................................................. 54 Timer0 .............................................................. 173, 174 Timer1 ...................................................................... 177 Timer1 Gate.............................................. 182, 183, 184 Timer2/4/6 ................................................................ 189 Voltage Reference.................................................... 135 Voltage Reference Output Buffer Example .............. 154 BORCON Register.............................................................. 75 BRA .................................................................................. 330 Break Character (12-bit) Transmit and Receive ............... 305 Brown-out Reset (BOR)...................................................... 75 Specifications ........................................................... 359 Timing and Characteristics ....................................... 358 C C Compilers MPLAB C18.............................................................. 380 CALL................................................................................. 331 CALLW ............................................................................. 331 Capacitive Sensing ........................................................... 315 Associated registers w/ Capacitive Sensing............. 319 Specifications ........................................................... 370 Capture Module. See Enhanced Capture/Compare/PWM (ECCP) Capture/Compare/PWM ................................................... 203 Capture/Compare/PWM (CCP) Associated Registers w/ Capture ............................. 205 Associated Registers w/ Compare ........................... 207 Associated Registers w/ PWM ......................... 211, 225 Capture Mode........................................................... 204 CCPx Pin Configuration............................................ 204 Compare Mode......................................................... 206 CCPx Pin Configuration.................................... 206 Software Interrupt Mode ........................... 204, 206 DS41391D-page 395 PIC16(L)F1826/27 Special Event Trigger........................................ 206 Timer1 Mode Resource ............................ 204, 206 Prescaler ................................................................... 204 PWM Mode Duty Cycle......................................................... 209 Effects of Reset................................................. 211 Example PWM Frequencies and Resolutions, 20 MHZ ................................ 210 Example PWM Frequencies and Resolutions, 32 MHZ ................................ 210 Example PWM Frequencies and Resolutions, 8 MHz................................... 210 Operation in Sleep Mode .................................. 211 Resolution ......................................................... 210 System Clock Frequency Changes................... 211 PWM Operation ........................................................ 208 PWM Overview ......................................................... 208 PWM Period .............................................................. 209 PWM Setup ............................................................... 209 CCP1CON Register ...................................................... 30, 31 CCPR1H Register ......................................................... 30, 31 CCPR1L Register.......................................................... 30, 31 CCPTMRS Register .......................................................... 227 CCPxAS Register.............................................................. 228 CCPxCON (ECCPx) Register ........................................... 226 CLKRCON Register ............................................................ 70 Clock Accuracy with Asynchronous Operation ................. 294 Clock Sources External Modes ........................................................... 53 EC ....................................................................... 53 HS ....................................................................... 53 LP........................................................................ 53 OST..................................................................... 54 RC....................................................................... 55 XT ....................................................................... 53 Internal Modes ............................................................ 56 HFINTOSC.......................................................... 56 Internal Oscillator Clock Switch Timing............... 58 LFINTOSC .......................................................... 57 MFINTOSC ......................................................... 56 Clock Switching................................................................... 60 CMOUT Register............................................................... 171 CMxCON0 Register .......................................................... 170 CMxCON1 Register .......................................................... 171 Code Examples A/D Conversion ......................................................... 144 Changing Between Capture Prescalers .................... 204 Initializing PORTA ..................................................... 117 Write Verify ............................................................... 112 Writing to Flash Program Memory ............................ 110 Comparator Associated Registers ................................................ 172 Operation .................................................................. 163 Comparator Module .......................................................... 163 Cx Output State Versus Input Conditions ................. 166 Comparator Specifications ................................................ 363 Comparators C2OUT as T1 Gate ................................................... 179 Compare Module. See Enhanced Capture/Compare/ PWM (ECCP) CONFIG1 Register.............................................................. 44 CONFIG2 Register.............................................................. 46 Core Function Register ....................................................... 27 CPSCON0 Register .......................................................... 318 CPSCON1 Register .......................................................... 319 DS41391D-page 396 Customer Change Notification Service............................. 403 Customer Notification Service .......................................... 403 Customer Support............................................................. 403 D DACCON0 (Digital-to-Analog Converter Control 0) Register .................................................................... 156 DACCON1 (Digital-to-Analog Converter Control 1) Register .................................................................... 