PIC18F2221/2321/4221/4321
Family Data Sheet
Enhanced Flash Microcontrollers with
10-Bit A/D and nanoWatt Technology
© 2009 Microchip Technology Inc.
DS39689F
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and may be superseded by updates.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
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OTHERWISE, RELATED TO THE INFORMATION,
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Trademarks
The Microchip name and logo, the Microchip logo, dsPIC,
KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART,
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, Octopus, Omniscient Code
Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit,
PICtail, PIC32 logo, 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.
© 2009, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.
Printed on recycled paper.
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.
DS39689F-page 2
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
28/40/44-Pin Enhanced Flash Microcontrollers with
10-Bit A/D and nanoWatt Technology
Power-Managed Modes:
Peripheral Highlights (Continued):
•
•
•
•
•
•
•
•
• Master Synchronous Serial Port (MSSP) module
Supporting 3-Wire SPI (all 4 modes) and I2C™
Master and Slave modes
• Enhanced Addressable USART module:
- Supports RS-485, RS-232 and LIN/J2602
- Auto-wake-up on Start bit
- Auto-Baud Detect
• 10-Bit, up to 13-Channel Analog-to-Digital
Converter module (A/D):
- Auto-acquisition capability
- Conversion available during Sleep
• Dual Analog Comparators with Input Multiplexing
• Programmable 16-Level High/Low-Voltage
Detection (HLVD) module:
- Supports interrupt on High/Low-Voltage Detection
Run: CPU On, Peripherals On
Idle: CPU Off, Peripherals On
Sleep: CPU Off, Peripherals Off
Idle mode Currents Down to 2.5 μA Typical
Sleep mode Currents Down to 500 nA Typical
Timer1 Oscillator: 1.8 μA, 32 kHz, 2V Typical
Watchdog Timer: 1.6 μA, 2V Typical
Two-Speed Oscillator Start-up
Flexible Oscillator Structure:
• Four Crystal modes, up to 40 MHz
• 4x Phase Lock Loop (PLL) – Available for Crystal
and Internal Oscillators
• Two External RC modes, up to 4 MHz
• Two External Clock modes, up to 40 MHz
• Internal Oscillator Block:
- 8 user-selectable frequencies, from 31 kHz to
8 MHz
- Provides a complete range of clock speeds
from 31 kHz to 32 MHz when used with PLL
- User-tunable to compensate for frequency drift
• Secondary Oscillator using Timer1 @ 32 kHz
• Fail-Safe Clock Monitor
- Allows for safe shutdown if peripheral clock stops
Special Microcontroller Features:
• C Compiler Optimized Architecture:
- Optional extended instruction set designed to
optimize re-entrant code
• 100,000 Erase/Write Cycle Enhanced Flash
Program Memory Typical
• 1,000,000 Erase/Write Cycle Data EEPROM
Memory Typical
• Flash/Data EEPROM Retention: 100 Years Typical
• Self-Programmable under Software Control
• Priority Levels for Interrupts
• 8 x 8 Single-Cycle Hardware Multiplier
• Extended Watchdog Timer (WDT):
- Programmable period from 4 ms to 131s
• Single-Supply 5V In-Circuit Serial
Programming™ (ICSP™) via Two Pins
• In-Circuit Debug (ICD) via Two Pins
• Wide Operating Voltage Range: 2.0V to 5.5V
• Programmable Brown-out Reset (BOR) with
Software Enable Option)
Peripheral Highlights:
•
•
•
•
High-Current Sink/Source 25 mA/25 mA
Three Programmable External Interrupts
Four Input Change Interrupts
Up to 2 Capture/Compare/PWM (CCP) modules,
one with Auto-Shutdown (28-pin devices)
• Enhanced Capture/Compare/PWM (ECCP)
module (40/44-pin devices only):
- One, two or four PWM outputs
- Selectable polarity
- Programmable dead time
- Auto-shutdown and auto-restart
Program Memory
Device
PIC18F2221
PIC18F2321
PIC18F4221
PIC18F4321
Data Memory
Flash # Single-Word SRAM EEPROM
(bytes) Instructions (bytes) (bytes)
4K
8K
4K
8K
2048
4096
2048
4096
© 2009 Microchip Technology Inc.
512
512
512
512
256
256
256
256
MSSP
I/O
10-Bit
A/D (ch)
CCP/
ECCP
(PWM)
SPI
Master
I2C™
25
25
36
36
10
10
13
13
2/0
2/0
1/1
1/1
Y
Y
Y
Y
Y
Y
Y
Y
EUSART
-
Comp.
Timers
8/16-Bit
1
1
1
1
2
2
2
2
1/3
1/3
1/3
1/3
DS39689F-page 3
PIC18F2221/2321/4221/4321 FAMILY
Pin Diagrams
28-Pin SPDIP, SOIC, SSOP
1
2
3
4
5
6
7
8
9
10
11
12
13
14
PIC18F2221
PIC18F2321
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
VSS
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2
RC2/CCP1
RC3/SCK/SCL
28
27
26
25
24
23
22
21
20
19
18
17
16
15
RB7/KBI3/PGD
RB6//KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2
RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
VDD
VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
21
20
19
18
17
16
15
RB3/AN9/CCP2(1)
RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
VDD
VSS
RC7/RX/DT
RA1/AN1
RA0/AN0
MCLR/VPP/RE3
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
28-Pin QFN
28 27 26 25 24 23 22
1
2
3
4
5
6
7
PIC18F2221
PIC18F2321
8 9 10 11 12 13 14
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
VSS
OSC1/CLKI/RA7
OSC2/CLKO/RA6
Note 1:
DS39689F-page 4
RB3 is the alternate pin for CCP2 multiplexing.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
Pin Diagrams (Continued)
PIC18F4321
RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2
RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
VDD
VSS
RD7/PSP7/P1D
RD6/PSP6/P1C
RD5/PSP5/P1B
RD4/PSP4
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
44
43
42
41
40
39
38
37
36
35
34
1
2
3
4
5
6
7
8
9
10
11
PIC18F4221
PIC18F4321
33
32
31
30
29
28
27
26
25
24
23
OSC2/CLKO/RA6
OSC1/CLKI/RA7
VSS
VSS
VDD
VDD
RE2/CS/AN7
RE1/WR/AN6
RE0/RD/AN5
RA5/AN4/SS/HLVDIN/C2OUT
RA4/T0CKI/C1OUT
RB3/AN9/CCP2(1)
NC
RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RC7/RX/DT
RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D
VSS
VDD
VDD
RB0/INT0/FLT0/AN12
RB1/INT1/AN10
RB2/INT2/AN8
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
12
13
14
15
16
17
18
19
20
21
22
44-Pin QFN(2)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1/P1A
RC1/T1OSI/CCP2(1)
RC0/T1OSO/T13CKI
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
VDD
VSS
OSC1/CLKI/RA7
OSC2/CLKO/RA6
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2
RC2/CCP1/P1A
RC3/SCK/SCL
RD0/PSP0
RD1/PSP1
PIC18F4221
40-Pin PDIP
Note 1:
2:
RB3 is the alternate pin for CCP2 multiplexing.
For the QFN package, it is recommended that the bottom pad be connected to VSS.
© 2009 Microchip Technology Inc.
DS39689F-page 5
PIC18F2221/2321/4221/4321 FAMILY
Pin Diagrams (Continued)
44
43
42
41
40
39
38
37
36
35
34
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2
RD1/PSP1
RD0/PSP0
RC3/SCK/SCL
RC2/CCP1/P1A
RC1/T1OSI/CCP2(1)
NC
44-Pin TQFP
PIC18F4221
PIC18F4321
33
32
31
30
29
28
27
26
25
24
23
12
13
14
15
16
17
18
19
20
21
22
1
2
3
4
5
6
7
8
9
10
11
NC
RC0/T1OSO/T13CKI
OSC2/CLKO/RA6
OSC1/CLKI/RA7
VSS
VDD
RE2/CS/AN7
RE1/WR/AN6
RE0/RD/AN5
RA5/AN4/SS/HLVDIN/C2OUT
RA4/T0CKI/C1OUT
NC
NC
RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
MCLR/VPP/RE3
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RC7/RX/DT
RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D
VSS
VDD
RB0/INT0/FLT0/AN12
RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2(1)
Note
DS39689F-page 6
1:
RB3 is the alternate pin for CCP2 multiplexing.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 9
2.0 Guidelines for Getting Started with PIC18F Microcontrollers ..................................................................................................... 25
3.0 Oscillator Configurations ............................................................................................................................................................ 29
4.0 Power-Managed Modes ............................................................................................................................................................. 39
5.0 Reset .......................................................................................................................................................................................... 47
6.0 Memory Organization ................................................................................................................................................................. 59
7.0 Flash Program Memory.............................................................................................................................................................. 79
8.0 Data EEPROM Memory ............................................................................................................................................................. 89
9.0 8 x 8 Hardware Multiplier............................................................................................................................................................ 95
10.0 Interrupts .................................................................................................................................................................................... 97
11.0 I/O Ports ................................................................................................................................................................................... 111
12.0 Timer0 Module ......................................................................................................................................................................... 129
13.0 Timer1 Module ......................................................................................................................................................................... 133
14.0 Timer2 Module ......................................................................................................................................................................... 139
15.0 Timer3 Module ......................................................................................................................................................................... 141
16.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 145
17.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................ 153
18.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 167
19.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 211
20.0 10-Bit Analog-to-Digital Converter (A/D) Module ..................................................................................................................... 233
21.0 Comparator Module.................................................................................................................................................................. 243
22.0 Comparator Voltage Reference Module................................................................................................................................... 249
23.0 High/Low-Voltage Detect (HLVD)............................................................................................................................................. 253
24.0 Special Features of the CPU.................................................................................................................................................... 259
25.0 Instruction Set Summary .......................................................................................................................................................... 279
26.0 Development Support............................................................................................................................................................... 329
27.0 Electrical Characteristics .......................................................................................................................................................... 333
28.0 Packaging Information.............................................................................................................................................................. 373
Appendix A: Revision History............................................................................................................................................................. 385
Appendix B: Device Differences ........................................................................................................................................................ 386
Appendix C: Conversion Considerations ........................................................................................................................................... 387
Appendix D: Migration from Baseline to Enhanced Devices.............................................................................................................. 387
Appendix E: Migration From Mid-Range to Enhanced Devices ......................................................................................................... 388
Appendix F: Migration From High-End to Enhanced Devices............................................................................................................ 388
Index ................................................................................................................................................................................................. 389
The Microchip Web Site ..................................................................................................................................................................... 399
Customer Change Notification Service .............................................................................................................................................. 399
Customer Support .............................................................................................................................................................................. 399
Reader Response .............................................................................................................................................................................. 400
PIC18F2221/2321/4221/4321 Product Identification System ............................................................................................................ 401
© 2009 Microchip Technology Inc.
DS39689F-page 7
PIC18F2221/2321/4221/4321 FAMILY
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.
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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
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To determine if an errata sheet exists for a particular device, please check with one of the following:
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When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
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DS39689F-page 8
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
1.0
DEVICE OVERVIEW
This document contains device specific information for
the following devices:
• PIC18F2221
• PIC18LF2221
• PIC18F2321
• PIC18LF2321
• PIC18F4221
• PIC18LF4221
• PIC18F4321
• PIC18LF4321
This family offers the advantages of all PIC18 microcontrollers – namely, high computational performance at
an economical price – with the addition of highendurance, Enhanced Flash program memory. On top of
these features, the PIC18F2221/2321/4221/4321 family
introduces design enhancements that make these microcontrollers a logical choice for many high-performance,
power sensitive applications.
1.1
1.1.1
New Core Features
nanoWatt TECHNOLOGY
All of the devices in the PIC18F2221/2321/4221/4321
family incorporate a range of features that can significantly reduce power consumption during operation.
Key items include:
• Alternate Run Modes: By clocking the controller
from the Timer1 source or the internal oscillator
block, power consumption during code execution
can be reduced by as much as 90%.
• Multiple Idle Modes: The controller can also run
with its CPU core disabled but the peripherals still
active. In these states, power consumption can be
reduced even further, to as little as 4% of normal
operation requirements.
• On-the-Fly Mode Switching: The
power-managed modes are invoked by user code
during operation, allowing the user to incorporate
power-saving ideas into their application’s
software design.
• Low Consumption in Key Modules: The
power requirements for both Timer1 and the
Watchdog Timer are minimized. See
Section 27.0 “Electrical Characteristics” for
values.
© 2009 Microchip Technology Inc.
1.1.2
MULTIPLE OSCILLATOR OPTIONS
AND FEATURES
All of the devices in the PIC18F2221/2321/4221/4321
family offer ten different oscillator options, allowing
users a wide range of choices in developing application
hardware. These include:
• Four Crystal modes, using crystals or ceramic
resonators.
• Two External Clock modes, offering the option of
using two pins (oscillator input and a divide-by-4
clock output) or one pin (oscillator input, with the
second pin reassigned as general I/O).
• Two External RC Oscillator modes with the same
pin options as the External Clock modes.
• Two Internal Oscillator modes which provide
an 8 MHz clock and an INTRC source
(approximately 31 kHz), as well as a range of
6 user-selectable clock frequencies, between
125 kHz to 4 MHz, for a total of 8 clock frequencies.
One or both of the oscillator pins can be used for
general purpose I/O.
• A Phase Lock Loop (PLL) frequency multiplier,
available to both the high-speed crystal and
internal oscillator modes, which allows clock
speeds of up to 40 MHz. Used with the internal
oscillator, the PLL gives users a complete selection
of clock speeds, from 31 kHz to 32 MHz – all
without using an external crystal or clock circuit.
Besides its availability as a clock source, the internal
oscillator block provides a stable reference source that
gives the family additional features for robust
operation:
• Fail-Safe Clock Monitor: This option constantly
monitors the main clock source against a reference
signal provided by the internal oscillator. If a clock
failure occurs, the controller is switched to the
internal oscillator block, allowing for continued
low-speed operation or a safe application
shutdown.
• Two-Speed Start-up: This option allows the
internal oscillator to serve as the clock source
from Power-on Reset, or wake-up from Sleep
mode, until the primary clock source is available.
DS39689F-page 9
PIC18F2221/2321/4221/4321 FAMILY
1.2
Other Special Features
• Memory Endurance: The Enhanced Flash cells
for both program memory and data EEPROM are
rated to last for many thousands of erase/write
cycles – up to 100,000 for program memory and
1,000,000 for EEPROM. Data retention without
refresh is conservatively estimated to be greater
than 40 years.
• Self-Programmability: These devices can write to
their own program memory spaces under internal
software control. By using a bootloader routine,
located in the protected Boot Block at the top of
program memory, it becomes possible to create an
application that can update itself in the field.
• Extended Instruction Set: The PIC18F2221/
2321/4221/4321 family introduces an optional
extension to the PIC18 instruction set, which adds
8 new instructions and an Indexed Addressing
mode. This extension, enabled as a device configuration option, has been specifically designed
to optimize re-entrant application code originally
developed in high-level languages, such as C.
• Enhanced CCP Module: In PWM mode, this
module provides 1, 2 or 4 modulated outputs for
controlling half-bridge and full-bridge drivers.
Other features include auto-shutdown, for
disabling PWM outputs on interrupt or other select
conditions and auto-restart, to reactivate outputs
once the condition has cleared.
• Enhanced Addressable USART: This serial
communication module is capable of standard
RS-232 operation and provides support for the
LIN/J2602 bus protocol. Other enhancements
include automatic baud rate detection and a 16-bit
Baud Rate Generator for improved resolution.
When the microcontroller is using the internal
oscillator block, the EUSART provides stable
operation for applications that talk to the outside
world without using an external crystal (or its
accompanying power requirement).
• 10-Bit A/D Converter: This module incorporates
programmable acquisition time, allowing for a
channel to be selected and a conversion to be
initiated without waiting for a sampling period and
thus, reducing code overhead.
• Extended Watchdog Timer (WDT): This
Enhanced version incorporates a 16-bit prescaler,
allowing an extended time-out range that is stable
across operating voltage and temperature. See
Section 27.0 “Electrical Characteristics” for
time-out periods.
DS39689F-page 10
1.3
Details on Individual Family
Members
Devices in the PIC18F2221/2321/4221/4321 family are
available in 28-pin and 40/44-pin packages. Block
diagrams for the two groups are shown in Figure 1-1 and
Figure 1-2.
The devices are differentiated from each other in five
ways:
1.
2.
3.
4.
5.
Flash program memory (4 Kbytes for
PIC18F2221/4221 devices, 8 Kbytes for
PIC18F2321/4321).
A/D channels (10 for 28-pin devices, 13 for
40/44-pin devices).
I/O ports (3 bidirectional ports on 28-pin devices,
5 bidirectional ports on 40/44-pin devices).
CCP and Enhanced CCP implementation
(28-pin devices have 2 standard CCP
modules, 40/44-pin devices have one standard
CCP module and one ECCP module).
Parallel Slave Port (present only on 40/44-pin
devices).
All other features for devices in this family are identical.
These are summarized in Table 1-1.
The pinouts for all devices are listed in Table 1-2 and
Table 1-3.
Like all Microchip PIC18 devices, members of the
PIC18F2221/2321/4221/4321 family are available as
both standard and low-voltage devices. Standard
devices with Enhanced Flash memory, designated with
an “F” in the part number (such as PIC18F2321),
accommodate an operating VDD range of 4.2V to 5.5V.
Low-voltage parts, designated by “LF” (such as
PIC18LF2321), function over an extended VDD range
of 2.0V to 5.5V.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-1:
DEVICE FEATURES
Features
PIC18F2221
PIC18F2321
PIC18F4221
PIC18F4321
Operating Frequency
DC – 40 MHz
DC – 40 MHz
DC – 40 MHz
DC – 40 MHz
Program Memory (Bytes)
4096
8192
4096
8192
Program Memory (Instructions)
2048
4096
2048
4096
Data Memory (Bytes)
512
512
512
512
Data EEPROM Memory (Bytes)
256
256
256
256
Interrupt Sources
19
19
20
20
Ports A, B, C, (E)
Ports A, B, C, (E)
4
4
I/O Ports
Timers
Ports A, B, C, D, E Ports A, B, C, D, E
4
4
Capture/Compare/PWM Modules
2
2
1
1
Enhanced Capture/Compare/
PWM Modules
0
0
1
1
Serial Communications
MSSP,
MSSP,
MSSP,
Enhanced USART Enhanced USART Enhanced USART
MSSP,
Enhanced USART
Parallel Communications (PSP)
No
No
Yes
Yes
10-bit Analog-to-Digital Module
10 Input Channels
10 Input Channels
13 Input Channels
13 Input Channels
Resets (and Delays)
POR, BOR,
POR, BOR,
POR, BOR,
RESET Instruction, RESET Instruction, RESET Instruction,
Stack Full,
Stack Full,
Stack Full,
Stack Underflow
Stack Underflow
Stack Underflow
(PWRT, OST),
(PWRT, OST),
(PWRT, OST),
MCLR (optional),
MCLR (optional),
MCLR (optional),
WDT
WDT
WDT
POR, BOR,
RESET Instruction,
Stack Full,
Stack Underflow
(PWRT, OST),
MCLR (optional),
WDT
Programmable Low-Voltage
Detect
Programmable Brown-out Reset
Instruction Set
Packages
© 2009 Microchip Technology Inc.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
75 Instructions;
83 with Extended
Instruction Set
enabled
75 Instructions;
83 with Extended
Instruction Set
enabled
75 Instructions;
83 with Extended
Instruction Set
enabled
75 Instructions;
83 with Extended
Instruction Set
enabled
28-pin SPDIP
28-pin SOIC
28-pin SSOP
28-pin QFN
28-pin SPDIP
28-pin SOIC
28-pin SSOP
28-pin QFN
40-pin PDIP
44-pin QFN
44-pin TQFP
40-pin PDIP
44-pin QFN
44-pin TQFP
DS39689F-page 11
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 1-1:
PIC18F2221/2321 (28-PIN) BLOCK DIAGRAM
Data Bus
Table Pointer
20
Address Latch
PCU PCH PCL
Program Counter
31 Level Stack
12
Data Address
4
BSR
Address Latch
Program Memory
(4 Kbytes)
STKPTR
12
FSR0
FSR1
FSR2
Data Latch
8
Instruction Bus
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
OSC2/CLKO(3)/RA6
OSC1/CLKI(3)/RA7
Data Memory
(3.9 Kbytes)
PCLATU PCLATH
21
PORTA
Data Latch
8
8
inc/dec logic
4
Access
Bank
12
PORTB
RB0/INT0/FLT0/AN12
RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2(1)
RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
inc/dec
logic
Table Latch
Address
Decode
ROM Latch
IR
8
State Machine
Control Signals
Instruction
Decode &
Control
PRODH PRODL
3
Internal
Oscillator
Block
OSC2(3)
T1OSI
INTRC
Oscillator
T1OSO
8 MHz
Oscillator
MCLR(2)
VDD, VSS
Power-up
Timer
W
8
ALU
Power-on
Reset
Watchdog
Timer
Brown-out
Reset
Fail-Safe
Clock Monitor
Single-Supply
Programming
In-Circuit
Debugger
8
Precision
Band Gap
Reference
PORTE
MCLR/VPP/RE3(2)
BOR
LVD
Data
EEPROM
Timer0
Timer1
Timer2
Timer3
Comparator
CCP1
CCP2
MSSP
EUSART
ADC
10-Bit
Note
8
8
8
Oscillator
Start-up Timer
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
8
BITOP
8
OSC1(3)
PORTC
8 x 8 Multiply
1:
CCP2 is multiplexed with RC1 when Configuration bit, CCP2MX, is set, or RB3 when CCP2MX is not set.
2:
RE3 is only available when MCLR functionality is disabled.
3:
OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.
Refer to Section 3.0 “Oscillator Configurations” for additional information.
DS39689F-page 12
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 1-2:
PIC18F4221/4321 (40/44-PIN) BLOCK DIAGRAM
Data Bus
Table Pointer
Data Memory
(3.9 Kbytes)
PCLATU PCLATH
21
20
Address Latch
PCU PCH PCL
Program Counter
12
Data Address
31 Level Stack
4
BSR
Address Latch
Program Memory
(8 Kbytes)
STKPTR
12
FSR0
FSR1
FSR2
Data Latch
8
Instruction Bus
RA0/AN0
RA1/AN1
RA2/AN2/VREF-/CVREF
RA3/AN3/VREF+
RA4/T0CKI/C1OUT
RA5/AN4/SS/HLVDIN/C2OUT
OSC2/CLKO(3)/RA6
OSC1/CLKI(3)/RA7
Data Latch
8
8
inc/dec logic
PORTA
PORTB
RB0/INT0/FLT0/AN12
RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2(1)
RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
4
Access
Bank
12
inc/dec
logic
Table Latch
PORTC
Address
Decode
ROM Latch
RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2(1)
RC2/CCP1/P1A
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT
IR
8
State Machine
Control Signals
Instruction
Decode &
Control
PRODH PRODL
3
8 x 8 Multiply
8
W
BITOP
8
Internal
Oscillator
Block
OSC1(3)
OSC2(3)
T1OSI
INTRC
Oscillator
T1OSO
8 MHz
Oscillator
Power-up
Timer
Brown-out
Reset
Fail-Safe
Clock Monitor
Single-Supply
Programming
In-Circuit
Debugger
MCLR(2)
VDD, VSS
ALU
8
PORTE
Precision
Band Gap
Reference
BOR
LVD
Data
EEPROM
Timer0
Timer1
Timer2
Timer3
Comparator
ECCP1
CCP2
MSSP
EUSART
ADC
10-Bit
Note
RD0/PSP0:RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D
8
8
8
Oscillator
Start-up Timer
Power-on
Reset
Watchdog
Timer
8
PORTD
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
MCLR/VPP/RE3(2)
1:
CCP2 is multiplexed with RC1 when Configuration bit, CCP2MX, is set, or RB3 when CCP2MX is not set.
2:
RE3 is only available when MCLR functionality is disabled.
3:
OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.
Refer to Section 3.0 “Oscillator Configurations” for additional information.
© 2009 Microchip Technology Inc.
DS39689F-page 13
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-2:
PIC18F2221/2321 PINOUT I/O DESCRIPTIONS
Pin Number
Pin Name
MCLR/VPP/RE3
MCLR
Pin Buffer
SPDIP,
Type
Type
SOIC, QFN
SSOP
1
26
VPP
RE3
OSC1/CLKI/RA7
OSC1
9
6
I
ST
P
I
ST
Analog
O
—
CLKO
O
—
RA6
I/O
TTL
RA7
OSC2/CLKO/RA6
OSC2
10
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage input.
Digital input.
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode; CMOS otherwise.
I CMOS
External clock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
I/O
TTL
General purpose I/O pin.
I
CLKI
Description
7
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC, EC and INTIO modes, OSC2 pin outputs CLKO
which has one-fourth the frequency of OSC1 and denotes
the instruction cycle rate.
General purpose I/O pin.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
DS39689F-page 14
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-2:
PIC18F2221/2321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
Pin Buffer
SPDIP,
SOIC, QFN Type Type
SSOP
Description
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
2
RA1/AN1
RA1
AN1
3
RA2/AN2/VREF-/CVREF
RA2
AN2
VREFCVREF
4
RA3/AN3/VREF+
RA3
AN3
VREF+
5
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
6
RA5/AN4/SS/HLVDIN/
C2OUT
RA5
AN4
SS
HLVDIN
C2OUT
7
27
I/O
TTL
I Analog
Digital I/O.
Analog Input 0.
I/O
TTL
I Analog
Digital I/O.
Analog Input 1.
I/O
TTL
I Analog
I Analog
O Analog
Digital I/O.
Analog Input 2.
A/D reference voltage (low) input.
Comparator reference voltage output.
I/O
TTL
I Analog
I Analog
Digital I/O.
Analog Input 3.
A/D reference voltage (high) input.
I/O
I
O
Digital I/O. Open-collector output.
Timer0 external clock input.
Comparator 1 output.
28
1
2
3
ST
ST
—
4
I/O
TTL
I Analog
I
TTL
I Analog
O
—
Digital I/O.
Analog Input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.
RA6
See the OSC2/CLKO/RA6 pin.
RA7
See the OSC1/CLKI/RA7 pin.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
I2C = ST with I2C™ or SMB levels
O
= Output
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc.
DS39689F-page 15
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-2:
PIC18F2221/2321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
Pin Buffer
SPDIP,
SOIC, QFN Type Type
SSOP
Description
PORTB is a bidirectional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.
RB0/INT0/FLT0/AN12
RB0
INT0
FLT0
AN12
21
RB1/INT1/AN10
RB1
INT1
AN10
22
RB2/INT2/AN8
RB2
INT2
AN8
23
RB3/AN9/CCP2
RB3
AN9
CCP2(2)
24
RB4/KBI0/AN11
RB4
KBI0
AN11
25
RB5/KBI1/PGM
RB5
KBI1
PGM
26
RB6/KBI2/PGC
RB6
KBI2
PGC
27
RB7/KBI3/PGD
RB7
KBI3
PGD
28
18
I/O
TTL
I
ST
I
ST
I Analog
Digital I/O.
External Interrupt 0.
PWM Fault input for CCP1.
Analog Input 12.
I/O
TTL
I
ST
I Analog
Digital I/O.
External Interrupt 1.
Analog Input 10.
I/O
TTL
I
ST
I Analog
Digital I/O.
External Interrupt 2.
Analog Input 8.
I/O
TTL
I Analog
I/O
ST
Digital I/O.
Analog Input 9.
Capture 2 input/Compare 2 output/PWM2 output.
I/O
TTL
I
TTL
I Analog
Digital I/O.
Interrupt-on-change pin.
Analog Input 11.
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP™ programming enable pin.
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming clock pin.
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming data pin.
19
20
21
22
23
24
25
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
DS39689F-page 16
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-2:
PIC18F2221/2321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
Pin Buffer
SPDIP,
Type
Type
SOIC, QFN
SSOP
Description
PORTC is a bidirectional I/O port.
RC0/T1OSO/T13CKI
RC0
T1OSO
T13CKI
11
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2(1)
12
RC2/CCP1
RC2
CCP1
13
RC3/SCK/SCL
RC3
SCK
SCL
14
RC4/SDI/SDA
RC4
SDI
SDA
15
RC5/SDO
RC5
SDO
16
RC6/TX/CK
RC6
TX
CK
17
RC7/RX/DT
RC7
RX
DT
18
8
I/O
O
I
ST
—
ST
Digital I/O.
Timer1 oscillator analog output.
Timer1/Timer3 external clock input.
9
I/O
ST
I Analog
I/O
ST
Digital I/O.
Timer1 oscillator analog input.
Capture 2 input/Compare 2 output/PWM2 output.
I/O
I/O
ST
ST
Digital I/O.
Capture 1 input/Compare 1 output/PWM1 output.
I/O
I/O
I/O
ST
ST
I2C
Digital I/O.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I2C™ mode.
I/O
I
I/O
ST
ST
I2C
Digital I/O.
SPI data in.
I2C data I/O.
I/O
O
ST
—
Digital I/O.
SPI data out.
I/O
O
I/O
ST
—
ST
Digital I/O.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).
I/O
I
I/O
ST
ST
ST
Digital I/O.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).
10
11
12
13
14
15
RE3
—
—
—
—
See MCLR/VPP/RE3 pin.
VSS
8, 19
5, 16
P
—
Ground reference for logic and I/O pins.
VDD
20
17
P
—
Positive supply for logic and I/O pins.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc.
DS39689F-page 17
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-3:
PIC18F4221/4321 PINOUT I/O DESCRIPTIONS
Pin Name
MCLR/VPP/RE3
MCLR
Pin Number
PDIP
1
Pin Buffer
Type
Type
QFN TQFP
18
18
VPP
RE3
OSC1/CLKI/RA7
OSC1
13
32
ST
P
I
ST
I
Analog
30
CLKI
I
RA7
OSC2/CLKO/RA6
OSC2
I
I/O
14
33
Description
Master Clear (input) or programming voltage (input).
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage input.
Digital input.
Oscillator crystal or external clock input.
Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode;
analog otherwise.
Analog
External clock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
TTL
General purpose I/O pin.
31
O
—
CLKO
O
—
RA6
I/O
TTL
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal
or resonator in Crystal Oscillator mode.
In RC, EC and INTIO modes, OSC2 pin outputs
CLKO which has one-fourth the frequency of OSC1
and denotes the instruction cycle rate.
General purpose I/O pin.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
DS39689F-page 18
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-3:
PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
PDIP
Pin Buffer
Type
Type
QFN TQFP
Description
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
2
RA1/AN1
RA1
AN1
3
RA2/AN2/VREF-/CVREF
RA2
AN2
VREFCVREF
4
RA3/AN3/VREF+
RA3
AN3
VREF+
5
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
6
RA5/AN4/SS/HLVDIN/
C2OUT
RA5
AN4
SS
HLVDIN
C2OUT
7
19
20
21
22
23
24
19
I/O
I
TTL
Analog
Digital I/O.
Analog Input 0.
I/O
I
TTL
Analog
Digital I/O.
Analog Input 1.
I/O
I
I
O
TTL
Analog
Analog
Analog
Digital I/O.
Analog Input 2.
A/D reference voltage (low) input.
Comparator reference voltage output.
I/O
I
I
TTL
Analog
Analog
Digital I/O.
Analog Input 3.
A/D reference voltage (high) input.
I/O
I
O
ST
ST
—
I/O
I
I
I
O
TTL
Analog
TTL
Analog
—
20
21
22
23
Digital I/O.
Timer0 external clock input.
Comparator 1 output.
24
Digital I/O.
Analog Input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.
RA6
See the OSC2/CLKO/RA6 pin.
RA7
See the OSC1/CLKI/RA7 pin.
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc.
DS39689F-page 19
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-3:
PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
PDIP
Pin Buffer
Type
Type
QFN TQFP
Description
PORTB is a bidirectional I/O port. PORTB can be
software programmed for internal weak pull-ups on all
inputs.
RB0/INT0/FLT0/AN12
RB0
INT0
FLT0
AN12
33
RB1/INT1/AN10
RB1
INT1
AN10
34
RB2/INT2/AN8
RB2
INT2
AN8
35
RB3/AN9/CCP2
RB3
AN9
CCP2(2)
36
RB4/KBI0/AN11
RB4
KBI0
AN11
37
RB5/KBI1/PGM
RB5
KBI1
PGM
38
RB6/KBI2/PGC
RB6
KBI2
PGC
39
RB7/KBI3/PGD
RB7
KBI3
PGD
40
9
10
11
12
14
15
16
17
8
I/O
I
I
I
TTL
ST
ST
Analog
Digital I/O.
External Interrupt 0.
PWM Fault input for Enhanced CCP1.
Analog input 12.
I/O
I
I
TTL
ST
Analog
Digital I/O.
External Interrupt 1.
Analog Input 10.
I/O
I
I
TTL
ST
Analog
Digital I/O.
External Interrupt 2.
Analog Input 8.
I/O
I
I/O
TTL
Analog
ST
Digital I/O.
Analog Input 9.
Capture 2 input/Compare 2 output/PWM2 output.
I/O
I
I
TTL
TTL
Analog
Digital I/O.
Interrupt-on-change pin.
Analog input 11.
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP™ Programming enable pin.
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming
clock pin.
I/O
I
I/O
TTL
TTL
ST
Digital I/O.
Interrupt-on-change pin.
In-circuit debugger and ICSP programming
data pin.
9
10
11
14
15
16
17
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
DS39689F-page 20
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-3:
PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Name
Pin Number
PDIP
Pin Buffer
Type
Type
QFN TQFP
Description
PORTC is a bidirectional I/O port.
RC0/T1OSO/T13CKI
RC0
T1OSO
T13CKI
15
RC1/T1OSI/CCP2
RC1
T1OSI
CCP2(1)
16
RC2/CCP1/P1A
RC2
CCP1
P1A
17
RC3/SCK/SCL
RC3
SCK
18
34
35
36
37
32
23
RC5/SDO
RC5
SDO
24
RC6/TX/CK
RC6
TX
CK
25
RC7/RX/DT
RC7
RX
DT
26
42
43
44
1
ST
—
ST
Digital I/O.
Timer1 oscillator analog output.
Timer1/Timer3 external clock input.
I/O
I
I/O
ST
CMOS
ST
Digital I/O.
Timer1 oscillator analog input.
Capture 2 input/Compare 2 output/PWM2 output.
I/O
I/O
O
ST
ST
—
Digital I/O.
Capture 1 input/Compare 1 output/PWM1 output.
Enhanced CCP1 output.
I/O
I/O
ST
ST
I/O
I2C
Digital I/O.
Synchronous serial clock input/output for
SPI mode.
Synchronous serial clock input/output for I2C™
mode.
I/O
I
I/O
ST
ST
I2C
Digital I/O.
SPI data in.
I2C data I/O.
I/O
O
ST
—
Digital I/O.
SPI data out.
I/O
O
I/O
ST
—
ST
Digital I/O.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).
I/O
I
I/O
ST
ST
ST
Digital I/O.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).
35
36
37
SCL
RC4/SDI/SDA
RC4
SDI
SDA
I/O
O
I
42
43
44
1
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc.
DS39689F-page 21
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-3:
Pin Name
PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
PDIP
Pin Buffer
Type
Type
QFN TQFP
Description
PORTD is a bidirectional I/O port or a Parallel Slave
Port (PSP) for interfacing to a microprocessor port.
These pins have TTL input buffers when the PSP
module is enabled.
RD0/PSP0
RD0
PSP0
19
RD1/PSP1
RD1
PSP1
20
RD2/PSP2
RD2
PSP2
21
RD3/PSP3
RD3
PSP3
22
RD4/PSP4
RD4
PSP4
27
RD5/PSP5/P1B
RD5
PSP5
P1B
28
RD6/PSP6/P1C
RD6
PSP6
P1C
29
RD7/PSP7/P1D
RD7
PSP7
P1D
30
38
39
40
41
2
3
4
5
38
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
I/O
I/O
ST
TTL
Digital I/O.
Parallel Slave Port data.
I/O
I/O
O
ST
TTL
—
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
I/O
I/O
O
ST
TTL
—
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
I/O
I/O
O
ST
TTL
—
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
39
40
41
2
3
4
5
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
DS39689F-page 22
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 1-3:
Pin Name
PIC18F4221/4321 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
PDIP
Pin Buffer
Type
Type
QFN TQFP
Description
PORTE is a bidirectional I/O port.
RE0/RD/AN5
RE0
RD
8
25
25
AN5
RE1/WR/AN6
RE1
WR
9
26
10
27
—
I
Analog
I/O
I
ST
TTL
I
Analog
I/O
I
ST
TTL
I
Analog
Digital I/O.
Read control for Parallel Slave Port
(see also WR and CS pins).
Analog Input 5.
Digital I/O.
Write control for Parallel Slave Port
(see CS and RD pins).
Analog Input 6.
27
AN7
RE3
ST
TTL
26
AN6
RE2/CS/AN7
RE2
CS
I/O
I
Digital I/O.
Chip Select control for Parallel Slave Port
(see related RD and WR).
Analog Input 7.
—
—
—
See MCLR/VPP/RE3 pin.
6, 29
P
—
Ground reference for logic and I/O pins.
7, 8, 7, 28
28, 29
P
—
Positive supply for logic and I/O pins.
—
—
No Connect.
—
VSS
12, 31 6, 30,
31
VDD
11, 32
NC
—
13
12, 13,
33, 34
Legend: TTL = TTL compatible input
CMOS = CMOS compatible input or output
ST = Schmitt Trigger input with CMOS levels
I
= Input
P = Power
O
= Output
I2C = ST with I2C™ or SMB levels
Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.
2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.
© 2009 Microchip Technology Inc.
DS39689F-page 23
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 24
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
• All VDD and VSS pins
(see Section 2.2 “Power Supply Pins”)
• All AVDD and AVSS pins, regardless of whether or
not the analog device features are used
(see Section 2.2 “Power Supply Pins”)
• MCLR pin
(see Section 2.3 “Master Clear (MCLR) Pin”)
R1
R2
MCLR
VDD
C1
Additionally, the following pins may be required:
• VREF+/VREF- pins used when external voltage
reference for analog modules is implemented
Note:
The AVDD and AVSS pins must always be
connected, regardless of whether any of
the analog modules are being used.
C3(1)
PIC18FXXXX
VSS
C6(1)
VSS
VDD
C5(1)
These pins must also be connected if they are being
used in the end application:
• PGC/PGD pins used for In-Circuit Serial
Programming™ (ICSP™) and debugging purposes
(see Section 2.4 “ICSP Pins”)
• OSCI and OSCO pins when an external oscillator
source is used
(see Section 2.5 “External Oscillator Pins”)
VSS
VDD
VSS
The following pins must always be connected:
C2(1)
VDD
Getting started with the PIC18F2221/2321/4221/4321
family family of 8-bit microcontrollers requires attention
to a minimal set of device pin connections before
proceeding with development.
RECOMMENDED
MINIMUM CONNECTIONS
VDD
Basic Connection Requirements
FIGURE 2-1:
AVSS
2.1
GUIDELINES FOR GETTING
STARTED WITH PIC18F
MICROCONTROLLERS
AVDD
2.0
C4(1)
Key (all values are recommendations):
C1 through C6: 0.1 μF, 20V ceramic
C7: 10 μF, 16V tantalum or ceramic
R1: 10 kΩ
R2: 100Ω to 470Ω
Note 1:
The example shown is for a PIC18F device
with five VDD/VSS and AVDD/AVSS pairs.
Other devices may have more or less pairs;
adjust the number of decoupling capacitors
appropriately.
The minimum mandatory connections are shown in
Figure 2-1.
© 2009 Microchip Technology Inc.
DS39689F-page 25
PIC18F2221/2321/4221/4321 FAMILY
2.2
2.2.1
Power Supply Pins
DECOUPLING CAPACITORS
The use of decoupling capacitors on every pair of
power supply pins, such as VDD, VSS, AVDD and
AVSS, is required.
Consider the following criteria when using decoupling
capacitors:
• Value and type of capacitor: A 0.1 μF (100 nF),
10-20V capacitor is recommended. The capacitor
should be a low-ESR device with a resonance
frequency in the range of 200 MHz and higher.
Ceramic capacitors are recommended.
• Placement on the printed circuit board: The
decoupling capacitors should be placed as close
to the pins as possible. It is recommended to
place the capacitors on the same side of the
board as the device. If space is constricted, the
capacitor can be placed on another layer on the
PCB using a via; however, ensure that the trace
length from the pin to the capacitor is no greater
than 0.25 inch (6 mm).
• Handling high-frequency noise: If the board is
experiencing high-frequency noise (upward of
tens of MHz), add a second ceramic type capacitor in parallel to the above described decoupling
capacitor. The value of the second capacitor can
be in the range of 0.01 μF to 0.001 μF. Place this
second capacitor next to each primary decoupling
capacitor. In high-speed circuit designs, consider
implementing a decade pair of capacitances as
close to the power and ground pins as possible
(e.g., 0.1 μF in parallel with 0.001 μF).
• Maximizing performance: On the board layout
from the power supply circuit, run the power and
return traces to the decoupling capacitors first,
and then to the device pins. This ensures that the
decoupling capacitors are first in the power chain.
Equally important is to keep the trace length
between the capacitor and the power pins to
a minimum, thereby reducing PCB trace
inductance.
2.2.2
TANK CAPACITORS
On boards with power traces running longer than six
inches in length, it is suggested to use a tank capacitor
for integrated circuits including microcontrollers to
supply a local power source. The value of the tank
capacitor should be determined based on the trace
resistance that connects the power supply source to
the device and the maximum current drawn by the
device in the application. In other words, select the tank
capacitor so that it meets the acceptable voltage sag at
the device. Typical values range from 4.7 μF to 47 μF.
DS39689F-page 26
2.3
Master Clear (MCLR) Pin
The MCLR pin provides two specific device
functions: device Reset, and device programming
and debugging. If programming and debugging are
not required in the end application, a direct
connection to VDD may be all that is required. The
addition of other components, to help increase the
application’s resistance to spurious Resets from
voltage sags, may be beneficial. A typical
configuration is shown in Figure 2-1. Other circuit
designs may be implemented depending on the
application’s requirements.
During programming and debugging, the resistance
and capacitance that can be added to the pin must
be considered. Device programmers and debuggers
drive the MCLR pin. Consequently, specific voltage
levels (VIH and VIL) and fast signal transitions must
not be adversely affected. Therefore, specific values
of R1 and C1 will need to be adjusted based on the
application and PCB requirements. For example, it is
recommended that the capacitor, C1, be isolated
from the MCLR pin during programming and
debugging operations by using a jumper (Figure 2-2).
The jumper is replaced for normal run-time
operations.
Any components associated with the MCLR pin
should be placed within 0.25 inch (6 mm) of the pin.
FIGURE 2-2:
EXAMPLE OF MCLR PIN
CONNECTIONS
VDD
R1
R2
JP
MCLR
PIC18FXXXX
C1
Note 1:
R1 ≤ 10 kΩ is recommended. A suggested
starting value is 10 kΩ. Ensure that the
MCLR pin VIH and VIL specifications are met.
2:
R2 ≤ 470Ω will limit any current flowing into
MCLR from the external capacitor, C, in the
event of MCLR pin breakdown, due to
Electrostatic Discharge (ESD) or Electrical
Overstress (EOS). Ensure that the MCLR pin
VIH and VIL specifications are met.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
2.4
ICSP Pins
The PGC and PGD pins are used for In-Circuit Serial
Programming (ICSP) and debugging purposes. It is
recommended to keep the trace length between the
ICSP connector and the ICSP pins on the device as
short as possible. If the ICSP connector is expected to
experience an ESD event, a series resistor is recommended, with the value in the range of a few tens of
ohms, not to exceed 100Ω.
Pull-up resistors, series diodes and capacitors on the
PGC and PGD pins are not recommended as they will
interfere with the programmer/debugger communications to the device. If such discrete components
are an application requirement, they should be removed
from the circuit during programming and debugging.
Alternatively, refer to the AC/DC characteristics and
timing requirements information in the respective device
Flash programming specification for information on
capacitive loading limits and pin input voltage high (VIH)
and input low (VIL) requirements.
Use a grounded copper pour around the oscillator
circuit to isolate it from surrounding circuits. The
grounded copper pour should be routed directly to the
MCU ground. Do not run any signal traces or power
traces inside the ground pour. Also, if using a
two-sided board, avoid any traces on the other side of
the board where the crystal is placed. A suggested
layout is shown in Figure 2-3.
For additional information and design guidance on
oscillator circuits, please refer to these Microchip
Application Notes, available at the corporate web site
(www.microchip.com):
• AN826, “Crystal Oscillator Basics and Crystal
Selection for rfPIC™ and PICmicro® Devices”
• AN849, “Basic PICmicro® Oscillator Design”
• AN943, “Practical PICmicro® Oscillator Analysis
and Design”
• AN949, “Making Your Oscillator Work”
FIGURE 2-3:
For device emulation, ensure that the “Communication
Channel Select” (i.e., PGC/PGD pins) programmed
into the device matches the physical connections for
the ICSP to the MPLAB® ICD 2, MPLAB ICD 3 or REAL
ICE™ emulator.
Main Oscillator
13
For more information on the ICD 2, ICD 3 and REAL
ICE emulator connection requirements, refer to the
following documents that are available on the
Microchip web site.