156 Data EEPROM Memory.................................................... 101 Associated Registers ................................................ 116 Code Protection ........................................................ 102 Reading .................................................................... 102 Writing ...................................................................... 102 Data Memory ...................................................................... 20 DC and AC Characteristics............................................... 371 Graphs and Tables ................................................... 371 DC Characteristics Extended and Industrial ............................................ 350 Industrial and Extended ............................................ 342 Development Support ....................................................... 379 Device Configuration .......................................................... 43 Code Protection .......................................................... 47 Configuration Word..................................................... 43 User ID ................................................................. 47, 48 Device ID Register.............................................................. 49 Device Overview............................................................. 9, 97 Digital-to-Analog Converter (DAC) ................................... 153 Associated Registers ................................................ 156 Effects of a Reset ..................................................... 154 Specifications ........................................................... 363 E ECCP/CCP. See Enhanced Capture/Compare/PWM EEADR Registers ............................................................. 101 EEADRH Registers........................................................... 101 EEADRL Register ............................................................. 113 EEADRL Registers ........................................................... 101 EECON1 Register..................................................... 101, 115 EECON2 Register..................................................... 101, 116 EEDATH Register..................................................... 113, 114 EEDATL Register ............................................................. 113 EEPROM Data Memory Avoiding Spurious Write ........................................... 102 Write Verify ............................................................... 112 Effects of Reset PWM mode ............................................................... 211 Electrical Specifications .................................................... 339 Enhanced Capture/Compare/PWM (ECCP)..................... 203 Enhanced PWM Mode.............................................. 212 Auto-Restart ..................................................... 221 Auto-shutdown.................................................. 220 Direction Change in Full-Bridge Output Mode.. 218 Full-Bridge Application...................................... 216 Full-Bridge Mode .............................................. 216 Half-Bridge Application ..................................... 215 Half-Bridge Application Examples .................... 222 Half-Bridge Mode.............................................. 215 Output Relationships (Active-High and Active-Low)............................................... 213 Output Relationships Diagram.......................... 214 Programmable Dead Band Delay..................... 222 Shoot-through Current ...................................... 222 Start-up Considerations .................................... 224 Specifications ........................................................... 360 Enhanced Mid-Range CPU ................................................ 15  2011 Microchip Technology Inc. PIC16(L)F1826/27 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART)............................... 285 Errata .................................................................................... 8 EUSART ........................................................................... 285 Associated Registers Baud Rate Generator........................................ 298 Asynchronous Mode ................................................. 287 12-bit Break Transmit and Receive .................. 305 Associated Registers Receive..................................................... 293 Transmit.................................................... 289 Auto-Wake-up on Break ................................... 303 Baud Rate Generator (BRG) ............................ 297 Clock Accuracy ................................................. 294 Receiver............................................................ 290 Setting up 9-bit Mode with Address Detect....... 292 Transmitter........................................................ 287 Baud Rate Generator (BRG) Auto Baud Rate Detect ..................................... 302 Baud Rate Error, Calculating ............................ 297 Baud Rates, Asynchronous Modes .................. 299 Formulas ........................................................... 298 High Baud Rate Select (BRGH Bit) .................. 297 Synchronous Master Mode ............................... 306, 311 Associated Registers Receive..................................................... 310 Transmit.................................................... 308 Reception.......................................................... 309 Transmission .................................................... 306 Synchronous Slave Mode Associated Registers Receive..................................................... 312 Transmit.................................................... 311 Reception.......................................................... 312 Transmission .................................................... 311 Extended Instruction Set ADDFSR ................................................................... 329 F Fail-Safe Clock Monitor....................................................... 63 Fail-Safe Condition Clearing ....................................... 63 Fail-Safe Detection ..................................................... 63 Fail-Safe Operation..................................................... 63 Reset or Wake-up from Sleep..................................... 63 Firmware Instructions........................................................ 325 Fixed Voltage Reference (FVR) Associated Registers ................................................ 136 Flash Program Memory .................................................... 101 Erasing...................................................................... 107 Modifying................................................................... 111 Writing....................................................................... 107 FSR Register ...................................................................... 27 FVRCON (Fixed Voltage Reference Control) Register ..... 136 I I2C Mode (MSSPx) Acknowledge Sequence Timing................................ 270 Bus Collision During a Repeated Start Condition ................... 275 During a Stop Condition.................................... 276 Effects of a Reset...................................................... 271 I2C Clock Rate w/BRG.............................................. 278 Master Mode Operation .......................................................... 262 Reception.......................................................... 268 Start Condition Timing .............................. 264, 265  2011 Microchip Technology Inc. Transmission .................................................... 266 Multi-Master Communication, Bus Collision and Arbitration ......................................................... 271 Multi-Master Mode.................................................... 271 Read/Write Bit Information (R/W Bit)........................ 247 Slave Mode Transmission .................................................... 252 Sleep Operation........................................................ 271 Stop Condition Timing .............................................. 270 INDF Register ..................................................................... 27 Indirect Addressing ............................................................. 39 Instruction Format............................................................. 326 Instruction Set................................................................... 325 ADDLW..................................................................... 329 ADDWF .................................................................... 329 ADDWFC.................................................................. 329 ANDLW..................................................................... 329 ANDWF .................................................................... 329 BRA .......................................................................... 330 CALL......................................................................... 331 CALLW ..................................................................... 331 LSLF ......................................................................... 333 LSRF ........................................................................ 333 MOVF ....................................................................... 333 MOVIW ..................................................................... 334 MOVLB ..................................................................... 334 MOVWI ..................................................................... 335 OPTION.................................................................... 335 RESET...................................................................... 335 SUBWFB .................................................................. 337 TRIS ......................................................................... 338 BCF .......................................................................... 330 BSF........................................................................... 330 BTFSC...................................................................... 330 BTFSS ...................................................................... 330 CALL......................................................................... 331 CLRF ........................................................................ 331 CLRW ....................................................................... 331 CLRWDT .................................................................. 331 COMF ....................................................................... 331 DECF........................................................................ 331 DECFSZ ................................................................... 332 GOTO ....................................................................... 332 INCF ......................................................................... 332 INCFSZ..................................................................... 332 IORLW ...................................................................... 332 IORWF...................................................................... 332 MOVLW .................................................................... 334 MOVWF.................................................................... 334 NOP.......................................................................... 335 RETFIE..................................................................... 336 RETLW ..................................................................... 336 RETURN................................................................... 336 RLF........................................................................... 336 RRF .......................................................................... 337 SLEEP ...................................................................... 337 SUBLW..................................................................... 337 SUBWF..................................................................... 337 SWAPF..................................................................... 338 XORLW .................................................................... 338 XORWF .................................................................... 338 INTCON Register................................................................ 86 Internal Oscillator Block INTOSC Specifications ................................................... 355 DS41391D-page 397 PIC16(L)F1826/27 Internal Sampling Switch (RSS) IMPEDANCE ...................... 149 Internet Address................................................................ 403 Interrupt-On-Change ......................................................... 131 Associated Registers ................................................ 133 Interrupts ............................................................................. 81 ADC .......................................................................... 144 Associated registers w/ Interrupts ............................... 94 Configuration Word w/ Clock Sources ........................ 67 Configuration Word w/ PORTA ................................. 124 Configuration Word w/ Reference Clock Sources....... 71 TMR1 ........................................................................ 181 INTOSC Specifications ..................................................... 355 IOCBF Register................................................................. 132 IOCBN Register ................................................................ 132 IOCBP Register................................................................. 132 L LATA Register................................................................... 122 LATB Register................................................................... 