• “MPLAB® ICD 2 In-Circuit Debugger User’s
Guide” (DS51331)
• “Using MPLAB® ICD 2” (poster) (DS51265)
• “MPLAB® ICD 2 Design Advisory” (DS51566)
• “Using MPLAB® ICD 3” (poster) (DS51765)
• “MPLAB® ICD 3 Design Advisory” (DS51764)
• “MPLAB® REAL ICE™ In-Circuit Emulator User’s
Guide” (DS51616)
• “Using MPLAB® REAL ICE™ In-Circuit Emulator”
(poster) (DS51749)
2.5
External Oscillator Pins
SUGGESTED PLACEMENT
OF THE OSCILLATOR
CIRCUIT
Guard Ring
14
15
Guard Trace
Secondary
Oscillator
16
17
18
19
20
2.6
Unused I/Os
Unused I/O pins should be configured as outputs and
driven to a logic low state. Alternatively, connect a 1 kΩ
to 10 kΩ resistor to VSS on unused pins and drive the
output to logic low.
Many microcontrollers have options for at least two
oscillators: a high-frequency primary oscillator and a
low-frequency
secondary
oscillator
(refer to
Section 3.0 “Oscillator Configurations” for details).
The oscillator circuit should be placed on the same
side of the board as the device. Place the oscillator
circuit close to the respective oscillator pins with no
more than 0.5 inch (12 mm) between the circuit
components and the pins. The load capacitors should
be placed next to the oscillator itself, on the same side
of the board.
© 2009 Microchip Technology Inc.
DS39689F-page 27
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 28
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
3.0
OSCILLATOR
CONFIGURATIONS
3.1
Oscillator Types
The PIC18F2221/2321/4221/4321 family of devices
can be operated in ten different oscillator modes. The
user can program the Configuration bits, FOSC,
in Configuration Register 1H to select one of these ten
modes:
1.
2.
3.
4.
LP
XT
HS
HSPLL
Low-Power Crystal
Crystal/Resonator
High-Speed Crystal/Resonator
High-Speed Crystal/Resonator
with PLL enabled
5. RC
External Resistor/Capacitor with
FOSC/4 output on RA6
6. RCIO
External Resistor/Capacitor with I/O
on RA6
7. INTIO1 Internal Oscillator with FOSC/4 output
on RA6 and I/O on RA7
8. INTIO2 Internal Oscillator with I/O on RA6
and RA7
9. EC
External Clock with FOSC/4 output
10. ECIO
External Clock with I/O on RA6
3.2
Crystal Oscillator/Ceramic
Resonators
In XT, LP, HS or HSPLL Oscillator modes, a crystal or
ceramic resonator is connected to the OSC1 and
OSC2 pins to establish oscillation. Figure 3-1 shows
the pin connections.
The oscillator design requires the use of a parallel cut
crystal.
Note:
Use of a series cut crystal may give a
frequency out of the crystal manufacturer’s
specifications.
FIGURE 3-1:
C1(1)
CRYSTAL/CERAMIC
RESONATOR OPERATION
(XT, LP, HS OR HSPLL
CONFIGURATION)
OSC1
XTAL
RF(3)
Sleep
RS(2)
C2(1)
To
Internal
Logic
PIC18FXXXX
OSC2
Note 1:
See Table 3-1 and Table 3-2 for initial values of
C1 and C2.
2:
A series resistor (RS) may be required for AT
strip cut crystals.
3:
RF varies with the oscillator mode chosen.
TABLE 3-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Typical Capacitor Values Used:
Mode
Freq
OSC1
OSC2
XT
3.58 MHz
22 pF
22 pF
Capacitor values are for design guidance only.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
VDD and temperature range for the application. Refer
to the following application notes for oscillator specific
information:
• AN588, “PIC® Microcontroller Oscillator Design
Guide”
• AN826, “Crystal Oscillator Basics and Crystal
Selection for rfPIC® and PIC® Devices”
• AN849, “Basic PIC® Oscillator Design”
• AN943, “Practical PIC® Oscillator Analysis and
Design”
• AN949, “Making Your Oscillator Work”
See the notes following Table 3-2 for additional
information.
Note:
© 2009 Microchip Technology Inc.
When using resonators with frequencies
above 3.5 MHz, the use of HS mode,
rather than XT mode, is recommended.
HS mode may be used at any VDD for
which the controller is rated. If HS is
selected, it is possible that the gain of the
oscillator will overdrive the resonator.
Therefore, a series resistor may be placed
between the OSC2 pin and the resonator.
As a good starting point, the
recommended value of RS is 330Ω.
DS39689F-page 29
PIC18F2221/2321/4221/4321 FAMILY
TABLE 3-2:
Osc Type
CAPACITOR SELECTION FOR
QUARTZ CRYSTALS
Crystal
Freq
Typical Capacitor Values
Tested:
C1
C2
LP
32 kHz
22 pF
22 pF
XT
1 MHz
4 MHz
22 pF
22 pF
22 pF
22 pF
HS
4 MHz
10 MHz
20 MHz
25 MHz
22 pF
22 pF
22 pF
22 pF
22 pF
22 pF
22 pF
22 pF
An external clock source may also be connected to the
OSC1 pin in the HS mode, as shown in Figure 3-2.
When operated in this mode, parameters D033 and
D043 apply.
FIGURE 3-2:
EXTERNAL CLOCK INPUT
OPERATION (HS OSC
CONFIGURATION)
OSC1
Clock from
Ext. System
PIC18FXXXX
Open
(HS Mode)
OSC2
Capacitor values are for design guidance only.
Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
VDD and temperature range for the application. Refer
to the following application notes for oscillator specific
information:
3.3
• AN588, “PIC® Microcontroller Oscillator Design
Guide”
• AN826, “Crystal Oscillator Basics and Crystal
Selection for rfPIC® and PIC® Devices”
• AN849, “Basic PIC® Oscillator Design”
• AN943, “Practical PIC® Oscillator Analysis and
Design”
• AN949, “Making Your Oscillator Work”
In the EC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic. Figure 3-3 shows the pin connections for the EC
Oscillator mode.
See the notes following this table for additional
information.
Note 1: Higher capacitance increases the stability
of the oscillator but also increases the
start-up time.
2: When operating below 3V VDD, or when
using certain ceramic resonators at any
voltage, it may be necessary to use the
HS mode or switch to a crystal oscillator.
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate
values
of
external
components.
4: Rs may be required to avoid overdriving
crystals with low drive level specification.
5: Always verify oscillator performance over
the VDD and temperature range that is
expected for the application.
DS39689F-page 30
External Clock Input
The EC and ECIO Oscillator modes require an external
clock source to be connected to the OSC1 pin. There is
no oscillator start-up time required after a Power-on
Reset or after an exit from Sleep mode.
FIGURE 3-3:
EXTERNAL CLOCK
INPUT OPERATION
(EC CONFIGURATION)
OSC1/CLKI
Clock from
Ext. System
PIC18FXXXX
FOSC/4
OSC2/CLKO
The ECIO Oscillator mode functions like the EC mode,
except that the OSC2 pin becomes an additional
general purpose I/O pin. The I/O pin becomes bit 6 of
PORTA (RA6). Figure 3-4 shows the pin connections
for the ECIO Oscillator mode. When operated in this
mode, parameters D033A and D043A apply.
FIGURE 3-4:
EXTERNAL CLOCK
INPUT OPERATION
(ECIO CONFIGURATION)
OSC1/CLKI
Clock from
Ext. System
PIC18FXXXX
RA6
I/O (OSC2)
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
3.4
RC Oscillator
3.5
For timing insensitive applications, the RC and RCIO
Oscillator modes offer additional cost savings. The
actual oscillator frequency is a function of several
factors:
• supply voltage
• values of the external resistor (REXT) and
capacitor (CEXT)
• operating temperature
Given the same device, operating voltage, temperature
and component values, there will also be unit-to-unit
frequency variations. These are due to factors such as:
• normal manufacturing variation
• difference in lead frame capacitance between
package types (especially for low CEXT values)
• variations within the tolerance of limits of REXT
and CEXT
In the RC Oscillator mode, the oscillator frequency
divided by 4 is available on the OSC2 pin. This signal
may be used for test purposes or to synchronize other
logic. Figure 3-5 shows how the R/C combination is
connected.
FIGURE 3-5:
PLL Frequency Multiplier
A Phase Locked Loop (PLL) circuit is provided as an
option for users who wish to use a lower frequency
oscillator circuit or to clock the device up to its highest
rated frequency from a crystal oscillator. This may be
useful for customers who are concerned with EMI due
to high-frequency crystals or users who require higher
clock speeds from an internal oscillator.
3.5.1
The HSPLL mode makes use of the HS mode oscillator
for frequencies up to 10 MHz. A PLL then multiplies the
oscillator output frequency by 4 to produce an internal
clock frequency up to 40 MHz. The PLLEN bit is not
available when this mode is configured as the primary
clock source.
The PLL is only available to the crystal oscillator when
the FOSC Configuration bits are programmed for
HSPLL mode (= 0110).
FIGURE 3-7:
HSPLL BLOCK DIAGRAM
HS Oscillator Enable
PLL Enable
(from Configuration Register 1H)
RC OSCILLATOR MODE
VDD
HSPLL OSCILLATOR MODE
OSC2
REXT
OSC1
Internal
Clock
HS Mode
OSC1 Crystal
Osc
FIN
FOUT
Loop
Filter
CEXT
PIC18FXXXX
VSS
FOSC/4
OSC2/CLKO
÷4
The RCIO Oscillator mode (Figure 3-6) functions like
the RC mode, except that the OSC2 pin becomes an
additional general purpose I/O pin. The I/O pin
becomes bit 6 of PORTA (RA6).
RCIO OSCILLATOR MODE
VDD
REXT
OSC1
Internal
Clock
VCO
MUX
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
20 pF ≤ CEXT ≤ 300 pF
FIGURE 3-6:
Phase
Comparator
3.5.2
SYSCLK
PLL AND INTOSC
The PLL is also available to the internal oscillator block
when the internal oscillator block is configured as the
primary clock source. In this configuration, the PLL is
enabled in software and generates a clock output of up
to 32 MHz. The operation of INTOSC with the PLL is
described in Section 3.6.4 “PLL in INTOSC Modes”.
CEXT
PIC18FXXXX
VSS
RA6
I/O (OSC2)
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
20 pF ≤ CEXT ≤ 300 pF
© 2009 Microchip Technology Inc.
DS39689F-page 31
PIC18F2221/2321/4221/4321 FAMILY
3.6
Internal Oscillator Block
The PIC18F2221/2321/4221/4321 family of devices
includes an internal oscillator block which generates
two different clock signals; either can be used as the
microcontroller’s clock source. This may eliminate the
need for external oscillator circuits on the OSC1 and/or
OSC2 pins.
The main output (INTOSC) is an 8 MHz clock source,
which can be used to directly drive the device clock. It
also drives a postscaler, which can provide a range of
clock frequencies from 31 kHz to 4 MHz. The INTOSC
output is enabled when a clock frequency from 125 kHz
to 8 MHz is selected. The INTOSC output can also be
enabled when 31 kHz is selected, depending on the
INTSRC bit (OSCTUNE).
The other clock source is the internal RC oscillator
(INTRC), which provides a nominal 31 kHz output.
INTRC is enabled if it is selected as the device clock
source; it is also enabled automatically when any of the
following are enabled:
3.6.2
INTOSC OUTPUT FREQUENCY
The internal oscillator block is calibrated at the factory
to produce an INTOSC output frequency of 8 MHz.
The INTRC oscillator operates independently of the
INTOSC source. Any changes in INTOSC across
voltage and temperature are not necessarily reflected
by changes in INTRC or vice versa.
3.6.3
OSCTUNE REGISTER
The INTOSC output has been calibrated at the
factory but can be adjusted in the user’s application.
This
is
done
by
writing
to
TUN
(OSCTUNE) in the OSCTUNE register
(Register 3-1).
When the OSCTUNE register is modified, the INTOSC
frequency will begin shifting to the new frequency.
Code execution continues during this shift. There is no
indication that the shift has occurred. The INTRC is not
affected by OSCTUNE.
These features are discussed in greater detail in
Section 24.0 “Special Features of the CPU”.
The OSCTUNE register also implements the INTSRC
(OSCTUNE) and PLLEN (OSCTUNE) bits,
which control certain features of the internal oscillator
block. The INTSRC bit allows users to select which
internal oscillator provides the clock source when the
31 kHz frequency option is selected. This is covered in
greater detail in Section 3.7.1 “Oscillator Control
Register”.
The clock source frequency (INTOSC direct, INTRC
direct or INTOSC postscaler) is selected by configuring
the IRCF bits of the OSCCON register (page 37).
The PLLEN bit controls the operation of the Phase
Locked Loop (PLL) in Internal Oscillator modes (see
Figure 3-10).
3.6.1
FIGURE 3-10:
•
•
•
•
Power-up Timer
Fail-Safe Clock Monitor
Watchdog Timer
Two-Speed Start-up
INTIO MODES
Using the internal oscillator as the clock source eliminates the need for up to two external oscillator pins,
which can then be used for digital I/O. Two distinct
configurations are available:
• In INTIO1 mode, the OSC2 pin outputs FOSC/4,
while OSC1 functions as RA7 (see Figure 3-8) for
digital input and output.
• In INTIO2 mode, OSC1 functions as RA7 and
OSC2 functions as RA6 (see Figure 3-9), both for
digital input and output.
FOSC/4
FIGURE 3-9:
OSC2
Loop
Filter
PIC18FXXXX
I/O (OSC1)
RA6
I/O (OSC2)
÷4
CLKO
INTIO2 OSCILLATOR MODE
RA7
DS39689F-page 32
FOUT
INTIO1 OSCILLATOR MODE
I/O (OSC1)
Phase
Comparator
FIN
INTOSC
OSC2
VCO
MUX
RA7
8 or 4 MHz
PLLEN
(OSCTUNE)
SYSCLK
MUX
FIGURE 3-8:
INTOSC AND PLL BLOCK
DIAGRAM
RA6
PIC18FXXXX
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
3.6.4
PLL IN INTOSC MODES
3.6.5
The 4x Phase Locked Loop (PLL) can be used with the
internal oscillator block to produce faster device clock
speeds than are normally possible with the internal
oscillator sources. When enabled, the PLL produces a
clock speed of 16 MHz or 32 MHz.
Unlike HSPLL mode, the PLL is controlled through
software. The control bit, PLLEN (OSCTUNE), is
used to enable or disable its operation. If PLL is
enabled and a Two-Speed Start-up from wake is
performed, execution is delayed until the PLL starts.
The PLL is available when the device is configured to
use the internal oscillator block as its primary clock
source (FOSC = 1001 or 1000). Additionally, the
PLL will only function when the selected output frequency is either 4 MHz or 8 MHz (OSCCON = 111
or 110). If both of these conditions are not met, the PLL
is disabled and the PLLEN bit remains clear (writes are
ignored).
REGISTER 3-1:
INTOSC FREQUENCY DRIFT
The factory calibrates the internal oscillator block
output (INTOSC) for 8 MHz. However, this frequency
may drift as VDD or temperature changes and can
affect the controller operation in a variety of ways. It is
possible to adjust the INTOSC frequency by modifying
the value in the OSCTUNE register. This has no effect
on the INTRC clock source frequency.
Tuning the INTOSC source requires knowing when to
make the adjustment, in which direction it should be
made and in some cases, how large a change is
needed. Three compensation techniques are discussed
in Section 3.6.5.1 “Compensating with the
EUSART”, Section 3.6.5.2 “Compensating with the
Timers” and Section 3.6.5.3 “Compensating with the
CCP Module in Capture Mode” but other techniques
may be used.
OSCTUNE: OSCILLATOR TUNING REGISTER
R/W-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
INTSRC
PLLEN(1)
—
TUN4
TUN3
TUN2
TUN1
TUN0
bit 7
bit 0
bit 7
INTSRC: Internal Oscillator Low-Frequency Source Select bit
1 = 31.25 kHz device clock derived from 8 MHz INTOSC source (divide-by-256 enabled)
0 = 31 kHz device clock derived directly from INTRC internal oscillator
bit 6
PLLEN: Frequency Multiplier PLL for INTOSC Enable bit(1)
1 = PLL enabled for INTOSC (4 MHz and 8 MHz only)
0 = PLL disabled
Note 1: Available only in certain oscillator configurations; otherwise, this bit is unavailable
and reads as ‘0’. See Section 3.6.4 “PLL in INTOSC Modes” for details.
bit 5
Unimplemented: Read as ‘0’
bit 4-0
TUN: Frequency Tuning bits
01111 = Maximum frequency
•
•
•
•
00001
00000 = Center frequency. Oscillator module is running at the calibrated frequency.
11111
•
•
•
•
10000 = Minimum frequency
Legend:
R = Readable bit
-n = Value at POR
© 2009 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
DS39689F-page 33
PIC18F2221/2321/4221/4321 FAMILY
3.6.5.1
Compensating with the EUSART
An adjustment may be required when the EUSART
begins to generate framing errors or receives data with
errors while in Asynchronous mode. Framing errors
indicate that the device clock frequency is too high. To
adjust for this, decrement the value in OSCTUNE to
reduce the clock frequency. On the other hand, errors
in data may suggest that the clock speed is too low. To
compensate, increment OSCTUNE to increase the
clock frequency.
3.6.5.2
Compensating with the Timers
This technique compares device clock speed to some
reference clock. Two timers may be used; one timer is
clocked by the peripheral clock, while the other is
clocked by a fixed reference source, such as the
Timer1 oscillator.
Both timers are cleared, but the timer clocked by the
reference generates interrupts. When an interrupt
occurs, the internally clocked timer is read and both
timers are cleared. If the internally clocked timer value
is much greater than expected, then the internal
oscillator block is running too fast. To adjust for this,
decrement the OSCTUNE register.
DS39689F-page 34
3.6.5.3
Compensating with the CCP Module
in Capture Mode
A CCP module can use free running Timer1 (or
Timer3), clocked by the internal oscillator block and an
external event with a known period (i.e., AC power
frequency). The time of the first event is captured in the
CCPRxH:CCPRxL registers and is recorded for use
later. When the second event causes a capture, the
time of the first event is subtracted from the time of the
second event. Since the period of the external event is
known, the time difference between events can be
calculated.
If the measured time is much greater than the
calculated time, the internal oscillator block is running
too fast. To compensate, decrement the OSCTUNE
register. If the measured time is much less than the
calculated time, the internal oscillator block is running
too slow. To compensate, increment the OSCTUNE
register.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
Clock Sources and Oscillator
Switching
The PIC18F2221/2321/4221/4321 family of devices
includes a feature that allows the device clock source
to be switched from the main oscillator to an alternate
clock source. These devices also offer two alternate
clock sources. When an alternate clock source is
enabled, the various power-managed operating modes
are available.
Essentially, there are three clock sources for these
devices:
• Primary oscillators
• Secondary oscillators
• Internal oscillator block
The PIC18F2221/2321/4221/4321 family of devices
offers the Timer1 oscillator as a secondary oscillator.
This oscillator, in all power-managed modes, is often
the time base for functions such as a Real-Time Clock.
Most often, a 32.768 kHz watch crystal is connected
between the RC0/T1OSO/T13CKI and RC1/T1OSI
pins. Like the LP mode oscillator circuit, loading
capacitors are also connected from each pin to ground.
The Timer1 oscillator is discussed in greater detail in
Section 13.3 “Timer1 Oscillator”.
The primary oscillators include the External Crystal
and Resonator modes, the External RC modes, the
External Clock modes and the internal oscillator block.
The particular mode is defined by the FOSC Configuration bits. The details of these modes are covered
earlier in this chapter.
FIGURE 3-11:
The secondary oscillators are those external sources
not connected to the OSC1 or OSC2 pins. These
sources may continue to operate even after the
controller is placed in a power-managed mode.
In addition to being a primary clock source, the internal
oscillator block is available as a power-managed
mode clock source. The INTRC source is also used as
the clock source for several special features, such as
the WDT and Fail-Safe Clock Monitor.
The clock sources for the PIC18F2221/2321/4221/4321
family of devices are shown in Figure 3-11. See
Section 24.0 “Special Features of the CPU” for
Configuration register details.
PIC18F2221/2321/4221/4321 FAMILY CLOCK DIAGRAM
Primary Oscillator
LP, XT, HS, RC, EC
OSC2
Sleep
4 x PLL
OSC1
Secondary Oscillator
T1OSC
T1OSO
T1OSCEN
Enable
Oscillator
OSCCON
8 MHz
OSCCON
INTRC
Source
2 MHz
8 MHz
(INTOSC)
31 kHz (INTRC)
Postscaler
Internal
Oscillator
Block
8 MHz
Source
4 MHz
1 MHz
500 kHz
250 kHz
125 kHz
Peripherals
Internal Oscillator
CPU
111
110
IDLEN
101
100
011
MUX
T1OSI
HSPLL, INTOSC/PLL
OSCTUNE
MUX
3.7
010
001
1 31 kHz
000
0
Clock
Control
FOSC
OSCCON
Clock Source Option
for Other Modules
OSCTUNE
WDT, PWRT, FSCM
and Two-Speed Start-up
© 2009 Microchip Technology Inc.
DS39689F-page 35
PIC18F2221/2321/4221/4321 FAMILY
3.7.1
OSCILLATOR CONTROL REGISTER
The OSCCON register (Register 3-2) controls several
aspects of the device clock’s operation, both in full
power operation and in power-managed modes.
The System Clock Select bits, SCS, select the
clock source. The available clock sources are the
primary clock (defined by the FOSC Configuration bits), the secondary clock (Timer1 oscillator) and
the internal oscillator block. The clock source changes
immediately after either of the SCS bits are
changed, following a brief clock transition interval. The
SCS bits are reset on all forms of Reset.
The Internal Oscillator Frequency Select bits
(IRCF) select the frequency output of the internal
oscillator block to drive the device clock. The choices
are the INTRC source (31 kHz), the INTOSC source
(8 MHz) or one of the frequencies derived from the
INTOSC postscaler (31.25 kHz to 4 MHz). If the
internal oscillator block is supplying the device clock,
changing the states of these bits will have an immediate change on the internal oscillator’s output. On
device Resets, the default output frequency of the
internal oscillator block is set at 1 MHz.
When a nominal output frequency of 31 kHz is selected
(IRCF = 000), users may choose which internal
oscillator acts as the source. This is done with the
INTSRC bit in the OSCTUNE register (OSCTUNE).
Setting this bit selects INTOSC as a 31.25 kHz clock
source derived from the INTOSC postscaler. Clearing
INTSRC selects INTRC (nominally 31 kHz) as the
clock source and disables the INTOSC to reduce
current consumption.
This option allows users to select the tunable and more
precise INTOSC as a clock source, while maintaining
power savings with a very low clock speed. Additionally, the INTOSC source will already be stable should a
switch to a higher frequency be needed quickly.
Regardless of the setting of INTSRC, INTRC always
remains the clock source for features such as the
Watchdog Timer and the Fail-Safe Clock Monitor.
the primary clock is providing the device clock in
primary clock modes. The IOFS bit indicates when the
internal oscillator block has stabilized and is providing
the device clock in RC Clock modes. The T1RUN bit
(T1CON) indicates when the Timer1 oscillator is
providing the device clock in secondary clock modes.
In power-managed modes, only one of these three bits
will be set at any time. If none of these bits are set, the
INTRC is providing the clock or the internal oscillator
block has just started and is not yet stable.
The IDLEN bit controls whether the device goes into
Sleep mode or one of the Idle modes when the SLEEP
instruction is executed.
The use of the flag and control bits in the OSCCON
register is discussed in more detail in Section 4.0
“Power-Managed Modes”.
Note 1: The Timer1 oscillator must be enabled to
select the secondary clock source. The
Timer1 oscillator is enabled by setting the
T1OSCEN bit in the Timer1 Control register (T1CON). If the Timer1 oscillator
is not enabled, then any attempt to select
a secondary clock source will be ignored.
2: It is recommended that the Timer1
oscillator be operating and stable before
selecting the secondary clock source or a
very long delay may occur while the
Timer1 oscillator starts.
3.7.2
OSCILLATOR TRANSITIONS
The PIC18F2221/2321/4221/4321 family of devices contains circuitry to prevent clock “glitches” when switching
between clock sources. A short pause in the device clock
occurs during the clock switch. The length of this pause
is the sum of two cycles of the old clock source and three
to four cycles of the new clock source. This formula
assumes that the new clock source is stable.
Clock transitions are discussed in greater detail in
Section 4.1.2 “Entering Power-Managed Modes”.
The OSTS, IOFS and T1RUN bits indicate which clock
source is currently providing the device clock. The
OSTS bit indicates that the Oscillator Start-up Timer
and PLL Start-up Timer (if enabled) have timed out and
DS39689F-page 36
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 3-2:
OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0
R/W-1
R/W-0
R/W-0
R(1)
R-0
R/W-0
R/W-0
IDLEN
IRCF2
IRCF1
IRCF0
OSTS
IOFS
SCS1
SCS0
bit 7
bit 0
bit 7
IDLEN: Idle Enable bit
1 = Device enters an Idle mode when a SLEEP instruction is executed
0 = Device enters Sleep mode when a SLEEP instruction is executed
bit 6-4
IRCF: Internal Oscillator Frequency Select bits
111 = 8 MHz (INTOSC drives clock directly)
110 = 4 MHz
101 = 2 MHz
100 = 1 MHz(3)
011 = 500 kHz
010 = 250 kHz
001 = 125 kHz
000 = 31 kHz (from either INTOSC/256 or INTRC directly)(2)
bit 3
OSTS: Oscillator Start-up Time-out Status bit(1)
1 = Oscillator Start-up Timer (OST) time-out has expired; primary oscillator is running
0 = Oscillator Start-up Timer (OST) time-out is running; primary oscillator is not ready
bit 2
IOFS: INTOSC Frequency Stable bit
1 = INTOSC frequency is stable
0 = INTOSC frequency is not stable
bit 1-0
SCS: System Clock Select bits
1x = Internal oscillator block
01 = Secondary (Timer1) oscillator
00 = Primary oscillator
Note 1: Reset state depends on state of the IESO Configuration bit.
2: Source selected by the INTSRC bit (OSCTUNE), see text.
3: Default output frequency of INTOSC on Reset.
Legend:
R = Readable bit
-n = Value at POR
© 2009 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
DS39689F-page 37
PIC18F2221/2321/4221/4321 FAMILY
3.8
Effects of Power-Managed Modes
on the Various Clock Sources
When PRI_IDLE mode is selected, the designated primary oscillator continues to run without interruption.
For all other power-managed modes, the oscillator
using the OSC1 pin is disabled. The OSC1 pin (and
OSC2 pin in Crystal Oscillator modes) will stop
oscillating.
In secondary clock modes (SEC_RUN and
SEC_IDLE), the Timer1 oscillator is operating and
providing the device clock. The Timer1 oscillator may
also run in all power-managed modes if required to
clock Timer1 or Timer3.
In internal oscillator modes (RC_RUN and RC_IDLE),
the internal oscillator block provides the device clock
source. The 31 kHz INTRC output can be used directly
to provide the clock and may be enabled to support
various special features, regardless of the powermanaged mode (see Section 24.2 “Watchdog Timer
(WDT)”, Section 24.3 “Two-Speed Start-up” and
Section 24.4 “Fail-Safe Clock Monitor” for more
information). The INTOSC output at 8 MHz may be
used directly to clock the device or may be divided
down by the postscaler. The INTOSC output is disabled
if the clock is provided directly from the INTRC output.
The INTOSC output is also enabled for Two-Speed
Start-up at 1 MHz after a Reset.
If the Sleep mode is selected, all clock sources are
stopped. Since all the transistor switching currents
have been stopped, Sleep mode achieves the lowest
current consumption of the device (only leakage
currents).
3.9
Power-up Delays
Power-up delays are controlled by two or three timers,
so that no external Reset circuitry is required for most
applications. The delays ensure that the device is kept
in Reset until the device power supply is stable under
normal circumstances and the primary clock is operating and stable. For additional information on power-up
delays, see Section 5.5 “Device Reset Timers”.
The first timer is the Power-up Timer (PWRT) which
provides a fixed delay on power-up (parameter 33,
Table 27-10). It is enabled by clearing (= 0) the
PWRTEN Configuration bit (CONFIG2L).
3.9.1
DELAYS FOR POWER-UP AND
RETURN TO PRIMARY CLOCK
The second timer is the Oscillator Start-up Timer
(OST), intended to delay execution until the crystal
oscillator is stable (LP, XT and HS modes). The OST
does this by counting 1024 oscillator cycles before
allowing the oscillator to clock the device.
When the HSPLL Oscillator mode is selected, a third
timer delays execution for an additional 2 ms following
the HS mode OST delay, so the PLL can lock to the
incoming clock frequency. At the end of these delays,
the OSTS bit (OSCCON) is set.
There is a delay of interval TCSD (parameter 38,
Table 27-10), once execution is allowed to start, when
the controller becomes ready to execute instructions.
This delay runs concurrently with any other delays.
This may be the only delay that occurs when any of the
EC, RC or INTIO modes are used as the primary clock
source.
Enabling any on-chip feature that will operate during
Sleep will increase the current consumed during Sleep.
The INTRC is required to support WDT operation. The
Timer1 oscillator may be operating to support a RealTime Clock. Other features may be operating that do
not require a device clock source (i.e., MSSP slave,
PSP, INTx pins and others). Peripherals that may add
significant current consumption are listed in
Section 27.2 “DC Characteristics”.
TABLE 3-3:
OSC1 AND OSC2 PIN STATES IN SLEEP MODE
OSC Mode
OSC1 Pin
OSC2 Pin
RC, INTIO1
Floating, external resistor pulls high
At logic low (clock/4 output)
RCIO
Floating, external resistor pulls high
Configured as PORTA, bit 6
INTIO2
Configured as PORTA, bit 7
Configured as PORTA, bit 6
ECIO
Floating, driven by external clock
Configured as PORTA, bit 6
EC
Floating, driven by external clock
At logic low (clock/4 output)
LP, XT and HS
Feedback inverter disabled at quiescent
voltage level
Feedback inverter disabled at quiescent
voltage level
Note:
See Table 5-2 in Section 5.0 “Reset” for time-outs due to Sleep and MCLR Reset.
DS39689F-page 38
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
4.0
POWER-MANAGED MODES
4.1.1
The SCS
; PRODH:PRODL
EXAMPLE 9-2:
Making multiplication a hardware operation allows it to
be completed in a single instruction cycle. This has the
advantages of higher computational throughput and
reduced code size for multiplication algorithms and
allows the PIC18 devices to be used in many applications previously reserved for digital signal processors.
A comparison of various hardware and software
multiply operations, along with the savings in memory
and execution time, is shown in Table 9-1.
9.2
8 x 8 UNSIGNED
MULTIPLY ROUTINE
8 x 8 SIGNED MULTIPLY
ROUTINE
MOVF
MULWF
ARG1, W
ARG2
BTFSC
SUBWF
ARG2, SB
PRODH, F
MOVF
BTFSC
SUBWF
ARG2, W
ARG1, SB
PRODH, F
Operation
;
;
;
;
;
ARG1 * ARG2 ->
PRODH:PRODL
Test Sign Bit
PRODH = PRODH
- ARG1
; Test Sign Bit
; PRODH = PRODH
;
- ARG2
Example 9-1 shows the instruction sequence for an 8 x 8
unsigned multiplication. Only one instruction is required
when one of the arguments is already loaded in the
WREG register.
Example 9-2 shows the sequence to do an 8 x 8 signed
multiplication. To account for the sign bits of the
arguments, each argument’s Most Significant bit (MSb)
is tested and the appropriate subtractions are done.
TABLE 9-1:
PERFORMANCE COMPARISON FOR VARIOUS MULTIPLY OPERATIONS
Routine
8 x 8 unsigned
8 x 8 signed
16 x 16 unsigned
16 x 16 signed
Multiply Method
Program
Memory
(Words)
Cycles
(Max)
@ 40 MHz
@ 10 MHz
@ 4 MHz
Without hardware multiply
13
69
6.9 μs
27.6 μs
69 μs
Time
Hardware multiply
1
1
100 ns
400 ns
1 μs
Without hardware multiply
33
91
9.1 μs
36.4 μs
91 μs
Hardware multiply
6
6
600 ns
2.4 μs
6 μs
Without hardware multiply
21
242
24.2 μs
96.8 μs
242 μs
Hardware multiply
28
28
2.8 μs
11.2 μs
28 μs
Without hardware multiply
52
254
25.4 μs
102.6 μs
254 μs
Hardware multiply
35
40
4.0 μs
16.0 μs
40 μs
© 2009 Microchip Technology Inc.
DS39689F-page 95
PIC18F2221/2321/4221/4321 FAMILY
Example 9-3 shows the sequence to do a 16 x 16
unsigned multiplication. Equation 9-1 shows the
algorithm that is used. The 32-bit result is stored in four
registers (RES3:RES0).
EQUATION 9-1:
RES3:RES0 =
=
16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
ARG1H:ARG1L • ARG2H:ARG2L
(ARG1H • ARG2H • 216) +
(ARG1H • ARG2L • 28) +
(ARG1L • ARG2H • 28) +
(ARG1L • ARG2L)
EXAMPLE 9-3:
EQUATION 9-2:
RES3:RES0 = ARG1H:ARG1L • ARG2H:ARG2L
= (ARG1H • ARG2H • 216) +
(ARG1H • ARG2L • 28) +
(ARG1L • ARG2H • 28) +
(ARG1L • ARG2L) +
(-1 • ARG2H • ARG1H:ARG1L • 216) +
(-1 • ARG1H • ARG2H:ARG2L • 216)
EXAMPLE 9-4:
16 x 16 UNSIGNED
MULTIPLY ROUTINE
MOVF
MULWF
ARG1L, W
ARG2L
MOVFF
MOVFF
PRODH, RES1
PRODL, RES0
MOVF
MULWF
ARG1H, W
ARG2H
MOVFF
MOVFF
PRODH, RES3
PRODL, RES2
MOVF
MULWF
ARG1L, W
ARG2H
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1, F
PRODH, W
RES2, F
WREG
RES3, F
MOVF
MULWF
ARG1H, W
ARG2L
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1, F
PRODH, W
RES2, F
WREG
RES3, F
; ARG1L * ARG2L->
; PRODH:PRODL
;
;
;
; ARG1H * ARG2H->
; PRODH:PRODL
;
;
;
;
;
;
;
;
;
;
;
;
;
ARG1L * ARG2H->
PRODH:PRODL
Add cross
products
ARG1H * ARG2L->
PRODH:PRODL
Add cross
products
Example 9-4 shows the sequence to do a 16 x 16
signed multiply. Equation 9-2 shows the algorithm
used. The 32-bit result is stored in four registers
(RES3:RES0). To account for the sign bits of the
arguments, the MSb for each argument pair is tested
and the appropriate subtractions are done.
DS39689F-page 96
16 x 16 SIGNED
MULTIPLY ROUTINE
MOVF
MULWF
ARG1L, W
ARG2L
MOVFF
MOVFF
PRODH, RES1
PRODL, RES0
MOVF
MULWF
ARG1H, W
ARG2H
MOVFF
MOVFF
PRODH, RES3
PRODL, RES2
MOVF
MULWF
ARG1L, W
ARG2H
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1, F
PRODH, W
RES2, F
WREG
RES3, F
MOVF
MULWF
ARG1H, W
ARG2L
MOVF
ADDWF
MOVF
ADDWFC
CLRF
ADDWFC
PRODL, W
RES1, F
PRODH, W
RES2, F
WREG
RES3, F
BTFSS
BRA
MOVF
SUBWF
MOVF
SUBWFB
ARG2H, 7
SIGN_ARG1
ARG1L, W
RES2
ARG1H, W
RES3
; ARG2H:ARG2L neg?
; no, check ARG1
;
;
;
ARG1H, 7
CONT_CODE
ARG2L, W
RES2
ARG2H, W
RES3
; ARG1H:ARG1L neg?
; no, done
;
;
;
; ARG1L * ARG2L ->
; PRODH:PRODL
;
;
; ARG1H * ARG2H ->
; PRODH:PRODL
;
;
;
;
;
;
;
;
;
;
ARG1L * ARG2H ->
PRODH:PRODL
Add cross
products
;
;
;
;
;
;
;
;
;
;
;
16 x 16 SIGNED
MULTIPLICATION
ALGORITHM
;
;
;
;
;
;
;
;
;
ARG1H * ARG2L ->
PRODH:PRODL
Add cross
products
;
;
SIGN_ARG1
BTFSS
BRA
MOVF
SUBWF
MOVF
SUBWFB
;
CONT_CODE
:
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
10.0
INTERRUPTS
The PIC18F2221/2321/4221/4321 family devices have
multiple interrupt sources and an interrupt priority
feature that allows most interrupt sources to be
assigned a high-priority level or a low-priority level. The
high-priority interrupt vector is at 0008h and the lowpriority interrupt vector is at 0018h. High-priority
interrupt events will interrupt any low-priority interrupts
that may be in progress.
There are ten registers which are used to control
interrupt operation. These registers are:
•
•
•
•
•
•
•
RCON
INTCON
INTCON2
INTCON3
PIR1, PIR2
PIE1, PIE2
IPR1, IPR2
It is recommended that the Microchip header files
supplied with MPLAB® IDE be used for the symbolic bit
names in these registers. This allows the assembler/
compiler to automatically take care of the placement of
these bits within the specified register.
In general, interrupt sources have three bits to control
their operation. They are:
• Flag bit to indicate that an interrupt event
occurred
• Enable bit that allows program execution to
branch to the interrupt vector address when the
flag bit is set
• Priority bit to select high priority or low priority
The interrupt priority feature is enabled by setting the
IPEN bit (RCON). When interrupt priority is
enabled, there are two bits which enable interrupts
globally. Setting the GIEH bit (INTCON) enables all
interrupts that have the priority bit set (high priority).
Setting the GIEL bit (INTCON) enables all
interrupts that have the priority bit cleared (low priority).
When the interrupt flag, enable bit and appropriate
global interrupt enable bit are set, the interrupt will vector immediately to address 0008h or 0018h, depending
on the priority bit setting. Individual interrupts can be
disabled through their corresponding enable bits.
© 2009 Microchip Technology Inc.
When the IPEN bit is cleared (default state), the
interrupt priority feature is disabled and interrupts are
compatible with PIC® mid-range devices. In
Compatibility mode, the interrupt priority bits for each
source have no effect. INTCON is the PEIE bit,
which enables/disables all peripheral interrupt sources.
INTCON is the GIE bit, which enables/disables all
interrupt sources. All interrupts branch to address
0008h in Compatibility mode.
When an interrupt is responded to, the global interrupt
enable bit is cleared to disable further interrupts. If the
IPEN bit is cleared, this is the GIE bit. If interrupt priority
levels are used, this will be either the GIEH or GIEL bit.
High-priority interrupt sources can interrupt a lowpriority interrupt. Low-priority interrupts are not
processed while high-priority interrupts are in progress.
The return address is pushed onto the stack and the
PC is loaded with the interrupt vector address (0008h
or 0018h). Once in the Interrupt Service Routine, the
source(s) of the interrupt can be determined by polling
the interrupt flag bits. The interrupt flag bits must be
cleared in software before re-enabling interrupts to
avoid recursive interrupts.
The “return from interrupt” instruction, RETFIE, exits
the interrupt routine and sets the GIE bit (GIEH or GIEL
if priority levels are used), which re-enables interrupts.
For external interrupt events, such as the INTx pins or
the PORTB input change interrupt, the interrupt latency
will be three to four instruction cycles. The exact
latency is the same for one or two-cycle instructions.
Individual interrupt flag bits are set, regardless of the
status of their corresponding enable bit or the GIE bit.
Note:
Do not use the MOVFF instruction to modify
any of the interrupt control registers while
any interrupt is enabled. Doing so may
cause erratic microcontroller behavior.
DS39689F-page 97
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 10-1:
PIC18 INTERRUPT LOGIC
Wake-up if in
Idle or Sleep modes
TMR0IF
TMR0IE
TMR0IP
RBIF
RBIE
RBIP
INT0IF
INT0IE
Interrupt to CPU
Vector to Location
0008h
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
SSPIF
SSPIE
SSPIP
GIE/GIEH
ADIF
ADIE
ADIP
IPEN
IPEN
RCIF
RCIE
RCIP
PEIE/GIEL
IPEN
Additional Peripheral Interrupts
High-Priority Interrupt Generation
Low-Priority Interrupt Generation
SSPIF
SSPIE
SSPIP
Interrupt to CPU
Vector to Location
0018h
TMR0IF
TMR0IE
TMR0IP
ADIF
ADIE
ADIP
RBIF
RBIE
RBIP
RCIF
RCIE
RCIP
Additional Peripheral Interrupts
GIE/GIEH
PEIE/GIEL
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
DS39689F-page 98
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
10.1
INTCON Registers
Note:
Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the global
interrupt enable bit. User software should
ensure the appropriate interrupt flag bits
are clear prior to enabling an interrupt.
This feature allows for software polling.
The INTCON registers are readable and writable
registers, which contain various enable, priority and
flag bits.
REGISTER 10-1:
INTCON: INTERRUPT CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-x
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
bit 7
bit 0
bit 7
GIE/GIEH: Global Interrupt Enable bit
When IPEN = 0:
1 = Enables all unmasked interrupts
0 = Disables all interrupts
When IPEN = 1:
1 = Enables all high-priority interrupts
0 = Disables all interrupts
bit 6
PEIE/GIEL: Peripheral Interrupt Enable bit
When IPEN = 0:
1 = Enables all unmasked peripheral interrupts
0 = Disables all peripheral interrupts
When IPEN = 1:
1 = Enables all low-priority peripheral interrupts
0 = Disables all low-priority peripheral interrupts
bit 5
TMR0IE: TMR0 Overflow Interrupt Enable bit
1 = Enables the TMR0 overflow interrupt
0 = Disables the TMR0 overflow interrupt
bit 4
INT0IE: INT0 External Interrupt Enable bit
1 = Enables the INT0 external interrupt
0 = Disables the INT0 external interrupt
bit 3
RBIE: RB Port Change Interrupt Enable bit
1 = Enables the RB port change interrupt
0 = Disables the RB port change interrupt
bit 2
TMR0IF: TMR0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed (must be cleared in software)
0 = TMR0 register did not overflow
bit 1
INT0IF: INT0 External Interrupt Flag bit
1 = The INT0 external interrupt occurred (must be cleared in software)
0 = The INT0 external interrupt did not occur
bit 0
RBIF: RB Port Change Interrupt Flag bit
1 = At least one of the RB pins changed state (must be cleared in software)
0 = None of the RB pins have changed state
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 99
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 10-2:
INTCON2: INTERRUPT CONTROL REGISTER 2
R/W-1
R/W-1
R/W-1
R/W-1
U-0
R/W-1
U-0
R/W-1
RBPU
INTEDG0
INTEDG1
INTEDG2
—
TMR0IP
—
RBIP
bit 7
bit 0
bit 7
RBPU: PORTB Pull-up Enable bit
1 = All PORTB pull-ups are disabled
0 = PORTB pull-ups are enabled by individual port latch values
bit 6
INTEDG0: External Interrupt 0 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 5
INTEDG1: External Interrupt 1 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 4
INTEDG2: External Interrupt 2 Edge Select bit
1 = Interrupt on rising edge
0 = Interrupt on falling edge
bit 3
Unimplemented: Read as ‘0’
bit 2
TMR0IP: TMR0 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1
Unimplemented: Read as ‘0’
bit 0
RBIP: RB Port Change Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Note:
DS39689F-page 100
x = Bit is unknown
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state
of its corresponding enable bit or the global interrupt enable bit. User software
should ensure the appropriate interrupt flag bits are clear prior to enabling an
interrupt. This feature allows for software polling.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 10-3:
INTCON3: INTERRUPT CONTROL REGISTER 3
R/W-1
R/W-1
U-0
R/W-0
R/W-0
U-0
R/W-0
R/W-0
INT2IP
INT1IP
—
INT2IE
INT1IE
—
INT2IF
INT1IF
bit 7
bit 0
bit 7
INT2IP: INT2 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6
INT1IP: INT1 External Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
Unimplemented: Read as ‘0’
bit 4
INT2IE: INT2 External Interrupt Enable bit
1 = Enables the INT2 external interrupt
0 = Disables the INT2 external interrupt
bit 3
INT1IE: INT1 External Interrupt Enable bit
1 = Enables the INT1 external interrupt
0 = Disables the INT1 external interrupt
bit 2
Unimplemented: Read as ‘0’
bit 1
INT2IF: INT2 External Interrupt Flag bit
1 = The INT2 external interrupt occurred (must be cleared in software)
0 = The INT2 external interrupt did not occur
bit 0
INT1IF: INT1 External Interrupt Flag bit
1 = The INT1 external interrupt occurred (must be cleared in software)
0 = The INT1 external interrupt did not occur
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
Note:
© 2009 Microchip Technology Inc.
x = Bit is unknown
Interrupt flag bits are set when an interrupt condition occurs, regardless of the state
of its corresponding enable bit or the global interrupt enable bit. User software
should ensure the appropriate interrupt flag bits are clear prior to enabling an
interrupt. This feature allows for software polling.
DS39689F-page 101
PIC18F2221/2321/4221/4321 FAMILY
10.2
PIR Registers
Note 1: Interrupt flag bits are set when an interrupt
condition occurs, regardless of the state of
its corresponding enable bit or the Global
Interrupt Enable bit, GIE (INTCON).