127 Load Conditions ................................................................ 353 LSLF.................................................................................. 333 LSRF ................................................................................. 333 M Master Synchronous Serial Port. See MSSPx MCLR .................................................................................. 76 Internal ........................................................................ 76 MDCARH Register ............................................................ 200 MDCARL Register............................................................. 201 MDCON Register .............................................................. 198 MDSRC Register............................................................... 199 Memory Organization.......................................................... 17 Data ............................................................................ 20 Program ...................................................................... 17 Microchip Internet Web Site .............................................. 403 Migrating from other PIC Microcontroller Devices............. 393 MOVIW.............................................................................. 334 MOVLB.............................................................................. 334 MOVWI.............................................................................. 335 MPLAB ASM30 Assembler, Linker, Librarian ................... 380 MPLAB Integrated Development Environment Software .. 379 MPLAB PM3 Device Programmer..................................... 382 MPLAB REAL ICE In-Circuit Emulator System................. 381 MPLINK Object Linker/MPLIB Object Librarian ................ 380 MSSPx .............................................................................. 231 I2C Mode ................................................................... 242 I2C Mode Operation .................................................. 244 SPI Mode .................................................................. 234 SSPxBUF Register ................................................... 237 SSPxSR Register...................................................... 237 O OPCODE Field Descriptions ............................................. 325 OPTION ............................................................................ 335 OPTION_REG Register .................................................... 176 OSCCON Register .............................................................. 65 Oscillator Associated Registers .................................................. 67 Oscillator Module ................................................................ 51 ECH ............................................................................ 51 ECL ............................................................................. 51 ECM ............................................................................ 51 HS ............................................................................... 51 INTOSC ...................................................................... 51 LP................................................................................ 51 RC ............................................................................... 51 DS41391D-page 398 XT ............................................................................... 51 Oscillator Parameters ....................................................... 355 Oscillator Specifications.................................................... 354 Oscillator Start-up Timer (OST) Specifications ........................................................... 359 Oscillator Switching Fail-Safe Clock Monitor .............................................. 63 Two-Speed Clock Start-up.......................................... 61 OSCSTAT Register ............................................................ 66 OSCTUNE Register............................................................ 67 P P1A/P1B/P1C/P1D.See Enhanced Capture/Compare/ PWM (ECCP)............................................................ 212 Packaging ......................................................................... 383 Marking ..................................................................... 383 PDIP Details ............................................................. 384 PCL and PCLATH............................................................... 16 PCL Register ...................................................................... 27 PCLATH Register ............................................................... 27 PCON Register ............................................................. 28, 79 PIE1 Register................................................................ 28, 87 PIE2 Register...................................................................... 88 PIE3 Register...................................................................... 89 PIE4 Register...................................................................... 90 Pin Diagram PIC16F/LF1826/27, 18-pin PDIP/SOIC ........................ 4 PIC16F/LF1826/27, 28-pin QFN/UQFN........................ 5 Pinout Descriptions PIC16F/LF1826/27 ..................................................... 11 PIR1 Register ............................................................... 28, 91 PIR2 Register ............................................................... 28, 92 PIR3 Register ..................................................................... 93 PIR4 Register ..................................................................... 94 PORTA ............................................................................. 120 ANSELA Register ..................................................... 120 Associated Registers ................................................ 124 PORTA Register ................................................... 28, 29 Specifications ........................................................... 357 PORTA Register ............................................................... 122 PORTB ............................................................................. 125 Additional Pin Functions Weak Pull-up .................................................... 127 ANSELB Register ..................................................... 125 Associated Registers ................................................ 129 Interrupt-on-Change ................................................. 125 P1B/P1C/P1D.See Enhanced Capture/Compare/ PWM+ (ECCP+) ............................................... 125 Pin Descriptions and Diagrams ................................ 129 PORTB Register ................................................... 28, 29 PORTB Register ............................................................... 127 Power-Down Mode (Sleep)................................................. 95 Associated Registers .......................................... 96, 201 Power-on Reset .................................................................. 74 Power-up Time-out Sequence ............................................ 76 Power-up Timer (PWRT) .................................................... 74 Specifications ........................................................... 359 PR2 Register ................................................................ 28, 32 Precision Internal Oscillator Parameters .......................... 355 Program Memory ................................................................ 17 Map and Stack (PIC16F/LF1826) ............................... 18 Map and Stack (PIC16F/LF1826/27) .................... 17, 18 Programming, Device Instructions .................................... 325 PSTRxCON Register ........................................................ 230 PWM (ECCP Module) PWM Steering........................................................... 223  2011 Microchip Technology Inc. PIC16(L)F1826/27 Steering Synchronization .......................................... 224 PWM Mode. See Enhanced Capture/Compare/PWM ...... 212 PWM Steering ................................................................... 223 PWMxCON Register ......................................................... 229 R RCREG ............................................................................. 292 RCREG Register................................................................. 29 RCSTA Register ......................................................... 29, 295 Reader Response ............................................................. 404 Read-Modify-Write Operations ......................................... 325 Reference Clock ................................................................. 69 Associated Registers .................................................. 71 Registers ADCON0 (ADC Control 0) ........................................ 145 ADCON1 (ADC Control 1) ........................................ 146 ADRESH (ADC Result High) with ADFM = 0)........... 147 ADRESH (ADC Result High) with ADFM = 1)........... 148 ADRESL (ADC Result Low) with ADFM = 0) ............ 147 ADRESL (ADC Result Low) with ADFM = 1) ............ 148 ANSELA (PORTA Analog Select)............................. 123 ANSELB (PORTB Analog Select)............................. 128 APFCON0 (Alternate Pin Function Control 0)........... 119 APFCON1 (Alternate Pin Function Control 1)........... 119 BAUDCON (Baud Rate Control) ............................... 296 BORCON Brown-out Reset Control)........................... 75 CCPTMRS (PWM Timer Selection Control) ............. 227 CCPxAS (CCPx Auto-Shutdown Control)................. 228 CCPxCON (ECCPx Control)..................................... 226 CLKRCON (Reference Clock Control)........................ 70 CMOUT (Comparator Output)................................... 171 CMxCON0 (Cx Control) ............................................ 170 CMxCON1 (Cx Control 1) ......................................... 171 Configuration Word 1 .................................................. 44 Configuration Word 2 .................................................. 46 Core Function, Summary ............................................ 27 CPSCON0 (Capacitive Sensing Control Register 0) 318 CPSCON1 (Capacitive Sensing Control Register 1) 319 DACCON0 ................................................................ 156 DACCON1 ................................................................ 156 Device ID .................................................................... 49 EEADRL (EEPROM Address) .................................. 113 EECON1 (EEPROM Control 1)................................. 115 EECON2 (EEPROM Control 2)................................. 116 EEDATH (EEPROM Data)................................ 113, 114 EEDATL (EEPROM Data) ........................................ 113 FVRCON................................................................... 136 INTCON (Interrupt Control)......................................... 86 IOCBF (Interrupt-on-Change Flag) ........................... 132 IOCBN (Interrupt-on-Change Negative Edge) .......... 132 IOCBP (Interrupt-on-Change Positive Edge) ............ 132 LATA (Data Latch PORTA)....................................... 122 LATB (Data Latch PORTB)....................................... 127 MDCARH (Modulation High Carrier Control Register) ........................................................... 200 MDCARL (Modulation Low Carrier Control Register) 201 MDCON (Modulation Control Register) .................... 198 MDSRC (Modulation Source Control Register) ........ 199 OPTION_REG (OPTION) ......................................... 176 OSCCON (Oscillator Control) ..................................... 65 OSCSTAT (Oscillator Status) ..................................... 66 OSCTUNE (Oscillator Tuning) .................................... 67 PCON (Power Control Register) ................................. 79 PCON (Power Control) ............................................... 79 PIE1 (Peripheral Interrupt Enable 1)........................... 87 PIE2 (Peripheral Interrupt Enable 2)........................... 88  2011 Microchip Technology Inc. PIE3 (Peripheral Interrupt Enable 3) .......................... 89 PIE4 (Peripheral Interrupt Enable 4) .......................... 90 PIR1 (Peripheral Interrupt Register 1) ........................ 91 PIR2 (Peripheral Interrupt Request 2) ........................ 92 PIR3 (Peripheral Interrupt Request 3) ........................ 93 PIR4 (Peripheral Interrupt Request 4) ........................ 94 PORTA ..................................................................... 122 PORTB ..................................................................... 127 PSTRxCON (PWM Steering Control) ....................... 230 PWMxCON (Enhanced PWM Control) ..................... 229 RCREG..................................................................... 302 RCSTA (Receive Status and Control) ...................... 295 SPBRGH .................................................................. 297 SPBRGL ................................................................... 297 Special Function, Summary........................................ 28 SRCON0 (SR Latch Control 0)................................. 159 SRCON1 (SR Latch Control 1)................................. 160 SSPxADD (MSSPx Address and Baud Rate, I2C Mode) ......................................................... 283 SSPxCON1 (MSSPx Control 1)................................ 280 SSPxCON2 (SSPx Control 2)................................... 281 SSPxCON3 (SSPx Control 3)................................... 282 SSPxMSK (SSPx Mask)........................................... 283 SSPxSTAT (SSPx Status)........................................ 279 STATUS ..................................................................... 21 T1CON (Timer1 Control) .......................................... 