The PIR registers contain the individual flag bits for the
peripheral interrupts. Due to the number of peripheral
interrupt sources, there are two Peripheral Interrupt
Request (Flag) registers (PIR1 and PIR2).
REGISTER 10-4:
2: User software should ensure the appropriate interrupt flag bits are cleared prior to
enabling an interrupt and after servicing
that interrupt.
PIR1: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 1
R/W-0
R/W-0
R-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
bit 7
bit 7
bit 0
PSPIF: Parallel Slave Port Read/Write Interrupt Flag bit(1)
1 = A read or a write operation has taken place (must be cleared in software)
0 = No read or write has occurred
Note 1: This bit is unimplemented on 28-pin devices and will read as ‘0’.
bit 6
ADIF: A/D Converter Interrupt Flag bit
1 = An A/D conversion completed (must be cleared in software)
0 = The A/D conversion is not complete
bit 5
RCIF: EUSART Receive Interrupt Flag bit
1 = The EUSART receive buffer, RCREG, is full (cleared when RCREG is read)
0 = The EUSART receive buffer is empty
bit 4
TXIF: EUSART Transmit Interrupt Flag bit
1 = The EUSART transmit buffer, TXREG, is empty (cleared when TXREG is written)
0 = The EUSART transmit buffer is full
bit 3
SSPIF: Master Synchronous Serial Port Interrupt Flag bit
1 = The transmission/reception is complete (must be cleared in software)
0 = Waiting to transmit/receive
bit 2
CCP1IF: CCP1 Interrupt Flag bit
Capture mode:
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare mode:
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM mode:
Unused in this mode.
bit 1
TMR2IF: TMR2 to PR2 Match Interrupt Flag bit
1 = TMR2 to PR2 match occurred (must be cleared in software)
0 = No TMR2 to PR2 match occurred
bit 0
TMR1IF: TMR1 Overflow Interrupt Flag bit
1 = TMR1 register overflowed (must be cleared in software)
0 = TMR1 register did not overflow
Legend:
DS39689F-page 102
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 10-5:
PIR2: PERIPHERAL INTERRUPT REQUEST (FLAG) REGISTER 2
R/W-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
OSCFIF
CMIF
—
EEIF
BCLIF
HLVDIF
TMR3IF
CCP2IF
bit 7
bit 0
bit 7
OSCFIF: Oscillator Fail Interrupt Flag bit
1 = Device oscillator failed, clock input has changed to INTOSC (must be cleared in software)
0 = Device clock operating
bit 6
CMIF: Comparator Interrupt Flag bit
1 = Comparator input has changed (must be cleared in software)
0 = Comparator input has not changed
bit 5
Unimplemented: Read as ‘0’
bit 4
EEIF: Data EEPROM/Flash Write Operation Interrupt Flag bit
1 = The write operation is complete (must be cleared in software)
0 = The write operation is not complete or has not been started
bit 3
BCLIF: Bus Collision Interrupt Flag bit
1 = A bus collision occurred (must be cleared in software)
0 = No bus collision occurred
bit 2
HLVDIF: High/Low-Voltage Detect Interrupt Flag bit
1 = A high/low-voltage condition occurred; direction determined by VDIRMAG bit
(HLVDCON)
0 = A high/low-voltage condition has not occurred
bit 1
TMR3IF: TMR3 Overflow Interrupt Flag bit
1 = TMR3 register overflowed (must be cleared in software)
0 = TMR3 register did not overflow
bit 0
CCP2IF: CCP2 Interrupt Flag bit
Capture mode:
1 = A TMR1 register capture occurred (must be cleared in software)
0 = No TMR1 register capture occurred
Compare mode:
1 = A TMR1 register compare match occurred (must be cleared in software)
0 = No TMR1 register compare match occurred
PWM mode:
Unused in this mode.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 103
PIC18F2221/2321/4221/4321 FAMILY
10.3
PIE Registers
The PIE registers contain the individual enable bits for
the peripheral interrupts. Due to the number of peripheral interrupt sources, there are two Peripheral Interrupt
Enable registers (PIE1 and PIE2). When IPEN = 0, the
PEIE bit must be set to enable any of these peripheral
interrupts.
REGISTER 10-6:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
bit 7
bit 7
bit 0
PSPIE: Parallel Slave Port Read/Write Interrupt Enable bit(1)
1 = Enables the PSP read/write interrupt
0 = Disables the PSP read/write interrupt
Note 1: This bit is unimplemented on 28-pin devices and will read as ‘0’.
bit 6
ADIE: A/D Converter Interrupt Enable bit
1 = Enables the A/D interrupt
0 = Disables the A/D interrupt
bit 5
RCIE: EUSART Receive Interrupt Enable bit
1 = Enables the EUSART receive interrupt
0 = Disables the EUSART receive interrupt
bit 4
TXIE: EUSART Transmit Interrupt Enable bit
1 = Enables the EUSART transmit interrupt
0 = Disables the EUSART transmit interrupt
bit 3
SSPIE: Master Synchronous Serial Port Interrupt Enable bit
1 = Enables the MSSP interrupt
0 = Disables the MSSP 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 TMR2 to PR2 match interrupt
0 = Disables the TMR2 to PR2 match interrupt
bit 0
TMR1IE: TMR1 Overflow Interrupt Enable bit
1 = Enables the TMR1 overflow interrupt
0 = Disables the TMR1 overflow interrupt
Legend:
DS39689F-page 104
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 10-7:
PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
R/W-0
R/W-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
OSCFIE
CMIE
—
EEIE
BCLIE
HLVDIE
TMR3IE
CCP2IE
bit 7
bit 0
bit 7
OSCFIE: Oscillator Fail Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 6
CMIE: Comparator Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 5
Unimplemented: Read as ‘0’
bit 4
EEIE: Data EEPROM/Flash Write Operation Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 3
BCLIE: Bus Collision Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 2
HLVDIE: High/Low-Voltage Detect Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 1
TMR3IE: TMR3 Overflow Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 0
CCP2IE: CCP2 Interrupt Enable bit
1 = Enabled
0 = Disabled
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 105
PIC18F2221/2321/4221/4321 FAMILY
10.4
IPR Registers
The IPR registers contain the individual priority bits for
the peripheral interrupts. Due to the number of peripheral interrupt sources, there are two Peripheral Interrupt
Priority registers (IPR1 and IPR2). Using the priority bits
requires that the Interrupt Priority Enable (IPEN) bit be
set.
REGISTER 10-8:
IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
bit 7
bit 7
bit 0
PSPIP: Parallel Slave Port Read/Write Interrupt Priority bit(1)
1 = High priority
0 = Low priority
Note 1: This bit is unimplemented on 28-pin devices and will read as ‘0’.
bit 6
ADIP: A/D Converter Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
RCIP: EUSART Receive Interrupt Priority bit
1 = High priority
0 = Low priority
bit 4
TXIP: EUSART Transmit Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3
SSPIP: Master Synchronous Serial Port Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2
CCP1IP: CCP1 Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1
TMR2IP: TMR2 to PR2 Match Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0
TMR1IP: TMR1 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
DS39689F-page 106
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 10-9:
IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
R/W-1
R/W-1
U-0
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
OSCFIP
CMIP
—
EEIP
BCLIP
HLVDIP
TMR3IP
CCP2IP
bit 7
bit 0
bit 7
OSCFIP: Oscillator Fail Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6
CMIP: Comparator Interrupt Priority bit
1 = High priority
0 = Low priority
bit 5
Unimplemented: Read as ‘0’
bit 4
EEIP: Data EEPROM/Flash Write Operation Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3
BCLIP: Bus Collision Interrupt Priority bit
1 = High priority
0 = Low priority
bit 2
HLVDIP: High/Low-Voltage Detect Interrupt Priority bit
1 = High priority
0 = Low priority
bit 1
TMR3IP: TMR3 Overflow Interrupt Priority bit
1 = High priority
0 = Low priority
bit 0
CCP2IP: CCP2 Interrupt Priority bit
1 = High priority
0 = Low priority
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 107
PIC18F2221/2321/4221/4321 FAMILY
10.5
RCON Register
The RCON register contains flag bits which are used to
determine the cause of the last Reset or wake-up from
Idle or Sleep modes. RCON also contains the IPEN bit
which enables interrupt priorities.
The operation of the SBOREN bit and the Reset flag
bits is discussed in more detail in Section 5.1 “RCON
Register”.
REGISTER 10-10: RCON: RESET CONTROL REGISTER
R/W-0
R/W-1(1)
U-0
R/W-1
R-1
R-1
R/W-0(2)
R/W-0
IPEN
SBOREN
—
RI
TO
PD
POR
BOR
bit 7
bit 0
bit 7
IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (PIC16XXX Compatibility mode)
bit 6
SBOREN: Software BOR Enable bit(1)
For details of bit operation, see Register 5-1.
bit 5
Unimplemented: Read as ‘0’
bit 4
RI: RESET Instruction Flag bit
For details of bit operation, see Register 5-1.
bit 3
TO: Watchdog Time-out Flag bit
For details of bit operation, see Register 5-1.
bit 2
PD: Power-down Detection Flag bit
For details of bit operation, see Register 5-1.
bit 1
POR: Power-on Reset Status bit(2)
For details of bit operation, see Register 5-1.
bit 0
BOR: Brown-out Reset Status bit
For details of bit operation, see Register 5-1.
Note 1: If SBOREN is enabled, its Reset state is ‘1’; otherwise, it is ‘0’.
2: Actual Reset values are determined by device configuration and the nature of the
device Reset. See Register 5-1 for additional information.
Legend:
DS39689F-page 108
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
10.6
INTx Pin Interrupts
10.7
External interrupts on the RB0/INT0, RB1/INT1 and
RB2/INT2 pins are edge-triggered. If the corresponding
INTEDGx bit in the INTCON2 register is set (= 1), the
interrupt is triggered by a rising edge; if the bit is clear,
the trigger is on the falling edge. When a valid edge
appears on the RBx/INTx pin, the corresponding flag
bit, INTxF, is set. This interrupt can be disabled by
clearing the corresponding enable bit, INTxE. Flag bit,
INTxF, must be cleared in software in the Interrupt
Service Routine before re-enabling the interrupt.
All external interrupts (INT0, INT1 and INT2) can wakeup the processor from Idle or Sleep modes if bit INTxE
was set prior to going into those modes. If the Global
Interrupt Enable bit, GIE, is set, the processor will
branch to the interrupt vector following wake-up.
Interrupt priority for INT1 and INT2 is determined by
the value contained in the interrupt priority bits,
INT1IP (INTCON3) and INT2IP (INTCON3).
There is no priority bit associated with INT0. It is
always a high-priority interrupt source.
TMR0 Interrupt
In 8-bit mode (which is the default), an overflow in the
TMR0 register (FFh → 00h) will set flag bit, TMR0IF. In
16-bit mode, an overflow in the TMR0H:TMR0L
register pair (FFFFh → 0000h) will set TMR0IF. The
interrupt can be enabled/disabled by setting/clearing
enable bit, TMR0IE (INTCON). Interrupt priority for
Timer0 is determined by the value contained in the
interrupt priority bit, TMR0IP (INTCON2). See
Section 12.0 “Timer0 Module” for further details on
the Timer0 module.
10.8
PORTB Interrupt-on-Change
An input change on PORTB sets flag bit, RBIF
(INTCON). The interrupt can be enabled/disabled
by setting/clearing enable bit, RBIE (INTCON).
Interrupt priority for PORTB interrupt-on-change is
determined by the value contained in the interrupt
priority bit, RBIP (INTCON2).
10.9
Context Saving During Interrupts
During interrupts, the return PC address is saved on
the stack. Additionally, the WREG, STATUS and BSR
registers are saved on the fast return stack. If a fast
return from interrupt is not used (see Section 6.3
“Data Memory Organization”), the user may need to
save the WREG, STATUS and BSR registers on entry
to the Interrupt Service Routine. Depending on the
user’s application, other registers may also need to be
saved. Example 10-1 saves and restores the WREG,
STATUS and BSR registers during an Interrupt Service
Routine.
EXAMPLE 10-1:
SAVING STATUS, WREG AND BSR REGISTERS IN RAM
MOVWF
W_TEMP
MOVFF
STATUS, STATUS_TEMP
MOVFF
BSR, BSR_TEMP
;
; USER ISR CODE
;
MOVFF
BSR_TEMP, BSR
MOVF
W_TEMP, W
MOVFF
STATUS_TEMP, STATUS
© 2009 Microchip Technology Inc.
; W_TEMP is in virtual bank
; STATUS_TEMP located anywhere
; BSR_TMEP located anywhere
; Restore BSR
; Restore WREG
; Restore STATUS
DS39689F-page 109
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 110
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
11.0
I/O PORTS
Depending on the device selected and features
enabled, there are up to five ports available. Some pins
of the I/O ports are multiplexed with an alternate
function from the peripheral features on the device. In
general, when a peripheral is enabled, that pin may not
be used as a general purpose I/O pin.
Each port has three registers for its operation. These
registers are:
• TRIS register (Data Direction register)
• PORT register (reads the levels on the pins of the
device)
• LAT register (Data Latch register)
The Data Latch (LAT register) is useful for read-modifywrite operations on the value that the I/O pins are
driving.
A simplified model of a generic I/O port, without the
interfaces to other peripherals, is shown in Figure 11-1.
FIGURE 11-1:
GENERIC I/O PORT
OPERATION
RD LAT
Reading the PORTA register reads the status of the
pins, whereas writing to it, will write to the port latch.
The Data Latch (LATA) register is also memory mapped.
Read-modify-write operations on the LATA register read
and write the latched output value for PORTA.
The RA4 pin is multiplexed with the Timer0 module
clock input and one of the comparator outputs to
become the RA4/T0CKI/C1OUT pin. Pins RA6 and
RA7 are multiplexed with the main oscillator pins. They
are enabled as oscillator or I/O pins by the selection of
the main oscillator in the Configuration register (see
Section 24.1 “Configuration Bits” for details). When
they are not used as port pins, RA6 and RA7 and their
associated TRIS and LAT bits are read as ‘0’.
The other PORTA pins are multiplexed with analog
inputs, the analog VREF+ and VREF- inputs and the
comparator voltage reference output. The operation of
pins RA and RA5 as A/D converter inputs is
selected by clearing or setting the control bits in the
ADCON1 register (A/D Control Register 1).
Pins RA0 through RA5 may also be used as comparator
inputs or outputs by setting the appropriate bits in the
CMCON register. To use RA as digital inputs, it is
also necessary to turn off the comparators.
Note:
Data
Bus
D
Q
I/O pin(1)
WR LAT
or PORT
CK
Data Latch
D
WR TRIS
Q
CK
TRIS Latch
Input
Buffer
The RA4/T0CKI/C1OUT pin is a Schmitt Trigger input.
All other PORTA pins have TTL input levels and full
CMOS output drivers.
The TRISA register controls the direction of the PORTA
pins, even when they are being used as analog inputs.
The user must ensure the bits in the TRISA register are
maintained set when using them as analog inputs.
EXAMPLE 11-1:
RD TRIS
CLRF
Q
D
CLRF
ENEN
RD PORT
Note 1:
11.1
On a Power-on Reset, RA5 and RA
are configured as analog inputs and read
as ‘0’. RA4 is configured as a digital input.
I/O pins have diode protection to VDD and VSS.
PORTA, TRISA and LATA Registers
PORTA is an 8-bit wide, bidirectional port. The corresponding Data Direction register is TRISA. Setting a
TRISA bit (= 1) will make the corresponding PORTA pin
an input (i.e., put the corresponding output driver in a
High-Impedance mode). Clearing a TRISA bit (= 0) will
make the corresponding PORTA pin an output (i.e., put
the contents of the output latch on the selected pin).
© 2009 Microchip Technology Inc.
MOVLW
MOVWF
MOVWF
MOVWF
MOVLW
MOVWF
PORTA
;
;
;
LATA
;
;
;
0Fh
;
ADCON1 ;
07h
;
CMCON
;
0CFh
;
;
;
TRISA
;
;
INITIALIZING PORTA
Initialize PORTA by
clearing output
data latches
Alternate method
to clear output
data latches
Configure all A/D
for digital inputs
Configure comparators
for digital input
Value used to
initialize data
direction
Set RA as inputs
RA as outputs
DS39689F-page 111
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-1:
PORTA I/O SUMMARY
Pin
RA0/AN0
RA1/AN1
RA2/AN2/
VREF-/CVREF
RA3/AN3/VREF+
Function
TRIS
Setting
I/O
I/O
Type
RA0
0
O
DIG
1
I
TTL
PORTA data input; disabled when analog input enabled.
AN0
1
I
ANA
A/D Input Channel 0 and Comparator C1- input. Default input
configuration on POR; does not affect digital output.
RA1
0
O
DIG
LATA data output; not affected by analog input.
1
I
TTL
PORTA data input; disabled when analog input enabled.
AN1
1
I
ANA
A/D Input Channel 1 and Comparator C2- input. Default input
configuration on POR; does not affect digital output.
RA2
0
O
DIG
LATA data output; not affected by analog input. Disabled when
CVREF output enabled.
1
I
TTL
PORTA data input. Disabled when analog functions enabled;
disabled when CVREF output enabled.
AN2
1
I
ANA
A/D Input Channel 2 and Comparator C2+ input. Default input
configuration on POR; not affected by analog output.
VREF-
1
I
ANA
A/D and comparator voltage reference low input.
CVREF
x
O
ANA
Comparator voltage reference output. Enabling this feature disables
digital I/O.
RA3
0
O
DIG
LATA data output; not affected by analog input.
1
I
TTL
PORTA data input; disabled when analog input enabled.
1
I
ANA
A/D Input Channel 3 and Comparator C1+ input. Default input
configuration on POR.
AN3
RA4/T0CKI/C1OUT
RA5/AN4/SS/
HLVDIN/C2OUT
OSC2/CLKO/RA6
OSC1/CLKI/RA7
Legend:
Description
LATA data output; not affected by analog input.
VREF+
1
I
ANA
A/D and comparator voltage reference high input.
RA4
0
O
DIG
LATA data output.
1
I
ST
PORTA data input; default configuration on POR.
T0CKI
1
I
ST
Timer0 clock input.
C1OUT
0
O
DIG
Comparator 1 output; takes priority over port data.
RA5
0
O
DIG
LATA data output; not affected by analog input.
1
I
TTL
PORTA data input; disabled when analog input enabled.
A/D Input Channel 4. Default configuration on POR.
AN4
1
I
ANA
SS
1
I
TTL
Slave Select input for MSSP (MSSP module).
HLVDIN
1
I
ANA
High/Low-Voltage Detect external trip point input.
C2OUT
0
O
DIG
Comparator 2 output; takes priority over port data.
RA6
0
O
DIG
LATA data output. Enabled in RCIO, INTIO2 and ECIO modes only.
1
I
TTL
PORTA data input. Enabled in RCIO, INTIO2 and ECIO modes only.
OSC2
x
O
ANA
Main oscillator feedback output connection (XT, HS and LP modes).
CLKO
x
O
DIG
System cycle clock output (FOSC/4) in RC, INTIO1 and EC Oscillator
modes.
RA7
0
O
DIG
LATA data output. Disabled in external oscillator modes.
1
I
TTL
PORTA data input. Disabled in external oscillator modes.
OSC1
x
I
ANA
Main oscillator input connection.
CLKI
x
I
ANA
Main clock input connection.
DIG = Digital level output; TTL = TTL input buffer; ST = Schmitt Trigger input buffer; ANA = Analog level input/output;
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
DS39689F-page 112
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-2:
Name
PORTA
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
RA7(1)
RA6(1)
RA5
RA4
RA3
RA2
RA1
RA0
(1)
LATA6(1) PORTA Data Latch Register (Read and Write to Data Latch)
LATA
LATA7
TRISA
TRISA7(1) TRISA6(1) PORTA Data Direction Register
Reset
Values
on page
58
58
58
ADCON1
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
57
CMCON
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
57
CVRCON
CVREN
CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
57
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTA.
Note 1: RA and their associated latch and data direction bits are enabled as I/O pins based on oscillator
configuration; otherwise, they are read as ‘0’.
© 2009 Microchip Technology Inc.
DS39689F-page 113
PIC18F2221/2321/4221/4321 FAMILY
11.2
PORTB, TRISB and LATB
Registers
PORTB is an 8-bit wide, bidirectional port. The
corresponding Data Direction register is TRISB. 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.,
put the contents of the output latch on the selected pin).
The Data Latch register (LATB) is also memory
mapped. Read-modify-write operations on the LATB
register read and write the latched output value for
PORTB.
EXAMPLE 11-2:
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
PORTB
;
;
;
LATB
;
;
;
0Fh
;
ADCON1 ;
;
;
0CFh
;
;
;
TRISB
;
;
;
INITIALIZING PORTB
Initialize PORTB by
clearing output
data latches
Alternate method
to clear output
data latches
Set RB as
digital I/O pins
(required if config bit
PBADEN is set)
Value used to
initialize data
direction
Set RB as inputs
RB as outputs
RB as inputs
Four of the PORTB pins (RB) have an interrupton-change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB pin
configured as an output is excluded from the interrupton-change comparison). The input pins (of RB)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB
are ORed together to generate the RB Port Change
Interrupt with Flag bit, RBIF (INTCON).
This interrupt can wake the device from Sleep mode or
any of the Idle modes. The user, in the Interrupt Service
Routine, can clear the interrupt in the following manner:
a)
b)
c)
Any read or write of PORTB (except with the
MOVFF (ANY), PORTB instruction).
1 TCY.
Clear flag bit, RBIF.
A mismatch condition will continue to set flag bit, RBIF.
Reading PORTB and waiting 1 TCY will end the
mismatch condition and allow flag bit, RBIF, to be
cleared. Also, if the port pin returns to its original state,
the mismatch condition will be cleared.
The interrupt-on-change feature is recommended for
wake-up on key depression operation and operations
where PORTB is only used for the interrupt-on-change
feature. Polling of PORTB is not recommended while
using the interrupt-on-change feature.
RB3 can be configured by the Configuration bit,
CCP2MX, as the alternate peripheral pin for the CCP2
module (CCP2MX = 0).
Each of the PORTB pins has a weak internal pull-up. A
single control bit can turn on all the pull-ups. This is
performed by clearing bit, RBPU (INTCON2). The
weak pull-up is automatically turned off when the port
pin is configured as an output. The pull-ups are
disabled on a Power-on Reset.
Note:
On a Power-on Reset, RB are
configured as analog inputs by default and
read as ‘0’; RB are configured as
digital inputs.
By clearing the Configuration bit,
PBADEN, RB will alternatively be
configured as digital inputs on POR.
DS39689F-page 114
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-3:
Pin
RB0/INT0/FLT0/
AN12
RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2
PORTB I/O SUMMARY
Function
TRIS
Setting
I/O
I/O
Type
RB0
0
O
DIG
LATB data output; not affected by analog input.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
Disabled when analog input enabled.(1)
External Interrupt 0 input.
INT0
1
I
ST
FLT0
1
I
ST
AN12
1
I
ANA
A/D Input Channel 12.(1)
RB1
0
O
DIG
LATB data output; not affected by analog input.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
Disabled when analog input enabled.(1)
INT1
1
I
ST
External Interrupt 1 input.
1
I
ANA
A/D Input Channel 10.(1)
RB2
0
O
DIG
LATB data output; not affected by analog input.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
Disabled when analog input enabled.(1)
INT2
1
I
ST
AN8
1
I
ANA
A/D Input Channel 8.(1)
RB3
0
O
DIG
LATB data output; not affected by analog input.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
Disabled when analog input enabled.(1)
1
I
ANA
A/D Input Channel 9.(1)
0
O
DIG
CCP2 compare and PWM output.
1
I
ST
CCP2 capture input.
0
O
DIG
LATB data output; not affected by analog input.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
Disabled when analog input enabled.(1)
KBI0
1
I
TTL
Interrupt-on-change pin.
AN11
1
I
ANA
A/D Input Channel 11.(1)
RB5
0
O
DIG
LATB data output.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
CCP2
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD
Legend:
Note 1:
2:
3:
Enhanced PWM Fault input (ECCP1 module); enabled in software.
AN10
AN9
RB4/KBI0/AN11
Description
(2)
RB4
External Interrupt 2 input.
KBI1
1
I
TTL
Interrupt-on-change pin.
PGM
x
I
ST
Single-Supply Programming mode entry (ICSP™). Enabled by LVP
Configuration bit; all other pin functions disabled.
RB6
0
O
DIG
LATB data output.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
KBI2
1
I
TTL
Interrupt-on-change pin.
PGC
x
I
ST
Serial execution (ICSP™) clock input for ICSP and ICD operation.(3)
RB7
0
O
DIG
LATB data output.
1
I
TTL
PORTB data input; weak pull-up when RBPU bit is cleared.
KBI3
1
I
TTL
Interrupt-on-change pin.
PGD
x
O
DIG
Serial execution data output for ICSP and ICD operation.(3)
x
I
ST
Serial execution data input for ICSP and ICD operation.(3)
DIG = Digital level output; TTL = TTL input buffer; ST = Schmitt Trigger input buffer; ANA = Analog level input/output;
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
Configuration on POR is determined by the PBADEN Configuration bit. Pins are configured as analog inputs by default
when PBADEN is set and digital inputs when PBADEN is cleared.
Alternate assignment for CCP2 when the CCP2MX Configuration bit is ‘0’. Default assignment is RC1.
All other pin functions are disabled when ICSP or ICD are enabled.
© 2009 Microchip Technology Inc.
DS39689F-page 115
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-4:
Name
PORTB
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0
58
LATB
PORTB Data Latch Register (Read and Write to Data Latch)
58
TRISB
PORTB Data Direction Register
58
INTCON
GIE/GIEH PEIE/GIEL
TMR0IE
INT0IE
INTEDG0 INTEDG1 INTEDG2
RBIE
TMR0IF
INT0IF
RBIF
55
—
TMR0IP
—
RBIP
55
INTCON2
RBPU
INTCON3
INT2IP
INT1IP
—
INT2IE
INT1IE
—
INT2IF
INT1IF
55
ADCON1
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
57
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTB.
DS39689F-page 116
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
11.3
PORTC, TRISC and LATC
Registers
PORTC is an 8-bit wide, bidirectional port. The
corresponding Data Direction register is TRISC. Setting a TRISC bit (= 1) will make the corresponding
PORTC pin an input (i.e., put the corresponding output
driver in a High-Impedance mode). Clearing a TRISC
bit (= 0) will make the corresponding PORTC pin an
output (i.e., put the contents of the output latch on the
selected pin).
The Data Latch register (LATC) is also memory
mapped. Read-modify-write operations on the LATC
register read and write the latched output value for
PORTC.
PORTC is multiplexed with several peripheral functions
(Table 11-5). The pins have Schmitt Trigger input
buffers. RC1 is normally configured by Configuration
bit, CCP2MX, as the default peripheral pin of the CCP2
module (default/erased state, CCP2MX = 1).
Note:
On a Power-on Reset, these pins are
configured as digital inputs.
The contents of the TRISC register are affected by
peripheral overrides. Reading TRISC always returns
the current contents, even though a peripheral device
may be overriding one or more of the pins.
EXAMPLE 11-3:
CLRF
PORTC
CLRF
LATC
MOVLW
0CFh
MOVWF
TRISC
INITIALIZING PORTC
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTC by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RC as inputs
RC as outputs
RC as inputs
When enabling peripheral functions, care should be
taken in defining TRIS bits for each PORTC pin. Some
peripherals override the TRIS bit to make a pin an output,
while other peripherals override the TRIS bit to make a
pin an input. The user should refer to the corresponding
peripheral section for additional information.
© 2009 Microchip Technology Inc.
DS39689F-page 117
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-5:
Pin
PORTC I/O SUMMARY
Function
TRIS
Setting
I/O
I/O
Type
RC0
0
O
DIG
RC0/T1OSO/
T13CKI
RC1/T1OSI/CCP2
RC2/CCP1/P1A
1
I
ST
x
O
ANA
T13CKI
1
I
ST
Timer1/Timer3 counter input.
RC1
0
O
DIG
LATC data output.
1
I
ST
T1OSI
x
I
ANA
Timer1 oscillator input; enabled when Timer1 oscillator enabled.
Disables digital I/O.
CCP2(1)
0
O
DIG
CCP2 compare and PWM output; takes priority over port data.
1
I
ST
CCP2 capture input.
0
O
DIG
LATC data output.
1
I
ST
PORTC data input.
0
O
DIG
CCP1 compare or PWM output; takes priority over port data.
1
I
ST
CCP1 capture input.
P1A(2)
0
O
DIG
ECCP1 Enhanced PWM output, Channel A. May be configured for
tri-state during Enhanced PWM shutdown events. Takes priority over
port data.
RC3
0
O
DIG
LATC data output.
1
I
ST
PORTC data input.
0
O
DIG
SPI clock output (MSSP module); takes priority over port data.
RC2
SCK
SCL
RC4/SDI/SDA
RC5/SDO
RC7/RX/DT
Legend:
Note 1:
2:
RC4
PORTC data input.
Timer1 oscillator output; enabled when Timer1 oscillator enabled.
Disables digital I/O.
PORTC data input.
1
I
ST
SPI clock input (MSSP module).
0
O
DIG
I2C™ clock output (MSSP module); takes priority over port data.
1
I
I2C/SMB
0
O
DIG
I2C clock input (MSSP module); input type depends on module setting.
LATC data output.
1
I
ST
PORTC data input.
SDI
1
I
ST
SPI data input (MSSP module).
SDA
1
O
DIG
I2C data output (MSSP module); takes priority over port data.
1
I
0
O
DIG
1
I
ST
PORTC data input.
SDO
0
O
DIG
SPI data output (MSSP module); takes priority over port data.
RC6
0
O
DIG
LATC data output.
RC5
RC6/TX/CK
LATC data output.
T1OSO
CCP1
RC3/SCK/SCL
Description
I2C/SMB I2C data input (MSSP module); input type depends on module setting.
LATC data output.
1
I
ST
PORTC data input.
TX
1
O
DIG
Asynchronous serial transmit data output (EUSART module);
takes priority over port data. User must configure as output.
CK
1
O
DIG
Synchronous serial clock output (EUSART module); takes priority
over port data.
1
I
ST
Synchronous serial clock input (EUSART module).
0
O
DIG
LATC data output.
1
I
ST
PORTC data input.
RX
1
I
ST
Asynchronous serial receive data input (EUSART module).
DT
1
O
DIG
Synchronous serial data output (EUSART module); takes priority over
port data.
1
I
ST
Synchronous serial data input (EUSART module). User must
configure as an input.
RC7
DIG = Digital level output; TTL = TTL input buffer; ST = Schmitt Trigger input buffer; ANA = Analog level input/output;
I2C/SMB = I2C/SMBus input buffer; x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
Default assignment for CCP2 when the CCP2MX Configuration bit is set. Alternate assignment is RB3.
Enhanced PWM output is available only on PIC18F4221/4321 devices.
DS39689F-page 118
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-6:
Name
PORTC
SUMMARY OF REGISTERS ASSOCIATED WITH PORTC
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
RC7
RC6
RC5
RC4
RC3
RC2
RC1
RC0
58
LATC
PORTC Data Latch Register (Read and Write to Data Latch)
58
TRISC
PORTC Data Direction Register
58
© 2009 Microchip Technology Inc.
DS39689F-page 119
PIC18F2221/2321/4221/4321 FAMILY
11.4
Note:
PORTD, TRISD and LATD
Registers
PORTD is only available on 40/44-pin
devices.
PORTD is an 8-bit wide, bidirectional port. The
corresponding Data Direction register is TRISD. Setting a TRISD bit (= 1) will make the corresponding
PORTD pin an input (i.e., put the corresponding output
driver in a High-Impedance mode). Clearing a TRISD
bit (= 0) will make the corresponding PORTD pin an
output (i.e., put the contents of the output latch on the
selected pin).
The Data Latch register (LATD) is also memory
mapped. Read-modify-write operations on the LATD
register read and write the latched output value for
PORTD.
All pins on PORTD are implemented with Schmitt Trigger
input buffers. Each pin is individually configurable as an
input or output.
Three of the PORTD pins are multiplexed with outputs
P1B, P1C and P1D of the Enhanced CCP module. The
operation of these additional PWM output pins is
covered in greater detail in Section 17.0 “Enhanced
Capture/Compare/PWM (ECCP) Module”.
Note:
PORTD can also be configured as an 8-bit wide microprocessor port (Parallel Slave Port) by setting control
bit, PSPMODE (TRISE). In this mode, the input
buffers are TTL. See Section 11.6 “Parallel Slave
Port” for additional information on the Parallel Slave
Port (PSP).
Note:
When the Enhanced PWM mode is used
with either dual or quad outputs, the PSP
functions of PORTD are automatically
disabled.
EXAMPLE 11-4:
CLRF
PORTD
CLRF
LATD
MOVLW
0CFh
MOVWF
TRISD
INITIALIZING PORTD
;
;
;
;
;
;
;
;
;
;
;
;
Initialize PORTD by
clearing output
data latches
Alternate method
to clear output
data latches
Value used to
initialize data
direction
Set RD as inputs
RD as outputs
RD as inputs
On a Power-on Reset, these pins are
configured as digital inputs.
DS39689F-page 120
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-7:
Pin
RD0/PSP0
PORTD I/O SUMMARY
Function
TRIS
Setting
I/O
I/O
Type
RD0
0
O
DIG
1
I
ST
PORTD data input.
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
0
O
DIG
LATD data output.
1
I
ST
PORTD data input.
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
LATD data output.
PSP0
RD1/PSP1
RD1
PSP1
RD2/PSP2
RD2
PSP2
RD3/PSP3
RD3
PSP3
RD4/PSP4
RD4
PSP4
RD5/PSP5/P1B
RD5
RD7/PSP7/P1D
0
O
DIG
1
I
ST
PORTD data input.
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
0
O
DIG
LATD data output.
1
I
ST
PORTD data input.
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
LATD data output.
0
O
DIG
1
I
ST
PORTD data input.
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
LATD data output.
0
O
DIG
I
ST
PORTD data input.
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
P1B
0
O
DIG
ECCP1 Enhanced PWM output, Channel B; takes priority over port and
PSP data. May be configured for tri-state during Enhanced PWM
shutdown events.
RD6
0
O
DIG
LATD data output.
1
I
ST
PORTD data input.
PSP6
x
O
DIG
PSP read data output (LATD); takes priority over port data.
x
I
TTL
PSP write data input.
P1C
0
O
DIG
ECCP1 Enhanced PWM output, channel C; takes priority over port and
PSP data. May be configured for tri-state during Enhanced PWM
shutdown events.
RD7
0
O
DIG
LATD data output.
1
I
ST
PORTD data input.
PSP read data output (LATD); takes priority over port data.
PSP7
P1D
Legend:
LATD data output.
1
PSP5
RD6/PSP6/P1C
Description
x
O
DIG
x
I
TTL
PSP write data input.
0
O
DIG
ECCP1 Enhanced PWM output, Channel D; takes priority over port
and PSP data. May be configured for tri-state during Enhanced PWM
shutdown events.
DIG = Digital level output; TTL = TTL input buffer; ST = Schmitt Trigger input buffer; x = Don’t care
(TRIS bit does not affect port direction or is overridden for this option).
© 2009 Microchip Technology Inc.
DS39689F-page 121
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-8:
Name
PORTD
SUMMARY OF REGISTERS ASSOCIATED WITH PORTD
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
RD7
RD6
RD5
RD4
RD3
RD2
RD1
RD0
58
LATD
PORTD Data Latch Register (Read and Write to Data Latch)
58
TRISD
PORTD Data Direction Register
58
TRISE
CCP1CON
IBF
OBF
IBOV
PSPMODE
—
TRISE2
TRISE1
TRISE0
58
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
57
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTD.
DS39689F-page 122
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
11.5
PORTE, TRISE and LATE
Registers
Depending on the particular PIC18F2221/2321/4221/
4321 family device selected, PORTE is implemented in
two different ways.
For 40/44-pin devices, PORTE is a 4-bit wide port.
Three pins (RE0/RD/AN5, RE1/WR/AN6 and RE2/CS/
AN7) are individually configurable as inputs or outputs.
These pins have Schmitt Trigger input buffers. When
selected as analog inputs, these pins will read as ‘0’.
The corresponding Data Direction register is TRISE.
Setting a TRISE bit (= 1) will make the corresponding
PORTE pin an input (i.e., put the corresponding output
driver in a High-Impedance mode). Clearing a TRISE
bit (= 0) will make the corresponding PORTE pin an
output (i.e., put the contents of the output latch on the
selected pin).
TRISE controls the direction of the RE pins, even when
they are being used as analog inputs. The user must
make sure to keep the pins configured as inputs when
using them as analog inputs.
Note:
On a Power-on Reset, RE are
configured as analog inputs.
The upper four bits of the TRISE register also control
the operation of the Parallel Slave Port. Their operation
is explained in Register 11-1.
The Data Latch register (LATE) is also memory
mapped. Read-modify-write operations on the LATE
register, read and write the latched output value for
PORTE.
© 2009 Microchip Technology Inc.
The fourth pin of PORTE (MCLR/VPP/RE3) is an input
only pin. Its operation is controlled by the MCLRE Configuration bit. When selected as a port pin (MCLRE = 0),
it functions as a digital input only pin; as such, it does not
have TRIS or LAT bits associated with its operation.
Otherwise, it functions as the device’s Master Clear
input. In either configuration, RE3 also functions as the
programming voltage input during programming.
Note:
On a Power-on Reset, RE3 is enabled as
a digital input only if Master Clear
functionality is disabled.
EXAMPLE 11-5:
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
11.5.1
PORTE
;
;
;
LATE
;
;
;
0Fh
;
ADCON1 ;
03h
;
;
;
TRISE
;
;
;
INITIALIZING PORTE
Initialize PORTE by
clearing output
data latches
Alternate method
to clear output
data latches
Configure A/D
for digital inputs
Value used to
initialize data
direction
Set RE as inputs
RE as outputs
RE as inputs
PORTE IN 28-PIN DEVICES
For 28-pin devices, PORTE is only available when
Master Clear functionality is disabled (MCLRE = 0). In
these cases, PORTE is a single bit, input only port
comprised of RE3 only. The pin operates as previously
described.
DS39689F-page 123
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 11-1:
TRISE REGISTER (40/44-PIN DEVICES ONLY)
R-0
R-0
R/W-0
R/W-0
U-0
R/W-1
R/W-1
R/W-1
IBF
OBF
IBOV
PSPMODE
—
TRISE2
TRISE1
TRISE0
bit 7
bit 0
bit 7
IBF: Input Buffer Full Status bit
1 = A word has been received and waiting to be read by the CPU
0 = No word has been received
bit 6
OBF: Output Buffer Full Status bit
1 = The output buffer still holds a previously written word
0 = The output buffer has been read
bit 5
IBOV: Input Buffer Overflow Detect bit (in Microprocessor mode)
1 = A write occurred when a previously input word has not been read (must be cleared in software)
0 = No overflow occurred
bit 4
PSPMODE: Parallel Slave Port Mode Select bit
1 = Parallel Slave Port mode
0 = General Purpose I/O mode
bit 3
Unimplemented: Read as ‘0’
bit 2
TRISE2: RE2 Direction Control bit
1 = Input
0 = Output
bit 1
TRISE1: RE1 Direction Control bit
1 = Input
0 = Output
bit 0
TRISE0: RE0 Direction Control bit
1 = Input
0 = Output
Legend:
DS39689F-page 124
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 11-9:
PORTE I/O SUMMARY
Pin
Function
TRIS
Setting
I/O
I/O
Type
RE0
0
O
DIG
LATE data output; not affected by analog input.
1
I
ST
PORTE data input; disabled when analog input enabled.
RE0/RD/AN5
RE1/WR/AN6
RE2/CS/AN7
MCLR/VPP/RE3(1)
Legend:
Note 1:
2:
Description
RD
1
I
TTL
PSP read enable input (PSP enabled).
AN5
1
I
ANA
A/D Input Channel 5; default input configuration on POR.
RE1
0
O
DIG
LATE data output; not affected by analog input.
1
I
ST
PORTE data input; disabled when analog input enabled.
WR
1
I
TTL
PSP write enable input (PSP enabled).
AN6
1
I
ANA
A/D Input Channel 6; default input configuration on POR.
RE2
0
O
DIG
LATE data output; not affected by analog input.
1
I
ST
PORTE data input; disabled when analog input enabled.
CS
1
I
TTL
PSP write enable input (PSP enabled).
AN7
1
I
ANA
A/D Input Channel 7; default input configuration on POR.
MCLR
—
I
ST
VPP
—
I
ANA
RE3
—(2)
I
ST
External Master Clear input; enabled when MCLRE Configuration bit
is set.
High-voltage detection; used for ICSP™ mode entry detection. Always
available, regardless of pin mode.
PORTE data input; enabled when MCLRE Configuration bit is
clear.
DIG = Digital level output; TTL = TTL input buffer; ST = Schmitt Trigger input buffer; ANA = Analog level input/output;
x = Don’t care (TRIS bit does not affect port direction or is overridden for this option).
RE3 is available on both 28-pin and 40/44-pin devices. All other PORTE pins are only implemented on 40/44-pin devices.
RE3 does not have a corresponding TRIS bit to control data direction.
TABLE 11-10: SUMMARY OF REGISTERS ASSOCIATED WITH PORTE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
PORTE
—
—
—
—
RE3(1,2)
RE2
RE1
RE0
58
(2)
LATE
—
—
—
—
—
PORTE Data Latch Register
(Read and Write to Data Latch)
58
TRISE
IBF
OBF
IBOV
PSPMODE
—
TRISE2
TRISE1
TRISE0
58
ADCON1
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
57
Name
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PORTE.
Note 1: Implemented only when Master Clear functionality is disabled (MCLRE Configuration bit = 0).
2: RE3 is the only PORTE bit implemented on both 28-pin and 40/44-pin devices. All other bits are
implemented only when PORTE is implemented (i.e., 40/44-pin devices).
© 2009 Microchip Technology Inc.
DS39689F-page 125
PIC18F2221/2321/4221/4321 FAMILY
11.6
Note:
Parallel Slave Port
The Parallel Slave Port is only available on
40/44-pin devices.
In addition to its function as a general I/O port, PORTD
can also operate as an 8-bit wide Parallel Slave Port
(PSP) or microprocessor port. PSP operation is
controlled by the 4 upper bits of the TRISE register
(Register 11-1). Setting control bit, PSPMODE
(TRISE), enables PSP operation as long as the
Enhanced CCP module is not operating in Dual Output
or Quad Output PWM mode. In Slave mode, the port is
asynchronously readable and writable by the external
world.
The PSP can directly interface to an 8-bit microprocessor data bus. The external microprocessor can
read or write the PORTD latch as an 8-bit latch. Setting
the control bit, PSPMODE, enables the PORTE I/O
pins to become control inputs for the microprocessor
port. When set, port pin RE0 is the RD input, RE1 is the
WR input and RE2 is the CS (Chip Select) input. For
this functionality, the corresponding data direction bits
of the TRISE register (TRISE) must be configured as inputs (set). The A/D port configuration bits,
PFCG (ADCON1), must also be set to a
value in the range of ‘1010’ through ‘1111’.
The timing for the control signals in Write and Read
modes is shown in Figure 11-3 and Figure 11-4,
respectively.
FIGURE 11-2:
One bit of PORTD
Data Bus
WR LATD
or
WR PORTD
Q
RDx pin
CK
Data Latch
RD PORTD
TTL
D
ENEN
RD LATD
Set Interrupt Flag
PSPIF (PIR1)
PORTE Pins
Read
A read from the PSP occurs when both the CS and RD
lines are first detected low. The data in PORTD is read
out and the OBF bit is clear. If the user writes new data
to PORTD to set OBF, the data is immediately read out;
however, the OBF bit is not set.
DS39689F-page 126
D
Q
A write to the PSP occurs when both the CS and WR
lines are first detected low and ends when either are
detected high. The PSPIF and IBF flag bits are both set
when the write ends.
When either the CS or RD lines are detected high, the
PORTD pins return to the input state and the PSPIF bit
is set. User applications should wait for PSPIF to be set
before servicing the PSP. When this happens, the IBF
and OBF bits can be polled and the appropriate action
taken.
PORTD AND PORTE
BLOCK DIAGRAM
(PARALLEL SLAVE PORT)
TTL
RD
Chip Select
TTL
CS
Write
Note:
TTL
WR
I/O pins have diode protection to VDD and VSS.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 11-3:
PARALLEL SLAVE PORT WRITE WAVEFORMS
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q4
Q1
Q2
Q3
Q4
CS
WR
RD
PORTD
IBF
OBF
PSPIF
FIGURE 11-4:
PARALLEL SLAVE PORT READ WAVEFORMS
Q1
Q2
Q3
Q4
Q1
Q2
Q3
CS
WR
RD
PORTD
IBF
OBF
PSPIF
TABLE 11-11: REGISTERS ASSOCIATED WITH PARALLEL SLAVE PORT
Name
PORTD
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values on
page
RD7
RD6
RD5
RD4
RD3
RD2
RD1
RD0
58
LATD
PORTD Data Latch Register (Read and Write to Data Latch)
TRISD
PORTD Data Direction Register
58
58
PORTE
—
—
—
—
RE3
LATE
—
—
—
—
—
TRISE
IBF
OBF
IBOV
PSPMODE
—
TRISE2
RE2
RE1
RE0
PORTE Data Latch Register
(Read and Write to Data Latch)
TRISE1
TRISE0
58
58
58
GIE/GIEH
PEIE/GIEL
TMR0IF
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
58
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
58
IPR1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
58
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
57
INTCON
ADCON1
Legend:
Note 1:
— = unimplemented, read as ‘0’. Shaded cells are not used by the Parallel Slave Port.
These bits are unimplemented on 28-pin devices and read as ‘0’.
© 2009 Microchip Technology Inc.
DS39689F-page 127
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 128
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
12.0
TIMER0 MODULE
The Timer0 module incorporates the following features:
• Software selectable operation as a timer or counter in both 8-bit or 16-bit modes
• Readable and writable registers
• Dedicated 8-bit, software programmable
prescaler
• Selectable clock source (internal or external)
• Edge select for external clock
• Interrupt-on-overflow
REGISTER 12-1:
The T0CON register (Register 12-1) controls all
aspects of the module’s operation, including the
prescale selection. It is both readable and writable.
A simplified block diagram of the Timer0 module in 8-bit
mode is shown in Figure 12-1. Figure 12-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
T0CON: TIMER0 CONTROL REGISTER
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
R/W-1
TMR0ON
T08BIT
T0CS
T0SE
PSA
T0PS2
T0PS1
T0PS0
bit 7
bit 0
bit 7
TMR0ON: Timer0 On/Off Control bit
1 = Enables Timer0
0 = Stops Timer0
bit 6
T08BIT: Timer0 8-Bit/16-Bit Control bit
1 = Timer0 is configured as an 8-bit timer/counter
0 = Timer0 is configured as a 16-bit timer/counter
bit 5
T0CS: Timer0 Clock Source Select bit
1 = Transition on T0CKI pin
0 = Internal instruction cycle clock (CLKO)
bit 4
T0SE: 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: Timer0 Prescaler Assignment bit
1 = TImer0 prescaler is NOT assigned. Timer0 clock input bypasses prescaler.
0 = Timer0 prescaler is assigned. Timer0 clock input comes from prescaler output.
bit 2-0
T0PS: Timer0 Prescaler Select bits
111 = 1:256 Prescale value
110 = 1:128 Prescale value
101 = 1:64 Prescale value
100 = 1:32 Prescale value
011 = 1:16 Prescale value
010 = 1:8 Prescale value
001 = 1:4 Prescale value
000 = 1:2 Prescale value
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 129
PIC18F2221/2321/4221/4321 FAMILY
12.1
Timer0 Operation
internal phase clock (TOSC). There is a delay between
synchronization and the onset of incrementing the
timer/counter.
Timer0 can operate as either a timer or a counter; the
mode is selected with the T0CS bit (T0CON). In
Timer mode (T0CS = 0), the module increments on
every clock by default unless a different prescaler value
is selected (see Section 12.3 “Prescaler”). If the
TMR0 register is written to, the increment is inhibited
for the following two instruction cycles. The user can
work around this by writing an adjusted value to the
TMR0 register.
12.2
TMR0H is not the actual high byte of Timer0 in 16-bit
mode; it is actually a buffered version of the real high
byte of Timer0 which is not directly readable nor
writable (refer to Figure 12-2). TMR0H is updated with
the contents of the high byte of Timer0 during a read of
TMR0L. This provides the ability to read all 16 bits of
Timer0 without having to verify that the read of the high
and low byte were valid, due to a rollover between
successive reads of the high and low byte.
The Counter mode is selected by setting the T0CS bit
(= 1). In this mode, Timer0 increments either on every
rising or falling edge of pin RA4/T0CKI. The incrementing edge is determined by the Timer0 Source Edge
Select bit, T0SE (T0CON); clearing this bit selects
the rising edge. Restrictions on the external clock input
are discussed below.
Similarly, a write to the high byte of Timer0 must also
take place through the TMR0H Buffer register. The high
byte is updated with the contents of TMR0H when a
write occurs to TMR0L. This allows all 16 bits of Timer0
to be updated at once.
An external clock source can be used to drive Timer0;
however, it must meet certain requirements to ensure
that the external clock can be synchronized with the
FIGURE 12-1:
Timer0 Reads and Writes in
16-Bit Mode
TIMER0 BLOCK DIAGRAM (8-BIT MODE)
FOSC/4
0
1
1
Programmable
Prescaler
T0CKI pin
T0SE
T0CS
0
Sync with
Internal
Clocks
(2 TOSC Delay)
8
3
T0PS
8
PSA
Note:
Set
TMR0IF
on Overflow
TMR0L
Internal Data Bus
Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
FIGURE 12-2:
FOSC/4
TIMER0 BLOCK DIAGRAM (16-BIT MODE)
0
1
1
T0CKI pin
T0SE
T0CS
Programmable
Prescaler
0
Sync with
Internal
Clocks
TMR0
High Byte
TMR0L
8
Set
TMR0IF
on Overflow
(2 TOSC Delay)
3
Read TMR0L
T0PS
Write TMR0L
PSA
8
8
TMR0H
8
8
Internal Data Bus
Note:
Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI max. prescale.
DS39689F-page 130
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12.3
Prescaler
12.3.1
An 8-bit counter is available as a prescaler for the Timer0
module. The prescaler is not directly readable or writable;
its value is set by the PSA and T0PS bits
(T0CON) which determine the prescaler
assignment and prescale ratio.
Clearing the PSA bit assigns the prescaler to the
Timer0 module. When it is assigned, prescale values
from 1:2 through 1:256 in power-of-2 increments are
selectable.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF TMR0, MOVWF
TMR0, BSF TMR0, etc.) clear the prescaler count.
Note:
Writing to TMR0 when the prescaler is
assigned to Timer0 will clear the prescaler
count but will not change the prescaler
assignment.
TABLE 12-1:
Name
SWITCHING PRESCALER
ASSIGNMENT
The prescaler assignment is fully under software
control and can be changed “on-the-fly” during program
execution.
12.4
Timer0 Interrupt
The TMR0 interrupt is generated when the TMR0
register overflows from FFh to 00h in 8-bit mode, or
from FFFFh to 0000h in 16-bit mode. This overflow sets
the TMR0IF flag bit. The interrupt can be masked by
clearing the TMR0IE bit (INTCON). Before reenabling the interrupt, the TMR0IF bit must be cleared
in software by the Interrupt Service Routine.
Since Timer0 is shut down in Sleep mode, the TMR0
interrupt cannot awaken the processor from Sleep.
REGISTERS ASSOCIATED WITH TIMER0
Bit 7
Bit 6
Bit 5
TMR0L
Timer0 Register Low Byte
TMR0H
Timer0 Register High Byte
INTCON
GIE/GIEH PEIE/GIEL TMR0IE
T0CON
TMR0ON
T08BIT
TRISA
RA7(1)
RA6(1)
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
56
56
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
T0CS
T0SE
PSA
T0PS2
T0PS1
T0PS0
56
RA5
RA4
RA3
RA2
RA1
RA0
58
Legend: Shaded cells are not used by Timer0.
Note 1: PORTA and their direction bits are individually configured as port pins based on various primary
oscillator modes. When disabled, these bits read as ‘0’.
© 2009 Microchip Technology Inc.
DS39689F-page 131
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NOTES:
DS39689F-page 132
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13.0
TIMER1 MODULE
The Timer1 timer/counter module incorporates these
features:
• Software selectable operation as a 16-bit timer or
counter
• Readable and writable 8-bit registers (TMR1H
and TMR1L)
• Selectable clock source (internal or external) with
device clock or Timer1 oscillator internal options
• Interrupt-on-overflow
• Reset on CCP Special Event Trigger
• Device clock status flag (T1RUN)
REGISTER 13-1:
A simplified block diagram of the Timer1 module is
shown in Figure 13-1. A block diagram of the module’s
operation in Read/Write mode is shown in Figure 13-2.
The module incorporates its own low-power oscillator
to provide an additional clocking option. The Timer1
oscillator can also be used as a low-power clock source
for the microcontroller in power-managed operation.
Timer1 can also be used to provide Real-Time Clock
(RTC) functionality to applications with only a minimal
addition of external components and code overhead.
Timer1 is controlled through the T1CON Control
register (Register 13-1). It also contains the Timer1
Oscillator Enable bit (T1OSCEN). Timer1 can be
enabled or disabled by setting or clearing control bit,
TMR1ON (T1CON).
T1CON: TIMER1 CONTROL REGISTER
R/W-0
R-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
RD16
T1RUN
T1CKPS1
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON
bit 7
bit 0
bit 7
RD16: 16-Bit Read/Write Mode Enable bit
1 = Enables register read/write of TImer1 in one 16-bit operation
0 = Enables register read/write of Timer1 in two 8-bit operations
bit 6
T1RUN: Timer1 System Clock Status bit
1 = Device clock is derived from Timer1 oscillator
0 = Device clock is derived from another source
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: Timer1 Oscillator Enable bit
1 = Timer1 oscillator is enabled
0 = Timer1 oscillator is shut off
The oscillator inverter and feedback resistor are turned off to eliminate power drain.
bit 2
T1SYNC: Timer1 External Clock Input Synchronization Select bit
When TMR1CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR1CS = 0:
This bit is ignored. Timer1 uses the internal clock when TMR1CS = 0.
bit 1
TMR1CS: Timer1 Clock Source Select bit
1 = External clock from pin RC0/T1OSO/T13CKI (on the rising edge)
0 = Internal clock (FOSC/4)
bit 0
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
Legend:
R = Readable bit
-n = Value at POR
© 2009 Microchip Technology Inc.
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
DS39689F-page 133
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13.1
Timer1 Operation
cycle (Fosc/4). When the bit is set, Timer1 increments
on every rising edge of the Timer1 external clock input
or the Timer1 oscillator, if enabled.
Timer1 can operate in one of these modes:
• Timer
• Synchronous Counter
• Asynchronous Counter
When Timer1 is enabled, the RC1/T1OSI and RC0/
T1OSO/T13CKI pins become inputs. This means the
values of TRISC are ignored and the pins are
read as ‘0’.
The operating mode is determined by the clock select
bit, TMR1CS (T1CON). When TMR1CS is cleared
(= 0), Timer1 increments on every internal instruction
FIGURE 13-1:
TIMER1 BLOCK DIAGRAM
Timer1 Oscillator
Timer1 Clock Input
1
On/Off
1
T1OSO/T13CKI
FOSC/4
Internal
Clock
T1OSI
Synchronize
Prescaler
1, 2, 4, 8
0
Detect
0
2
T1OSCEN(1)
Peripheral Clock
TMR1CS
Timer1
On/Off
T1CKPS
T1SYNC
TMR1ON
Clear TMR1
(CCP Special Event Trigger)
Set
TMR1IF
on Overflow
TMR1
High Byte
TMR1L
Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
FIGURE 13-2:
TIMER1 BLOCK DIAGRAM (16-BIT READ/WRITE MODE)
Timer1 Oscillator
Timer1 Clock Input
1
1
T1OSO/T13CKI
FOSC/4
Internal
Clock
T1OSI
Synchronize
Prescaler
1, 2, 4, 8
0
Detect
0
2
T1OSCEN(1)
T1CKPS
T1SYNC
TMR1ON
Peripheral Clock
TMR1CS
Clear TMR1
(CCP Special Event Trigger)
Timer1
On/Off
TMR1
High Byte
TMR1L
8
Set
TMR1IF
on Overflow
Read TMR1L
Write TMR1L
8
8
TMR1H
8
8
Internal Data Bus
Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
DS39689F-page 134
© 2009 Microchip Technology Inc.
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13.2
Timer1 16-Bit Read/Write Mode
Timer1 can be configured for 16-bit reads and writes
(see Figure 13-2). When the RD16 control bit
(T1CON) is set, the address for TMR1H is mapped
to a buffer register for the high byte of Timer1. A read
from TMR1L will load the contents of the high byte of
Timer1 into the Timer1 high byte buffer. This provides
the user with the ability to accurately read all 16 bits of
Timer1 without having to determine whether a read of
the high byte, followed by a read of the low byte, has
become invalid due to a rollover between reads.
TABLE 13-1:
Osc Type
LP
13.3
Timer1 Oscillator
An on-chip crystal oscillator circuit is incorporated
between pins T1OSI (input) and T1OSO (amplifier
output). It is enabled by setting the Timer1 Oscillator
Enable bit, T1OSCEN (T1CON). The oscillator is a
low-power circuit rated for 32 kHz crystals. It will
continue to run during all power-managed modes. The
circuit for a typical LP oscillator is shown in Figure 13-3.
Table 13-1 shows the capacitor selection for the Timer1
oscillator.
The user must provide a software time delay to ensure
proper start-up of the Timer1 oscillator.
FIGURE 13-3:
EXTERNAL COMPONENTS
FOR THE TIMER1
LP OSCILLATOR
C1
27 pF
PIC18FXXXX
T1OSI
XTAL
32.768 kHz
T1OSO
C2
27 pF
Note:
See the Notes with Table 13-1 for additional
information about capacitor selection.
Freq
32 kHz
C1
27
C2
pF(1)
27 pF(1)
Note 1: Microchip suggests these values as a
starting point in validating the oscillator
circuit.
2: Higher capacitance increases the stability
of the oscillator but also increases the
start-up time.
A write to the high byte of Timer1 must also take place
through the TMR1H Buffer register. The Timer1 high
byte is updated with the contents of TMR1H when a
write occurs to TMR1L. This allows a user to write all
16 bits to both the high and low bytes of Timer1 at once.
The high byte of Timer1 is not directly readable or
writable in this mode. All reads and writes must take
place through the Timer1 High Byte Buffer register.
Writes to TMR1H do not clear the Timer1 prescaler.
The prescaler is only cleared on writes to TMR1L.
CAPACITOR SELECTION FOR
THE TIMER OSCILLATOR
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate
values
of
external
components.
4: Capacitor values are for design guidance
only.
13.3.1
USING TIMER1 AS A
CLOCK SOURCE
The Timer1 oscillator is also available as a clock source
in power-managed modes. By setting the clock select
bits, SCS (OSCCON), to ‘01’, the device
switches to SEC_RUN mode; both the CPU and
peripherals are clocked from the Timer1 oscillator. If the
IDLEN bit (OSCCON) is cleared and a SLEEP
instruction is executed, the device enters SEC_IDLE
mode. Additional details are available in Section 4.0
“Power-Managed Modes”.
Whenever the Timer1 oscillator is providing the clock
source, the Timer1 system clock status flag, T1RUN
(T1CON), is set. This can be used to determine the
controller’s current clocking mode. It can also indicate
the clock source being currently used by the Fail-Safe
Clock Monitor. If the Clock Monitor is enabled and the
Timer1 oscillator fails while providing the clock, polling
the T1RUN bit will indicate whether the clock is being
provided by the Timer1 oscillator or another source.
13.3.2
LOW-POWER TIMER1 OPTION
The Timer1 oscillator can operate at two distinct levels
of power consumption based on device configuration.
When the LPT1OSC Configuration bit is set, the Timer1
oscillator operates in a low-power mode. When
LPT1OSC is not set, Timer1 operates at a higher power
level. Power consumption for a particular mode is
relatively constant, regardless of the device’s operating
mode. The default Timer1 configuration is the higher
power mode.
As the low-power Timer1 mode tends to be more
sensitive to interference, high noise environments may
cause some oscillator instability. The low-power option is,
therefore, best suited for low noise applications where
power conservation is an important design consideration.
© 2009 Microchip Technology Inc.
DS39689F-page 135
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13.3.3
TIMER1 OSCILLATOR LAYOUT
CONSIDERATIONS
The Timer1 oscillator circuit draws very little power
during operation. Due to the low-power nature of the
oscillator, it may also be sensitive to rapidly changing
signals in close proximity.
The oscillator circuit, shown in Figure 13-3, should be
located as close as possible to the microcontroller.
There should be no circuits passing within the oscillator
circuit boundaries other than VSS or VDD.
If a high-speed circuit must be located near the
oscillator (such as the CCP1 pin in Output Compare or
PWM mode, or the primary oscillator using the OSC2
pin), a grounded guard ring around the oscillator circuit,
as shown in Figure 13-4, may be helpful when used on
a single-sided PCB or in addition to a ground plane.
FIGURE 13-4:
OSCILLATOR CIRCUIT
WITH GROUNDED
GUARD RING
13.5
If either of the CCP modules is configured to use
Timer1 and generate a Special Event Trigger in Compare mode (CCP1M or CCP2M = 1011),
this signal will reset Timer1. The trigger from CCP2 will
also start an A/D conversion if the A/D module is
enabled (see Section 16.3.4 “Special Event Trigger”
for more information).
The module must be configured as either a timer or a
synchronous counter to take advantage of this feature.
When used this way, the CCPRH:CCPRL register pair
effectively becomes a period register for Timer1.
If Timer1 is running in Asynchronous Counter mode,
this Reset operation may not work.
In the event that a write to Timer1 coincides with a
Special Event Trigger, the write operation will take
precedence.
Note:
VDD
VSS
OSC1
OSC2
RC0
RC1
RC2
Note: Not drawn to scale.
13.4
Timer1 Interrupt
The TMR1 register pair (TMR1H:TMR1L) increments
from 0000h to FFFFh and rolls over to 0000h. The
Timer1 interrupt, if enabled, is generated on overflow
which is latched in interrupt flag bit, TMR1IF
(PIR1). This interrupt can be enabled or disabled
by setting or clearing the Timer1 Interrupt Enable bit,
TMR1IE (PIE1).
Resetting Timer1 Using the CCP
Special Event Trigger
13.6
The Special Event Triggers from the
CCP2 module will not set the TMR1IF
interrupt flag bit (PIR1).
Using Timer1 as a Real-Time Clock
Adding an external LP oscillator to Timer1 (such as the
one described in Section 13.3 “Timer1 Oscillator”)
gives users the option to include RTC functionality to
their applications. This is accomplished with an
inexpensive watch crystal to provide an accurate time
base and several lines of application code to calculate
the time. When operating in Sleep mode and using a
battery or supercapacitor as a power source, it can
completely eliminate the need for a separate RTC
device and battery backup.
The application code routine, RTCisr, shown in
Example 13-1, demonstrates a simple method to
increment a counter at one-second intervals using an
Interrupt Service Routine. Incrementing the TMR1
register pair to overflow, triggers the interrupt and calls
the routine, which increments the seconds counter by
one. Additional counters for minutes and hours are
incremented as the previous counter overflow.
Since the register pair is 16 bits wide, counting up to
overflow the register directly from a 32.768 kHz clock
would take 2 seconds. To force the overflow at the
required one-second intervals, it is necessary to
preload it. The simplest method is to set the MSb of
TMR1H with a BSF instruction. Note that the TMR1L
register is never preloaded or altered. Doing so may
introduce cumulative errors over many cycles.
For this method to be accurate, Timer1 must operate in
Asynchronous mode and the Timer1 overflow interrupt
must be enabled (PIE1 = 1), as shown in the
routine, RTCinit. The Timer1 oscillator must also be
enabled and running at all times.
DS39689F-page 136
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EXAMPLE 13-1:
IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
RTCinit
MOVLW
MOVWF
CLRF
MOVLW
MOVWF
CLRF
CLRF
MOVLW
MOVWF
BSF
RETURN
80h
TMR1H
TMR1L
b'00001111'
T1CON
secs
mins
.12
hours
PIE1, TMR1IE
BSF
BCF
INCF
MOVLW
CPFSGT
RETURN
CLRF
INCF
MOVLW
CPFSGT
RETURN
CLRF
INCF
MOVLW
CPFSGT
RETURN
CLRF
RETURN
TMR1H, 7
PIR1, TMR1IF
secs, F
.59
secs
; Preload TMR1 register pair
; for 1 second overflow
; Configure for external clock,
; Asynchronous operation, external oscillator
; Initialize timekeeping registers
;
; Enable Timer1 interrupt
RTCisr
TABLE 13-2:
Name
secs
mins, F
.59
mins
mins
hours, F
.23
hours
;
;
;
;
Preload for 1 sec overflow
Clear interrupt flag
Increment seconds
60 seconds elapsed?
;
;
;
;
No, done
Clear seconds
Increment minutes
60 minutes elapsed?
;
;
;
;
No, done
clear minutes
Increment hours
24 hours elapsed?
; No, done
; Reset hours
; Done
hours
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
INTCON
GIE/GIEH PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
58
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
58
IPR1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
58
TMR1L
Timer1 Register Low Byte
56
TMR1H
Timer1 Register High Byte
56
T1CON
RD16
T1RUN
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR1CS
TMR1ON
56
Legend: Shaded cells are not used by the Timer1 module.
Note 1: These bits are unimplemented on 28-pin devices and read as ‘0’.
© 2009 Microchip Technology Inc.
DS39689F-page 137
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NOTES:
DS39689F-page 138
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14.0
TIMER2 MODULE
14.1
The Timer2 timer module incorporates the following
features:
• 8-bit timer and period registers (TMR2 and PR2,
respectively)
• Readable and writable (both registers)
• Software programmable prescaler (1:1, 1:4 and
1:16)
• Software programmable postscaler (1:1 through
1:16)
• Interrupt on TMR2 to PR2 match
• Optional use as the shift clock for the MSSP
module
The module is controlled through the T2CON register
(Register 14-1), which enables or disables the timer
and configures the prescaler and postscaler. Timer2
can be shut off by clearing control bit, TMR2ON
(T2CON), to minimize power consumption.
A simplified block diagram of the module is shown in
Figure 14-1.
Timer2 Operation
In normal operation, TMR2 is incremented from 00h on
each clock (FOSC/4). A 4-bit counter/prescaler on the
clock input gives direct input, divide-by-4 and divide-by16 prescale options. These are selected by the prescaler
control bits, T2CKPS (T2CON). The value of
TMR2 is compared to that of the Period register, PR2, 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 TMR2 to 00h on the
next cycle and drives the output counter/postscaler (see
Section 14.2 “Timer2 Interrupt”).
The TMR2 and PR2 registers are both directly readable
and writable. The TMR2 register is cleared on any
device Reset, while the PR2 register initializes at FFh.
Both the prescaler and postscaler counters are cleared
on the following events:
• a write to the TMR2 register
• a write to the T2CON register
• any device Reset (Power-on Reset, MCLR Reset,
Watchdog Timer Reset or Brown-out Reset)
TMR2 is not cleared when T2CON is written.
REGISTER 14-1:
T2CON: TIMER2 CONTROL REGISTER
U-0
—
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1
R/W-0
T2CKPS0
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6-3
T2OUTPS: Timer2 Output Postscale Select bits
0000 = 1:1 Postscale
0001 = 1:2 Postscale
•
•
•
1111 = 1:16 Postscale
bit 2
TMR2ON: Timer2 On bit
1 = Timer2 is on
0 = Timer2 is off
bit 1-0
T2CKPS: Timer2 Clock Prescale Select bits
00 = Prescaler is 1
01 = Prescaler is 4
1x = Prescaler is 16
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 139
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14.2
Timer2 Interrupt
14.3
Timer2 can also generate an optional device interrupt.
The Timer2 output signal (TMR2 to PR2 match)
provides the input for the 4-bit output counter/postscaler. This counter generates the TMR2 match interrupt flag which is latched in TMR2IF (PIR1). The
interrupt is enabled by setting the TMR2 Match Interrupt Enable bit, TMR2IE (PIE1).
Timer2 Output
The unscaled output of TMR2 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 MSSP module operating in SPI mode.
Additional information is provided in Section 18.0
“Master Synchronous Serial Port (MSSP) Module”.
A range of 16 postscale options (from 1:1 through 1:16
inclusive) can be selected with the postscaler control
bits, T2OUTPS (T2CON).
FIGURE 14-1:
TIMER2 BLOCK DIAGRAM
4
T2OUTPS
1:1 to 1:16
Postscaler
Set TMR2IF
2
T2CKPS
TMR2/PR2
Match
Reset
1:1, 1:4, 1:16
Prescaler
FOSC/4
TMR2
TMR2 Output
(to PWM or MSSP)
Comparator
8
PR2
8
8
Internal Data Bus
TABLE 14-1:
Name
REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Bit 7
Bit 6
INTCON GIE/GIEH PEIE/GIEL
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
55
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
58
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
58
IPR1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
58
TMR2
T2CON
PR2
Timer2 Register
—
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON
56
T2CKPS1 T2CKPS0
Timer2 Period Register
56
56
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.
Note 1: These bits are unimplemented on 28-pin devices and read as ‘0’.
DS39689F-page 140
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15.0
TIMER3 MODULE
The Timer3 timer/counter module incorporates these
features:
• Software selectable operation as a 16-bit timer or
counter
• Readable and writable 8-bit registers (TMR3H
and TMR3L)
• Selectable clock source (internal or external) with
device clock or Timer1 oscillator internal options
• Interrupt-on-overflow
• Module Reset on CCP Special Event Trigger
REGISTER 15-1:
A simplified block diagram of the Timer3 module is
shown in Figure 15-1. A block diagram of the module’s
operation in Read/Write mode is shown in Figure 15-2.
The Timer3 module is controlled through the T3CON
register (Register 15-1). It also selects the clock source
options for the CCP modules (see Section 16.1.1
“CCP Modules and Timer Resources” for more
information).
T3CON: TIMER3 CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
RD16
T3CCP2
T3CKPS1
T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
bit 7
bit 0
bit 7
RD16: 16-Bit Read/Write Mode Enable bit
1 = Enables register read/write of Timer3 in one 16-bit operation
0 = Enables register read/write of Timer3 in two 8-bit operations
bit 6,3
T3CCP: Timer3 and Timer1 to CCPx Enable bits
1x = Timer3 is the capture/compare clock source for the CCP modules
01 = Timer3 is the capture/compare clock source for CCP2; Timer1 is the capture/compare
clock source for CCP1
00 = Timer1 is the capture/compare clock source for the CCP modules
bit 5-4
T3CKPS: Timer3 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 2
T3SYNC: Timer3 External Clock Input Synchronization Control bit
(Not usable if the device clock comes from Timer1/Timer3.)
When TMR3CS = 1:
1 = Do not synchronize external clock input
0 = Synchronize external clock input
When TMR3CS = 0:
This bit is ignored. Timer3 uses the internal clock when TMR3CS = 0.
bit 1
TMR3CS: Timer3 Clock Source Select bit
1 = External clock input from Timer1 oscillator or T13CKI (on the rising edge after the first
falling edge)
0 = Internal clock (FOSC/4)
bit 0
TMR3ON: Timer3 On bit
1 = Enables Timer3
0 = Stops Timer3
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 141
PIC18F2221/2321/4221/4321 FAMILY
15.1
Timer3 Operation
The operating mode is determined by the clock select
bit, TMR3CS (T3CON). When TMR3CS is cleared
(= 0), Timer3 increments on every internal instruction
cycle (FOSC/4). When the bit is set, Timer3 increments
on every rising edge of the Timer1 external clock input
or the Timer1 oscillator, if enabled.
Timer3 can operate in one of three modes:
• Timer
• Synchronous Counter
• Asynchronous Counter
FIGURE 15-1:
As with Timer1, the RC1/T1OSI and RC0/T1OSO/
T13CKI pins become inputs when the Timer1 oscillator
is enabled. This means the values of TRISC are
ignored and the pins are read as ‘0’.
TIMER3 BLOCK DIAGRAM (8-BIT READ/WRITE MODE)
Timer1 Oscillator
Timer1 Clock Input
1
1
T1OSO/T13CKI
FOSC/4
Internal
Clock
T1OSI
Synchronize
Prescaler
1, 2, 4, 8
0
Detect
0
2
T1OSCEN
(1)
Sleep Input
TMR3CS
Timer3
On/Off
T3CKPS
T3SYNC
TMR3ON
CCP1/CCP2 Special Event Trigger
CCP1/CCP2 Select from T3CON
Clear TMR3
Set
TMR3IF
on Overflow
TMR3
High Byte
TMR3L
Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
FIGURE 15-2:
TIMER3 BLOCK DIAGRAM (16-BIT READ/WRITE MODE)
Timer1 Oscillator
Timer1 Clock Input
1
1
T13CKI/T1OSO
FOSC/4
Internal
Clock
T1OSI
Synchronize
Detect
Prescaler
1, 2, 4, 8
0
0
2
(1)
T1OSCEN
T3CKPS
Sleep Input
TMR3CS
Timer3
On/Off
T3SYNC
TMR3ON
CCP1/CCP2 Special Event Trigger
CCP1/CCP2 Select from T3CON
Clear TMR3
Set
TMR3IF
on Overflow
TMR3
High Byte
TMR3L
8
Read TMR1L
Write TMR1L
8
8
TMR3H
8
8
Internal Data Bus
Note 1: When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off to eliminate power drain.
DS39689F-page 142
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
15.2
Timer3 16-Bit Read/Write Mode
15.4
Timer3 Interrupt
Timer3 can be configured for 16-bit reads and writes
(see Figure 15-2). When the RD16 control bit
(T3CON) is set, the address for TMR3H is mapped
to a buffer register for the high byte of Timer3. A read
from TMR3L will load the contents of the high byte of
Timer3 into the Timer3 High Byte Buffer register. This
provides the user with the ability to accurately read all
16 bits of Timer1 without having to determine whether
a read of the high byte, followed by a read of the low
byte, has become invalid due to a rollover between
reads.
The TMR3 register pair (TMR3H:TMR3L) increments
from 0000h to FFFFh and overflows to 0000h. The
Timer3 interrupt, if enabled, is generated on overflow
and is latched in interrupt flag bit, TMR3IF (PIR2).
This interrupt can be enabled or disabled by setting or
clearing the Timer3 Interrupt Enable bit, TMR3IE
(PIE2).
A write to the high byte of Timer3 must also take place
through the TMR3H Buffer register. The Timer3 high
byte is updated with the contents of TMR3H when a
write occurs to TMR3L. This allows a user to write all
16 bits to both the high and low bytes of Timer3 at once.
If either of the CCP modules is configured to use Timer3
and to generate a Special Event Trigger in Compare
mode (CCP1M or CCP2M = 1011), this
signal will reset Timer3. It will also start an A/D conversion if the A/D module is enabled (see Section 16.3.4
“Special Event Trigger” for more information).
The high byte of Timer3 is not directly readable or
writable in this mode. All reads and writes must take
place through the Timer3 High Byte Buffer register.
Writes to TMR3H do not clear the Timer3 prescaler.
The prescaler is only cleared on writes to TMR3L.
15.3
Using the Timer1 Oscillator as the
Timer3 Clock Source
The Timer1 internal oscillator may be used as the clock
source for Timer3. The Timer1 oscillator is enabled by
setting the T1OSCEN (T1CON) bit. To use it as the
Timer3 clock source, the TMR3CS bit must also be set.
As previously noted, this also configures Timer3 to
increment on every rising edge of the oscillator source.
15.5
Resetting Timer3 Using the CCP
Special Event Trigger
The module must be configured as either a timer or
synchronous counter to take advantage of this feature.
When used this way, the CCPR2H:CCPR2L register
pair effectively becomes a period register for Timer3.
If Timer3 is running in Asynchronous Counter mode,
the Reset operation may not work.
In the event that a write to Timer3 coincides with a
Special Event Trigger from a CCP module, the write will
take precedence.
Note:
The Special Event Triggers from the
CCP2 module will not set the TMR3IF
interrupt flag bit (PIR2).
The Timer1 oscillator is described in Section 13.0
“Timer1 Module”.
TABLE 15-1:
Name
INTCON
REGISTERS ASSOCIATED WITH TIMER3 AS A TIMER/COUNTER
Bit 7
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
Bit 6
GIE/GIEH PEIE/GIEL
PIR2
OSCFIF
CMIF
—
EEIF
BCLIF
HLVDIF
TMR3IF
CCP2IF
58
PIE2
OSCFIE
CMIE
—
EEIE
BCLIE
HLVDIE
TMR3IE
CCP2IE
58
IPR2
OSCFIP
CMIP
—
EEIP
BCLIP
HLVDIP
TMR3IP
CCP2IP
58
TMR3L
Timer3 Register Low Byte
57
TMR3H
Timer3 Register High Byte
57
T1CON
RD16
T1RUN
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR1CS
TMR1ON
56
T3CON
RD16
T3CCP2
T3CKPS1 T3CKPS0
TMR3CS
TMR3ON
57
T3CCP1
T3SYNC
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Timer3 module.
© 2009 Microchip Technology Inc.
DS39689F-page 143
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 144
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
16.0
CAPTURE/COMPARE/PWM
(CCP) MODULES
The Capture and Compare operations described in this
chapter apply to all standard and Enhanced CCP
modules.
PIC18F2221/2321/4221/4321 family devices all have
two CCP (Capture/Compare/PWM) modules. Each
module contains a 16-bit register which can operate as
a 16-bit Capture register, a 16-bit Compare register or
a PWM Master/Slave Duty Cycle register.
Note: Throughout this section and Section 17.0
“Enhanced Capture/Compare/PWM (ECCP)
Module”, references to the register and bit
names for CCP modules are referred to
generically by the use of ‘x’ or ‘y’ in place
of the specific module number. Thus,
“CCPxCON” might refer to the control register for CCP1, CCP2 or ECCP1. “CCPxCON”
is used throughout these sections to refer to
the module control register, regardless of
whether the CCP module is a standard or
Enhanced implementation.
In 28-pin devices, the two standard CCP modules
(CCP1 and CCP2) operate as described in this
chapter. In 40/44-pin devices, CCP1 is implemented
as an Enhanced CCP module with standard Capture
and Compare modes and Enhanced PWM modes.
The ECCP implementation is discussed in
Section 17.0 “Enhanced Capture/Compare/PWM
(ECCP) Module”.
REGISTER 16-1:
CCPxCON REGISTER (CCP2 MODULE, CCP1 MODULE IN 28-PIN DEVICES)
U-0
U-0
R/W-0
R/W-0
R/W-0
R/W-0
—
—
DCxB1
DCxB0
CCPxM3
CCPxM2
R/W-0
R/W-0
CCPxM1 CCPxM0
bit 7
bit 0
bit 7-6
Unimplemented: Read as ‘0’
bit 5-4
DCxB: PWM Duty Cycle bit 1 and bit 0 for CCP Module x
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs (bit 1 and bit 0) of the 10-bit PWM duty cycle. The eight MSbs
(DCxB) of the duty cycle are found in CCPRxL.
bit 3-0
CCPxM: CCPx Module Mode Select bits
0000 = Capture/Compare/PWM disabled (resets CCP module)
0001 = Reserved
0010 = Compare mode, toggle output on match (CCPxIF bit is set)
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 CCP pin low; on compare match, force CCP pin high
(CCPxIF bit is set)
1001 = Compare mode: initialize CCP pin high; on compare match, force CCP pin low
(CCPxIF bit is set)
1010 = Compare mode: generate software interrupt on compare match (CCPxIF bit is set,
CCP pin reflects I/O state)
1011 = Compare mode: trigger special event, reset timer, start A/D conversion on
CCPx match (CCPxIF bit is set)
11xx = PWM mode
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 145
PIC18F2221/2321/4221/4321 FAMILY
16.1
CCP Module Configuration
Each Capture/Compare/PWM module is associated
with a control register (generically, CCPxCON) and a
data register (CCPRx). The data register, in turn, is
comprised of two 8-bit registers: CCPRxL (low byte)
and CCPRxH (high byte). All registers are both
readable and writable.
16.1.1
CCP MODULES AND TIMER
RESOURCES
The CCP modules utilize Timers 1, 2 or 3, depending
on the mode selected. Timer1 and Timer3 are available
to modules in Capture or Compare modes, while
Timer2 is available for modules in PWM mode.
TABLE 16-1:
CCP MODE – TIMER
RESOURCES
CCP/ECCP Mode
Timer Resource
Capture
Compare
PWM
Timer1 or Timer3
Timer1 or Timer3
Timer2
TABLE 16-2:
The assignment of a particular timer to a module is
determined by the Timer to CCP enable bits in the
T3CON register (Register 15-1). Both modules may be
active at any given time and may share the same timer
resource if they are configured to operate in the same
mode (Capture/Compare or PWM) at the same time. The
interactions between the two modules are summarized in
Figure 16-1 and Figure 16-2. In Timer1 in Asynchronous
Counter mode, the capture operation will not work.
16.1.2
CCP2 PIN ASSIGNMENT
The pin assignment for CCP2 (Capture input, Compare
and PWM output) can change, based on device configuration. The CCP2MX Configuration bit determines
which pin CCP2 is multiplexed to. By default, it is
assigned to RC1 (CCP2MX = 1). If the Configuration bit
is cleared, CCP2 is multiplexed with RB3.
Changing the pin assignment of CCP2 does not
automatically change any requirements for configuring
the port pin. Users must always verify that the appropriate TRIS register is configured correctly for CCP2
operation, regardless of where it is located.
INTERACTIONS BETWEEN CCP1 AND CCP2 FOR TIMER RESOURCES
CCP1 Mode CCP2 Mode
Interaction
Capture
Capture
Each module can use TMR1 or TMR3 as the time base. The time base can be different
for each CCP.
Capture
Compare
CCP2 can be configured for the Special Event Trigger to reset TMR1 or TMR3
(depending upon which time base is used). Automatic A/D conversions on trigger event
can also be done. Operation of CCP1 could be affected if it is using the same timer as a
time base.
Compare
Capture
CCP1 can be configured for the Special Event Trigger to reset TMR1 or TMR3
(depending upon which time base is used). Operation of CCP2 could be affected if it is
using the same timer as a time base.
Compare
Compare
Either module can be configured for the Special Event Trigger to reset the time base.
Automatic A/D conversions on CCP2 trigger event can be done. Conflicts may occur if
both modules are using the same time base.
Capture
PWM(1)
None
Compare
PWM(1)
None
PWM(1)
Capture
None
Compare
None
(1)
PWM
PWM(1)
Note 1:
PWM
Both PWMs will have the same frequency and update rate (TMR2 interrupt).
Includes standard and Enhanced PWM operation.
DS39689F-page 146
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
16.2
Capture Mode
16.2.3
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep the
CCPxIE interrupt enable bit clear to avoid false
interrupts. The interrupt flag bit, CCPxIF, should also be
cleared following any such change in operating mode.
In Capture mode, the CCPRxH:CCPRxL register pair
captures the 16-bit value of the TMR1 or TMR3
registers when an event occurs on the corresponding
CCPx pin. An event is defined as one of the following:
•
•
•
•
every falling edge
every rising edge
every 4th rising edge
every 16th rising edge
16.2.4
Switching from one capture prescaler to another may
generate an interrupt. Also, the prescaler counter will
not be cleared; therefore, the first capture may be from
a non-zero prescaler. Example 16-1 shows the
recommended method for switching between capture
prescalers. This example also clears the prescaler
counter and will not generate the “false” interrupt.
CCP PIN CONFIGURATION
In Capture mode, the appropriate CCPx pin should be
configured as an input by setting the corresponding
TRIS direction bit.
Note:
16.2.2
If RB3/CCP2 or RC1/CCP2 is configured
as an output, a write to the port can cause
a capture condition.
EXAMPLE 16-1:
TIMER1/TIMER3 MODE SELECTION
The timers that are to be used with the capture feature
(Timer1 and/or Timer3) must be running in Timer mode or
Synchronized Counter mode. In Asynchronous Counter
mode, the capture operation will not work. The timer to be
used with each CCP module is selected in the T3CON
register (see Section 16.1.1 “CCP Modules and Timer
Resources”).
FIGURE 16-1:
CCP PRESCALER
There are four prescaler settings in Capture mode.
They are specified as part of the operating mode
selected by the mode select bits (CCPxM).
Whenever the CCP module is turned off or Capture
mode is disabled, the prescaler counter is cleared. This
means that any Reset will clear the prescaler counter.
The event is selected by the mode select bits,
CCPxM (CCPxCON). When a capture is
made, the interrupt request flag bit, CCPxIF, is set; it
must be cleared in software. If another capture occurs
before the value in register CCPRx is read, the old
captured value is overwritten by the new captured value.
16.2.1
SOFTWARE INTERRUPT
CHANGING BETWEEN
CAPTURE PRESCALERS
(CCP2 SHOWN)
CLRF
MOVLW
CCP2CON
NEW_CAPT_PS
MOVWF
CCP2CON
;
;
;
;
;
;
Turn CCP module off
Load WREG with the
new prescaler mode
value and CCP ON
Load CCP2CON with
this value
CAPTURE MODE OPERATION BLOCK DIAGRAM
TMR3H
Set CCP1IF
T3CCP2
CCP1 pin
Prescaler
÷ 1, 4, 16
and
Edge Detect
CCP1CON
Q1:Q4
CCP2CON
4
4
CCPR1L
TMR1
Enable
TMR1H
TMR1L
TMR3H
TMR3L
Set CCP2IF
4
T3CCP1
T3CCP2
CCP2 pin
Prescaler
÷ 1, 4, 16
TMR3
Enable
CCPR1H
T3CCP2
TMR3L
and
Edge Detect
TMR3
Enable
CCPR2H
CCPR2L
TMR1
Enable
T3CCP2
T3CCP1
© 2009 Microchip Technology Inc.
TMR1H
TMR1L
DS39689F-page 147
PIC18F2221/2321/4221/4321 FAMILY
16.3
Compare Mode
16.3.2
TIMER1/TIMER3 MODE SELECTION
In Compare mode, the 16-bit CCPRx register value is
constantly compared against either the TMR1 or TMR3
register pair value. When a match occurs, the CCPx pin
can be:
Timer1 and/or Timer3 must be running in Timer mode
or Synchronized Counter mode if the CCP module is
using the compare feature. In Asynchronous Counter
mode, the compare operation may not work.
•
•
•
•
16.3.3
driven high
driven low
toggled (high-to-low or low-to-high)
remain unchanged (that is, reflects the state of the
I/O latch)
When the Generate Software Interrupt mode is chosen
(CCPxM = 1010), the corresponding CCPx pin is
not affected. Only a CCP interrupt is generated, if
enabled and the CCPxIE bit is set.
The action on the pin is based on the value of the mode
select bits (CCPxM). At the same time, the
interrupt flag bit, CCPxIF, is set.
16.3.1
16.3.4
SPECIAL EVENT TRIGGER
Both CCP modules are equipped with a Special Event
Trigger. This is an internal hardware signal generated
in Compare mode to trigger actions by other modules.
The Special Event Trigger is enabled by selecting
the Compare Special Event Trigger mode
(CCPxM = 1011).
CCP PIN CONFIGURATION
The user must configure the CCPx pin as an output by
clearing the appropriate TRIS bit.
Note:
SOFTWARE INTERRUPT MODE
Clearing the CCP2CON register will force
the RB3 or RC1 compare output latch
(depending on device configuration) to the
default low level. This is not the PORTB or
PORTC I/O data latch.
For either CCP module, the Special Event Trigger resets
the Timer register pair for whichever timer resource is
currently assigned as the module’s time base. This
allows the CCPRx registers to serve as a programmable
period register for either timer.
The Special Event Trigger for CCP2 can also start an
A/D conversion. In order to do this, the A/D converter
must already be enabled.
FIGURE 16-2:
COMPARE MODE OPERATION BLOCK DIAGRAM
CCPR1H
Set CCP1IF
CCPR1L
Special Event Trigger
(Timer1/Timer3 Reset)
CCP1 pin
Comparator
Output
Logic
Compare
Match
S
Q
R
TRIS
Output Enable
4
CCP1CON
0
1
TMR1H
TMR1L
TMR3H
TMR3L
0
Special Event Trigger
(Timer1/Timer3 Reset, A/D Trigger)
1
T3CCP1
T3CCP2
Set CCP2IF
Comparator
CCPR2H
CCPR2L
Compare
Match
CCP2 pin
Output
Logic
4
S
Q
R
TRIS
Output Enable
CCP2CON
DS39689F-page 148
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 16-3:
Name
INTCON
REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, TIMER1 AND TIMER3
Bit 7
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
Bit 6
GIE/GIEH PEIE/GIEL
(1)
—
RI
TO
PD
POR
BOR
54
PIR1
PSPIF(2)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
58
PIE1
(2)
PSPIE
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
58
IPR1
PSPIP(2)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
58
RCON
IPEN
SBOREN
PIR2
OSCFIF
CMIF
—
EEIF
BCLIF
HLVDIF
TMR3IF
CCP2IF
58
PIE2
OSCFIE
CMIE
—
EEIE
BCLIE
HLVDIE
TMR3IE
CCP2IE
58
OSCFIP
CMIP
—
EEIP
BCLIP
HLVDIP
TMR3IP
CCP2IP
IPR2
TRISB
PORTB Data Direction Register
58
58
TRISC
PORTC Data Direction Register
58
TMR1L
Timer1 Register Low Byte
56
TMR1H
Timer1 Register High Byte
T1CON
RD16
T1RUN
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
TMR3H
Timer3 Register High Byte
TMR3L
Timer3 Register Low Byte
T3CON
RD16
T3CCP2
56
TMR1CS
TMR1ON
56
57
57
T3CKPS1 T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
57
CCPR1L
Capture/Compare/PWM Register 1 Low Byte
57
CCPR1H
Capture/Compare/PWM Register 1 High Byte
57
CCP1CON
P1M1(2)
P1M0(2)
DC1B1
DC1B0
CCPR2L
Capture/Compare/PWM Register 2 Low Byte
CCPR2H
Capture/Compare/PWM Register 2 High Byte
CCP2CON
—
—
DC2B1
DC2B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
57
57
57
CCP2M3
CCP2M2
CCP2M1
CCP2M0
57
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by Capture/Compare, Timer1 or Timer3.
Note 1: The SBOREN bit is only available when the BOREN Configuration bits = 01; otherwise, it is disabled
and reads as ‘0’. See Section 5.4 “Brown-out Reset (BOR)”.