185 T1GCON (Timer1 Gate Control)............................... 186 TRISA (Tri-State PORTA) ........................................ 122 TRISB (Tri-State PORTB) ........................................ 127 TXCON ..................................................................... 191 TXSTA (Transmit Status and Control)...................... 294 WDTCON (Watchdog Timer Control) ......................... 99 WPUB (Weak Pull-up PORTB)......................... 123, 128 RESET.............................................................................. 335 Reset .................................................................................. 73 Reset Instruction................................................................. 76 Resets ................................................................................ 73 Associated Registers.................................................. 80 Revision History................................................................ 393 S Shoot-through Current ...................................................... 222 Software Simulator (MPLAB SIM) .................................... 381 SPBRG Register................................................................. 29 SPBRGH Register ............................................................ 297 SPBRGL Register............................................................. 297 Special Event Trigger ....................................................... 143 Special Function Registers (SFRs)..................................... 28 SPI Mode (MSSPx) Associated Registers................................................ 241 SPI Clock.................................................................. 237 SR Latch ........................................................................... 157 Associated registers w/ SR Latch............................. 161 SRCON0 Register ............................................................ 159 SRCON1 Register ............................................................ 160 SSP1ADD Register............................................................. 30 SSP1BUF Register ............................................................. 30 SSP1CON Register ............................................................ 30 SSP1CON2 Register .......................................................... 30 SSP1CON3 Register .......................................................... 30 SSP1MSK Register ............................................................ 30 SSP1STAT Register ........................................................... 30 SSP2ADD Register............................................................. 30 SSP2BUF Register ............................................................. 30 SSP2CON1 Register .......................................................... 30 SSP2CON2 Register .......................................................... 30 DS41391D-page 399 PIC16(L)F1826/27 SSP2CON3 Register........................................................... 30 SSP2MSK Register............................................................. 30 SSP2STAT Register ........................................................... 30 SSPxADD Register ........................................................... 283 SSPxCON1 Register......................................................... 280 SSPxCON2 Register......................................................... 281 SSPxCON3 Register......................................................... 282 SSPxMSK Register ........................................................... 283 SSPxOV ............................................................................ 268 SSPxOV Status Flag......................................................... 268 SSPxSTAT Register.......................................................... 279 R/W Bit ...................................................................... 247 Stack ................................................................................... 37 Accessing.................................................................... 37 Reset........................................................................... 39 Stack Overflow/Underflow................................................... 76 STATUS Register................................................................ 21 SUBWFB........................................................................... 337 T T1CON Register.......................................................... 28, 185 T1GCON Register............................................................. 186 T2CON Register............................................................ 28, 32 Temperature Indicator Module .......................................... 137 Thermal Considerations .................................................... 352 Timer0 ....................................................................... 173, 192 Associated Registers ................................................ 176 Operation .................................................................. 173 Specifications ............................................................ 360 Timer1 ............................................................................... 177 Associated registers.................................................. 187 Asynchronous Counter Mode ................................... 179 Reading and Writing ......................................... 179 Clock Source Selection ............................................. 178 Interrupt..................................................................... 181 Operation .................................................................. 178 Operation During Sleep ............................................ 181 Oscillator ................................................................... 179 Prescaler ................................................................... 179 Specifications ............................................................ 360 Timer1 Gate Selecting Source............................................... 179 TMR1H Register ....................................................... 177 TMR1L Register ........................................................ 177 Timer2 Associated registers.................................................. 192 Timer2/4/6 ......................................................................... 189 Associated registers.................................................. 192 Timers Timer1 T1CON.............................................................. 185 T1GCON ........................................................... 186 Timer2/4/6 TXCON ............................................................. 191 Timing Diagrams A/D Conversion ......................................................... 362 A/D Conversion (Sleep Mode) .................................. 362 Acknowledge Sequence ........................................... 270 Asynchronous Reception .......................................... 