2: These bits are unimplemented on 28-pin devices and read as ‘0’.
© 2009 Microchip Technology Inc.
DS39689F-page 149
PIC18F2221/2321/4221/4321 FAMILY
16.4
PWM Mode
16.4.1
In Pulse-Width Modulation (PWM) mode, the CCPx pin
produces up to a 10-bit resolution PWM output. Since
the CCP2 pin is multiplexed with a PORTB or PORTC
data latch, the appropriate TRIS bit must be cleared to
make the CCP2 pin an output.
Note:
Clearing the CCP2CON register will force
the RB3 or RC1 output latch (depending on
device configuration) to the default low
level. This is not the PORTB or PORTC I/O
data latch.
Figure 16-3 shows a simplified block diagram of the
CCP module in PWM mode.
For a step-by-step procedure on how to set up the CCP
module for PWM operation, see Section 16.4.4
“Setup for PWM Operation”.
FIGURE 16-3:
SIMPLIFIED PWM BLOCK
DIAGRAM
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following formula:
EQUATION 16-1:
PWM Period = [(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
PWM frequency is defined as 1/[PWM period].
When TMR2 is equal to PR2, the following three events
occur on the next increment cycle:
• TMR2 is cleared
• The CCPx pin is set (exception: if PWM duty
cycle = 0%, the CCPx pin will not be set)
• The PWM duty cycle is latched from CCPRxL into
CCPRxH
Note:
CCPxCON
Duty Cycle Registers
CCPRxL
16.4.2
CCPRxH (Slave)
CCPx Output
Comparator
R
Q
(Note 1)
TMR2
S
Comparator
Clear Timer,
CCPx pin and
latch D.C.
PR2
Corresponding
TRIS bit
Note 1: The 8-bit TMR2 value is concatenated with the 2-bit
internal Q clock, or 2 bits of the prescaler, to create the
10-bit time base.
A PWM output (Figure 16-4) has a time base (period)
and a time that the output stays high (duty cycle).
The frequency of the PWM is the inverse of the
period (1/period).
FIGURE 16-4:
PWM PERIOD
The Timer2 postscalers (see Section 14.0
“Timer2 Module”) are not used in the
determination of the PWM frequency. The
postscaler could be used to have a servo
update rate at a different frequency than
the PWM output.
PWM DUTY CYCLE
The PWM duty cycle is specified by writing to the
CCPRxL register and to the CCPxCON bits. Up
to 10-bit resolution is available. The CCPRxL contains
the eight MSbs and the CCPxCON contains the
two LSbs. This 10-bit value is represented by
CCPRxL:CCPxCON. The following equation is
used to calculate the PWM duty cycle in time:
EQUATION 16-2:
PWM Duty Cycle = (CCPRXL:CCPXCON) •
TOSC • (TMR2 Prescale Value)
CCPRxL and CCPxCON can be written to at any
time, but the duty cycle value is not latched into
CCPRxH until after a match between PR2 and TMR2
occurs (i.e., the period is complete). In PWM mode,
CCPRxH is a read-only register.
PWM OUTPUT
Period
Duty Cycle
TMR2 = PR2
TMR2 = Duty Cycle
TMR2 = PR2
DS39689F-page 150
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
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.
EQUATION 16-3:
F OSC
log ⎛ ---------------⎞
⎝ F PWM⎠
PWM Resolution (max) = -----------------------------bits
log ( 2 )
When the CCPRxH and 2-bit latch match TMR2,
concatenated with an internal 2-bit Q clock or 2 bits of
the TMR2 prescaler, the CCPx pin is cleared.
Note:
The maximum PWM resolution (bits) for a given PWM
frequency is given by the equation:
TABLE 16-4:
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
PWM Frequency
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
16.4.3
If the PWM duty cycle value is longer than
the PWM period, the CCPx pin will not be
cleared.
2.44 kHz
9.77 kHz
39.06 kHz
156.25 kHz
312.50 kHz
416.67 kHz
16
4
1
1
1
1
FFh
FFh
FFh
3Fh
1Fh
17h
10
10
10
8
7
6.58
PWM AUTO-SHUTDOWN
(CCP1 ONLY)
The PWM auto-shutdown features of the Enhanced CCP
module are also available to CCP1 in 28-pin devices. The
operation of this feature is discussed in detail in
Section 17.4.7 “Enhanced PWM Auto-Shutdown”.
16.4.4
The following steps should be taken when configuring
the CCP module for PWM operation:
1.
2.
Auto-shutdown features are not available for CCP2.
3.
4.
5.
© 2009 Microchip Technology Inc.
SETUP FOR PWM OPERATION
Set the PWM period by writing to the PR2
register.
Set the PWM duty cycle by writing to the
CCPRxL register and CCPxCON bits.
Make the CCPx pin an output by clearing the
appropriate TRIS bit.
Set the TMR2 prescale value, then enable
Timer2 by writing to T2CON.
Configure the CCPx module for PWM operation.
DS39689F-page 151
PIC18F2221/2321/4221/4321 FAMILY
TABLE 16-5:
Name
INTCON
REGISTERS ASSOCIATED WITH PWM AND TIMER2
Bit 7
Bit 6
GIE/GIEH PEIE/GIEL
(1)
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
—
RI
TO
PD
POR
BOR
54
PIR1
PSPIF(2)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
58
PIE1
PSPIE
(2)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
58
IPR1
PSPIP(2)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
58
RCON
IPEN
SBOREN
Bit 5
TRISB
PORTB Data Direction Register
58
TRISC
PORTC Data Direction Register
58
TMR2
Timer2 Register
56
PR2
Timer2 Period Register
56
T2CON
—
T2OUTPS3 T2OUTPS2 T2OUTPS1 T2OUTPS0 TMR2ON T2CKPS1 T2CKPS0
CCPR1L
Capture/Compare/PWM Register 1 Low Byte
CCPR1H
Capture/Compare/PWM Register 1 High Byte
CCP1CON
P1M1(2)
P1M0(2)
DC1B1
DC1B0
56
57
57
CCP1M3
CCP1M2
CCP1M1
CCP1M0
57
CCPR2L
Capture/Compare/PWM Register 2 Low Byte
57
CCPR2H
Capture/Compare/PWM Register 2 High Byte
57
CCP2CON
ECCP1AS
ECCP1DEL
—
—
ECCPASE ECCPAS2
PRSEN
PDC6(2)
DC2B1
DC2B0
CCP2M3
CCP2M2
ECCPAS1
ECCPAS0
PSSAC1
PSSAC0 PSSBD1(2) PSSBD0(2)
CCP2M1
57
PDC5(2)
PDC4(2)
PDC3(2)
PDC2(2)
57
PDC1(2)
CCP2M0
PDC0(2)
57
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by PWM or Timer2.
Note 1: The SBOREN bit is only available when the BOREN Configuration bits = 01; otherwise, it is disabled
and reads as ‘0’. See Section 5.4 “Brown-out Reset (BOR)”.
2: These bits are unimplemented on 28-pin devices and read as ‘0’.
DS39689F-page 152
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
17.0
Note:
ENHANCED CAPTURE/
COMPARE/PWM (ECCP)
MODULE
Enhanced features are discussed in detail in
Section 17.4 “Enhanced PWM Mode”. Capture,
Compare and single-output PWM functions of the
ECCP module are the same as described for the
standard CCP module.
The ECCP module is implemented only in
40/44-pin devices.
The control register for the Enhanced CCP module is
shown in Register 17-1. It differs from the CCPxCON
registers in PIC18F2221/2321 devices in that the two
Most Significant bits are implemented to control PWM
functionality.
In PIC18F4221/4321 devices, CCP1 is implemented
as a standard CCP module with Enhanced PWM
capabilities. These include the provision for 2 or
4 output channels, user-selectable polarity, dead-band
control and automatic shutdown and restart. The
REGISTER 17-1:
CCP1CON REGISTER (ECCP1 MODULE, 40/44-PIN DEVICES)
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
bit 7
bit 0
bit 7-6
P1M: Enhanced PWM Output Configuration bits
If CCP1M = 00, 01, 10:
xx = P1A assigned as Capture/Compare input/output; P1B, P1C, P1D assigned as port pins
If CCP1M = 11:
00 = Single output: P1A modulated; P1B, P1C, P1D assigned as port pins
01 = Full-bridge output forward: P1D modulated; P1A active; P1B, P1C inactive
10 = Half-bridge output: P1A, P1B modulated with dead-band control; P1C, P1D assigned
as port pins
11 = Full-bridge output reverse: P1B modulated; P1C active; P1A, P1D inactive
bit 5-4
DC1B: PWM Duty Cycle bit 1 and bit 0
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the 10-bit PWM duty cycle. The eight MSbs of the duty cycle are
found in CCPR1L.
bit 3-0
CCP1M: Enhanced CCP Mode Select bits
0000 = Capture/Compare/PWM off (resets ECCP module)
0001 = Reserved
0010 = Compare mode, toggle output on match
0011 = Capture mode
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 CCP1 pin low, set output on compare match (set CCP1IF)
1001 = Compare mode, initialize CCP1 pin high, clear output on compare match (set CCP1IF)
1010 = Compare mode, generate software interrupt only, CCP1 pin reverts to I/O state
1011 = Compare mode, trigger special event (ECCP resets TMR1 or TMR3, sets CC1IF bit)
1100 = PWM mode; P1A, P1C active-high; P1B, P1D active-high
1101 = PWM mode; P1A, P1C active-high; P1B, P1D active-low
1110 = PWM mode; P1A, P1C active-low; P1B, P1D active-high
1111 = PWM mode; P1A, P1C active-low; P1B, P1D active-low
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 153
PIC18F2221/2321/4221/4321 FAMILY
In addition to the expanded range of modes available
through the CCP1CON and ECCP1AS registers, the
ECCP module has an additional register associated
with Enhanced PWM operation and auto-shutdown
features; it is:
• ECCP1DEL (PWM Dead-Band Delay)
17.1
ECCP Outputs and Configuration
The Enhanced CCP module may have up to four PWM
outputs, depending on the selected operating mode.
These outputs, designated P1A through P1D, are
multiplexed with I/O pins on PORTC and PORTD. The
outputs that are active depend on the CCP operating
mode selected. The pin assignments are summarized
in Table 17-1.
To configure the I/O pins as PWM outputs, the proper
PWM mode must be selected by setting the P1M
and CCP1M bits. The appropriate TRISC and
TRISD direction bits for the port pins must also be set
as outputs.
17.1.1
ECCP MODULES AND TIMER
RESOURCES
Like the standard CCP modules, the ECCP module can
utilize Timers 1, 2 or 3, depending on the mode
selected. Timer1 and Timer3 are available for modules
in Capture or Compare modes, while Timer2 is available for modules in PWM mode. Interactions between
the standard and Enhanced CCP modules are identical
to those described for standard CCP modules.
Additional details on timer resources are provided in
Section 16.1.1
“CCP
Modules
and
Timer
Resources”.
TABLE 17-1:
17.2
Capture and Compare Modes
Except for the operation of the Special Event Trigger
discussed below, the Capture and Compare modes of
the ECCP module are identical in operation to that of
CCP2. These are discussed in detail in Section 16.2
“Capture Mode” and Section 16.3 “Compare
Mode”. No changes are required when moving
between 28-pin and 40/44-pin devices.
17.2.1
SPECIAL EVENT TRIGGER
The Special Event Trigger output of ECCP1 resets the
TMR1 or TMR3 register pair, depending on which timer
resource is currently selected. This allows the CCPR1
register to effectively be a 16-bit programmable period
register for Timer1 or Timer3.
17.3
Standard PWM Mode
When configured in Single Output mode, the ECCP
module functions identically to the standard CCP
module in PWM mode, as described in Section 16.4
“PWM Mode”. This is also sometimes referred to as
“Compatible CCP” mode, as in Table 17-1.
Note:
When setting up single output PWM
operations, users are free to use either
of
the
processes
described
in
Section 16.4.4 “Setup for PWM
Operation” or Section 17.4.9 “Setup
for PWM Operation”. The latter is more
generic and will work for either single or
multi-output PWM.
PIN ASSIGNMENTS FOR VARIOUS ECCP1 MODES
ECCP Mode
CCP1CON
Configuration
RC2
RD5
RD6
RD7
All 40/44-pin devices:
Compatible CCP
00xx 11xx
CCP1
RD5/PSP5
RD6/PSP6
RD7/PSP7
Dual PWM
10xx 11xx
P1A
P1B
RD6/PSP6
RD7/PSP7
Quad PWM
x1xx 11xx
P1A
P1B
P1C
P1D
Legend: x = Don’t care. Shaded cells indicate pin assignments not used by ECCP1 in a given mode.
DS39689F-page 154
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
17.4
Enhanced PWM Mode
17.4.1
PWM PERIOD
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
following equation.
The Enhanced PWM mode provides additional PWM
output options for a broader range of control applications. The module is a backward compatible version of
the standard CCP module and offers up to four outputs,
designated P1A through P1D. Users are also able to
select the polarity of the signal (either active-high or
active-low). The module’s output mode and polarity are
configured by setting the P1M and CCP1M
bits of the CCP1CON register.
EQUATION 17-1:
PWM Period =
PWM frequency is defined as 1/[PWM period]. When
TMR2 is equal to PR2, the following three events occur
on the next increment cycle:
Figure 17-1 shows a simplified block diagram of PWM
operation. All control registers are double-buffered and
are loaded at the beginning of a new PWM cycle (the
period boundary when Timer2 resets) in order to
prevent glitches on any of the outputs. The exception is
the PWM Dead-Band Delay register, ECCP1DEL,
which is loaded at either the duty cycle boundary or the
period boundary (whichever comes first). Because of
the buffering, the module waits until the assigned timer
resets, instead of starting immediately. This means that
Enhanced PWM waveforms do not exactly match the
standard PWM waveforms, but are instead offset by
one full instruction cycle (4 TOSC).
• TMR2 is cleared
• The CCP1 pin is set (if PWM duty cycle = 0%, the
CCP1 pin will not be set)
• The PWM duty cycle is copied from CCPR1L into
CCPR1H
Note:
As before, the user must manually configure the
appropriate TRIS bits for output.
FIGURE 17-1:
[(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
The Timer2 postscaler (see Section 14.0
“Timer2 Module”) is not used in the
determination of the PWM frequency. The
postscaler could be used to have a servo
update rate at a different frequency than
the PWM output.
SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODULE
Duty Cycle Registers
CCP1CON
CCP1M
4
P1M1
2
CCPR1L
CCP1/P1A
CCP1/P1A
TRISx
CCPR1H (Slave)
P1B
R
Comparator
Q
Output
Controller
P1B
TRISx
P1C
TMR2
Comparator
PR2
(Note 1)
P1C
TRISx
S
P1D
Clear Timer,
set CCP1 pin and
latch D.C.
P1D
TRISx
ECCP1DEL
Note: The 8-bit TMR2 register is concatenated with the 2-bit internal Q clock, or 2 bits of the prescaler, to create the 10-bit
time base.
© 2009 Microchip Technology Inc.
DS39689F-page 155
PIC18F2221/2321/4221/4321 FAMILY
17.4.2
PWM DUTY CYCLE
EQUATION 17-3:
The PWM duty cycle is specified by writing to the
CCPR1L register and to the CCP1CON bits. Up
to 10-bit resolution is available. The CCPR1L contains
the eight MSbs and the CCP1CON contains the
two LSbs. This 10-bit value is represented by
CCPR1L:CCP1CON. The PWM duty cycle is
calculated by the following equation.
(
log FOSC
FPWM
PWM Resolution (max) =
log(2)
Note:
EQUATION 17-2:
17.4.3
PWM Duty Cycle = (CCPR1L:CCP1CON) •
TOSC • (TMR2 Prescale Value)
CCPR1L and CCP1CON can be written to at any
time, but the duty cycle value is not copied into
CCPR1H until a match between PR2 and TMR2 occurs
(i.e., the period is complete). In PWM mode, CCPR1H
is a read-only register.
The CCPR1H 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. When the CCPR1H and 2-bit latch match
TMR2, concatenated with an internal 2-bit Q clock or
two bits of the TMR2 prescaler, the CCP1 pin is
cleared. The maximum PWM resolution (bits) for a
given PWM frequency is given by the following
equation.
TABLE 17-2:
) bits
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
PWM OUTPUT CONFIGURATIONS
The P1M bits in the CCP1CON register allow one
of four configurations:
•
•
•
•
Single Output
Half-Bridge Output
Full-Bridge Output, Forward mode
Full-Bridge Output, Reverse mode
The Single Output mode is the standard PWM mode
discussed in Section 17.4 “Enhanced PWM Mode”.
The Half-Bridge and Full-Bridge Output modes are
covered in detail in the sections that follow.
The general relationship of the outputs in all
configurations is summarized in Figure 17-2.
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
PWM Frequency
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
DS39689F-page 156
2.44 kHz
9.77 kHz
39.06 kHz
156.25 kHz
312.50 kHz
416.67 kHz
16
4
1
1
1
1
FFh
FFh
FFh
3Fh
1Fh
17h
10
10
10
8
7
6.58
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 17-2:
PWM OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE)
CCP1CON
00
(Single Output)
SIGNAL
0
P1A Modulated
Duty
Cycle
Delay(1)
PR2 + 1
Period
Delay(1)
P1A Modulated
10
(Half-Bridge)
P1B Modulated
P1A Active
01
(Full-Bridge,
Forward)
P1B Inactive
P1C Inactive
P1D Modulated
P1A Inactive
11
(Full-Bridge,
Reverse)
P1B Modulated
P1C Active
P1D Inactive
FIGURE 17-3:
PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
CCP1CON
00
(Single Output)
SIGNAL
0
Duty
Cycle
PR2 + 1
Period
P1A Modulated
P1A Modulated
10
(Half-Bridge)
Delay(1)
Delay(1)
P1B Modulated
P1A Active
01
(Full-Bridge,
Forward)
P1B Inactive
P1C Inactive
P1D Modulated
P1A Inactive
11
(Full-Bridge,
Reverse)
P1B Modulated
P1C Active
P1D Inactive
Relationships:
• Period = 4 * TOSC * (PR2 + 1) * (TMR2 Prescale Value)
• Duty Cycle = TOSC * (CCPR1L:CCP1CON) * (TMR2 Prescale Value)
• Delay = 4 * TOSC * (ECCP1DEL)
Note 1: Dead-band delay is programmed using the ECCP1DEL register (see Section 17.4.6 “Programmable
Dead-Band Delay”).
© 2009 Microchip Technology Inc.
DS39689F-page 157
PIC18F2221/2321/4221/4321 FAMILY
17.4.4
HALF-BRIDGE MODE
FIGURE 17-4:
In the Half-Bridge Output mode, two pins are used as
outputs to drive push-pull loads. The PWM output signal
is output on the P1A pin, while the complementary PWM
output signal is output on the P1B pin (Figure 17-4). This
mode can be used for half-bridge applications, as shown
in Figure 17-5, or for full-bridge applications where four
power switches are being modulated with two PWM
signals.
In Half-Bridge Output mode, the programmable deadband delay can be used to prevent shoot-through
current in half-bridge power devices. The value of bits,
PDC, 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 17.4.6
“Programmable Dead-Band Delay” for more details
of the dead-band delay operations.
HALF-BRIDGE PWM
OUTPUT
Period
Period
Duty Cycle
P1A(2)
td
td
P1B(2)
(1)
(1)
(1)
td = Dead-Band Delay
Note 1: At this time, the TMR2 register is equal to the
PR2 register.
2: Output signals are shown as active-high.
Since the P1A and P1B outputs are multiplexed with
the PORTC and PORTD data latches, the
TRISC and TRISD bits must be cleared to
configure P1A and P1B as outputs.
FIGURE 17-5:
EXAMPLES OF HALF-BRIDGE OUTPUT MODE APPLICATIONS
V+
Standard Half-Bridge Circuit (“Push-Pull”)
PIC18F4X21
FET
Driver
+
V
-
P1A
Load
FET
Driver
+
V
-
P1B
VHalf-Bridge Output Driving a Full-Bridge Circuit
V+
PIC18F4X21
FET
Driver
FET
Driver
P1A
FET
Driver
Load
FET
Driver
P1B
V-
DS39689F-page 158
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
17.4.5
FULL-BRIDGE MODE
In Full-Bridge Output mode, four pins are used as
outputs; however, only two outputs are active at a time.
In the Forward mode, pin P1A is continuously active
and pin P1D is modulated. In the Reverse mode, pin
P1C is continuously active and pin P1B is modulated.
These are illustrated in Figure 17-6.
FIGURE 17-6:
P1A, P1B, P1C and P1D outputs are multiplexed with
the PORTC and PORTD data latches. The
TRISC and TRISD bits must be cleared to
make the P1A, P1B, P1C and P1D pins outputs.
FULL-BRIDGE PWM OUTPUT
Forward Mode
Period
P1A
(2)
Duty Cycle
P1B(2)
P1C(2)
P1D(2)
(1)
(1)
Reverse Mode
Period
Duty Cycle
P1A(2)
P1B(2)
P1C(2)
P1D(2)
(1)
(1)
Note 1: At this time, the TMR2 register is equal to the PR2 register.
Note 2: Output signal is shown as active-high.
© 2009 Microchip Technology Inc.
DS39689F-page 159
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 17-7:
EXAMPLE OF FULL-BRIDGE APPLICATION
V+
PIC18F4X21
FET
Driver
QC
QA
FET
Driver
P1A
Load
P1B
FET
Driver
P1C
FET
Driver
QD
QB
VP1D
17.4.5.1
Direction Change in Full-Bridge Mode
In the Full-Bridge Output mode, the P1M1 bit in the
CCP1CON register allows user to control the forward/
reverse direction. When the application firmware
changes this direction control bit, the module will
assume the new direction on the next PWM cycle.
Just before the end of the current PWM period, the
modulated outputs (P1B and P1D) are placed in their
inactive state, while the unmodulated outputs (P1A and
P1C) are switched to drive in the opposite direction.
This occurs in a time interval of 4 TOSC * (Timer2
Prescale Value) before the next PWM period begins.
The Timer2 prescaler will be either 1, 4 or 16, depending on the value of the T2CKPS bits
(T2CON). During the interval from the switch of
the unmodulated outputs to the beginning of the next
period, the modulated outputs (P1B and P1D) remain
inactive. This relationship is shown in Figure 17-8.
Note that in the Full-Bridge Output mode, the ECCP1
module does not provide any dead-band delay. In
general, since only one output is modulated at all times,
dead-band delay is not required. However, there is a
situation where a dead-band delay might be required.
This situation occurs when both of the following
conditions are true:
1.
2.
Figure 17-9 shows an example where the PWM
direction changes from forward to reverse at a near
100% duty cycle. At time t1, the outputs P1A and P1D
become inactive, while output P1C becomes active. In
this example, since the turn-off time of the power
devices is longer than the turn-on time, a shoot-through
current may flow through power devices, QC and QD
(see Figure 17-7), 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, one of the following requirements
must be met:
1.
2.
Reduce PWM for a 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.
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.
DS39689F-page 160
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 17-8:
PWM DIRECTION CHANGE
Period(1)
SIGNAL
Period
P1A (Active-High)
P1B (Active-High)
DC
P1C (Active-High)
(Note 2)
P1D (Active-High)
DC
Note 1: The direction bit in the CCP1 Control register (CCP1CON) is written any time during the PWM cycle.
2: When changing directions, the P1A and P1C signals switch before the end of the current PWM cycle at intervals
of 4 TOSC, 16 TOSC or 64 TOSC, depending on the Timer2 prescaler value. The modulated P1B and P1D signals
are inactive at this time.
FIGURE 17-9:
PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE
Forward Period
t1
Reverse Period
P1A(1)
P1B(1)
DC
P1C(1)
P1D(1)
DC
tON(2)
External Switch C(1)
tOFF(3)
External Switch D(1)
Potential
Shoot-Through
Current(1)
t = tOFF – tON(2,3)
Note 1: 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.
© 2009 Microchip Technology Inc.
DS39689F-page 161
PIC18F2221/2321/4221/4321 FAMILY
17.4.6
Note:
PROGRAMMABLE DEAD-BAND
DELAY
Programmable dead-band delay is not
implemented in 28-pin devices with
standard CCP modules.
In half-bridge applications, where all power switches
are modulated at the PWM frequency at all times, 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 (shootthrough current) may 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.
In the Half-Bridge Output 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 nonactive
state to the active state (see Figure 17-4 for illustration). Bits PDC of the ECCP1DEL register
(Register 17-2) set the delay period in terms of microcontroller instruction cycles (TCY or 4 TOSC). These bits
are not available on 28-pin devices as the standard
CCP module does not support half-bridge operation.
17.4.7
ENHANCED PWM AUTO-SHUTDOWN
A shutdown event can be caused by either of the
comparator modules, a low level on the Fault input pin
(FLT0) or any combination of these three sources. The
comparators may be used to monitor a voltage input
proportional to a current being monitored in the bridge
circuit. If the voltage exceeds a threshold, the
comparator switches state and triggers a shutdown.
Alternatively, a low digital signal on FLT0 can also trigger
a shutdown. The auto-shutdown feature can be disabled
by not selecting any auto-shutdown sources. The autoshutdown sources to be used are selected using the
ECCPAS bits (ECCP1AS).
When a shutdown occurs, the output pins are asynchronously placed in their shutdown states, specified
by the PSSAC and PSSBD bits
(ECCP1AS). Each pin pair (P1A/P1C and P1B/
P1D) may be set to drive high, drive low or be tri-stated
(not driving). The ECCPASE bit (ECCP1AS) is also
set to hold the Enhanced PWM outputs in their
shutdown states.
The ECCPASE bit is set by hardware when a shutdown
event occurs. If automatic restarts are not enabled, the
ECCPASE bit is cleared by firmware when the cause of
the shutdown clears. If automatic restarts are enabled,
the ECCPASE bit is automatically cleared when the
cause of the auto-shutdown has cleared.
If the ECCPASE bit is set when a PWM period begins,
the PWM outputs remain in their shutdown state for that
entire PWM period. When the ECCPASE bit is cleared,
the PWM outputs will return to normal operation at the
beginning of the next PWM period.
Note:
When the ECCP1 is programmed for any of the
Enhanced PWM modes, the active output pins may be
configured for auto-shutdown. Auto-shutdown immediately places the Enhanced PWM output pins into a
defined shutdown state when a shutdown event occurs.
REGISTER 17-2:
Writing to the ECCPASE bit is disabled
while a shutdown condition is active.
ECCP1DEL: PWM DEAD-BAND DELAY REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
PRSEN
PDC6(1)
PDC5(1)
PDC4(1)
PDC3(1)
PDC2(1)
PDC1(1)
PDC0(1)
bit 7
bit 0
bit 7
PRSEN: PWM Restart Enable bit
1 = Upon auto-shutdown, the ECCPASE bit clears automatically once the shutdown event
goes away; the PWM restarts automatically
0 = Upon auto-shutdown, ECCPASE must be cleared in software to restart the PWM
bit 6-0
PDC: PWM Delay Count bits(1)
Delay time, in number of FOSC/4 (4 * TOSC) cycles, between the scheduled and actual time for
a PWM signal to transition to active.
Note 1: Unimplemented on 28-pin devices; bits read ‘0’.
Legend:
DS39689F-page 162
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
x = Bit is unknown
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 17-3:
ECCP1AS: ENHANCED CAPTURE/COMPARE/PWM AUTO-SHUTDOWN
CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 PSSAC1 PSSAC0 PSSBD1(1) PSSBD0(1)
bit 7
bit 0
bit 7
ECCPASE: ECCP Auto-Shutdown Event Status bit
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
0 = ECCP outputs are operating
bit 6-4
ECCPAS: ECCP Auto-Shutdown Source Select bits
111 = FLT0 or Comparator 1 or Comparator 2
110 = FLT0 or Comparator 2
101 = FLT0 or Comparator 1
100 = FLT0
011 = Either Comparator 1 or 2
010 = Comparator 2 output
001 = Comparator 1 output
000 = Auto-shutdown is disabled
bit 3-2
PSSAC: Pins A and C Shutdown State Control bits
1x = Pins A and C are tri-state (40/44-pin devices);
PWM output is tri-state (28-pin devices)
01 = Drive Pins A and C to ‘1’
00 = Drive Pins A and C to ‘0’
bit 1-0
PSSBD: Pins B and D Shutdown State Control bits(1)
1x = Pins B and D tri-state
01 = Drive Pins B and D to ‘1’
00 = Drive Pins B and D to ‘0’
Note 1: Unimplemented on 28-pin devices; bits read as ‘0’.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 163
PIC18F2221/2321/4221/4321 FAMILY
17.4.7.1
Auto-Shutdown and
Automatic Restart
The auto-shutdown feature can be configured to allow
automatic restarts of the module following a shutdown
event. This is enabled by setting the PRSEN bit of the
ECCP1DEL register (ECCP1DEL).
In Shutdown mode with PRSEN = 1 (Figure 17-10), the
ECCPASE bit will remain set for as long as the cause
of the shutdown continues. When the shutdown condition clears, the ECCP1ASE bit is cleared. If PRSEN = 0
(Figure 17-11), once a shutdown condition occurs, the
ECCPASE bit will remain set until it is cleared by
firmware. Once ECCPASE is cleared, the Enhanced
PWM will resume at the beginning of the next PWM
period.
Note:
Writing to the ECCPASE bit is disabled
while a shutdown condition is active.
Independent of the PRSEN bit setting, if the autoshutdown source is one of the comparators, the
shutdown condition is a level. The ECCPASE bit
cannot be cleared as long as the cause of the shutdown
persists.
The Auto-Shutdown mode can be forced by writing a ‘1’
to the ECCPASE bit.
FIGURE 17-10:
17.4.8
START-UP CONSIDERATIONS
When the ECCP module is used in the PWM mode, the
application hardware must use the proper external pullup and/or pull-down resistors on the PWM output pins.
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).
The CCP1M bits (CCP1CON) allow the
user to choose whether the PWM output signals are
active-high or active-low for each pair of PWM output
pins (P1A/P1C and P1B/P1D). The PWM output
polarities must be selected before the PWM pins are
configured as outputs. Changing the polarity configuration while the PWM pins are configured as outputs is
not recommended, since it may result in damage to the
application circuits.
The P1A, P1B, P1C and P1D output latches may not be
in the proper states when the PWM module is initialized.
Enabling the PWM pins for output at the same time as
the ECCP module may cause damage to the application circuit. The ECCP module must be enabled in the
proper output mode and complete a full PWM cycle
before configuring the PWM pins as outputs. The completion of a full PWM cycle is indicated by the TMR2IF
bit being set as the second PWM period begins.
PWM AUTO-SHUTDOWN (PRSEN = 1, AUTO-RESTART ENABLED)
PWM Period
PWM Activity
Dead Time
Duty Cycle
PWM Period
Dead Time
Duty Cycle
PWM Period
Dead Time
Duty Cycle
Shutdown Event
ECCPASE bit
FIGURE 17-11:
PWM AUTO-SHUTDOWN (PRSEN = 0, AUTO-RESTART DISABLED)
PWM Period
PWM Activity
Dead Time
Duty Cycle
PWM Period
Dead Time
Duty Cycle
PWM Period
Dead Time
Duty Cycle
Shutdown Event
ECCPASE bit
ECCPASE
Cleared by Firmware
DS39689F-page 164
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
17.4.9
SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the ECCP module for PWM operation:
1.
Configure the PWM pins, P1A and P1B (and
P1C and P1D, if used), as inputs by setting the
corresponding TRIS bits.
2. Set the PWM period by loading the PR2 register.
3. If auto-shutdown is required, do the following:
• Disable auto-shutdown (ECCPASE = 0)
• Configure source (FLT0, Comparator 1 or
Comparator 2)
• Wait for non-shutdown condition
4. Configure the ECCP module for the desired
PWM mode and configuration by loading the
CCP1CON register with the appropriate values:
• Select one of the available output
configurations and direction with the P1M 25°C. Below 25°C, TCOFF = 0 ms.
TC
=
-(CHOLD)(RIC + RSS + RS) ln(1/2047)
-(25 pF) (1 kΩ + 2 kΩ + 2.5 kΩ) ln(0.0004883)
1.05 μs
TACQ
=
0.2 μs + 1 μs + 1.2 μs
2.4 μs
DS39689F-page 238
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
20.2
Selecting and Configuring
Acquisition Time
20.3
Selecting the A/D Conversion
Clock
The ADCON2 register allows the user to select an
acquisition time that occurs each time the GO/DONE
bit is set. It also gives users the option to use an
automatically determined acquisition time.
The A/D conversion time per bit is defined as TAD. The
A/D conversion requires 11 TAD per 10-bit conversion.
The source of the A/D conversion clock is software
selectable. There are seven possible options for TAD:
Acquisition time may be set with the ACQT bits
(ADCON2), which provides a range of 2 to
20 TAD. When the GO/DONE bit is set, the A/D module
continues to sample the input for the selected acquisition time, then automatically begins a conversion.
Since the acquisition time is programmed, there may
be no need to wait for an acquisition time between
selecting a channel and setting the GO/DONE bit.
•
•
•
•
•
•
•
Manual
acquisition
is
selected
when
ACQT = 000. When the GO/DONE bit is set,
sampling is stopped and a conversion begins. The user
is responsible for ensuring the required acquisition time
has passed between selecting the desired input
channel and setting the GO/DONE bit. This option is
also the default Reset state of the ACQT bits and
is compatible with devices that do not offer
programmable acquisition times.
For correct A/D conversions, the A/D conversion clock
(TAD) must be as short as possible, but greater than the
minimum TAD (see parameter 130 for more
information).
2 TOSC
4 TOSC
8 TOSC
16 TOSC
32 TOSC
64 TOSC
Internal RC Oscillator
Table 20-1 shows the resultant TAD times derived from
the device operating frequencies and the A/D clock
source selected.
In either case, when the conversion is completed, the
GO/DONE bit is cleared, the ADIF flag is set and the
A/D begins sampling the currently selected channel
again. If an acquisition time is programmed, there is
nothing to indicate if the acquisition time has ended or
if the conversion has begun.
TABLE 20-1:
TAD vs. DEVICE OPERATING FREQUENCIES
AD Clock Source (TAD)
Operation
ADCS
PIC18F2X21/4X21
PIC18LF2X21/4X21(4)
2 TOSC
000
2.86 MHz
1.43 kHz
4 TOSC
100
5.71 MHz
2.86 MHz
8 TOSC
001
11.43 MHz
5.72 MHz
16 TOSC
101
22.86 MHz
11.43 MHz
32 TOSC
010
40.0 MHz
22.86 MHz
64 TOSC
110
40.0 MHz
22.86 MHz
RC(3)
Note 1:
2:
3:
4:
Maximum Device Frequency
x11
1.00
MHz(1)
1.00 MHz(2)
The RC source has a typical TAD time of 1.2 μs.
The RC source has a typical TAD time of 2.5 μs.
For device frequencies above 1 MHz, the device must be in Sleep for the entire conversion or the A/D
accuracy may be out of specification.
Low-power (PIC18LFXXXX) devices only.
© 2009 Microchip Technology Inc.
DS39689F-page 239
PIC18F2221/2321/4221/4321 FAMILY
20.4
Operation in Power-Managed
Modes
The selection of the automatic acquisition time and A/D
conversion clock is determined in part by the clock
source and frequency while in a power-managed mode.
If the A/D is expected to operate while the device is in
a power-managed mode, the ACQT and
ADCS bits in ADCON2 should be updated in
accordance with the clock source to be used in that
mode. After entering the mode, an A/D acquisition or
conversion may be started. Once started, the device
should continue to be clocked by the same clock
source until the conversion has been completed.
If desired, the device may be placed into the
corresponding Idle mode during the conversion. If the
device clock frequency is less than 1 MHz, the A/D RC
clock source should be selected.
Operation in Sleep mode requires the A/D FRC clock to
be selected. If bits ACQT are set to ‘000’ and a
conversion is started, the conversion will be delayed
one instruction cycle to allow execution of the SLEEP
instruction and entry to Sleep mode. The IDLEN bit
(OSCCON) must have already been cleared prior
to starting the conversion.
DS39689F-page 240
20.5
Configuring Analog Port Pins
The ADCON1, TRISA, TRISB and TRISE registers all
configure the A/D port pins. The port pins needed as
analog inputs must have their corresponding TRIS bits
set (input). If the TRIS bit is cleared (output), the digital
output level (VOH or VOL) will be converted.
The A/D operation is independent of the state of the
CHS bits and the TRIS bits.
Note 1: When reading the Port register, all pins
configured as analog input channels will
read as cleared (a low level). Pins
configured as digital inputs will convert as
analog inputs. Analog levels on a digitally
configured input will be accurately
converted.
2: Analog levels on any pin defined as a
digital input may cause the digital input
buffer to consume current out of the
device’s specification limits.
3: The PBADEN bit in Configuration
Register 3H configures PORTB pins to
reset as analog or digital pins by controlling how the PCFG bits in ADCON1
are reset.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
20.6
A/D Conversions
After the A/D conversion is completed or aborted, a
2 TAD wait is required before the next acquisition can be
started. After this wait, acquisition on the selected
channel is automatically started.
Figure 20-4 shows the operation of the A/D converter
after the GO/DONE bit has been set and the
ACQT bits are cleared. A conversion is started
after the following instruction to allow entry into Sleep
mode before the conversion begins.
Note:
Figure 20-5 shows the operation of the A/D converter
after the GO/DONE bit has been set and the
ACQT bits are set to ‘010’ and selecting a 4 TAD
acquisition time before the conversion starts.
20.7
Discharge
The discharge phase is used to initialize the value of
the capacitor array. The array is discharged before
every sample. This feature helps to optimize the unitygain amplifier, as the circuit always needs to charge the
capacitor array, rather than charge/discharge based on
previous measure values.
Clearing the GO/DONE bit during a conversion will abort
the current conversion. The A/D Result register pair will
NOT be updated with the partially completed A/D
conversion sample. This means the ADRESH:ADRESL
registers will continue to contain the value of the last
completed conversion (or the last value written to the
ADRESH:ADRESL registers).
FIGURE 20-4:
The GO/DONE bit should NOT be set in
the same instruction that turns on the A/D.
A/D CONVERSION TAD CYCLES (ACQT = 000, TACQ = 0)
TCY - TAD TAD1 TAD2 TAD3 TAD4 TAD5 TAD6 TAD7 TAD8 TAD9 TAD10 TAD11 TAD1
b4
b1
b0
b6
b7
b2
b9
b8
b3
b5
Conversion starts
Discharge
Holding capacitor is disconnected from analog input (typically 100 ns)
Set GO/DONE bit
On the following cycle:
ADRESH:ADRESL is loaded, GO/DONE bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
FIGURE 20-5:
A/D CONVERSION TAD CYCLES (ACQT = 010, TACQ = 4 TAD)
TAD Cycles
TACQT Cycles
1
2
3
Automatic
Acquisition
Time
4
1
2
3
4
5
6
7
8
9
10
11
b9
b8
b7
b6
b5
b4
b3
b2
b1
b0
Conversion starts
(Holding capacitor is disconnected)
Set GO/DONE bit
(Holding capacitor continues
acquiring input)
© 2009 Microchip Technology Inc.
TAD1
Discharge
On the following cycle:
ADRESH:ADRESL is loaded, GO/DONE bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
DS39689F-page 241
PIC18F2221/2321/4221/4321 FAMILY
20.8
Use of the CCP2 Trigger
An A/D conversion can be started by the Special Event
Trigger of the CCP2 module. This requires that the
CCP2M bits (CCP2CON) be programmed
as ‘1011’ and that the A/D module is enabled (ADON
bit is set). When the trigger occurs, the GO/DONE bit
will be set, starting the A/D acquisition and conversion
and the Timer1 (or Timer3) counter will be reset to zero.
Timer1 (or Timer3) is reset to automatically repeat the
A/D acquisition period with minimal software overhead
TABLE 20-2:
Name
(moving ADRESH:ADRESL to the desired location).
The appropriate analog input channel must be selected
and the minimum acquisition period is either timed by
the user, or an appropriate TACQ time selected before
the Special Event Trigger sets the GO/DONE bit (starts
a conversion).
If the A/D module is not enabled (ADON is cleared), the
Special Event Trigger will be ignored by the A/D module
but will still reset the Timer1 (or Timer3) counter.
REGISTERS ASSOCIATED WITH A/D OPERATION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
INTCON
GIE/GIEH PEIE/GIEL
PIR1
PSPIF(1)
ADIF
RCIF
TXIF
SSPIF
CCP1IF
TMR2IF
TMR1IF
58
PIE1
PSPIE(1)
ADIE
RCIE
TXIE
SSPIE
CCP1IE
TMR2IE
TMR1IE
58
IPR1
PSPIP(1)
ADIP
RCIP
TXIP
SSPIP
CCP1IP
TMR2IP
TMR1IP
58
PIR2
OSCFIF
CMIF
—
EEIF
BCLIF
HLVDIF
TMR3IF
CCP2IF
58
PIE2
OSCFIE
CMIE
—
EEIE
BCLIE
HLVDIE
TMR3IE
CCP2IE
58
IPR2
OSCFIP
CMIP
—
EEIP
BCLIP
HLVDIP
TMR3IP
CCP2IP
58
ADRESH
A/D Result Register High Byte
57
ADRESL
A/D Result Register Low Byte
57
ADCON0
—
—
CHS3
CHS2
CHS1
CHS0
GO/DONE
ADON
57
ADCON1
—
—
VCFG1
VCFG0
PCFG3
PCFG2
PCFG1
PCFG0
57
ADCON2
ADFM
—
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
57
PORTA
RA7(2)
RA6(2)
RA5
RA4
RA3
RA2
RA1
RA0
58
RB1
RB0
58
TRISA
PORTB
TRISA7(2) TRISA6(2) PORTA Data Direction Control Register
RB7
RB6
RB5
RB4
RB3
RB2
58
TRISB
PORTB Data Direction Control Register
58
LATB
PORTB Data Latch Register (Read and Write to Data Latch)
58
—
—
—
—
RE3(3)
RE2(1)
RE1(1)
RE0(1)
58
TRISE
IBF
OBF
IBOV
PSPMODE
—
TRISE2
TRISE1
TRISE0
58
LATE(1)
—
—
—
—
—
PORTE
(1)
PORTE Data Latch Register
58
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used for A/D conversion.
Note 1: These registers and/or bits are unimplemented on 28-pin devices and are read as ‘0’.
2: PORTA and their direction bits are individually configured as port pins based on various primary
oscillator modes. When disabled, these bits read as ‘0’.
3: RE3 port bit is available only as an input pin when the MCLRE Configuration bit is ‘0’.
DS39689F-page 242
© 2009 Microchip Technology Inc.
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21.0
COMPARATOR MODULE
The analog comparator module contains two
comparators that can be configured in a variety of
ways. The inputs can be selected from the analog
inputs multiplexed with pins RA0 through RA5, as well
as the on-chip voltage reference (see Section 22.0
“Comparator Voltage Reference Module”). The digital outputs (normal or inverted) are available at the pin
level and can also be read through the control register.
REGISTER 21-1:
The CMCON register (Register 21-1) selects the
comparator input and output configuration. Block
diagrams of the various comparator configurations are
shown in Figure 21-1.
CMCON: COMPARATOR CONTROL REGISTER
R-0
R-0
R/W-0
R/W-0
R/W-0
R/W-1
R/W-1
R/W-1
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
bit 7
bit 0
bit 7
C2OUT: Comparator 2 Output bit
When C2INV = 0:
1 = C2 VIN+ > C2 VIN0 = C2 VIN+ < C2 VINWhen C2INV = 1:
1 = C2 VIN+ < C2 VIN0 = C2 VIN+ > C2 VIN-
bit 6
C1OUT: Comparator 1 Output bit
When C1INV = 0:
1 = C1 VIN+ > C1 VIN0 = C1 VIN+ < C1 VINWhen C1INV = 1:
1 = C1 VIN+ < C1 VIN0 = C1 VIN+ > C1 VIN-
bit 5
C2INV: Comparator 2 Output Inversion bit
1 = C2 output inverted
0 = C2 output not inverted
bit 4
C1INV: Comparator 1 Output Inversion bit
1 = C1 output inverted
0 = C1 output not inverted
bit 3
CIS: Comparator Input Switch bit
When CM = 110:
1 = C1 VIN- connects to RA3/AN3/VREF+
C2 VIN- connects to RA2/AN2/VREF-/CVREF
0 = C1 VIN- connects to RA0/AN0
C2 VIN- connects to RA1/AN1
bit 2-0
CM: Comparator Mode bits
Figure 21-1 shows the Comparator modes and the CM bit settings.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 243
PIC18F2221/2321/4221/4321 FAMILY
21.1
Comparator Configuration
There are eight modes of operation for the comparators,
shown in Figure 21-1. Bits CM of the CMCON
register are used to select these modes. The TRISA register controls the data direction of the comparator pins
for each mode. If the Comparator mode is changed, the
FIGURE 21-1:
VIN-
RA3/AN3/ A
VREF+
VIN+
A
VIN-
RA2/AN2/ A
VREF-/CVREF
VIN+
C1
Off (Read as ‘0’)
C2
Off (Read as ‘0’)
Two Independent Comparators
CM = 010
A
VIN-
RA3/AN3/ A
VREF+
VIN+
A
VIN-
RA2/AN2/ A
VREF-/CVREF
VIN+
RA0/AN0
Comparator interrupts should be disabled
during a Comparator mode change;
otherwise, a false interrupt may occur.
Comparators Off (POR Default Value)
CM = 111
A
RA1/AN1
Note:
COMPARATOR I/O OPERATING MODES
Comparators Reset
CM = 000
RA0/AN0
comparator output level may not be valid for the
specified mode change delay shown in Section 27.0
“Electrical Characteristics”.
C1
RA0/AN0
D
VIN-
RA3/AN3/
VREF+
D
VIN+
RA1/AN1
D
VIN-
D
RA2/AN2/
VREF-/CVREF
VIN+
C1
Off (Read as ‘0’)
C2
Off (Read as ‘0’)
Two Independent Comparators with Outputs
CM = 011
C1OUT
RA0/AN0
RA3/AN3/
VREF+
A
VIN-
A
VIN+
C1
C1OUT
C2
C2OUT
RA4/T0CKI/C1OUT*
RA1/AN1
C2
C2OUT
A
VIN-
RA2/AN2/ A
VREF-/CVREF
VIN+
RA1/AN1
RA5/AN4/SS/HLVDIN/C2OUT*
Two Common Reference Comparators
CM = 100
A
VIN-
RA3/AN3/ A
VREF+
VIN+
A
VIN-
RA2/AN2/ D
VREF-/CVREF
VIN+
RA0/AN0
C1
Two Common Reference Comparators with Outputs
CM = 101
C1OUT
RA0/AN0
RA3/AN3/
VREF+
A
VIN-
A
VIN+
C1
C1OUT
C2
C2OUT
RA4/T0CKI/C1OUT*
RA1/AN1
C2
C2OUT
A
VIN-
RA2/AN2/
D
VREF-/CVREF
VIN+
RA1/AN1
RA5/AN4/SS/HLVDIN/C2OUT*
One Independent Comparator with Output
CM = 001
A
VIN-
RA3/AN3/ A
VREF+
VIN+
RA0/AN0
C1
C1OUT
RA4/T0CKI/C1OUT*
D
VIN-
RA2/AN2/ D
VREF-/CVREF
VIN+
RA1/AN1
Four Inputs Multiplexed to Two Comparators
CM = 110
RA0/AN0
A
RA3/AN3/
VREF+
A
RA1/AN1
A
A
RA2/AN2/
VREF-/CVREF
C2
Off (Read as ‘0’)
CIS = 0
CIS = 1
VIN-
CIS = 0
CIS = 1
VIN-
VIN+
VIN+
C1
C1OUT
C2
C2OUT
CVREF
From VREF Module
A = Analog Input, port reads zeros always
D = Digital Input
CIS (CMCON) is the Comparator Input Switch
* Setting the TRISA bits will disable the comparator outputs by configuring the pins as inputs.
DS39689F-page 244
© 2009 Microchip Technology Inc.
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21.2
Comparator Operation
21.3.2
INTERNAL REFERENCE SIGNAL
A single comparator is shown in Figure 21-2, along with
the relationship between the analog input levels and
the digital output. When the analog input at VIN+ is less
than the analog input VIN-, the output of the comparator
is a digital low level. When the analog input at VIN+ is
greater than the analog input VIN-, the output of the
comparator is a digital high level. The shaded areas of
the output of the comparator in Figure 21-2 represent
the uncertainty, due to input offsets and response time.
The comparator module also allows the selection of an
internally generated voltage reference from the
comparator voltage reference module. This module is
described in more detail in Section 22.0 “Comparator
Voltage Reference Module”.
21.3
21.4
Comparator Reference
Depending on the comparator operating mode, either
an external or internal voltage reference may be used.
The analog signal present at VIN- is compared to the
signal at VIN+ and the digital output of the comparator
is adjusted accordingly (Figure 21-2).
FIGURE 21-2:
VIN+
VIN-
SINGLE COMPARATOR
+
–
The internal reference is only available in the mode
where four inputs are multiplexed to two comparators
(CM = 110). In this mode, the internal voltage reference is applied to the VIN+ pin of both comparators.
Response time is the minimum time, after selecting a
new reference voltage or input source, before the
comparator output has a valid level. If the internal reference is changed, the maximum delay of the internal
voltage reference must be considered when using the
comparator outputs. Otherwise, the maximum delay of
the comparators should be used (see Section 27.0
“Electrical Characteristics”).
21.5
Output
VINVIN+
Comparator Response Time
Comparator Outputs
The comparator outputs are read through the CMCON
register. These bits are read-only. The comparator
outputs may also be directly output to the RA4 and RA5
I/O pins. When enabled, multiplexors in the output path
of the RA4 and RA5 pins will switch and the output of
each pin will be the unsynchronized output of the
comparator. The uncertainty of each of the
comparators is related to the input offset voltage and
the response time given in the specifications.
Figure 21-3 shows the comparator output block
diagram.
The TRISA bits will still function as an output enable/
disable for the RA4 and RA5 pins while in this mode.
Output
The polarity of the comparator outputs can be changed
using the C2INV and C1INV bits (CMCON).
21.3.1
EXTERNAL REFERENCE SIGNAL
When external voltage references are used, the
comparator module can be configured to have the
comparators operate from the same or different
reference sources. However, threshold detector
applications may require the same reference. The
reference signal must be between VSS and VDD and
can be applied to either pin of the comparator(s).
© 2009 Microchip Technology Inc.
Note 1: When reading the Port register, all pins
configured as analog inputs will read as a
‘0’. Pins configured as digital inputs will
convert an analog input according to the
Schmitt Trigger 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.
DS39689F-page 245
PIC18F2221/2321/4221/4321 FAMILY
+
To RA4 or
RA5 pin
-
Port Pins
COMPARATOR OUTPUT BLOCK DIAGRAM
MULTIPLEX
FIGURE 21-3:
D
Q
Bus
Data
CxINV
Read CMCON
EN
D
Q
EN
CL
From
Other
Comparator
Reset
21.6
Comparator Interrupts
The comparator interrupt flag is set whenever there is
a change in the output value of either comparator.
Software will need to maintain information about the
status of the output bits, as read from CMCON, to
determine the actual change that occurred. The CMIF
bit (PIR2) is the Comparator Interrupt Flag. The
CMIF bit must be reset by clearing it. Since it is also
possible to write a ‘1’ to this register, a simulated
interrupt may be initiated.
Both the CMIE bit (PIE2) and the PEIE bit
(INTCON) must be set to enable the interrupt. In
addition, the GIE bit (INTCON) must also be set. If
any of these bits are clear, the interrupt is not enabled,
though the CMIF bit will still be set if an interrupt
condition occurs.
Note:
If a change in the CMCON register
(C1OUT or C2OUT) should occur when a
read operation is being executed (start of
the Q2 cycle), then the CMIF (PIR2
register) interrupt flag may not get set.
The user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
b)
Set
CMIF
bit
21.7
Comparator Operation
During Sleep
When a comparator is active and the device is placed
in Sleep mode, the comparator remains active and the
interrupt is functional if enabled. This interrupt will
wake-up the device from Sleep mode, when enabled.
Each operational comparator will consume additional
current, as shown in the comparator specifications. To
minimize power consumption while in Sleep mode, turn
off the comparators (CM = 111) before entering
Sleep. If the device wakes up from Sleep, the contents
of the CMCON register are not affected.
21.8
Effects of a Reset
A device Reset forces the CMCON register to its Reset
state, causing the comparator modules to be turned off
(CM = 111). However, the input pins (RA0
through RA3) are configured as analog inputs by
default on device Reset. The I/O configuration for these
pins is determined by the setting of the PCFG bits
(ADCON1). Therefore, device current is
minimized when analog inputs are present at Reset
time.
Any read or write of CMCON will end the
mismatch condition.
Clear flag bit CMIF.
A mismatch condition will continue to set flag bit CMIF.
Reading CMCON will end the mismatch condition and
allow flag bit CMIF to be cleared.
DS39689F-page 246
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21.9
Analog Input Connection
Considerations
range by more than 0.6V in either direction, one of the
diodes is forward biased and a latch-up condition may
occur. A maximum source impedance of 10 kΩ is
recommended for the analog sources. Any external
component connected to an analog input pin, such as
a capacitor or a Zener diode, should have very little
leakage current.
A simplified circuit for an analog input is shown in
Figure 21-4. Since the analog pins are connected to a
digital output, they have reverse biased diodes to VDD
and VSS. The analog input, therefore, must be between
VSS and VDD. If the input voltage deviates from this
FIGURE 21-4:
COMPARATOR ANALOG INPUT MODEL
VDD
VT = 0.6V
RS < 10k
RIC
Comparator
Input
AIN
CPIN
5 pF
VA
VT = 0.6V
ILEAKAGE
±100 nA
VSS
Legend:
TABLE 21-1:
Name
CMCON
CVRCON
INTCON
CPIN
VT
ILEAKAGE
RIC
RS
VA
=
=
=
=
=
=
Input Capacitance
Threshold Voltage
Leakage Current at the pin due to various junctions
Interconnect Resistance
Source Impedance
Analog Voltage
REGISTERS ASSOCIATED WITH COMPARATOR MODULE
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
C2OUT
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
57
CVREN
CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
57
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
58
GIE/GIEH PEIE/GIEL
PIR2
OSCFIF
CMIF
—
EEIF
BCLIF
HLVDIF
TMR3IF
CCP2IF
58
PIE2
OSCFIE
CMIE
—
EEIE
BCLIE
HLVDIE
TMR3IE
CCP2IE
58
IPR2
OSCFIP
CMIP
—
EEIP
BCLIP
HLVDIP
TMR3IP
CCP2IP
58
RA7(1)
RA6(1)
RA5
RA4
RA3
RA2
RA1
RA0
58
LATA7(1)
LATA6(1)
PORTA
LATA
TRISA
TRISA7
(1)
PORTA Data Latch Register (Read and Write to Data Latch)
TRISA6(1) PORTA Data Direction Control Register
58
58
Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the comparator module.
Note 1: PORTA and their direction and latch bits are individually configured as port pins based on various
primary oscillator modes. When disabled, these bits read as ‘0’.
© 2009 Microchip Technology Inc.
DS39689F-page 247
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NOTES:
DS39689F-page 248
© 2009 Microchip Technology Inc.
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22.0
COMPARATOR VOLTAGE
REFERENCE MODULE
The comparator voltage reference is a 16-tap resistor
ladder network that provides a selectable reference
voltage. Although its primary purpose is to provide a
reference for the analog comparators, it may also be
used independently of them.
A block diagram of the module is shown in Figure 22-1.
The resistor ladder is segmented to provide two ranges
of CVREF values and has a power-down function to
conserve power when the reference is not being used.
The module’s supply reference can be provided from
either device VDD/VSS or an external voltage reference.
22.1
Configuring the Comparator
Voltage Reference
The voltage reference module is controlled through the
CVRCON register (Register 22-1). The comparator
voltage reference provides two ranges of output
voltage, each with 16 distinct levels. The range to be
REGISTER 22-1:
used is selected by the CVRR bit (CVRCON). The
primary difference between the ranges is the size of the
steps selected by the CVREF selection bits
(CVR), with one range offering finer resolution.
The equations used to calculate the output of the
comparator voltage reference are as follows:
If CVRR = 1:
CVREF = ((CVR)/24) x CVRSRC
If CVRR = 0:
CVREF = (CVRSRC x 1/4) + (((CVR)/32) x
CVRSRC)
The comparator reference supply voltage can come
from either VDD and VSS, or the external VREF+ and
VREF- that are multiplexed with RA2 and RA3. The
voltage source is selected by the CVRSS bit
(CVRCON).
The settling time of the comparator voltage reference
must be considered when changing the CVREF
output (see Table 27-3 in Section 27.0 “Electrical
Characteristics”).
CVRCON: COMPARATOR VOLTAGE REFERENCE CONTROL REGISTER
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
R/W-0
CVREN
CVROE(1)
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
bit 7
bit 0
bit 7
CVREN: Comparator Voltage Reference Enable bit
1 = CVREF circuit powered on
0 = CVREF circuit powered down
bit 6
CVROE: Comparator VREF Output Enable bit(1)
1 = CVREF voltage level is also output on the RA2/AN2/VREF-/CVREF pin
0 = CVREF voltage is disconnected from the RA2/AN2/VREF-/CVREF pin
Note 1: CVROE overrides the TRISA bit setting.
bit 5
CVRR: Comparator VREF Range Selection bit
1 = 0.00 CVRSRC to 0.667 CVRSRC, with CVRSRC/24 step size (low range)
0 = 0.25 CVRSRC to 0.75 CVRSRC, with CVRSRC/32 step size (high range)
bit 4
CVRSS: Comparator VREF Source Selection bit
1 = Comparator reference source, CVRSRC = (VREF+) – (VREF-)
0 = Comparator reference source, CVRSRC = VDD – VSS
bit 3-0
CVR: Comparator VREF Value Selection bits (0 ≤ (CVR) ≤ 15)
When CVRR = 1:
CVREF = ((CVR)/24) • (CVRSRC)
When CVRR = 0:
CVREF = (CVRSRC/4) + ((CVR)/32) • (CVRSRC)
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
© 2009 Microchip Technology Inc.
x = Bit is unknown
DS39689F-page 249
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 22-1:
COMPARATOR VOLTAGE REFERENCE BLOCK DIAGRAM
VREF+
VDD
CVRSS = 1
8R
CVRSS = 0
CVR
R
CVREN
R
R
16-to-1 MUX
R
16 Steps
R
CVREF
R
R
CVRR
VREF-
8R
CVRSS = 1
CVRSS = 0
22.2
Voltage Reference Accuracy/Error
The full range of voltage reference cannot be realized
due to the construction of the module. The transistors
on the top and bottom of the resistor ladder network
(Figure 22-1) keep CVREF from approaching the
reference source rails. The voltage reference is derived
from the reference source; therefore, the CVREF output
changes with fluctuations in that source. The tested
absolute accuracy of the voltage reference can be
found in Section 27.0 “Electrical Characteristics”.
22.3
Operation During Sleep
When the device wakes up from Sleep through an
interrupt or a Watchdog Timer time-out, the contents of
the CVRCON register are not affected. To minimize
current consumption in Sleep mode, the voltage
reference should be disabled.
22.4
Effects of a Reset
A device Reset disables the voltage reference by
clearing bit, CVREN (CVRCON). This Reset also
disconnects the reference from the RA2 pin by clearing
bit, CVROE (CVRCON) and selects the high-voltage
range by clearing bit, CVRR (CVRCON). The CVR
value select bits are also cleared.
22.5
Connection Considerations
The voltage reference module operates independently
of the comparator module. The output of the reference
generator may be connected to the RA2 pin if the
CVROE bit is set. Enabling the voltage reference
output onto RA2 when it is configured as a digital input
will increase current consumption. Connecting RA2 as
a digital output with CVRSS enabled will also increase
current consumption.
The RA2 pin can be used as a simple D/A output with
limited drive capability. Due to the limited current drive
capability, a buffer must be used on the voltage
reference output for external connections to VREF.
Figure 22-2 shows an example buffering technique.
DS39689F-page 250
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 22-2:
COMPARATOR VOLTAGE REFERENCE OUTPUT BUFFER EXAMPLE
PIC18FXXXX
CVREF
Module
R(1)
Voltage
Reference
Output
Impedance
Note 1:
TABLE 22-1:
Name
CVREF Output
R is dependent upon the voltage reference configuration bits, CVRCON and CVRCON.
REGISTERS ASSOCIATED WITH COMPARATOR VOLTAGE REFERENCE
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
CVROE
CVRR
CVRSS
CVR3
CVR2
CVR1
CVR0
57
C1OUT
C2INV
C1INV
CIS
CM2
CM1
CM0
57
Bit 7
Bit 6
CVRCON
CVREN
CMCON
C2OUT
TRISA
+
–
RA2
TRISA7
(1)
TRISA6(1)
PORTA Data Direction Control Register
58
Legend: Shaded cells are not used with the comparator voltage reference.
Note 1: PORTA pins are enabled based on oscillator configuration.
© 2009 Microchip Technology Inc.
DS39689F-page 251
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NOTES:
DS39689F-page 252
© 2009 Microchip Technology Inc.
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23.0
HIGH/LOW-VOLTAGE DETECT
(HLVD)
PIC18F2221/2321/4221/4321 family devices have a
High/Low-Voltage Detect module (HLVD). This is a
programmable circuit that allows the user to specify both
a device voltage trip point and the direction of change
from that point. If the device experiences an excursion
past the trip point in that direction, an interrupt flag is set.
If the interrupt is enabled, the program execution will
branch to the interrupt vector address and the software
can then respond to the interrupt.
REGISTER 23-1:
The High/Low-Voltage Detect Control register
(Register 23-1) completely controls the operation of the
HLVD module. This allows the circuitry to be “turned
off” by the user under software control, which
minimizes the current consumption for the device.
The block diagram for the HLVD module is shown in
Figure 23-1.
HLVDCON: HIGH/LOW-VOLTAGE DETECT CONTROL REGISTER
R/W-0
U-0
R-0
R/W-0
R/W-0
R/W-1
R/W-0
R/W-1
VDIRMAG
—
IRVST
HLVDEN
HLVDL3
HLVDL2
HLVDL1
HLVDL0
bit 7
bit 0
bit 7
VDIRMAG: Voltage Direction Magnitude Select bit
1 = Event occurs when voltage equals or exceeds trip point (HLVDL)
0 = Event occurs when voltage equals or falls below trip point (HLVDL)
bit 6
Unimplemented: Read as ‘0’
bit 5
IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the voltage detect logic will generate the interrupt flag at the specified voltage
range
0 = Indicates that the voltage detect logic will not generate the interrupt flag at the specified
voltage range and the HLVD interrupt should not be enabled
bit 4
HLVDEN: High/Low-Voltage Detect Power Enable bit
1 = HLVD enabled
0 = HLVD disabled
bit 3-0
HLVDL: Voltage Detection Limit bits
1111 = External analog input is used (input comes from the HLVDIN pin)
1110 = Maximum setting
.
.
.
0000 = Minimum setting
Note:
See Table 27-4 in Section 27.0 “Electrical Characteristics” for the specifications.
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
‘1’ = Bit is set
‘0’ = Bit is cleared
The module is enabled by setting the HLVDEN bit.
Each time that the HLVD module is enabled, the
circuitry requires some time to stabilize. The IRVST bit
is a read-only bit and is used to indicate when the circuit
is stable. The module can only generate an interrupt
after the circuit is stable and IRVST is set.
© 2009 Microchip Technology Inc.
x = Bit is unknown
The VDIRMAG bit determines the overall operation of
the module. When VDIRMAG is cleared, the module
monitors for drops in VDD below a predetermined set
point. When the bit is set, the module monitors for rises
in VDD above the set point.
DS39689F-page 253
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23.1
Operation
When the HLVD module is enabled, a comparator uses
an internally generated reference voltage as the set
point. The set point is compared with the trip point,
where each node in the resistor divider represents a
trip point voltage. The “trip point” voltage is the voltage
level at which the device detects a high or low-voltage
event, depending on the configuration of the module.
When the supply voltage is equal to the trip point, the
voltage tapped off of the resistor array is equal to the
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal by setting the HLVDIF bit.
FIGURE 23-1:
VDD
The HLVD module has an additional feature that allows
the user to supply the trip voltage to the module from an
external source. This mode is enabled when bits
HLVDL are set to ‘1111’. In this state, the
comparator input is multiplexed from the external input
pin, HLVDIN. This gives users flexibility because it
allows them to configure the High/Low-Voltage Detect
interrupt to occur at any voltage in the valid operating
range.
HLVD MODULE BLOCK DIAGRAM (WITH EXTERNAL INPUT)
Externally Generated
Trip Point
VDD
HLVDL
HLVDCON
Register
HLVDEN
HLVDIN
16-to-1 MUX
HLVDIN
The trip point voltage is software programmable to
any one of 16 values. The trip point is selected by
programming the HLVDL bits (HLVDCON).
VDIRMAG
Set
HLVDIF
HLVDEN
BOREN
DS39689F-page 254
Internal Voltage
Reference
© 2009 Microchip Technology Inc.
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23.2
HLVD Setup
The following steps are needed to set up the HLVD
module:
1.
2.
3.
4.
5.
6.
Disable the module by clearing the HLVDEN bit
(HLVDCON).
Write the value to the HLVDL bits that
selects the desired HLVD trip point.
Set the VDIRMAG bit to detect high voltage
(VDIRMAG = 1) or low voltage (VDIRMAG = 0).
Enable the HLVD module by setting the
HLVDEN bit.
Clear the HLVD interrupt flag (PIR2), which
may have been set from a previous interrupt.
Enable the HLVD interrupt if interrupts are
desired by setting the HLVDIE and GIE bits
(PIE and INTCON). An interrupt will not
be generated until the IRVST bit is set.
23.3
23.4
HLVD Start-up Time
The internal reference voltage of the HLVD module,
specified in electrical specification parameter D420,
may be used by other internal circuitry, such as the
Programmable Brown-out Reset. If the HLVD or other
circuits using the voltage reference are disabled to
lower the device’s current consumption, the reference
voltage circuit will require time to become stable before
a low or high-voltage condition can be reliably
detected. This start-up time, TIRVST, is an interval that
is independent of device clock speed. It is specified in
electrical specification parameter 36.
Current Consumption
When the module is enabled, the HLVD comparator
and voltage divider are enabled and will consume static
current. The total current consumption, when enabled,
is specified in electrical specification parameter D022B.
FIGURE 23-2:
Depending on the application, the HLVD module does
not need to be operating constantly. To decrease the
current requirements, the HLVD circuitry may only
need to be enabled for short periods where the voltage
is checked. After doing the check, the HLVD module
may be disabled.
The HLVD interrupt flag is not enabled until TIRVST has
expired and a stable reference voltage is reached. For
this reason, brief excursions beyond the set point may
not be detected during this interval. Refer to
Figure 23-2 or Figure 23-3.
LOW-VOLTAGE DETECT OPERATION (VDIRMAG = 0)
CASE 1:
HLVDIF may not be set
VDD
VLVD
HLVDIF
Enable HLVD
TIRVST
IRVST
Internal Reference is stable
HLVDIF cleared in software
CASE 2:
VDD
VLVD
HLVDIF
Enable HLVD
TIRVST
IRVST
Internal Reference is stable
HLVDIF cleared in software
HLVDIF cleared in software,
HLVDIF remains set since HLVD condition still exists
© 2009 Microchip Technology Inc.
DS39689F-page 255
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 23-3:
HIGH-VOLTAGE DETECT OPERATION (VDIRMAG = 1)
CASE 1:
HLVDIF may not be set
VLVD
VDD
HLVDIF
Enable HLVD
TIRVST
IRVST
HLVDIF cleared in software
Internal Reference is stable
CASE 2:
VLVD
VDD
HLVDIF
Enable HLVD
TIRVST
IRVST
Internal Reference is stable
HLVDIF cleared in software
HLVDIF cleared in software,
HLVDIF remains set since HLVD condition still exists
Applications
In many applications, the ability to detect a drop below
or rise above a particular threshold is desirable. For
example, the HLVD module could be periodically
enabled to detect a Universal Serial Bus (USB) attach
or detach. This assumes the device is powered by a
lower voltage source than the USB when detached. An
attach would indicate a high-voltage detect from, for
example, 3.3V to 5V (the voltage on USB) and vice
versa for a detach. This feature could save a design a
few extra components and an attach signal (input pin).
For general battery applications, Figure 23-4 shows a
possible voltage curve. Over time, the device voltage
decreases. When the device voltage reaches voltage
VA, the HLVD logic generates an interrupt at time TA.
The interrupt could cause the execution of an ISR,
which would allow the application to perform “housekeeping tasks” and perform a controlled shutdown
before the device voltage exits the valid operating
range at TB. The HLVD, thus, would give the application a time window, represented by the difference
between TA and TB, to safely exit.
DS39689F-page 256
FIGURE 23-4:
TYPICAL LOW-VOLTAGE
DETECT APPLICATION
VA
VB
Voltage
23.5
Time
TA
TB
Legend: VA = HLVD trip point
VB = Minimum valid device
operating voltage
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
23.6
Operation During Sleep
23.7
When enabled, the HLVD circuitry continues to operate
during Sleep. If the device voltage crosses the trip
point, the HLVDIF bit will be set and the device will
wake-up from Sleep. Device execution will continue
from the interrupt vector address if interrupts have
been globally enabled.
TABLE 23-1:
Effects of a Reset
A device Reset forces all registers to their Reset state.
This forces the HLVD module to be turned off.
REGISTERS ASSOCIATED WITH HIGH/LOW-VOLTAGE DETECT MODULE
Name
Bit 7
Bit 6
HLVDCON
VDIRMAG
—
INTCON
GIE/GIEH PEIE/GIEL
Reset
Values
on Page
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
IRVST
HLVDEN
HLVDL3
HLVDL2
HLVDL1
HLVDL0
56
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
55
PIR2
OSCFIF
CMIF
—
EEIF
BCLIF
HLVDIF
TMR3IF
CCP2IF
58
PIE2
OSCFIE
CMIE
—
EEIE
BCLIE
HLVDIE
TMR3IE
CCP2IE
58
IPR2
OSCFIP
CMIP
—
EEIP
BCLIP
HLVDIP
TMR3IP
CCP2IP
58
Legend: — = unimplemented, read as ‘0’. Shaded cells are unused by the HLVD module.
© 2009 Microchip Technology Inc.
DS39689F-page 257
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 258
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
24.0
SPECIAL FEATURES OF THE
CPU
The inclusion of an internal RC oscillator also provides
the additional benefits of a Fail-Safe Clock Monitor
(FSCM) and Two-Speed Start-up. FSCM provides for
background monitoring of the peripheral clock and
automatic switchover in the event of its failure. TwoSpeed Start-up enables code to be executed almost
immediately on start-up, while the primary clock source
completes its start-up delays.
PIC18F2221/2321/4221/4321 family devices include
several features intended to maximize reliability and
minimize cost through elimination of external
components. These are:
• Oscillator Selection
• Resets:
- Power-on Reset (POR)
- Power-up Timer (PWRT)
- Oscillator Start-up Timer (OST)
- Brown-out Reset (BOR)
• Interrupts
• Watchdog Timer (WDT)
• Fail-Safe Clock Monitor
• Two-Speed Start-up
• Code Protection
• ID Locations
• In-Circuit Serial Programming
All of these features are enabled and configured by
setting the appropriate Configuration register bits.
24.1
The Configuration bits can be programmed (read as
‘0’) or left unprogrammed (read as ‘1’) to select various
device configurations. These bits are mapped starting
at program memory location 300000h.
The user will note that address 300000h is beyond the
user program memory space. In fact, it belongs to the
configuration memory space (300000h-3FFFFFh), which
can only be accessed using table reads and table writes.
The oscillator can be configured for the application
depending on frequency, power, accuracy and cost. All
of the options are discussed in detail in Section 3.0
“Oscillator Configurations”.
A complete discussion of device Resets and interrupts
is available in previous sections of this data sheet.
In addition to their Power-up and Oscillator Start-up
Timers provided for Resets, PIC18F2221/2321/4221/
4321 family devices have a Watchdog Timer, which is
either permanently enabled via the Configuration bits
or software controlled (if configured as disabled).
TABLE 24-1:
Configuration Bits
Programming the Configuration registers is done in a
manner similar to programming the Flash memory. The
WR bit in the EECON1 register starts a self-timed write
to the Configuration register. In normal operation mode,
a TBLWT instruction with the TBLPTR pointing to the
Configuration register sets up the address and the data
for the Configuration register write. Setting the WR bit
starts a long write to the Configuration register. The
Configuration registers are written a byte at a time. To
write or erase a configuration cell, a TBLWT instruction
can write a ‘1’ or a ‘0’ into the cell. For additional details
on Flash programming, refer to Section 7.5 “Writing
to Flash Program Memory”.
CONFIGURATION BITS AND DEVICE IDs
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
300001h
CONFIG1H
IESO
FCMEN
—
—
FOSC3
FOSC2
300002h
CONFIG2L
—
—
—
BORV1
BORV0
BOREN1
300003h
CONFIG2H
—
—
—
Default/
Unprogrammed
Value
Bit 1
Bit 0
FOSC1
FOSC0
BOREN0 PWRTEN
WDTPS3 WDTPS2 WDTPS1 WDTPS0
LPT1OSC PBADEN
00-- 0111
---1 1111
WDTEN
---1 1111
CCP2MX
1--- -011
300005h
CONFIG3H
MCLRE
—
—
—
—
300006h
CONFIG4L
DEBUG
XINST
BBSIZ1
BBSIZ0
r
LVP
—
STVREN
1000 01-1
300008h
CONFIG5L
—
—
—
—
—
—
CP1
CP0
---- --11
11-- ----
300009h
CONFIG5H
CPD
CPB
—
—
—
—
—
—
30000Ah
CONFIG6L
—
—
—
—
—
—
WRT1
WRT0
---- --11
30000Bh
CONFIG6H
WRTD
WRTB
WRTC
—
—
—
—
—
111- ----
30000Ch
CONFIG7L
—
—
—
—
—
—
EBTR1
EBTR0
---- --11
30000Dh
CONFIG7H
-1-- ----
—
EBTRB
—
—
—
—
—
—
3FFFFEh DEVID1(1)
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
xxxx xxxx(2)
3FFFFFh
DEVID2(1)
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
0000 1100
Legend:
x = unknown, u = unchanged, - = unimplemented, q = value depends on condition, r = reserved, maintain as ‘0’.
Shaded cells are unimplemented, read as ‘0’.
Unimplemented in PIC18F2221/4221 devices; maintain these bits set.
See Register 24-14 for DEVID1 values. DEVID registers are read-only and cannot be programmed by the user.
Note 1:
2:
© 2009 Microchip Technology Inc.
DS39689F-page 259
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-1:
CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
R/P-0
R/P-0
U-0
U-0
R/P-0
R/P-1
R/P-1
R/P-1
IESO
FCMEN
—
—
FOSC3
FOSC2
FOSC1
FOSC0
bit 7
bit 0
bit 7
IESO: Internal/External Oscillator Switchover bit
1 = Oscillator Switchover mode enabled
0 = Oscillator Switchover mode disabled
bit 6
FCMEN: Fail-Safe Clock Monitor Enable bit
1 = Fail-Safe Clock Monitor enabled
0 = Fail-Safe Clock Monitor disabled
bit 5-4
Unimplemented: Read as ‘0’
bit 3-0
FOSC: Oscillator Selection bits
11xx = External RC oscillator, CLKO function on RA6
101x = External RC oscillator, CLKO function on RA6
1001 = Internal oscillator block, CLKO function on RA6, port function on RA7
1000 = Internal oscillator block, port function on RA6 and RA7
0111 = External RC oscillator, port function on RA6
0110 = HS oscillator, PLL enabled (Clock Frequency = 4 x FOSC1)
0101 = EC oscillator, port function on RA6
0100 = EC oscillator, CLKO function on RA6
0011 = External RC oscillator, CLKO function on RA6
0010 = HS oscillator
0001 = XT oscillator
0000 = LP oscillator
Legend:
R = Readable bit
P = Programmable bit
-n = Value when device is unprogrammed
DS39689F-page 260
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-2:
CONFIG2L: CONFIGURATION REGISTER 2 LOW (BYTE ADDRESS 300002h)
U-0
U-0
—
—
U-0
—
R/P-1
BORV1
(1)
R/P-1
BORV0
(1)
R/P-1
R/P-1
(2)
BOREN1
R/P-1
(2)
BOREN0
PWRTEN(2)
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-3
BORV: Brown-out Reset Voltage bits(1)
11 = Minimum setting
.
.
.
00 = Maximum setting
bit 2-1
BOREN: Brown-out Reset Enable bits(2)
11 = Brown-out Reset enabled in hardware only (SBOREN is disabled)
10 = Brown-out Reset enabled in hardware only and disabled in Sleep mode
(SBOREN is disabled)
01 = Brown-out Reset enabled and controlled by software (SBOREN is enabled)
00 = Brown-out Reset disabled in hardware and software
bit 0
PWRTEN: Power-up Timer Enable bit(2)
1 = PWRT disabled
0 = PWRT enabled
Note 1: See Section 27.1 “DC Characteristics” for the specifications.
2: The Power-up Timer is decoupled from Brown-out Reset, allowing these features to
be independently controlled.
Legend:
R = Readable bit
P = Programmable bit
-n = Value when device is unprogrammed
© 2009 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
DS39689F-page 261
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-3:
CONFIG2H: CONFIGURATION REGISTER 2 HIGH (BYTE ADDRESS 300003h)
U-0
U-0
U-0
R/P-1
R/P-1
R/P-1
R/P-1
R/P-1
—
—
—
WDTPS3
WDTPS2
WDTPS1
WDTPS0
WDTEN
bit 7
bit 0
bit 7-5
Unimplemented: Read as ‘0’
bit 4-1
WDTPS: Watchdog Timer Postscale Select bits
1111 = 1:32,768
1110 = 1:16,384
1101 = 1:8,192
1100 = 1:4,096
1011 = 1:2,048
1010 = 1:1,024
1001 = 1:512
1000 = 1:256
0111 = 1:128
0110 = 1:64
0101 = 1:32
0100 = 1:16
0011 = 1:8
0010 = 1:4
0001 = 1:2
0000 = 1:1
bit 0
WDTEN: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled (control is placed on the SWDTEN bit)
Legend:
R = Readable bit
P = Programmable bit
-n = Value when device is unprogrammed
DS39689F-page 262
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-4:
CONFIG3H: CONFIGURATION REGISTER 3 HIGH (BYTE ADDRESS 300005h)
R/P-1
U-0
U-0
U-0
U-0
R/P-0
R/P-1
R/P-1
MCLRE
—
—
—
—
LPT1OSC
PBADEN
CCP2MX
bit 7
bit 0
bit 7
MCLRE: MCLR Pin Enable bit
1 = MCLR pin enabled; RE3 input pin disabled
0 = RE3 input pin enabled; MCLR disabled
bit 6-3
Unimplemented: Read as ‘0’
bit 2
LPT1OSC: Low-Power Timer1 Oscillator Enable bit
1 = Timer1 configured for low-power operation
0 = Timer1 configured for higher power operation
bit 1
PBADEN: PORTB A/D Enable bit
(Affects ADCON1 Reset state. ADCON1 controls PORTB pin configuration.)
1 = PORTB pins are configured as analog input channels on Reset
0 = PORTB pins are configured as digital I/O on Reset
bit 0
CCP2MX: CCP2 MUX bit
1 = CCP2 input/output is multiplexed with RC1
0 = CCP2 input/output is multiplexed with RB3
Legend:
R = Readable bit
P = Programmable bit
-n = Value when device is unprogrammed
© 2009 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
DS39689F-page 263
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-5:
CONFIG4L: CONFIGURATION REGISTER 4 LOW (BYTE ADDRESS 300006h)
R/P-1
R/P-0
U-0
U-0
r-0
R/P-1
U-0
R/P-1
DEBUG
XINST
BBSIZ1
BBSIZ0
—
LVP
—
STVREN
bit 7
bit 0
bit 7
DEBUG: Background Debugger Enable bit
1 = Background debugger disabled, RB6 and RB7 configured as general purpose I/O pins
0 = Background debugger enabled, RB6 and RB7 are dedicated to in-circuit debug
bit 6
XINST: Extended Instruction Set Enable bit
1 = Instruction set extension and Indexed Addressing mode enabled
0 = Instruction set extension and Indexed Addressing mode disabled (Legacy mode)
bit 5-4 BBSIZ: Boot Block Size Select bits
PIC18F4221/4321 Devices:
1x = 1024 Words
01 = 512 Words
00 = 256 Words
PIC18F2221/2321 Devices:
1x = 512 Words
x1 = 512 Words
00 = 256 Words
bit 3
Reserved: Maintain as ‘0’
bit 2
LVP: Single-Supply ICSP™ Enable bit
1 = Single-Supply ICSP enabled
0 = Single-Supply ICSP disabled
bit 1
Unimplemented: Read as ‘0’
bit 0
STVREN: Stack Full/Underflow Reset Enable bit
1 = Stack full/underflow will cause Reset
0 = Stack full/underflow will not cause Reset
Legend:
r = Reserved bit, program as ‘0’
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
DS39689F-page 264
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-6:
CONFIG5L: CONFIGURATION REGISTER 5 LOW (BYTE ADDRESS 300008h)
U-0
U-0
U-0
U-0
U-0
U-0
R/C-1
R/C-1
—
—
—
—
—
—
CP1
CP0
bit 7
bit 0
bit 7-2
Unimplemented: Read as ‘0’
bit 1
CP1: Code Protection bit
1 = Block 1 not code-protected(1)
0 = Block 1 code-protected(1)
bit 0
CP0: Code Protection bit
1 = Block 0 not code-protected(1)
0 = Block 0 code-protected(1)
Note 1: See Figure 24-5 for variable block boundaries.
Legend:
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
REGISTER 24-7:
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
CONFIG5H: CONFIGURATION REGISTER 5 HIGH (BYTE ADDRESS 300009h)
R/C-1
R/C-1
U-0
U-0
U-0
U-0
U-0
U-0
CPD
CPB
—
—
—
—
—
—
bit 7
bit 0
bit 7
CPD: Data EEPROM Code Protection bit
1 = Data EEPROM not code-protected
0 = Data EEPROM code-protected
bit 6
CPB: Boot Block Code Protection bit
1 = Boot block not code-protected(1)
0 = Boot block code-protected(1)
bit 5-0
Unimplemented: Read as ‘0’
Note 1: See Figure 24-5 for variable block boundaries.
Legend:
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
© 2009 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
DS39689F-page 265
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-8:
CONFIG6L: CONFIGURATION REGISTER 6 LOW (BYTE ADDRESS 30000Ah)
U-0
U-0
U-0
U-0
U-0
U-0
R/C-1
R/C-1
—
—
—
—
—
—
WRT1
WRT0
bit 7
bit 0
bit 7-2
Unimplemented: Read as ‘0’
bit 1
WRT1: Write Protection bit
1 = Block 1 not write-protected(1)
0 = Block 1 write-protected(1)
bit 0
WRT0: Write Protection bit
1 = Block 0 not write-protected(1)
0 = Block 0 write-protected(1)
Note 1: See Figure 24-5 for variable block boundaries.
Legend:
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
REGISTER 24-9:
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
CONFIG6H: CONFIGURATION REGISTER 6 HIGH (BYTE ADDRESS 30000Bh)
R/C-1
WRTD
R/C-1
R-1
U-0
U-0
U-0
U-0
U-0
WRTB
WRTC(1)
—
—
—
—
—
bit 7
bit 0
bit 7
WRTD: Data EEPROM Write Protection bit
1 = Data EEPROM not write-protected
0 = Data EEPROM write-protected
bit 6
WRTB: Boot Block Write Protection bit
1 = Boot block not write-protected(2)
0 = Boot block write-protected(2)
bit 5
WRTC: Configuration Register Write Protection bit(1)
1 = Configuration registers (300000-3000FFh) not write-protected
0 = Configuration registers (300000-3000FFh) write-protected
bit 4-0
Unimplemented: Read as ‘0’
Note 1: This bit is read-only in normal execution mode; it can be written only in Program mode.
2: See Figure 24-5 for block boundaries.
Legend:
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
DS39689F-page 266
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-10: CONFIG7L: CONFIGURATION REGISTER 7 LOW (BYTE ADDRESS 30000Ch)
U-0
U-0
U-0
U-0
U-0
U-0
R/C-1
R/C-1
—
—
—
—
—
—
EBTR1
EBTR0
bit 7
bit 0
bit 7-2
Unimplemented: Read as ‘0’
bit 1
EBTR1: Table Read Protection bit
1 = Block 1 not protected from table reads executed in other blocks(1)
0 = Block 1 protected from table reads executed in other blocks(1)
bit 0
EBTR0: Table Read Protection bit
1 = Block 0 not protected from table reads executed in other blocks(1)
0 = Block 0 protected from table reads executed in other blocks(1)
Note 1: See Figure 24-5 for variable block boundaries.
Legend:
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 24-11: CONFIG7H: CONFIGURATION REGISTER 7 HIGH (BYTE ADDRESS 30000Dh)
U-0
R/C-1
U-0
U-0
U-0
U-0
U-0
U-0
—
EBTRB
—
—
—
—
—
—
bit 7
bit 0
bit 7
Unimplemented: Read as ‘0’
bit 6
EBTRB: Boot Block Table Read Protection bit
1 = Boot block not protected from table reads executed in other blocks(1)
0 = Boot block protected from table reads executed in other blocks(1)
bit 5-0
Unimplemented: Read as ‘0’
Note 1: See Figure 24-5 for variable block boundaries.
Legend:
R = Readable bit
C = Clearable bit
-n = Value when device is unprogrammed
© 2009 Microchip Technology Inc.
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
DS39689F-page 267
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-12: DEVID1: DEVICE ID REGISTER 1 FOR PIC18F2221/2321/4221/4321 DEVICES
R
R
R
R
R
R
R
R
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
bit 7
bit 0
bit 7-5
DEV: Device ID bits
000 = PIC18F4321
010 = PIC18F4221
001 = PIC18F2321
011 = PIC18F2221
bit 4-0
REV: Revision ID bits
These bits are used to indicate the device revision.
Legend:
R = Read-only bit
P = Programmable bit
-n = Value when device is unprogrammed
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
REGISTER 24-13: DEVID2: DEVICE ID REGISTER 2 FOR PIC18F2221/2321/4221/4321 DEVICES
R
R
R
R
R
R
R
R
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
bit 7
bit 7-0
bit 0
DEV: Device ID bits
These bits are used with the DEV bits in the Device ID Register 1 to identify the
part number.
0010 0001 = PIC18F2221/2321/4221/4321 devices
Note:
These values for DEV may be shared with other devices. The specific
device is always identified by using the entire DEV bit sequence.
Legend:
R = Read-only bit
P = Programmable bit
-n = Value when device is unprogrammed
DS39689F-page 268
U = Unimplemented bit, read as ‘0’
u = Unchanged from programmed state
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
24.2
Watchdog Timer (WDT)
For PIC18F2221/2321/4221/4321 family devices, the
WDT is driven by the INTRC source. When the WDT is
enabled, the clock source is also enabled. The nominal
WDT period is 4 ms and has the same stability as the
INTRC oscillator.
The 4 ms period of the WDT is multiplied by a 16-bit
postscaler. Any output of the WDT postscaler is
selected by a multiplexer, controlled by bits in Configuration Register 2H. Available periods range from 4 ms
to 131.072 seconds (2.18 minutes). The WDT and
postscaler are cleared when any of the following events
occur: a SLEEP or CLRWDT instruction is executed, the
IRCF bits (OSCCON) are changed or a clock
failure has occurred.
FIGURE 24-1:
Note 1: The CLRWDT and SLEEP instructions
clear the WDT and postscaler counts
when executed.
2: Changing the setting of the IRCF bits
(OSCCON) clears the WDT and
postscaler counts.
3: When a CLRWDT instruction is executed,
the postscaler count will be cleared.
24.2.1
CONTROL REGISTER
Register 24-14 shows the WDTCON register. This is a
readable and writable register which contains a control
bit that allows software to override the WDT enable
Configuration bit, but only if the Configuration bit has
disabled the WDT.
WDT BLOCK DIAGRAM
SWDTEN
WDTEN
Enable WDT
WDT Counter
INTRC Source
Wake-up from
Power-Managed
Modes
÷128
Change on IRCF bits
Programmable Postscaler
1:1 to 1:32,768
CLRWDT
Reset
WDT
Reset
All Device Resets
WDTPS
4
Sleep
© 2009 Microchip Technology Inc.
DS39689F-page 269
PIC18F2221/2321/4221/4321 FAMILY
REGISTER 24-14: WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0
U-0
U-0
U-0
U-0
U-0
U-0
R/W-0
—
—
—
—
—
—
—
SWDTEN(1)
bit 7
bit 0
bit 7-1
Unimplemented: Read as ‘0’
bit 0
SWDTEN: Software Controlled Watchdog Timer Enable bit(1)
1 = Watchdog Timer is on
0 = Watchdog Timer is off
Note 1: This bit has no effect if the Configuration bit, WDTEN, is enabled.
Legend:
TABLE 24-2:
Name
RCON
WDTCON
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
-n = Value at POR
SUMMARY OF WATCHDOG TIMER REGISTERS
Bit 0
Reset
Values
on page
POR
BOR
56
—
SWDTEN
56
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
IPEN
SBOREN(1)
—
RI
TO
PD
—
—
—
—
—
—
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Watchdog Timer.
Note 1: The SBOREN bit is only available when the BOREN Configuration bits = 01; otherwise, it is disabled
and reads as ‘0’. See Section 5.4 “Brown-out Reset (BOR)”.
DS39689F-page 270
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
24.3
Two-Speed Start-up
In all other power-managed modes, Two-Speed Startup is not used. The device will be clocked by the
currently selected clock source until the primary clock
source becomes available. The setting of the IESO bit
is ignored.
The Two-Speed Start-up feature helps to minimize the
latency period from oscillator start-up to code execution
by allowing the microcontroller to use the INTOSC
oscillator as a clock source until the primary clock
source is available. It is enabled by setting the IESO
Configuration bit.
24.3.1
Two-Speed Start-up should be enabled only if the
primary oscillator mode is LP, XT, HS or HSPLL
(crystal-based modes). Other sources do not require
an OST start-up delay; for these, Two-Speed Start-up
should be disabled.