292 Asynchronous Transmission ..................................... 288 Asynchronous Transmission (Back to Back) ............ 288 Auto Wake-up Bit (WUE) During Normal Operation . 304 Auto Wake-up Bit (WUE) During Sleep .................... 304 Automatic Baud Rate Calibration .............................. 302 Baud Rate Generator with Clock Arbitration ............. 263 DS41391D-page 400 BRG Reset Due to SDA Arbitration During Start Condition .......................................................... 274 Brown-out Reset (BOR)............................................ 358 Brown-out Reset Situations ........................................ 75 Bus Collision During a Repeated Start Condition (Case 1)............................................................ 275 Bus Collision During a Repeated Start Condition (Case 2)............................................................ 275 Bus Collision During a Start Condition (SCL = 0) ..... 274 Bus Collision During a Stop Condition (Case 1) ....... 276 Bus Collision During a Stop Condition (Case 2) ....... 276 Bus Collision During Start Condition (SDA only) ...... 273 Bus Collision for Transmit and Acknowledge ........... 272 CLKOUT and I/O ...................................................... 356 Clock Synchronization .............................................. 260 Clock Timing ............................................................. 354 Comparator Output ................................................... 163 Enhanced Capture/Compare/PWM (ECCP)............. 360 Fail-Safe Clock Monitor (FSCM)................................. 64 First Start Bit Timing ................................................. 264 Full-Bridge PWM Output........................................... 217 Half-Bridge PWM Output .................................. 215, 222 I2C Bus Data............................................................. 368 I2C Bus Start/Stop Bits ............................................. 367 I2C Master Mode (7 or 10-Bit Transmission) ............ 267 I2C Master Mode (7-Bit Reception)........................... 269 I2C Stop Condition Receive or Transmit Mode......... 271 INT Pin Interrupt ......................................................... 84 Internal Oscillator Switch Timing ................................ 59 PWM Auto-shutdown ................................................ 221 Firmware Restart .............................................. 220 PWM Direction Change ............................................ 218 PWM Direction Change at Near 100% Duty Cycle... 219 PWM Output (Active-High) ....................................... 213 PWM Output (Active-Low) ........................................ 214 Repeat Start Condition ............................................. 265 Reset Start-up Sequence ........................................... 77 Reset, WDT, OST and Power-up Timer ................... 357 Send Break Character Sequence ............................. 305 SPI Master Mode (CKE = 1, SMP = 1) ..................... 365 SPI Mode (Master Mode).......................................... 237 SPI Slave Mode (CKE = 0) ....................................... 366 SPI Slave Mode (CKE = 1) ....................................... 366 Synchronous Reception (Master Mode, SREN) ....... 310 Synchronous Transmission ...................................... 307 Synchronous Transmission (Through TXEN) ........... 307 Timer0 and Timer1 External Clock ........................... 359 Timer1 Incrementing Edge ....................................... 181 Two Speed Start-up.................................................... 62 USART Synchronous Receive (Master/Slave) ......... 364 USART Synchronous Transmission (Master/Slave). 364 Wake-up from Interrupt............................................... 96 Timing Diagrams and Specifications PLL Clock ................................................................. 355 Timing Parameter Symbology .......................................... 353 Timing Requirements I2C Bus Data............................................................. 369 I2C Bus Start/Stop Bits ............................................. 368 SPI Mode .................................................................. 367 TMR0 Register.................................................................... 28 TMR1H Register ................................................................. 28 TMR1L Register.................................................................. 28 TMR2 Register.............................................................. 28, 32 TRIS.................................................................................. 338 TRISA Register........................................................... 28, 122  2011 Microchip Technology Inc. PIC16(L)F1826/27 TRISB ............................................................................... 125 TRISB Register ........................................................... 28, 127 Two-Speed Clock Start-up Mode ........................................ 61 TXCON (Timer2/4/6) Register .......................................... 191 TXREG.............................................................................. 287 TXREG Register ................................................................. 29 TXSTA Register .......................................................... 29, 294 BRGH Bit .................................................................. 297 U USART Synchronous Master Mode Requirements, Synchronous Receive .............. 364 Requirements, Synchronous Transmission ...... 364 Timing Diagram, Synchronous Receive ........... 364 Timing Diagram, Synchronous Transmission ... 364 V VREF. SEE ADC Reference Voltage W Wake-up on Break ............................................................ 303 Wake-up Using Interrupts ................................................... 96 Watchdog Timer (WDT) ...................................................... 76 Associated Registers ................................................ 100 Configuration Word w/ Watchdog Timer ................... 100 Modes ......................................................................... 98 Specifications............................................................ 359 WCOL ....................................................... 263, 266, 268, 270 WCOL Status Flag .................................... 263, 266, 268, 270 WDTCON Register ............................................................. 99 WPUB Register ......................................................... 123, 128 Write Protection .................................................................. 47 WWW Address.................................................................. 403 WWW, On-Line Support ....................................................... 