While using the INTOSC oscillator in Two-Speed Startup, the device still obeys the normal command
sequences for entering power-managed modes,
including multiple SLEEP instructions (refer to
Section 4.1.4 “Multiple Sleep Commands”). In
practice, this means that user code can change the
SCS bit settings or issue SLEEP instructions
before the OST times out. This would allow an application to briefly wake-up, perform routine “housekeeping”
tasks and return to Sleep before the device starts to
operate from the primary oscillator.
When enabled, Resets and wake-ups from Sleep mode
cause the device to configure itself to run from the
internal oscillator block as the clock source, following
the time-out of the Power-up Timer after a Power-on
Reset is enabled. This allows almost immediate code
execution while the primary oscillator starts and the
OST is running. Once the OST times out, the device
automatically switches to PRI_RUN mode.
User code can also check if the primary clock source is
currently providing the device clocking by checking the
status of the OSTS bit (OSCCON). If the bit is set,
the primary oscillator is providing the clock. Otherwise,
the internal oscillator block is providing the clock during
wake-up from Reset or Sleep mode.
To use a higher clock speed on wake-up, the INTOSC
or postscaler clock sources can be selected to provide
a higher clock speed by setting bits, IRCF,
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected
by setting the IRCF bits prior to entering Sleep
mode.
FIGURE 24-2:
SPECIAL CONSIDERATIONS FOR
USING TWO-SPEED START-UP
TIMING TRANSITION FOR TWO-SPEED START-UP (INTOSC TO HSPLL)
Q1
Q3
Q2
Q4
Q2 Q3 Q4 Q1 Q2 Q3
Q1
INTOSC
Multiplexer
OSC1
TOST(1)
TPLL(1)
1
PLL Clock
Output
2
n-1 n
Clock
Transition(2)
CPU Clock
Peripheral
Clock
Program
Counter
PC
Wake from Interrupt Event
Note 1:
2:
PC + 2
PC + 4
PC + 6
OSTS bit Set
TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
Clock transition typically occurs within 2-4 TOSC.
© 2009 Microchip Technology Inc.
DS39689F-page 271
PIC18F2221/2321/4221/4321 FAMILY
24.4
Fail-Safe Clock Monitor
The Fail-Safe Clock Monitor (FSCM) allows the
microcontroller to continue operation in the event of an
external oscillator failure by automatically switching the
device clock to the internal oscillator block. The FSCM
function is enabled by setting the FCMEN Configuration
bit.
When FSCM is enabled, the INTRC oscillator runs at
all times to monitor clocks to peripherals and provide a
backup clock in the event of a clock failure. Clock
monitoring (shown in Figure 24-3) is accomplished by
creating a sample clock signal, which is the INTRC
output divided by 64. This allows ample time between
FSCM sample clocks for a peripheral clock edge to
occur. The peripheral device clock and the sample
clock are presented as inputs to the Clock Monitor latch
(CM). The CM is set on the falling edge of the device
clock source, but cleared on the rising edge of the
sample clock.
FIGURE 24-3:
FSCM BLOCK DIAGRAM
Clock Monitor
Latch (CM)
(edge-triggered)
Peripheral
Clock
INTRC
Source
(32 μs)
÷ 64
S
Q
C
Q
To use a higher clock speed on wake-up, the INTOSC
or postscaler clock sources can be selected to provide
a higher clock speed by setting bits, IRCF,
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected
by setting the IRCF bits prior to entering Sleep
mode.
The FSCM will detect failures of the primary or secondary clock sources only. If the internal oscillator block
fails, no failure would be detected, nor would any action
be possible.
24.4.1
Both the FSCM and the WDT are clocked by the
INTRC oscillator. Since the WDT operates with a
separate divider and counter, disabling the WDT has
no effect on the operation of the INTRC oscillator when
the FSCM is enabled.
As already noted, the clock source is switched to the
INTOSC clock when a clock failure is detected.
Depending on the frequency selected by the
IRCF bits, this may mean a substantial change in
the speed of code execution. If the WDT is enabled
with a small prescale value, a decrease in clock speed
allows a WDT time-out to occur and a subsequent
device Reset. For this reason, fail-safe clock events
also reset the WDT and postscaler, allowing it to start
timing from when execution speed was changed and
decreasing the likelihood of an erroneous time-out.
24.4.2
488 Hz
(2.048 ms)
Clock
Failure
Detected
Clock failure is tested for on the falling edge of the
sample clock. If a sample clock falling edge occurs
while CM is still set, a clock failure has been detected
(Figure 24-4). This causes the following:
• the FSCM generates an oscillator fail interrupt by
setting bit, OSCFIF (PIR2);
• the device clock source is switched to the internal
oscillator block (OSCCON is not updated to show
the current clock source – this is the fail-safe
condition); and
• the WDT is reset.
FSCM AND THE WATCHDOG TIMER
EXITING FAIL-SAFE OPERATION
The fail-safe condition is terminated by either a device
Reset or by entering a power-managed mode. On
Reset, the controller starts the primary clock source
specified in Configuration Register 1H (with any
required start-up delays that are required for the
oscillator mode, such as OST or PLL timer). The
INTOSC multiplexer provides the device clock until the
primary clock source becomes ready (similar to a TwoSpeed Start-up). The clock source is then switched to
the primary clock (indicated by the OSTS bit in the
OSCCON register becoming set). The Fail-Safe Clock
Monitor then resumes monitoring the peripheral clock.
The primary clock source may never become ready
during start-up. In this case, operation is clocked by the
INTOSC multiplexer. The OSCCON register will remain
in its Reset state until a power-managed mode is
entered.
During switchover, the postscaler frequency from the
internal oscillator block may not be sufficiently stable
for timing sensitive applications. In these cases, it may
be desirable to select another clock configuration and
enter an alternate power-managed mode. This can be
done to attempt a partial recovery or execute a
controlled shutdown. See Section 4.1.4 “Multiple
Sleep Commands” and Section 24.3.1 “Special
Considerations for Using Two-Speed Start-up” for
more details.
DS39689F-page 272
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 24-4:
FSCM TIMING DIAGRAM
Sample Clock
Oscillator
Failure
Device
Clock
Output
CM Output
(Q)
Failure
Detected
OSCFIF
CM Test
Note:
24.4.3
CM Test
CM Test
The device clock is normally at a much higher frequency than the sample clock. The relative frequencies in this
example have been chosen for clarity.
FSCM INTERRUPTS IN
POWER-MANAGED MODES
By entering a power-managed mode, the clock
multiplexer selects the clock source selected by the
OSCCON register. Fail-Safe Monitoring of the powermanaged clock source resumes in the power-managed
mode.
If an oscillator failure occurs during power-managed
operation, the subsequent events depend on whether
or not the oscillator failure interrupt is enabled. If
enabled (OSCFIF = 1), code execution will be clocked
by the INTOSC multiplexer. An automatic transition
back to the failed clock source will not occur.
If the interrupt is disabled, subsequent interrupts while
in Idle mode will cause the CPU to begin executing
instructions while being clocked by the INTOSC
source.
24.4.4
POR OR WAKE FROM SLEEP
The FSCM is designed to detect oscillator failure at any
point after the device has exited Power-on Reset
(POR) or low-power Sleep mode. When the primary
device clock is EC, RC or INTRC modes, monitoring
can begin immediately following these events.
For oscillator modes involving a crystal or resonator
(HS, HSPLL, LP or XT), the situation is somewhat
different. Since the oscillator may require a start-up
time considerably longer than the FCSM sample clock
time, a false clock failure may be detected. To prevent
this, the internal oscillator block is automatically configured as the device clock and functions until the primary
clock is stable (the OST and PLL timers have timed
out). This is identical to Two-Speed Start-up mode.
Once the primary clock is stable, the INTRC returns to
its role as the FSCM source.
Note:
The same logic that prevents false oscillator failure interrupts on POR, or wake from
Sleep, will also prevent the detection of
the oscillator’s failure to start at all following these events. This can be avoided by
monitoring the OSTS bit and using a
timing routine to determine if the oscillator
is taking too long to start. Even so, no
oscillator failure interrupt will be flagged.
As noted in Section 24.3.1 “Special Considerations
for Using Two-Speed Start-up”, it is also possible to
select another clock configuration and enter an
alternate power-managed mode while waiting for the
primary clock to become stable. When the new powermanaged mode is selected, the primary clock is
disabled.
© 2009 Microchip Technology Inc.
DS39689F-page 273
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24.5
Program Verification and
Code Protection
Each of the three blocks has three code protection bits
associated with them. They are:
The overall structure of the code protection on the
PIC18 Flash devices differs significantly from other
PIC® devices.
• Code-Protect bit (CPn)
• Write-Protect bit (WRTn)
• External Block Table Read bit (EBTRn)
The user program memory is divided into three blocks.
One of these is a boot block of variable size. The
remainder of the memory is divided into two blocks on
binary boundaries.
Figure 24-5 shows the program memory organization
for 4 and 8-Kbyte devices and the specific code
protection bit associated with each block. The actual
locations of the bits are summarized in Table 24-3.
FIGURE 24-5:
CODE-PROTECTED PROGRAM MEMORY FOR PIC18F2221/2321/4221/4321
FAMILY DEVICES
Address
Range
MEMORY SIZE/DEVICE
8 Kbytes
(PIC18FX321)
Block Code Protection
Controlled By:
4 Kbytes
(PIC18FX221)
BBSIZ
11/10
01
Boot Block
512 words
00
Boot Block
256 words
11/10/01
Boot Block
512 words
Boot Block
1K word
Block 0
0.5K words
Block 0
1.5K words
00
Boot Block
256 words
Block 0
0.75K words
CPB, WRTB, EBTRB
0001FFh
000200h
0003FFh
000400h
0007FFh
000800h
Block 0
1.75K words
Block 0
1K word
000000h
Block 1
1K word
Block 1
1K word
000FFFh
001000h
Block 1
2K words
Block 1
2K words
Unimplemented
Reads all ‘0’s
DS39689F-page 274
Block 1
2K words
CP0, WRT0, EBTR0
CP1, WRT1, EBTR1
Unimplemented
Reads all ‘0’s
001FFFh
002000h
1FFFFFh
(Unimplemented Memory
Space)
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 24-3:
SUMMARY OF CODE PROTECTION REGISTERS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
300008h
CONFIG5L
—
—
—
—
—
—
CP1
CP0
300009h
CONFIG5H
CPD
CPB
—
—
—
—
—
—
30000Ah
CONFIG6L
—
—
—
—
—
—
WRT1
WRT0
30000Bh
CONFIG6H
WRTD
WRTB
WRTC
—
—
—
—
—
30000Ch
CONFIG7L
—
—
—
—
—
—
EBTR1
EBTR0
30000Dh
CONFIG7H
—
EBTRB
—
—
—
—
—
—
Legend: Shaded cells are unimplemented.
24.5.1
PROGRAM MEMORY
CODE PROTECTION
The program memory may be read to or written from
any location using the table read and table write
instructions. The device ID may be read with table
reads. The Configuration registers may be read and
written with the table read and table write instructions.
A table read instruction that executes from a location
outside of that block is not allowed to read and will result
in reading ‘0’s. Figures 24-6 through 24-8 illustrate table
write and table read protection.
Note:
In normal execution mode, the CPn bits have no direct
effect. CPn bits inhibit external reads and writes. A
block of user memory may be protected from table
writes if the WRTn Configuration bit is ‘0’. The EBTRn
bits control table reads. For a block of user memory
with the EBTRn bit set to ‘0’, a table read instruction
that executes from within that block is allowed to read.
FIGURE 24-6:
Code protection bits may only be written to
a ‘0’ from a ‘1’ state. It is not possible to
write a ‘1’ to a bit in the ‘0’ state. Code
protection bits are only set to ‘1’ by a full
chip erase or block erase function. The full
chip erase and block erase functions can
only be initiated via ICSP operation or an
external programmer.
TABLE WRITE (WRTn) DISALLOWED
Register Values
TBLPTR = 0008FFh
PC = 003FFEh
Program Memory(1)
Configuration Bit Settings
Boot Block
WRTB, EBTRB = 11
Block 0
WRT0, EBTR0 = 01
TBLWT*
Block 1
PC = 00BFFEh
WRT1, EBTR1 = 11
TBLWT*
Results: All table writes disabled to Blockn whenever WRTn = 0.
Note 1: See Figure 24-5 for block boundaries.
© 2009 Microchip Technology Inc.
DS39689F-page 275
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 24-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED
Register Values
TBLPTR = 0008FFh
PC = 007FFEh
Program Memory(1)
Configuration Bit Settings
Boot Block
WRTB, EBTRB = 11
Block 0
WRT0, EBTR0 = 10
Block 1
WRT1, EBTR1 = 11
TBLRD*
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
Note 1: See Figure 24-5 for block boundaries.
FIGURE 24-8:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED
Register Values
TBLPTR = 0008FFh
PC = 003FFEh
Program Memory(1)
Configuration Bit Settings
Boot Block
WRTB, EBTRB = 11
Block 0
WRT0, EBTR0 = 10
TBLRD*
Block 1
WRT1, EBTR1 = 11
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
Note 1: See Figure 24-5 for block boundaries.
DS39689F-page 276
© 2009 Microchip Technology Inc.
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24.5.2
DATA EEPROM
CODE PROTECTION
The entire data EEPROM is protected from external
reads and writes by two bits: CPD and WRTD. CPD
inhibits external reads and writes of data EEPROM.
WRTD inhibits internal and external writes to data
EEPROM. The CPU can always read data EEPROM
under normal operation, regardless of the protection bit
settings.
24.5.3
CONFIGURATION REGISTER
PROTECTION
The Configuration registers can be write-protected.
The WRTC bit controls protection of the Configuration
registers. In normal execution mode, the WRTC bit is
readable only. WRTC can only be written via ICSP
operation or an external programmer.
24.6
ID Locations
Eight memory locations (200000h-200007h) are
designated as ID locations, where the user can store
checksum or other code identification numbers. These
locations are both readable and writable during normal
execution through the TBLRD and TBLWT instructions
or during program/verify. The ID locations can be read
when the device is code-protected.
24.7
In-Circuit Serial Programming
PIC18F2221/2321/4221/4321 family microcontrollers
can be serially programmed while in the end application circuit. This is simply done with two lines for clock
and data and three other lines for power, ground and
the programming voltage. This allows customers to
manufacture boards with unprogrammed devices and
then program the microcontroller just before shipping
the product. This also allows the most recent firmware
or a custom firmware to be programmed.
24.8
In-Circuit Debugger
When the DEBUG Configuration bit is programmed to
a ‘0’, the In-Circuit Debugger functionality is enabled.
This function allows simple debugging functions when
used with MPLAB® IDE. When the microcontroller has
this feature enabled, some resources are not available
for general use. Table 24-4 shows which resources are
required by the background debugger.
TABLE 24-4:
DEBUGGER RESOURCES
I/O Pins:
RB6, RB7
Stack:
2 levels
Program Memory:
512 bytes
Data Memory:
10 bytes
© 2009 Microchip Technology Inc.
To use the In-Circuit Debugger function of the microcontroller, the design must implement In-Circuit Serial
Programming connections to MCLR/VPP/RE3, VDD,
VSS, RB7 and RB6. This will interface to the In-Circuit
Debugger module available from Microchip or one of
the third party development tool companies.
24.9
Single-Supply ICSP Programming
The LVP Configuration bit enables Single-Supply ICSP
Programming (formerly known as Low-Voltage ICSP
Programming or LVP). When Single-Supply Programming is enabled, the microcontroller can be programmed
without requiring high voltage being applied to the
MCLR/VPP/RE3 pin, but the RB5/KBI1/PGM pin is then
dedicated to controlling Program mode entry and is not
available as a general purpose I/O pin.
While programming, using Single-Supply Programming, VDD is applied to the MCLR/VPP/RE3 pin as in
normal execution mode. To enter Programming mode,
VDD is applied to the PGM pin.
Note 1: High-voltage programming is always
available, regardless of the state of the
LVP bit or the PGM pin, by applying VIHH
to the MCLR pin.
2: By default, Single-Supply ICSP Programming is enabled in unprogrammed
devices (as supplied from Microchip) and
erased devices.
3: When Single-Supply ICSP Programming
is enabled, the RB5 pin can no longer be
used as a general purpose I/O pin.
4: When LVP is enabled, externally pull the
PGM pin to VSS to allow normal program
execution.
If Single-Supply ICSP Programming mode will not be
used, the LVP bit can be cleared. RB5/KBI1/PGM then
becomes available as the digital I/O pin, RB5. The LVP
bit may be set or cleared only when using standard
high-voltage programming (VIHH applied to the MCLR/
VPP/RE3 pin). Once LVP has been disabled, only the
standard high-voltage programming is available and
must be used to program the device.
Memory that is not code-protected can be erased using
either a block erase, or erased row by row, then written
at any specified VDD. If code-protected memory is to be
erased, a block erase is required. If a block erase is to
be performed when using Low-Voltage ICSP
Programming, the device must be supplied with VDD of
4.5V to 5.5V.
DS39689F-page 277
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NOTES:
DS39689F-page 278
© 2009 Microchip Technology Inc.
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25.0
INSTRUCTION SET SUMMARY
PIC18F2221/2321/4221/4321 family devices incorporate the standard set of 75 PIC18 core instructions, as
well as an extended set of 8 new instructions for the
optimization of code that is recursive or that utilizes a
software stack. The extended set is discussed later in
this section.
25.1
Standard Instruction Set
The standard PIC18 instruction set adds many
enhancements to the previous PIC® MCU instruction
sets, while maintaining an easy migration from these
PIC MCU instruction sets. Most instructions are a
single program memory word (16 bits), but there are
four instructions that require two program memory
locations.
Each single-word instruction is a 16-bit word divided
into an opcode, which specifies the instruction type and
one or more operands, which further specify the
operation of the instruction.
The instruction set is highly orthogonal and is grouped
into four basic categories:
•
•
•
•
Byte-oriented operations
Bit-oriented operations
Literal operations
Control operations
The PIC18 instruction set summary in Table 25-2 lists
byte-oriented, bit-oriented, literal and control
operations. Table 25-1 shows the opcode field
descriptions.
Most byte-oriented instructions have three operands:
1.
2.
3.
The file register (specified by ‘f’)
The destination of the result (specified by ‘d’)
The accessed memory (specified by ‘a’)
The file register designator ‘f’ specifies which file
register is to be used by the instruction. The destination
designator ‘d’ specifies where the result of the
operation is to be placed. If ‘d’ is zero, the result is
placed in the WREG register. If ‘d’ is one, the result is
placed in the file register specified in the instruction.
All bit-oriented instructions have three operands:
1.
2.
3.
The file register (specified by ‘f’)
The bit in the file register (specified by ‘b’)
The accessed memory (specified by ‘a’)
The literal instructions may use some of the following
operands:
• A literal value to be loaded into a file register
(specified by ‘k’)
• The desired FSR register to load the literal value
into (specified by ‘f’)
• No operand required
(specified by ‘—’)
The control instructions may use some of the following
operands:
• A program memory address (specified by ‘n’)
• The mode of the CALL or RETURN instructions
(specified by ‘s’)
• The mode of the table read and table write
instructions (specified by ‘m’)
• No operand required
(specified by ‘—’)
All instructions are a single word, except for four
double-word instructions. These instructions were
made double-word to contain the required information
in 32 bits. In the second word, the 4 MSbs are ‘1’s. If
this second word is executed as an instruction (by
itself), it will execute as a NOP.
All single-word instructions are executed in a single
instruction cycle, unless a conditional test is true or the
program counter is changed as a result of the
instruction. In these cases, the execution takes two
instruction cycles, with the additional instruction
cycle(s) executed as a NOP.
The double-word instructions execute in two instruction
cycles.
One instruction cycle consists of four oscillator periods.
Thus, for an oscillator frequency of 4 MHz, the normal
instruction execution time is 1 μs. If a conditional test is
true, or the program counter is changed as a result of
an instruction, the instruction execution time is 2 μs.
Two-word branch instructions (if true) would take 3 μs.
Figure 25-1 shows the general formats that the
instructions can have. All examples use the convention
‘nnh’ to represent a hexadecimal number.
The Instruction Set Summary, shown in Table 25-2,
lists the standard instructions recognized by the
Microchip MPASM™ Assembler.
Section 25.1.1 “Standard Instruction Set” provides
a description of each instruction.
The bit field designator ‘b’ selects the number of the bit
affected by the operation, while the file register
designator ‘f’ represents the number of the file in which
the bit is located.
© 2009 Microchip Technology Inc.
DS39689F-page 279
PIC18F2221/2321/4221/4321 FAMILY
TABLE 25-1:
OPCODE FIELD DESCRIPTIONS
Field
Description
a
RAM access bit
a = 0: RAM location in Access RAM (BSR register is ignored)
a = 1: RAM bank is specified by BSR register
bbb
Bit address within an 8-bit file register (0 to 7).
BSR
Bank Select Register. Used to select the current RAM bank.
C, DC, Z, OV, N
ALU Status bits: Carry, Digit Carry, Zero, Overflow, Negative.
d
Destination select bit
d = 0: store result in WREG
d = 1: store result in file register f
dest
Destination: either the WREG register or the specified register file location.
f
8-bit Register file address (00h to FFh) or 2-bit FSR designator (0h to 3h).
fs
12-bit Register file address (000h to FFFh). This is the source address.
fd
12-bit Register file address (000h to FFFh). This is the destination address.
GIE
Global Interrupt Enable bit.
k
Literal field, constant data or label (may be either an 8-bit, 12-bit or a 20-bit value).
label
Label name.
mm
The mode of the TBLPTR register for the table read and table write instructions.
Only used with table read and table write instructions:
*
No change to register (such as TBLPTR with table reads and writes)
*+
Post-Increment register (such as TBLPTR with table reads and writes)
*-
Post-Decrement register (such as TBLPTR with table reads and writes)
Pre-Increment register (such as TBLPTR with table reads and writes)
+*
n
The relative address (2’s complement number) for relative branch instructions or the direct address for
Call/Branch and Return instructions.
PC
Program Counter.
PCL
Program Counter Low Byte.
PCH
Program Counter High Byte.
PCLATH
Program Counter High Byte Latch.
PCLATU
Program Counter Upper Byte Latch.
PD
Power-Down bit.
PRODH
Product of Multiply High Byte.
PRODL
Product of Multiply Low Byte.
s
Fast Call/Return mode select bit
s = 0: do not update into/from shadow registers
s = 1: certain registers loaded into/from shadow registers (Fast mode)
TBLPTR
21-bit Table Pointer (points to a program memory location).
TABLAT
8-bit Table Latch.
TO
Time-out bit.
TOS
Top-of-Stack.
u
Unused or unchanged.
WDT
Watchdog Timer.
WREG
Working register (accumulator).
x
Don’t care (‘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.
zs
7-bit offset value for indirect addressing of register files (source).
7-bit offset value for indirect addressing of register files (destination).
zd
{
}
Optional argument.
[text]
Indicates an indexed address.
(text)
The contents of text.
[expr]
Specifies bit n of the register indicated by the pointer expr.
→
Assigned to.
< >
Register bit field.
∈
In the set of.
italics
User-defined term (font is Courier New).
DS39689F-page 280
© 2009 Microchip Technology Inc.
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FIGURE 25-1:
GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations
15
10
9
OPCODE
Example Instruction
8 7
d
0
a
ADDWF MYREG, W, B
f (FILE #)
d = 0 for result destination to be WREG register
d = 1 for result destination to be file register (f)
a = 0 to force Access Bank
a = 1 for BSR to select bank
f = 8-bit file register address
Byte to Byte move operations (2-word)
15
12 11
0
OPCODE
15
f (Source FILE #)
12 11
MOVFF MYREG1, MYREG2
0
f (Destination FILE #)
1111
f = 12-bit file register address
Bit-oriented file register operations
15
12 11
9 8 7
0
OPCODE b (BIT #) a
f (FILE #)
BSF MYREG, bit, B
b = 3-bit position of bit in file register (f)
a = 0 to force Access Bank
a = 1 for BSR to select bank
f = 8-bit file register address
Literal operations
15
8
7
0
OPCODE
MOVLW 7Fh
k (literal)
k = 8-bit immediate value
Control operations
CALL, GOTO and Branch operations
15
8 7
0
OPCODE
15
n (literal)
12 11
GOTO Label
0
n (literal)
1111
n = 20-bit immediate value
15
8 7
OPCODE
15
S
0
CALL MYFUNC
n (literal)
12 11
0
n (literal)
1111
S = Fast bit
15
11 10
OPCODE
15
0
8 7
OPCODE
© 2009 Microchip Technology Inc.
BRA MYFUNC
n (literal)
0
n (literal)
BC MYFUNC
DS39689F-page 281
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TABLE 25-2:
PIC18FXXXX INSTRUCTION SET
Mnemonic,
Operands
Description
Cycles
16-Bit Instruction Word
MSb
LSb
Status
Affected
Notes
BYTE-ORIENTED OPERATIONS
Add WREG and f
Add WREG and Carry bit to f
AND WREG with f
Clear f
Complement f
Compare f with WREG, Skip =
Compare f with WREG, Skip >
Compare f with WREG, Skip <
Decrement f
Decrement f, Skip if 0
Decrement f, Skip if Not 0
Increment f
Increment f, Skip if 0
Increment f, Skip if Not 0
Inclusive OR WREG with f
Move f
Move fs (source) to 1st Word
fd (destination) 2nd Word
Move WREG to f
Multiply WREG with f
Negate f
Rotate Left f through Carry
Rotate Left f (No Carry)
Rotate Right f through Carry
Rotate Right f (No Carry)
Set f
Subtract f from WREG with
Borrow
Subtract WREG from f
Subtract WREG from f with
Borrow
Swap Nibbles in f
Test f, Skip if 0
Exclusive OR WREG with f
1
1
1
1
1
1 (2 or 3)
1 (2 or 3)
1 (2 or 3)
1
1 (2 or 3)
1 (2 or 3)
1
1 (2 or 3)
1 (2 or 3)
1
1
2
ADDWF
ADDWFC
ANDWF
CLRF
COMF
CPFSEQ
CPFSGT
CPFSLT
DECF
DECFSZ
DCFSNZ
INCF
INCFSZ
INFSNZ
IORWF
MOVF
MOVFF
f, d, a
f, d, a
f, d, a
f, a
f, d, a
f, a
f, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
f, d, a
fs, fd
MOVWF
MULWF
NEGF
RLCF
RLNCF
RRCF
RRNCF
SETF
SUBFWB
f, a
f, a
f, a
f, d, a
f, d, a
f, d, a
f, d, a
f, a
f, d, a
SUBWF
SUBWFB
f, d, a
f, d, a
SWAPF
TSTFSZ
XORWF
f, d, a
f, a
f, d, a
Note 1:
When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value
present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is driven low by an
external device, the data will be written back with a ‘0’.
If this instruction is executed on the TMR0 register (and where applicable, ‘d’ = 1), the prescaler will be cleared if
assigned.
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.
Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP unless the
first word of the instruction retrieves the information embedded in these 16 bits. This ensures that all program memory
locations have a valid instruction.
2:
3:
4:
DS39689F-page 282
C, DC, Z, OV, N
C, DC, Z, OV, N
Z, N
Z
Z, N
None
None
None
C, DC, Z, OV, N
None
None
C, DC, Z, OV, N
None
None
Z, N
Z, N
None
1, 2
1, 2
1,2
2
1, 2
4
4
1, 2
1, 2, 3, 4
1, 2, 3, 4
1, 2
1, 2, 3, 4
4
1, 2
1, 2
1
1
1
1
1
1
1
1
1
1
0010 01da0
0010 0da
0001 01da
0110 101a
0001 11da
0110 001a
0110 010a
0110 000a
0000 01da
0010 11da
0100 11da
0010 10da
0011 11da
0100 10da
0001 00da
0101 00da
1100 ffff
1111 ffff
0110 111a
0000 001a
0110 110a
0011 01da
0100 01da
0011 00da
0100 00da
0110 100a
0101 01da
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
1
1
0101
0101
11da
10da
ffff
ffff
ffff C, DC, Z, OV, N
ffff C, DC, Z, OV, N
1, 2
1
1 (2 or 3)
1
0011
0110
0001
10da
011a
10da
ffff
ffff
ffff
ffff None
ffff None
ffff Z, N
4
1, 2
None
None
C, DC, Z, OV, N
C, Z, N
Z, N
C, Z, N
Z, N
None
C, DC, Z, OV, N
1, 2
1, 2
1, 2
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 25-2:
PIC18FXXXX INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands
Description
Cycles
16-Bit Instruction Word
MSb
LSb
Status
Affected
Notes
BIT-ORIENTED OPERATIONS
BCF
BSF
BTFSC
BTFSS
BTG
f, b, a
f, b, a
f, b, a
f, b, a
f, d, a
Bit Clear f
Bit Set f
Bit Test f, Skip if Clear
Bit Test f, Skip if Set
Bit Toggle f
1
1
1 (2 or 3)
1 (2 or 3)
1
1001
1000
1011
1010
0111
bbba
bbba
bbba
bbba
bbba
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
None
None
None
None
None
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
2
1 (2)
2
0010
0110
0011
0111
0101
0001
0100
0nnn
0000
110s
kkkk
0000
0000
1111
kkkk
0000
xxxx
0000
0000
1nnn
0000
0000
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0000
0000
kkkk
kkkk
0000
xxxx
0000
0000
nnnn
1111
0001
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
nnnn
kkkk
kkkk
0100
0111
kkkk
kkkk
0000
xxxx
0110
0101
nnnn
1111
000s
None
None
None
None
None
None
None
None
None
None
1
1
1
1
2
1
2
1110
1110
1110
1110
1110
1110
1110
1101
1110
1110
1111
0000
0000
1110
1111
0000
1111
0000
0000
1101
0000
0000
2
2
1
0000
0000
0000
1100
0000
0000
kkkk
0001
0000
1, 2
1, 2
3, 4
3, 4
1, 2
CONTROL OPERATIONS
BC
BN
BNC
BNN
BNOV
BNZ
BOV
BRA
BZ
CALL
n
n
n
n
n
n
n
n
n
n, s
CLRWDT
DAW
GOTO
—
—
n
NOP
NOP
POP
PUSH
RCALL
RESET
RETFIE
—
—
—
—
n
s
Branch if Carry
Branch if Negative
Branch if Not Carry
Branch if Not Negative
Branch if Not Overflow
Branch if Not Zero
Branch if Overflow
Branch Unconditionally
Branch if Zero
Call Subroutine 1st Word
2nd Word
Clear Watchdog Timer
Decimal Adjust WREG
Go to Address 1st Word
2nd Word
No Operation
No Operation
Pop Top of Return Stack (TOS)
Push Top of Return Stack (TOS)
Relative Call
Software Device Reset
Return from Interrupt Enable
RETLW
RETURN
SLEEP
k
s
—
Return with Literal in WREG
Return from Subroutine
Go into Standby mode
Note 1:
When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value
present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is driven low by an
external device, the data will be written back with a ‘0’.
If this instruction is executed on the TMR0 register (and where applicable, ‘d’ = 1), the prescaler will be cleared if
assigned.
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.
Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP unless the
first word of the instruction retrieves the information embedded in these 16 bits. This ensures that all program memory
locations have a valid instruction.
2:
3:
4:
© 2009 Microchip Technology Inc.
1
1
2
TO, PD
C
None
None
None
None
None
None
All
GIE/GIEH,
PEIE/GIEL
kkkk None
001s None
0011 TO, PD
4
DS39689F-page 283
PIC18F2221/2321/4221/4321 FAMILY
TABLE 25-2:
PIC18FXXXX INSTRUCTION SET (CONTINUED)
Mnemonic,
Operands
Description
Cycles
16-Bit Instruction Word
MSb
LSb
Status
Affected
Notes
LITERAL OPERATIONS
ADDLW
ANDLW
IORLW
LFSR
k
k
k
f, k
MOVLB
MOVLW
MULLW
RETLW
SUBLW
XORLW
k
k
k
k
k
k
Add Literal and WREG
AND Literal with WREG
Inclusive OR Literal with WREG
Move Literal (12-bit) 2nd Word
to FSR(f)
1st Word
Move Literal to BSR
Move Literal to WREG
Multiply Literal with WREG
Return with Literal in WREG
Subtract WREG from Literal
Exclusive OR Literal with WREG
1
1
1
2
1
1
1
2
1
1
0000
0000
0000
1110
1111
0000
0000
0000
0000
0000
0000
1111
1011
1001
1110
0000
0001
1110
1101
1100
1000
1010
kkkk
kkkk
kkkk
00ff
kkkk
0000
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
kkkk
C, DC, Z, OV, N
Z, N
Z, N
None
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
0000
1000
1001
1010
1011
1100
1101
1110
1111
None
None
None
None
None
None
None
None
None
None
None
None
C, DC, Z, OV, N
Z, N
DATA MEMORY ↔ PROGRAM MEMORY OPERATIONS
TBLRD*
TBLRD*+
TBLRD*TBLRD+*
TBLWT*
TBLWT*+
TBLWT*TBLWT+*
Note 1:
2:
3:
4:
Table Read
Table Read with Post-Increment
Table Read with Post-Decrement
Table Read with Pre-Increment
Table Write
Table Write with Post-Increment
Table Write with Post-Decrement
Table Write with Pre-Increment
2
2
When a PORT register is modified as a function of itself (e.g., MOVF PORTB, 1, 0), the value used will be that value
present on the pins themselves. For example, if the data latch is ‘1’ for a pin configured as input and is driven low by an
external device, the data will be written back with a ‘0’.
If this instruction is executed on the TMR0 register (and where applicable, ‘d’ = 1), the prescaler will be cleared if
assigned.
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.
Some instructions are two-word instructions. The second word of these instructions will be executed as a NOP unless the
first word of the instruction retrieves the information embedded in these 16 bits. This ensures that all program memory
locations have a valid instruction.
DS39689F-page 284
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
25.1.1
STANDARD INSTRUCTION SET
ADDLW
ADD Literal to W
ADDWF
ADD W to f
Syntax:
ADDLW
Syntax:
ADDWF
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(W) + (f) → dest
Status Affected:
N, OV, C, DC, Z
k
Operands:
0 ≤ k ≤ 255
Operation:
(W) + k → W
Status Affected:
N, OV, C, DC, Z
Encoding:
0000
1111
kkkk
kkkk
Description:
The contents of W are added to the
8-bit literal ‘k’ and the result is placed in
W.
Words:
1
Cycles:
1
Encoding:
0010
Q1
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example:
ADDLW
=
25h
ffff
Words:
1
Cycles:
1
Before Instruction
W
ffff
Add W to register ‘f’. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’
(default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
15h
W
= 10h
After Instruction
01da
Description:
Q Cycle Activity:
Decode
f {,d {,a}}
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
ADDWF
REG, 0, 0
Before Instruction
W
=
REG
=
After Instruction
W
REG
Note:
=
=
17h
0C2h
0D9h
0C2h
All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in
symbolic addressing. If a label is used, the instruction format then becomes: {label} instruction argument(s).
© 2009 Microchip Technology Inc.
DS39689F-page 285
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ADDWFC
ADD W and Carry bit to f
ANDLW
Syntax:
ADDWFC
Syntax:
ANDLW
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ k ≤ 255
Operation:
(W) .AND. k → W
Status Affected:
N, Z
f {,d {,a}}
Operation:
(W) + (f) + (C) → dest
Status Affected:
N,OV, C, DC, Z
Encoding:
0010
Description:
00da
Encoding:
ffff
ffff
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’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
AND Literal with W
0000
k
1011
kkkk
kkkk
Description:
The contents of W are ANDed with the
8-bit literal ‘k’. The result is placed in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal
‘k’
Process
Data
Write to W
Example:
ANDLW
05Fh
Before Instruction
W
=
After Instruction
W
=
A3h
03h
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
ADDWFC
Before Instruction
Carry bit =
REG
=
W
=
After Instruction
Carry bit =
REG
=
W
=
DS39689F-page 286
REG, 0, 1
1
02h
4Dh
0
02h
50h
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
ANDWF
AND W with f
BC
Branch if Carry
Syntax:
ANDWF
Syntax:
BC
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
-128 ≤ n ≤ 127
Operation:
If Carry bit is ‘1’,
(PC) + 2 + 2n → PC
Status Affected:
None
f {,d {,a}}
Operation:
(W) .AND. (f) → dest
Status Affected:
N, Z
Encoding:
0001
Description:
Encoding:
01da
ffff
ffff
The contents of W are ANDed with
register ‘f’. If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored back
in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
ANDWF
REG, 0, 0
Before Instruction
W
=
REG
=
After Instruction
W
REG
=
=
17h
C2h
02h
C2h
© 2009 Microchip Technology Inc.
n
1110
Description:
0010
nnnn
nnnn
If the Carry bit is ‘1’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words:
1
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Example:
HERE
Before Instruction
PC
After Instruction
If Carry
PC
If Carry
PC
BC
5
=
address (HERE)
=
=
=
=
1;
address (HERE + 12)
0;
address (HERE + 2)
DS39689F-page 287
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BCF
Bit Clear f
BN
Branch if Negative
Syntax:
BCF
Syntax:
BN
Operands:
0 ≤ f ≤ 255
0≤b≤7
a ∈ [0,1]
Operands:
-128 ≤ n ≤ 127
Operation:
If Negative bit is ‘1’,
(PC) + 2 + 2n → PC
Status Affected:
None
f, b {,a}
Operation:
0 → f
Status Affected:
None
Encoding:
Encoding:
1001
Description:
bbba
ffff
ffff
Bit ‘b’ in register ‘f’ is cleared.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
BCF
Before Instruction
FLAG_REG
After Instruction
FLAG_REG
DS39689F-page 288
FLAG_REG,
=
C7h
=
47h
7, 0
n
1110
Description:
0110
nnnn
nnnn
If the Negative bit is ‘1’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words:
1
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
If No Jump:
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Example:
HERE
Before Instruction
PC
After Instruction
If Negative
PC
If Negative
PC
BN
Jump
=
address (HERE)
=
=
=
=
1;
address (Jump)
0;
address (HERE + 2)
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
BNC
Branch if Not Carry
BNN
Branch if Not Negative
Syntax:
BNC
Syntax:
BNN
n
n
Operands:
-128 ≤ n ≤ 127
Operands:
-128 ≤ n ≤ 127
Operation:
If Carry bit is ‘0’,
(PC) + 2 + 2n → PC
Operation:
If Negative bit is ‘0’,
(PC) + 2 + 2n → PC
Status Affected:
None
Status Affected:
None
Encoding:
1110
0011
nnnn
nnnn
Encoding:
1110
0111
nnnn
nnnn
Description:
If the Carry bit is ‘0’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Description:
If the Negative bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Words:
1
Words:
1
Cycles:
1(2)
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to
PC
Decode
Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Decode
Read literal
‘n’
Process
Data
No
operation
If No Jump:
Example:
If No Jump:
HERE
Before Instruction
PC
After Instruction
If Carry
PC
If Carry
PC
BNC
Jump
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
© 2009 Microchip Technology Inc.
Example:
HERE
Before Instruction
PC
After Instruction
If Negative
PC
If Negative
PC
BNN
Jump
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
DS39689F-page 289
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BNOV
Branch if Not Overflow
BNZ
Branch if Not Zero
Syntax:
BNOV
Syntax:
BNZ
Operands:
-128 ≤ n ≤ 127
Operands:
-128 ≤ n ≤ 127
Operation:
If Overflow bit is ‘0’,
(PC) + 2 + 2n → PC
Operation:
If Zero bit is ‘0’,
(PC) + 2 + 2n → PC
Status Affected:
None
Status Affected:
None
Encoding:
n
1110
Description:
0101
nnnn
nnnn
Encoding:
1110
If the Overflow bit is ‘0’, then the
program will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Description:
Words:
1
Words:
1
Cycles:
1(2)
Cycles:
1(2)
Q Cycle Activity:
If Jump:
n
0001
nnnn
nnnn
If the Zero bit is ‘0’, then the program
will branch.
The 2’s complement number ‘2n’ is
added to the PC. Since the PC will have
incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is then a
two-cycle instruction.
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to
PC
Decode
Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
No
operation
Decode
Read literal
‘n’
Process
Data
No
operation
If No Jump:
If No Jump:
Example:
HERE
Before Instruction
PC
After Instruction
If Overflow
PC
If Overflow
PC
DS39689F-page 290
BNOV Jump
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
Example:
HERE
Before Instruction
PC
After Instruction
If Zero
PC
If Zero
PC
BNZ
Jump
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
BRA
Unconditional Branch
BSF
Syntax:
BRA
Syntax:
BSF
Operands:
-1024 ≤ n ≤ 1023
Operands:
0 ≤ f ≤ 255
0≤b≤7
a ∈ [0,1]
Operation:
1 → f
Status Affected:
None
n
Operation:
(PC) + 2 + 2n → PC
Status Affected:
None
Encoding:
1101
Description:
0nnn
nnnn
nnnn
Add the 2’s complement number ‘2n’ to
the PC. Since the PC will have
incremented to fetch the next instruction,
the new address will be PC + 2 + 2n. This
instruction is a two-cycle instruction.
Words:
1
Cycles:
2
Bit Set f
Encoding:
1000
Q1
Q2
Q3
Q4
Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
No
operation
No
operation
Example:
HERE
Before Instruction
PC
After Instruction
PC
BRA
Jump
=
address (HERE)
=
address (Jump)
ffff
ffff
Bit ‘b’ in register ‘f’ is set.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
BSF
Before Instruction
FLAG_REG
After Instruction
FLAG_REG
© 2009 Microchip Technology Inc.
bbba
Description:
Q Cycle Activity:
Decode
f, b {,a}
FLAG_REG, 7, 1
=
0Ah
=
8Ah
DS39689F-page 291
PIC18F2221/2321/4221/4321 FAMILY
BTFSC
Bit Test File, Skip if Clear
BTFSS
Bit Test File, Skip if Set
Syntax:
BTFSC f, b {,a}
Syntax:
BTFSS f, b {,a}
Operands:
0 ≤ f ≤ 255
0≤b≤7
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
0≤b (W)
(unsigned comparison)
Operation:
(f) – (W),
skip if (f) < (W)
(unsigned comparison)
Status Affected:
None
Status Affected:
None
Encoding:
0110
Description:
Words:
f {,a}
010a
ffff
ffff
Compares the contents of data memory
location ‘f’ to the contents of the W by
performing an unsigned subtraction.
If the contents of ‘f’ are greater than the
contents of WREG, then the fetched
instruction is discarded and a NOP is
executed instead, making this a
two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Encoding:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q2
Read
register ‘f’
Q3
Process
Data
Q4
No
operation
Q1
Q2
Q3
No
No
No
operation
operation
operation
If skip and followed by 2-word instruction:
Q1
Q2
Q3
No
No
No
operation
operation
operation
No
No
No
operation
operation
operation
Q4
No
operation
Example:
HERE
NGREATER
GREATER
CPFSGT REG, 0
:
:
Before Instruction
PC
W
After Instruction
=
=
Address (HERE)
?
If REG
PC
If REG
PC
>
=
≤
=
W;
Address (GREATER)
W;
Address (NGREATER)
© 2009 Microchip Technology Inc.
ffff
ffff
Words:
1
Cycles:
1(2)
Note:
3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
No
operation
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
If skip:
If skip and followed by 2-word instruction:
If skip:
Q4
No
operation
No
operation
000a
Compares the contents of data memory
location ‘f’ to the contents of W by
performing an unsigned subtraction.
If the contents of ‘f’ are less than the
contents of W, then the fetched
instruction is discarded and a NOP is
executed instead, making this a
two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
Q Cycle Activity:
Q1
Decode
0110
Description:
1
Cycles:
f {,a}
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NLESS
LESS
CPFSLT REG, 1
:
:
Before Instruction
PC
W
After Instruction
=
=
Address (HERE)
?
If REG
PC
If REG
PC
<
=
≥
=
W;
Address (LESS)
W;
Address (NLESS)
DS39689F-page 297
PIC18F2221/2321/4221/4321 FAMILY
DAW
Decimal Adjust W Register
DECF
Syntax:
DAW
Syntax:
DECF f {,d {,a}}
Operands:
None
Operands:
Operation:
If [W > 9] or [DC = 1] then,
(W) + 6 → W;
else,
(W) → W
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) – 1 → dest
Status Affected:
C, DC, N, OV, Z
If [W + DC > 9] or [C = 1] then,
(W) + 6 + DC → W;
else,
(W) + DC → W
Status Affected:
Decrement f
Encoding:
0000
0000
0000
DAW adjusts the eight-bit value in W
resulting from the earlier addition of two
variables (each in packed BCD format)
and produces a correct packed BCD
result.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register W
Process
Data
Write
W
Example 1:
DAW
=
=
=
A5h
0
0
05h
1
0
ffff
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Before Instruction
W
=
C
=
DC
=
After Instruction
ffff
Words:
0111
Description:
01da
Decrement register ‘f’. If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’
(default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
C
Encoding:
W
C
DC
Example 2:
0000
Description:
Example:
DECF
Before Instruction
CNT
=
Z
=
After Instruction
CNT
=
Z
=
CNT,
1, 0
01h
0
00h
1
Before Instruction
W
=
C
=
DC
=
After Instruction
W
C
DC
=
=
=
DS39689F-page 298
CEh
0
0
34h
1
0
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
DECFSZ
Decrement f, Skip if 0
DCFSNZ
Syntax:
DECFSZ f {,d {,a}}
Syntax:
DCFSNZ
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) – 1 → dest,
skip if result = 0
Operation:
(f) – 1 → dest,
skip if result ≠ 0
Status Affected:
None
Status Affected:
None
Encoding:
0010
Description:
11da
ffff
ffff
The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
If the result is ‘0’, the next instruction,
which is already fetched, is discarded
and a NOP is executed instead, making
it a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Decrement f, Skip if Not 0
Encoding:
0100
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
HERE
DECFSZ
GOTO
Example:
CNT, 1, 1
LOOP
CONTINUE
Before Instruction
PC
=
After Instruction
CNT
=
If CNT
=
PC =
If CNT
≠
PC =
Address (HERE)
CNT – 1
0;
Address (CONTINUE)
0;
Address (HERE + 2)
© 2009 Microchip Technology Inc.
ffff
ffff
The contents of register ‘f’ are
decremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
If the result is not ‘0’, the next
instruction, which is already fetched, is
discarded and a NOP is executed
instead, making it a two-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1(2)
Note:
3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
If skip:
If skip and followed by 2-word instruction:
11da
Description:
Q Cycle Activity:
Q1
f {,d {,a}}
If skip:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
ZERO
NZERO
Before Instruction
TEMP
After Instruction
TEMP
If TEMP
PC
If TEMP
PC
DCFSNZ
:
:
TEMP, 1, 0
=
?