8  2011 Microchip Technology Inc. DS41391D-page 401 PIC16(L)F1826/27 NOTES: DS41391D-page 402  2011 Microchip Technology Inc. PIC16(L)F1826/27 THE MICROCHIP WEB SITE CUSTOMER SUPPORT Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a means to make files and information easily available to customers. Accessible by using your favorite Internet browser, the web site contains the following information: Users of Microchip products can receive assistance through several channels: • Product Support – Data sheets and errata, application notes and sample programs, design resources, user’s guides and hardware support documents, latest software releases and archived software • General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online discussion groups, Microchip consultant program member listing • Business of Microchip – Product selector and ordering guides, latest Microchip press releases, listing of seminars and events, listings of Microchip sales offices, distributors and factory representatives • • • • • Distributor or Representative Local Sales Office Field Application Engineer (FAE) Technical Support Development Systems Information Line Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales offices are also available to help customers. A listing of sales offices and locations is included in the back of this document. Technical support is available through the web site at: http://microchip.com/support CUSTOMER CHANGE NOTIFICATION SERVICE Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or development tool of interest. To register, access the Microchip web site at www.microchip.com. Under “Support”, click on “Customer Change Notification” and follow the registration instructions.  2011 Microchip Technology Inc. DS41391D-page 403 PIC16(L)F1826/27 READER RESPONSE It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our documentation can better serve you, please FAX your comments to the Technical Publications Manager at (480) 792-4150. Please list the following information, and use this outline to provide us with your comments about this document. TO: Technical Publications Manager RE: Reader Response Total Pages Sent ________ From: Name Company Address City / State / ZIP / Country Telephone: (_______) _________ - _________ FAX: (______) _________ - _________ Application (optional): Would you like a reply? Y N Device: PIC16(L)F1826/27 Literature Number: DS41391D Questions: 1. What are the best features of this document? 2. How does this document meet your hardware and software development needs? 3. Do you find the organization of this document easy to follow? If not, why? 4. What additions to the document do you think would enhance the structure and subject? 5. What deletions from the document could be made without affecting the overall usefulness? 6. Is there any incorrect or misleading information (what and where)? 7. How would you improve this document? DS41391D-page 404  2011 Microchip Technology Inc. PIC16(L)F1826/27 PRODUCT IDENTIFICATION SYSTEM To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office. PART NO. X /XX XXX Device Temperature Range Package Pattern Examples: a) b) Device: PIC16F1826(1), PIC16F1827(1), PIC16F1826T(2), PIC16F1827T(2); VDD range 1.8V to 5.5V PIC16LF1826(1), PIC16LF1827(1), PIC16LF1826T(2), PIC16LF1827T(2); VDD range 1.8V to 3.6V Temperature Range: I E Package: ML MV P SO SS Pattern: = -40C to +85C = -40C to +125C = = = = = c) PIC16F1826 - I/ML 301 = Industrial temp., QFN package, Extended VDD limits, QTP pattern #301. PIC16F1826 - I/P = Industrial temp., PDIP package, Extended VDD limits. PIC16F1827 - E/SS= Extended temp., SSOP package, normal VDD limits. (Industrial) (Extended) Micro Lead Frame (QFN) 6x6 Micro Lead Frame (UQFN) 4x4 Plastic DIP SOIC SSOP Note 1: 2: F = Wide Voltage Range LF = Standard Voltage Range T = in tape and reel SOIC, SSOP, and QFN/UQFN packages only. QTP, SQTP, Code or Special Requirements (blank otherwise)  2011 Microchip Technology Inc. DS41391D-page 405 Worldwide Sales and Service AMERICAS ASIA/PACIFIC ASIA/PACIFIC EUROPE Corporate Office 2355 West Chandler Blvd. Chandler, AZ 85224-6199 Tel: 480-792-7200 Fax: 480-792-7277 Technical Support: http://www.microchip.com/ support Web Address: www.microchip.com Asia Pacific Office Suites 3707-14, 37th Floor Tower 6, The Gateway Harbour City, Kowloon Hong Kong Tel: 852-2401-1200 Fax: 852-2401-3431 India - Bangalore Tel: 91-80-3090-4444 Fax: 91-80-3090-4123 India - New Delhi Tel: 91-11-4160-8631 Fax: 91-11-4160-8632 Austria - Wels Tel: 43-7242-2244-39 Fax: 43-7242-2244-393 Denmark - Copenhagen Tel: 45-4450-2828 Fax: 45-4485-2829 India - Pune Tel: 91-20-2566-1512 Fax: 91-20-2566-1513 France - Paris Tel: 33-1-69-53-63-20 Fax: 33-1-69-30-90-79 Japan - Yokohama Tel: 81-45-471- 6166 Fax: 81-45-471-6122 Germany - Munich Tel: 49-89-627-144-0 Fax: 49-89-627-144-44 Atlanta Duluth, GA Tel: 678-957-9614 Fax: 678-957-1455 Boston Westborough, MA Tel: 774-760-0087 Fax: 774-760-0088 Chicago Itasca, IL Tel: 630-285-0071 Fax: 630-285-0075 Cleveland Independence, OH Tel: 216-447-0464 Fax: 216-447-0643 Dallas Addison, TX Tel: 972-818-7423 Fax: 972-818-2924 Detroit Farmington Hills, MI Tel: 248-538-2250 Fax: 248-538-2260 Indianapolis Noblesville, IN Tel: 317-773-8323 Fax: 317-773-5453 Los Angeles Mission Viejo, CA Tel: 949-462-9523 Fax: 949-462-9608 Santa Clara Santa Clara, CA Tel: 408-961-6444 Fax: 408-961-6445 Toronto Mississauga, Ontario, Canada Tel: 905-673-0699 Fax: 905-673-6509 Australia - Sydney Tel: 61-2-9868-6733 Fax: 61-2-9868-6755 China - Beijing Tel: 86-10-8528-2100 Fax: 86-10-8528-2104 China - Chengdu Tel: 86-28-8665-5511 Fax: 86-28-8665-7889 Korea - Daegu Tel: 82-53-744-4301 Fax: 82-53-744-4302 China - Chongqing Tel: 86-23-8980-9588 Fax: 86-23-8980-9500 Korea - Seoul Tel: 82-2-554-7200 Fax: 82-2-558-5932 or 82-2-558-5934 China - Hong Kong SAR Tel: 852-2401-1200 Fax: 852-2401-3431 Malaysia - Kuala Lumpur Tel: 60-3-6201-9857 Fax: 60-3-6201-9859 China - Nanjing Tel: 86-25-8473-2460 Fax: 86-25-8473-2470 Malaysia - Penang Tel: 60-4-227-8870 Fax: 60-4-227-4068 China - Qingdao Tel: 86-532-8502-7355 Fax: 86-532-8502-7205 Philippines - Manila Tel: 63-2-634-9065 Fax: 63-2-634-9069 China - Shanghai Tel: 86-21-5407-5533 Fax: 86-21-5407-5066 Singapore Tel: 65-6334-8870 Fax: 65-6334-8850 China - Shenyang Tel: 86-24-2334-2829 Fax: 86-24-2334-2393 Taiwan - Hsin Chu Tel: 886-3-6578-300 Fax: 886-3-6578-370 China - Shenzhen Tel: 86-755-8203-2660 Fax: 86-755-8203-1760 Taiwan - Kaohsiung Tel: 886-7-213-7830 Fax: 886-7-330-9305 China - Wuhan Tel: 86-27-5980-5300 Fax: 86-27-5980-5118 Taiwan - Taipei Tel: 886-2-2500-6610 Fax: 886-2-2508-0102 China - Xian Tel: 86-29-8833-7252 Fax: 86-29-8833-7256 Thailand - Bangkok Tel: 66-2-694-1351 Fax: 66-2-694-1350 Italy - Milan Tel: 39-0331-742611 Fax: 39-0331-466781 Netherlands - Drunen Tel: 31-416-690399 Fax: 31-416-690340 Spain - Madrid Tel: 34-91-708-08-90 Fax: 34-91-708-08-91 UK - Wokingham Tel: 44-118-921-5869 Fax: 44-118-921-5820 China - Xiamen Tel: 86-592-2388138 Fax: 86-592-2388130 China - Zhuhai Tel: 86-756-3210040 Fax: 86-756-3210049 02/18/11 DS41391D-page 406  2011 Microchip Technology Inc.