=
=
=
≠
=
TEMP – 1
0;
Address (ZERO)
0;
Address (NZERO)
DS39689F-page 299
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GOTO
Unconditional Branch
INCF
Syntax:
GOTO k
Syntax:
INCF
Operands:
0 ≤ k ≤ 1048575
Operands:
Operation:
k → PC
Status Affected:
None
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) + 1 → dest
Status Affected:
C, DC, N, OV, Z
Encoding:
1st word (k)
2nd word(k)
1110
1111
1111
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
GOTO allows an unconditional branch
Description:
Increment f
Encoding:
0010
2
Cycles:
2
Q1
Q2
Q3
Q4
Read literal
‘k’,
No
operation
Read literal
‘k’,
Write to PC
No
operation
No
operation
No
operation
No
operation
ffff
ffff
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Decode
10da
Description:
anywhere within entire
2-Mbyte memory range. The 20-bit
value ‘k’ is loaded into PC.
GOTO is always a two-cycle
instruction.
Words:
f {,d {,a}}
Q Cycle Activity:
Example:
GOTO THERE
After Instruction
PC =
Address (THERE)
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
INCF
Before Instruction
CNT
=
Z
=
C
=
DC
=
After Instruction
CNT
=
Z
=
C
=
DC
=
DS39689F-page 300
CNT, 1, 0
FFh
0
?
?
00h
1
1
1
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
INCFSZ
Increment f, Skip if 0
INFSNZ
Syntax:
INCFSZ
Syntax:
INFSNZ
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
f {,d {,a}}
Increment f, Skip if Not 0
f {,d {,a}}
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
Operation:
(f) + 1 → dest,
skip if result = 0
Operation:
(f) + 1 → dest,
skip if result ≠ 0
Status Affected:
None
Status Affected:
None
Encoding:
0011
Description:
11da
ffff
ffff
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
If the result is ‘0’, the next instruction,
which is already fetched, is discarded
and a NOP is executed instead, making
it a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Encoding:
0100
Description:
Words:
1
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Cycles:
1(2)
Note:
Q Cycle Activity:
10da
ffff
ffff
The contents of register ‘f’ are
incremented. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
If the result is not ‘0’, the next
instruction, which is already fetched, is
discarded and a NOP is executed
instead, making it a two-cycle
instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
If skip:
If skip:
If skip and followed by 2-word instruction:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NZERO
ZERO
Before Instruction
PC
=
After Instruction
CNT
=
If CNT
=
PC
=
If CNT
≠
PC
=
INCFSZ
:
:
Address (HERE)
CNT + 1
0;
Address (ZERO)
0;
Address (NZERO)
© 2009 Microchip Technology Inc.
CNT, 1, 0
Example:
HERE
ZERO
NZERO
Before Instruction
PC
=
After Instruction
REG
=
≠
If REG
PC
=
If REG
=
PC
=
INFSNZ
REG, 1, 0
Address (HERE)
REG + 1
0;
Address (NZERO)
0;
Address (ZERO)
DS39689F-page 301
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IORLW
Inclusive OR Literal with W
IORWF
Syntax:
IORLW k
Syntax:
IORWF
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
(W) .OR. k → W
Status Affected:
N, Z
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(W) .OR. (f) → dest
Status Affected:
N, Z
Encoding:
0000
Description:
1001
kkkk
kkkk
The contents of W are ORed with the
eight-bit literal ‘k’. The result is placed in
W.
Words:
1
Cycles:
1
Inclusive OR W with f
Encoding:
0001
Q1
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example:
IORLW
W
=
ffff
Words:
1
Cycles:
1
35h
9Ah
BFh
ffff
Inclusive OR W with register ‘f’. If ‘d’ is
‘0’, the result is placed in W. If ‘d’ is ‘1’,
the result is placed back in register ‘f’
(default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Before Instruction
W
=
After Instruction
00da
Description:
Q Cycle Activity:
Decode
f {,d {,a}}
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
IORWF
Before Instruction
RESULT =
W
=
After Instruction
RESULT =
W
=
DS39689F-page 302
RESULT, 0, 1
13h
91h
13h
93h
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
LFSR
Load FSR
MOVF
Syntax:
LFSR f, k
Syntax:
MOVF
Operands:
0≤f≤2
0 ≤ k ≤ 4095
Operands:
Operation:
k → FSRf
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Status Affected:
None
Operation:
f → dest
Status Affected:
N, Z
Encoding:
1110
1111
1110
0000
00ff
k7kkk
k11kkk
kkkk
Description:
The 12-bit literal ‘k’ is loaded into the
File Select Register pointed to by ‘f’.
Words:
2
Cycles:
2
Move f
Encoding:
0101
Q1
Q2
Q3
Q4
Read literal
‘k’ MSB
Process
Data
Write
literal ‘k’
MSB to
FSRfH
Decode
Read literal
‘k’ LSB
Process
Data
Write literal
‘k’ to FSRfL
Example:
After Instruction
FSR2H
FSR2L
03h
ABh
ffff
ffff
The contents of register ‘f’ are moved to
a destination dependent upon the
status of ‘d’. If ‘d’ is ‘0’, the result is
placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
Location ‘f’ can be anywhere in the
256-byte bank.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
LFSR 2, 3ABh
=
=
00da
Description:
Q Cycle Activity:
Decode
f {,d {,a}}
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write W
Example:
MOVF
Before Instruction
REG
W
After Instruction
REG
W
© 2009 Microchip Technology Inc.
REG, 0, 0
=
=
22h
FFh
=
=
22h
22h
DS39689F-page 303
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MOVFF
Move f to f
MOVLB
Move Literal to Low Nibble in BSR
Syntax:
MOVFF fs,fd
Syntax:
MOVLW k
Operands:
0 ≤ fs ≤ 4095
0 ≤ fd ≤ 4095
Operands:
0 ≤ k ≤ 255
Operation:
k → BSR
Operation:
(fs) → fd
Status Affected:
None
Status Affected:
None
Encoding:
Encoding:
1st word (source)
2nd word (destin.)
1100
1111
Description:
ffff
ffff
ffff
ffff
ffffs
ffffd
The contents of source register ‘fs’ are
moved to destination register ‘fd’.
Location of source ‘fs’ can be anywhere
in the 4096-byte data space (000h to
FFFh) and location of destination ‘fd’
can also be anywhere from 000h to
FFFh.
Either source or destination can be W
(a useful special situation).
MOVFF is particularly useful for
transferring a data memory location to a
peripheral register (such as the transmit
buffer or an I/O port).
The MOVFF instruction cannot use the
PCL, TOSU, TOSH or TOSL as the
destination register.
Words:
2
Cycles:
2 (3)
0000
0001
kkkk
kkkk
Description:
The eight-bit literal ‘k’ is loaded into the
Bank Select Register (BSR). The value of
BSR always remains ‘0’, regardless
of the value of k7:k4.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write literal
‘k’ to BSR
MOVLB
5
Example:
Before Instruction
BSR Register =
After Instruction
BSR Register =
02h
05h
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
(src)
Process
Data
No
operation
Decode
No
operation
No
operation
Write
register ‘f’
(dest)
No dummy
read
Example:
MOVFF
Before Instruction
REG1
REG2
After Instruction
REG1
REG2
DS39689F-page 304
REG1, REG2
=
=
33h
11h
=
=
33h
33h
© 2009 Microchip Technology Inc.
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MOVLW
Move Literal to W
MOVWF
Syntax:
MOVLW k
Syntax:
MOVWF
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
k→W
0 ≤ f ≤ 255
a ∈ [0,1]
Status Affected:
None
Operation:
(W) → f
Status Affected:
None
Encoding:
0000
1110
kkkk
kkkk
Description:
The eight-bit literal ‘k’ is loaded into W.
Words:
1
Cycles:
1
Move W to f
Encoding:
0110
Q1
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example:
MOVLW
=
ffff
ffff
Move data from W to register ‘f’.
Location ‘f’ can be anywhere in the
256-byte bank.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
5Ah
After Instruction
W
111a
Description:
Q Cycle Activity:
Decode
f {,a}
5Ah
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
MOVWF
REG, 0
Before Instruction
W
=
REG
=
After Instruction
W
REG
© 2009 Microchip Technology Inc.
=
=
4Fh
FFh
4Fh
4Fh
DS39689F-page 305
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MULLW
Multiply Literal with W
MULWF
Multiply W with f
Syntax:
MULLW
Syntax:
MULWF
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
(W) x k → PRODH:PRODL
0 ≤ f ≤ 255
a ∈ [0,1]
Status Affected:
None
Operation:
(W) x (f) → PRODH:PRODL
Status Affected:
None
Encoding:
0000
Description:
k
1101
kkkk
kkkk
An unsigned multiplication is carried
out between the contents of W and the
8-bit literal ‘k’. The 16-bit result is
placed in the PRODH:PRODL register
pair. PRODH contains the high byte.
W is unchanged.
None of the Status flags are affected.
Note that neither Overflow nor Carry is
possible in this operation. A Zero result
is possible but not detected.
Words:
1
Cycles:
1
Encoding:
0000
Q1
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write
registers
PRODH:
PRODL
Example:
MULLW
W
PRODH
PRODL
After Instruction
W
PRODH
PRODL
=
=
=
E2h
?
?
=
=
=
E2h
ADh
08h
ffff
ffff
An unsigned multiplication is carried
out between the contents of W and the
register file location ‘f’. The 16-bit
result is stored in the PRODH:PRODL
register pair. PRODH contains the
high byte. Both W and ‘f’ are
unchanged.
None of the Status flags are affected.
Note that neither Overflow nor Carry is
possible in this operation. A Zero
result is possible but not detected.
If ‘a’ is ‘0’, the Access Bank is
selected. If ‘a’ is ‘1’, the BSR is used
to select the GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction
operates in Indexed Literal Offset
Addressing mode whenever
f ≤ 95 (5Fh). See Section 25.2.3
“Byte-Oriented and Bit-Oriented
Instructions in Indexed Literal Offset
Mode” for details.
Words:
1
Cycles:
1
0C4h
Before Instruction
001a
Description:
Q Cycle Activity:
Decode
f {,a}
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
registers
PRODH:
PRODL
Example:
MULWF
REG, 1
Before Instruction
W
REG
PRODH
PRODL
After Instruction
W
REG
PRODH
PRODL
DS39689F-page 306
=
=
=
=
C4h
B5h
?
?
=
=
=
=
C4h
B5h
8Ah
94h
© 2009 Microchip Technology Inc.
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NEGF
Negate f
NOP
No Operation
Syntax:
NEGF
Syntax:
NOP
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operands:
None
Operation:
(f) + 1 → f
Status Affected:
N, OV, C, DC, Z
Encoding:
f {,a}
0110
Description:
1
Cycles:
1
No operation
Status Affected:
None
Encoding:
110a
ffff
0000
1111
ffff
Location ‘f’ is negated using two’s
complement. The result is placed in the
data memory location ‘f’.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
Operation:
0000
xxxx
Description:
No operation.
Words:
1
Cycles:
1
0000
xxxx
0000
xxxx
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
No
operation
No
operation
No
operation
Example:
None.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
NEGF
Before Instruction
REG
=
After Instruction
REG
=
REG, 1
0011 1010 [3Ah]
1100 0110 [C6h]
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POP
Pop Top of Return Stack
PUSH
Push Top of Return Stack
Syntax:
POP
Syntax:
PUSH
Operands:
None
Operands:
None
Operation:
(TOS) → bit bucket
Operation:
(PC + 2) → TOS
Status Affected:
None
Status Affected:
None
Encoding:
0000
0000
0000
0110
Description:
The TOS value is pulled off the return
stack and is discarded. The TOS value
then becomes the previous value that
was pushed onto the return stack.
This instruction is provided to enable
the user to properly manage the return
stack to incorporate a software stack.
Words:
1
Cycles:
1
Encoding:
0000
0101
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
No
operation
POP TOS
value
No
operation
POP
GOTO
NEW
Q1
Q2
Q3
Q4
Decode
PUSH
PC + 2 onto
return stack
No
operation
No
operation
Example:
Before Instruction
TOS
Stack (1 level down)
=
=
0031A2h
014332h
After Instruction
TOS
PC
=
=
014332h
NEW
DS39689F-page 308
0000
The PC + 2 is pushed onto the top of
the return stack. The previous TOS
value is pushed down on the stack.
This instruction allows implementing a
software stack by modifying TOS and
then pushing it onto the return stack.
Q Cycle Activity:
Example:
0000
Description:
PUSH
Before Instruction
TOS
PC
=
=
345Ah
0124h
After Instruction
PC
TOS
Stack (1 level down)
=
=
=
0126h
0126h
345Ah
© 2009 Microchip Technology Inc.
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RCALL
Relative Call
RESET
Reset
Syntax:
RCALL
Syntax:
RESET
Operands:
-1024 ≤ n ≤ 1023
Operands:
None
Operation:
(PC) + 2 → TOS,
(PC) + 2 + 2n → PC
Operation:
Reset all registers and flags that are
affected by a MCLR Reset.
Status Affected:
None
Status Affected:
All
Encoding:
n
1101
Description:
1nnn
nnnn
nnnn
Subroutine call with a jump up to 1K
from the current location. First, return
address (PC + 2) is pushed onto the
stack. Then, add the 2’s complement
number ‘2n’ to the PC. Since the PC will
have incremented to fetch the next
instruction, the new address will be
PC + 2 + 2n. This instruction is a
two-cycle instruction.
Words:
1
Cycles:
2
Encoding:
0000
Q1
Q2
Q3
Q4
Decode
Read literal
‘n’
Process
Data
Write to
PC
No
operation
No
operation
1111
1111
Description:
This instruction provides a way to
execute a MCLR Reset in software.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Start
Reset
No
operation
No
operation
Example:
Q Cycle Activity:
0000
After Instruction
Registers =
Flags*
=
RESET
Reset Value
Reset Value
PUSH PC
to stack
No
operation
Example:
No
operation
HERE
RCALL Jump
Before Instruction
PC =
Address (HERE)
After Instruction
PC =
Address (Jump)
TOS =
Address (HERE + 2)
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RETFIE
Return from Interrupt
RETLW
Return Literal to W
Syntax:
RETFIE {s}
Syntax:
RETLW k
Operands:
s ∈ [0,1]
Operands:
0 ≤ k ≤ 255
Operation:
(TOS) → PC,
1 → GIE/GIEH or PEIE/GIEL;
if s = 1,
(WS) → W,
(STATUSS) → STATUS,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged
Operation:
k → W,
(TOS) → PC,
PCLATU, PCLATH are unchanged
Status Affected:
None
Status Affected:
0000
0000
0001
1
Cycles:
2
Q Cycle Activity:
Q2
Q3
Q4
Decode
No
operation
No
operation
POP PC
from stack
Set GIEH or
GIEL
No
operation
RETFIE
After Interrupt
PC
W
BSR
STATUS
GIE/GIEH, PEIE/GIEL
DS39689F-page 310
kkkk
kkkk
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
POP PC
from stack,
Write to W
No
operation
No
operation
No
operation
No
operation
Example:
Q1
Example:
1100
W is loaded with the eight-bit literal ‘k’.
The program counter is loaded from the
top of the stack (the return address).
The high address latch (PCLATH)
remains unchanged.
000s
Return from interrupt. Stack is popped
and Top-of-Stack (TOS) is loaded into
the PC. Interrupts are enabled by
setting either the high or low-priority
global interrupt enable bit. If ‘s’ = 1, the
contents of the shadow registers, WS,
STATUSS and BSRS, are loaded into
their corresponding registers, W,
STATUS and BSR. If ‘s’ = 0, no update
of these registers occurs (default).
Words:
No
operation
0000
Description:
GIE/GIEH, PEIE/GIEL
Encoding:
Description:
Encoding:
No
operation
No
operation
1
=
=
=
=
=
TOS
WS
BSRS
STATUSS
1
CALL TABLE ;
;
;
;
:
TABLE
ADDWF PCL ;
RETLW k0
;
RETLW k1
;
:
:
RETLW kn
;
Before Instruction
W
=
After Instruction
W
=
W contains table
offset value
W now has
table value
W = offset
Begin table
End of table
07h
value of kn
© 2009 Microchip Technology Inc.
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RETURN
Return from Subroutine
RLCF
Syntax:
RETURN {s}
Syntax:
RLCF
Operands:
s ∈ [0,1]
Operands:
Operation:
(TOS) → PC;
if s = 1,
(WS) → W,
(STATUSS) → STATUS,
(BSRS) → BSR,
PCLATU, PCLATH are unchanged
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) → dest,
(f) → C,
(C) → dest
Status Affected:
C, N, Z
Status Affected:
None
Encoding:
0000
Rotate Left f through Carry
Encoding:
0000
0001
001s
Description:
Return from subroutine. The stack is
popped and the top of the stack (TOS)
is loaded into the program counter. If
‘s’= 1, the contents of the shadow
registers, WS, STATUSS and BSRS,
are loaded into their corresponding
registers, W, STATUS and BSR. If
‘s’ = 0, no update of these registers
occurs (default).
Words:
1
Cycles:
2
0011
Description:
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
No
operation
Process
Data
POP PC
from stack
No
operation
No
operation
No
operation
No
operation
f {,d {,a}}
01da
ffff
ffff
The contents of register ‘f’ are rotated
one bit to the left through the Carry
flag. If ‘d’ is ‘0’, the result is placed in
W. If ‘d’ is ‘1’, the result is stored back
in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is
selected. If ‘a’ is ‘1’, the BSR is used to
select the GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction
operates in Indexed Literal Offset
Addressing mode whenever
f ≤ 95 (5Fh). See Section 25.2.3
“Byte-Oriented and Bit-Oriented
Instructions in Indexed Literal Offset
Mode” for details.
register f
C
Words:
1
Cycles:
1
Q Cycle Activity:
Example:
RETURN
After Instruction:
PC = TOS
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
Before Instruction
REG
=
C
=
After Instruction
REG
=
W
=
C
=
© 2009 Microchip Technology Inc.
RLCF
REG, 0, 0
1110 0110
0
1110 0110
1100 1100
1
DS39689F-page 311
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RLNCF
Rotate Left f (No Carry)
RRCF
Syntax:
RLNCF
Syntax:
RRCF
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) → dest,
(f) → dest
Operation:
Status Affected:
N, Z
(f) → dest,
(f) → C,
(C) → dest
Status Affected:
C, N, Z
Encoding:
0100
Description:
f {,d {,a}}
01da
ffff
ffff
The contents of register ‘f’ are rotated
one bit to the left. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result is
stored back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Rotate Right f through Carry
Encoding:
0011
Description:
register f
Words:
1
Cycles:
1
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Before Instruction
REG
=
After Instruction
REG
=
DS39689F-page 312
00da
RLNCF
Words:
1
Cycles:
1
0101 0111
ffff
register f
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
RRCF
REG, 0, 0
REG, 1, 0
1010 1011
ffff
The contents of register ‘f’ are rotated
one bit to the right through the Carry
flag. If ‘d’ is ‘0’, the result is placed in W.
If ‘d’ is ‘1’, the result is placed back in
register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
C
Q Cycle Activity:
Example:
f {,d {,a}}
Example:
Before Instruction
REG
=
C
=
After Instruction
REG
=
W
=
C
=
1110 0110
0
1110 0110
0111 0011
0
© 2009 Microchip Technology Inc.
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RRNCF
Rotate Right f (No Carry)
SETF
Syntax:
RRNCF
Syntax:
SETF
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operation:
FFh → f
Operation:
(f) → dest,
(f) → dest
Status Affected:
None
Status Affected:
f {,d {,a}}
Encoding:
N, Z
Encoding:
0100
Description:
00da
ffff
ffff
The contents of register ‘f’ are rotated
one bit to the right. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result is
placed back in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank will be
selected, overriding the BSR value. If ‘a’
is ‘1’, then the bank will be selected as
per the BSR value (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
register f
Words:
1
Cycles:
1
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
RRNCF
Before Instruction
REG
=
After Instruction
REG
=
Example 2:
f {,a}
0110
100a
ffff
ffff
Description:
The contents of the specified register
are set to FFh.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
Q Cycle Activity:
Example 1:
Set f
SETF
Before Instruction
REG
After Instruction
REG
REG, 1
=
5Ah
=
FFh
REG, 1, 0
1101 0111
1110 1011
RRNCF
REG, 0, 0
Before Instruction
W
=
REG
=
After Instruction
W
REG
=
=
?
1101 0111
1110 1011
1101 0111
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SLEEP
Enter Sleep mode
SUBFWB
Syntax:
SLEEP
Syntax:
SUBFWB
Operands:
None
Operands:
Operation:
00h → WDT,
0 → WDT postscaler,
1 → TO,
0 → PD
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(W) – (f) – (C) → dest
Status Affected:
N, OV, C, DC, Z
Status Affected:
TO, PD
Encoding:
0000
Encoding:
0000
0000
0011
Description:
The Power-Down status bit (PD) is
cleared. The Time-out status bit (TO)
is set. Watchdog Timer and its
postscaler are cleared.
The processor is put into Sleep mode
with the oscillator stopped.
Words:
1
Cycles:
1
0101
Q1
Q2
Q3
Q4
Decode
No
operation
Process
Data
Go to
Sleep
SLEEP
Before Instruction
TO =
?
PD =
?
After Instruction
1†
TO =
0
PD =
† If WDT causes wake-up, this bit is cleared.
DS39689F-page 314
f {,d {,a}}
01da
ffff
ffff
Description:
Subtract register ‘f’ and Carry flag
(borrow) from W (2’s complement
method). If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored in
register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Example:
Subtract f from W with Borrow
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example 1:
SUBFWB
REG, 1, 0
Before Instruction
REG
=
3
W
=
2
C
=
1
After Instruction
REG
=
FF
W
=
2
C
=
0
Z
=
0
N
=
1 ; result is negative
SUBFWB
REG, 0, 0
Example 2:
Before Instruction
REG
=
2
W
=
5
C
=
1
After Instruction
REG
=
2
W
=
3
C
=
1
Z
=
0
N
=
0 ; result is positive
SUBFWB
REG, 1, 0
Example 3:
Before Instruction
REG
=
1
W
=
2
C
=
0
After Instruction
REG
=
0
W
=
2
C
=
1
Z
=
1 ; result is zero
N
=
0
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
SUBLW
Subtract W from Literal
SUBWF
Syntax:
SUBLW k
Syntax:
SUBWF
Operands:
0 ≤ k ≤ 255
Operands:
Operation:
k – (W) → W
Status Affected:
N, OV, C, DC, Z
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) – (W) → dest
Status Affected:
N, OV, C, DC, Z
Encoding:
0000
Description
1000
kkkk
kkkk
W is subtracted from the eight-bit
literal ‘k’. The result is placed in W.
Words:
1
Cycles:
1
Subtract W from f
Encoding:
0101
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to W
Example 1:
Before Instruction
W
=
C
=
After Instruction
W
=
C
=
Z
=
N
=
Example 2:
Before Instruction
W
=
C
=
After Instruction
W
=
C
=
Z
=
N
=
Example 3:
Before Instruction
W
=
C
=
After Instruction
W
=
C
=
Z
=
N
=
SUBLW
02h
1
Cycles:
1
Q Cycle Activity:
02h
?
00h
1
; result is zero
1
0
SUBLW
ffff
Words:
01h
?
SUBLW
ffff
Subtract W from register ‘f’ (2’s
complement method). If ‘d’ is ‘0’, the
result is stored in W. If ‘d’ is ‘1’, the
result is stored back in register ‘f’
(default).
If ‘a’ is ‘0’, the Access Bank is
selected. If ‘a’ is ‘1’, the BSR is used
to select the GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction
operates in Indexed Literal Offset
Addressing mode whenever
f ≤ 95 (5Fh). See Section 25.2.3
“Byte-Oriented and Bit-Oriented
Instructions in Indexed Literal Offset
Mode” for details.
02h
01h
1
; result is positive
0
0
11da
Description:
Q Cycle Activity:
Q1
f {,d {,a}}
02h
03h
?
FFh ; (2’s complement)
0
; result is negative
0
1
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
SUBWF
REG, 1, 0
Example 1:
Before Instruction
REG
=
W
=
C
=
After Instruction
REG
=
W
=
C
=
Z
=
N
=
Example 2:
Before Instruction
REG
=
W
=
C
=
After Instruction
REG
=
W
=
C
=
Z
=
N
=
Example 3:
Before Instruction
REG
=
W
=
C
=
After Instruction
REG
=
W
=
C
=
Z
=
N
=
© 2009 Microchip Technology Inc.
3
2
?
1
2
1
0
0
; result is positive
SUBWF
REG, 0, 0
2
2
?
2
0
1
1
0
SUBWF
; result is zero
REG, 1, 0
1
2
?
FFh
2
0
0
1
;(2’s complement)
; result is negative
DS39689F-page 315
PIC18F2221/2321/4221/4321 FAMILY
SUBWFB
Subtract W from f with Borrow
SWAPF
Swap f
Syntax:
SUBWFB
Syntax:
SWAPF f {,d {,a}}
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(f) – (W) – (C) → dest
Operation:
Status Affected:
N, OV, C, DC, Z
(f) → dest,
(f) → dest
Status Affected:
None
Encoding:
0101
Description:
f {,d {,a}}
10da
ffff
ffff
Subtract W and the Carry flag (borrow)
from register ‘f’ (2’s complement
method). If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored back
in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Read
register ‘f’
Example 1:
SUBWFB
Before Instruction
REG
=
W
=
C
=
After Instruction
REG
=
W
=
C
=
Z
=
N
=
Example 2:
Q4
Write to
destination
(0001 1001)
(0000 1101)
0Ch
0Dh
1
0
0
(0000 1011)
(0000 1101)
10da
ffff
ffff
Description:
The upper and lower nibbles of register
‘f’ are exchanged. If ‘d’ is ‘0’, the result
is placed in W. If ‘d’ is ‘1’, the result is
placed in register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
REG, 1, 0
19h
0Dh
1
0011
Example:
SWAPF
Before Instruction
REG
=
After Instruction
REG
=
REG, 1, 0
53h
35h
; result is positive
SUBWFB REG, 0, 0
Before Instruction
REG
=
W
=
C
=
After Instruction
REG
=
W
=
C
=
Z
=
N
=
Example 3:
1Bh
1Ah
0
(0001 1011)
(0001 1010)
1Bh
00h
1
1
0
(0001 1011)
SUBWFB
Before Instruction
REG
=
W
=
C
=
After Instruction
REG
=
W
C
Z
N
Q3
Process
Data
Encoding:
=
=
=
=
DS39689F-page 316
; result is zero
REG, 1, 0
03h
0Eh
1
(0000 0011)
(0000 1101)
F5h
(1111 0100)
; [2’s comp]
(0000 1101)
0Eh
0
0
1
; result is negative
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TBLRD
Table Read
TBLRD
Table Read (Continued)
Syntax:
TBLRD ( *; *+; *-; +*)
Example 1:
TBLRD
Operands:
None
Operation:
if TBLRD *,
(Prog Mem (TBLPTR)) → TABLAT,
TBLPTR – No Change;
if TBLRD *+,
(Prog Mem (TBLPTR)) → TABLAT,
(TBLPTR) + 1 → TBLPTR;
if TBLRD *-,
(Prog Mem (TBLPTR)) → TABLAT,
(TBLPTR) – 1 → TBLPTR;
if TBLRD +*,
(TBLPTR) + 1 → TBLPTR,
(Prog Mem (TBLPTR)) → TABLAT
Example 2:
Status Affected: None
Encoding:
0000
0000
0000
*+ ;
Before Instruction
TABLAT
TBLPTR
MEMORY (00A356h)
After Instruction
TABLAT
TBLPTR
10nn
nn=0 *
=1 *+
=2 *=3 +*
Description:
This instruction is used to read the contents
of Program Memory (P.M.). To address the
program memory, a pointer called Table
Pointer (TBLPTR) is used.
The TBLPTR (a 21-bit pointer) points to
each byte in the program memory. TBLPTR
has a 2-Mbyte address range.
TBLPTR[0] = 0: Least Significant Byte of
Program Memory Word
TBLPTR[0] = 1: Most Significant Byte of
Program Memory Word
The TBLRD instruction can modify the value
of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words:
1
Cycles:
2
TBLRD
=
=
=
55h
00A356h
34h
=
=
34h
00A357h
+* ;
Before Instruction
TABLAT
TBLPTR
MEMORY (01A357h)
MEMORY (01A358h)
After Instruction
TABLAT
TBLPTR
=
=
=
=
AAh
01A357h
12h
34h
=
=
34h
01A358h
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
No
operation
No
operation
No
operation
No
operation
No operation
(Read Program
Memory)
No
operation
No operation
(Write
TABLAT)
© 2009 Microchip Technology Inc.
DS39689F-page 317
PIC18F2221/2321/4221/4321 FAMILY
TBLWT
Table Write
TBLWT
Table Write (Continued)
Syntax:
TBLWT ( *; *+; *-; +*)
Example 1:
TBLWT *+;
Operands:
None
Operation:
if TBLWT*,
(TABLAT) → Holding Register,
TBLPTR – No Change;
if TBLWT*+,
(TABLAT) → Holding Register,
(TBLPTR) + 1 → TBLPTR;
if TBLWT*-,
(TABLAT) → Holding Register,
(TBLPTR) – 1 → TBLPTR;
if TBLWT+*,
(TBLPTR) + 1 → TBLPTR,
(TABLAT) → Holding Register
Status Affected:
Before Instruction
TABLAT
=
55h
TBLPTR
=
00A356h
HOLDING REGISTER
(00A356h)
=
FFh
After Instructions (table write completion)
TABLAT
=
55h
TBLPTR
=
00A357h
HOLDING REGISTER
(00A356h)
=
55h
Example 2:
None
Encoding:
0000
0000
0000
11nn
nn=0 *
=1 *+
=2 *=3 +*
Description:
This instruction uses the 3 LSBs of
TBLPTR to determine which of the
8 holding registers the TABLAT is written
to. The holding registers are used to
program the contents of Program
Memory (P.M.). (Refer to Section 7.0
“Flash Program Memory” for additional
details on programming Flash memory.)
The TBLPTR (a 21-bit pointer) points to
each byte in the program memory.
TBLPTR has a 2-Mbyte address range.
The LSb of the TBLPTR selects which
byte of the program memory location to
access.
TBLPTR[0] = 0: Least Significant Byte
of Program Memory
Word
TBLPTR[0] = 1: Most Significant Byte
of Program Memory
Word
The TBLWT instruction can modify the
value of TBLPTR as follows:
• no change
• post-increment
• post-decrement
• pre-increment
Words:
1
Cycles:
2
TBLWT +*;
Before Instruction
TABLAT
=
34h
TBLPTR
=
01389Ah
HOLDING REGISTER
(01389Ah)
=
FFh
HOLDING REGISTER
(01389Bh)
=
FFh
After Instruction (table write completion)
TABLAT
=
34h
TBLPTR
=
01389Bh
HOLDING REGISTER
(01389Ah)
=
FFh
HOLDING REGISTER
(01389Bh)
=
34h
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
No
No
No
operation operation operation
No
No
No
No
operation operation operation operation
(Read
(Write to
TABLAT)
Holding
Register )
DS39689F-page 318
© 2009 Microchip Technology Inc.
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TSTFSZ
Test f, Skip if 0
XORLW
Syntax:
TSTFSZ f {,a}
Syntax:
XORLW k
Operands:
0 ≤ f ≤ 255
a ∈ [0,1]
Operands:
0 ≤ k ≤ 255
Operation:
(W) .XOR. k → W
Operation:
skip if f = 0
Status Affected:
N, Z
Status Affected:
None
Encoding:
Encoding:
0110
Description:
Exclusive OR Literal with W
011a
ffff
ffff
If ‘f’ = 0, the next instruction fetched
during the current instruction execution
is discarded and a NOP is executed,
making this a two-cycle instruction.
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
0000
1010
kkkk
kkkk
Description:
The contents of W are XORed with
the 8-bit literal ‘k’. The result is placed
in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to W
Example:
XORLW
0AFh
Before Instruction
W
=
After Instruction
W
=
B5h
1Ah
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
No
operation
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
If skip:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NZERO
ZERO
Before Instruction
PC
After Instruction
If CNT
PC
If CNT
PC
TSTFSZ
:
:
CNT, 1
=
Address (HERE)
=
=
≠
=
00h,
Address (ZERO)
00h,
Address (NZERO)
© 2009 Microchip Technology Inc.
DS39689F-page 319
PIC18F2221/2321/4221/4321 FAMILY
XORWF
Exclusive OR W with f
Syntax:
XORWF
Operands:
0 ≤ f ≤ 255
d ∈ [0,1]
a ∈ [0,1]
Operation:
(W) .XOR. (f) → dest
Status Affected:
N, Z
Encoding:
0001
f {,d {,a}}
10da
ffff
ffff
Description:
Exclusive OR the contents of W with
register ‘f’. If ‘d’ is ‘0’, the result is stored
in W. If ‘d’ is ‘1’, the result is stored back
in the register ‘f’ (default).
If ‘a’ is ‘0’, the Access Bank is selected.
If ‘a’ is ‘1’, the BSR is used to select the
GPR bank (default).
If ‘a’ is ‘0’ and the extended instruction
set is enabled, this instruction operates
in Indexed Literal Offset Addressing
mode whenever f ≤ 95 (5Fh). See
Section 25.2.3 “Byte-Oriented and
Bit-Oriented Instructions in Indexed
Literal Offset Mode” for details.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Example:
XORWF
Before Instruction
REG
=
W
=
After Instruction
REG
=
W
=
DS39689F-page 320
REG, 1, 0
AFh
B5h
1Ah
B5h
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
25.2
Extended Instruction Set
A summary of the instructions in the extended instruction
set is provided in Table 25-3. Detailed descriptions are
provided in Section 25.2.2 “Extended Instruction
Set”. The opcode field descriptions in Table 25-1
(page 280) apply to both the standard and extended
PIC18 instruction sets.
In addition to the standard 75 instructions of the PIC18
instruction set, PIC18F2221/2321/4221/4321 family
devices also provide an optional extension to the core
CPU functionality. The added features include eight
additional instructions that augment indirect and
indexed addressing operations and the implementation
of Indexed Literal Offset Addressing mode for many of
the standard PIC18 instructions.
Note:
The additional features of the extended instruction set
are disabled by default. To enable them, users must set
the XINST Configuration bit.
The instructions in the extended set (with the exception
of CALLW, MOVSF and MOVSS) can all be classified as
literal operations, which either manipulate the File
Select Registers, or use them for indexed addressing.
Two of the instructions, ADDFSR and SUBFSR, each
have an additional special instantiation for using FSR2.
These versions (ADDULNK and SUBULNK) allow for
automatic return after execution.
25.2.1
EXTENDED INSTRUCTION SYNTAX
Most of the extended instructions use indexed
arguments, using one of the File Select Registers and
some offset to specify a source or destination register.
When an argument for an instruction serves as part of
indexed addressing, it is enclosed in square brackets
(“[ ]”). This is done to indicate that the argument is used
as an index or offset. The MPASM™ Assembler will
flag an error if it determines that an index or offset value
is not bracketed.
The extended instructions are specifically implemented
to optimize re-entrant program code (that is, code that
is recursive or that uses a software stack) written in
high-level languages, particularly C. Among other
things, they allow users working in high-level
languages to perform certain operations on data
structures more efficiently. These include:
When the extended instruction set is enabled, brackets
are also used to indicate index arguments in byteoriented and bit-oriented instructions. This is in addition
to other changes in their syntax. For more details, see
Section 25.2.3.1 “Extended Instruction Syntax with
Standard PIC18 Commands”.
• Dynamic allocation and deallocation of software
stack space when entering and leaving
subroutines
• Function Pointer invocation
• Software Stack Pointer manipulation
• Manipulation of variables located in a software
stack
TABLE 25-3:
The instruction set extension and the
Indexed Literal Offset Addressing mode
were designed for optimizing applications
written in C; the user may likely never use
these instructions directly in the assembler.
The syntax for these commands is
provided as a reference for users who may
be reviewing code that has been generated
by a compiler.
Note:
In the past, square brackets have been
used to denote optional arguments in the
PIC18 and earlier instruction sets. In this
text and going forward, optional
arguments are denoted by braces (“{ }”).
EXTENSIONS TO THE PIC18 INSTRUCTION SET
Mnemonic,
Operands
ADDFSR
ADDULNK
CALLW
MOVSF
f, k
k
MOVSS
zs, zd
PUSHL
k
SUBFSR
SUBULNK
f, k
k
zs, fd
Description
Add Literal to FSR
Add Literal to FSR2 and Return
Call Subroutine using WREG
Move zs (source) to 1st Word
fd (destination) 2nd Word
Move zs (source) to 1st word
zd (destination) 2nd Word
Store Literal at FSR2,
Decrement FSR2
Subtract Literal from FSR
Subtract Literal from FSR2 and
Return
© 2009 Microchip Technology Inc.
Cycles
1
2
2
2
16-Bit Instruction Word
MSb
LSb
Status
Affected
1000
1000
0000
1011
ffff
1011
xxxx
1010
ffkk
11kk
0001
0zzz
ffff
1zzz
xzzz
kkkk
kkkk
kkkk
0100
zzzz
ffff
zzzz
zzzz
kkkk
None
None
None
None
1
1110
1110
0000
1110
1111
1110
1111
1110
1
2
1110
1110
1001
1001
ffkk
11kk
kkkk
kkkk
None
None
2
None
None
DS39689F-page 321
PIC18F2221/2321/4221/4321 FAMILY
25.2.2
EXTENDED INSTRUCTION SET
ADDFSR
Add Literal to FSR
ADDULNK
Syntax:
ADDFSR f, k
Syntax:
ADDULNK k
Operands:
0 ≤ k ≤ 63
f ∈ [ 0, 1, 2 ]
Operands:
0 ≤ k ≤ 63
Operation:
Operation:
FSR(f) + k → FSR(f)
FSR2 + k → FSR2,
(TOS) → PC
Status Affected:
None
Status Affected:
None
Encoding:
1110
1000
ffkk
kkkk
Description:
The 6-bit literal ‘k’ is added to the
contents of the FSR specified by ‘f’.
Words:
1
Cycles:
1
Encoding:
1110
Description:
The 6-bit literal ‘k’ is added to the
contents of FSR2. A RETURN is then
executed by loading the PC with the
TOS.
The instruction takes two cycles to
execute; a NOP is performed during the
second cycle.
This may be thought of as a special
case of the ADDFSR instruction, where
f = 3 (binary ‘11’); it operates only on
FSR2.
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to
FSR
Example:
ADDFSR 2, 23h
Before Instruction
FSR2
=
After Instruction
FSR2
=
03FFh
Add Literal to FSR2 and Return
11kk
kkkk
Q Cycle Activity:
0422h
Q1
Q2
Q3
Q4
Decode
Read
literal ‘k’
Process
Data
Write to
FSR
No
Operation
No
Operation
No
Operation
No
Operation
Example:
Note:
1000
ADDULNK 23h
Before Instruction
FSR2
=
PC
=
03FFh
0100h
After Instruction
FSR2
=
PC
=
0422h
(TOS)
All PIC18 instructions may take an optional label argument preceding the instruction mnemonic for use in
symbolic addressing. If a label is used, the instruction syntax then becomes: {label} instruction argument(s).
DS39689F-page 322
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
CALLW
Subroutine Call Using WREG
MOVSF
Syntax:
CALLW
Syntax:
MOVSF [zs], fd
Operands:
None
Operands:
Operation:
(PC + 2) → TOS,
(W) → PCL,
(PCLATH) → PCH,
(PCLATU) → PCU
0 ≤ zs ≤ 127
0 ≤ fd ≤ 4095
Operation:
((FSR2) + zs) → fd
Status Affected:
None
Status Affected:
None
Encoding:
0000
0000
0001
0100
Description
First, the return address (PC + 2) is
pushed onto the return stack. Next, the
contents of W are written to PCL; the
existing value is discarded. Then, the
contents of PCLATH and PCLATU are
latched into PCH and PCU,
respectively. The second cycle is
executed as a NOP instruction while the
new next instruction is fetched.
Unlike CALL, there is no option to
update W, STATUS or BSR.
Words:
1
Cycles:
2
Move Indexed to f
Encoding:
1st word (source)
2nd word (destin.)
Q1
Q2
Q3
Q4
Read
WREG
PUSH PC to
stack
No
operation
No
operation
No
operation
No
operation
No
operation
HERE
Before Instruction
PC
=
PCLATH =
PCLATU =
W
=
After Instruction
PC
=
TOS
=
PCLATH =
PCLATU =
W
=
2
Cycles:
2
Q Cycle Activity:
Q1
Decode
address (HERE)
10h
00h
06h
© 2009 Microchip Technology Inc.
zzzzs
ffffd
Words:
CALLW
001006h
address (HERE + 2)
10h
00h
06h
0zzz
ffff
The contents of the source register are
moved to destination register ‘fd’. The
actual address of the source register is
determined by adding the 7-bit literal
offset ‘zs’ in the first word to the value of
FSR2. The address of the destination
register is specified by the 12-bit literal
‘fd’ in the second word. Both addresses
can be anywhere in the 4096-byte data
space (000h to FFFh).
The MOVSF instruction cannot use the
PCL, TOSU, TOSH or TOSL as the
destination register.
If the resultant source address points to
an indirect addressing register, the
value returned will be 00h.
Decode
Example:
1011
ffff
Description:
Q Cycle Activity:
Decode
1110
1111
Q2
Q3
Determine
Determine
source addr source addr
No
operation
No
operation
No dummy
read
Example:
MOVSF
Before Instruction
FSR2
Contents
of 85h
REG2
After Instruction
FSR2
Contents
of 85h
REG2
Q4
Read
source reg
Write
register ‘f’
(dest)
[05h], REG2
=
80h
=
=
33h
11h
=
80h
=
=
33h
33h
DS39689F-page 323
PIC18F2221/2321/4221/4321 FAMILY
MOVSS
Move Indexed to Indexed
PUSHL
Syntax:
Syntax:
PUSHL k
Operands:
MOVSS [zs], [zd]
0 ≤ zs ≤ 127
0 ≤ zd ≤ 127
Operands:
0 ≤ k ≤ 255
Operation:
((FSR2) + zs) → ((FSR2) + zd)
Operation:
k → (FSR2),
FSR2 – 1 → FSR2
Status Affected:
None
Status Affected:
None
Encoding:
1st word (source)
2nd word (dest.)
1110
1111
Description
1011
xxxx
1zzz
xzzz
zzzzs
zzzzd
The contents of the source register are
moved to the destination register. The
addresses of the source and destination
registers are determined by adding the
7-bit literal offsets ‘zs’ or ‘zd’,
respectively, to the value of FSR2. Both
registers can be located anywhere in
the 4096-byte data memory space
(000h to FFFh).
The MOVSS instruction cannot use the
PCL, TOSU, TOSH or TOSL as the
destination register.
If the resultant source address points to
an indirect addressing register, the
value returned will be 00h. If the
resultant destination address points to
an indirect addressing register, the
instruction will execute as a NOP.
Words:
2
Cycles:
2
Q Cycle Activity:
Q1
Decode
Decode
Q2
Q3
Determine
Determine
source addr source addr
Determine
dest addr
Example:
Encoding:
1111
1010
kkkk
kkkk
Description:
The 8-bit literal ‘k’ is written to the data
memory address specified by FSR2. FSR2
is decremented by 1 after the operation.
This instruction allows users to push values
onto a software stack.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read ‘k’
Process
data
Write to
destination
Example:
PUSHL 08h
Before Instruction
FSR2H:FSR2L
Memory (01ECh)
=
=
01ECh
00h
After Instruction
FSR2H:FSR2L
Memory (01ECh)
=
=
01EBh
08h
Q4
Read
source reg
Write
to dest reg
MOVSS [05h], [06h]
Before Instruction
FSR2
Contents
of 85h
Contents
of 86h
After Instruction
FSR2
Contents
of 85h
Contents
of 86h
DS39689F-page 324
Determine
dest addr
Store Literal at FSR2, Decrement FSR2
=
80h
=
33h
=
11h
=
80h
=
33h
=
33h
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
SUBFSR
Subtract Literal from FSR
SUBULNK
Syntax:
SUBFSR f, k
Syntax:
SUBULNK k
Operands:
0 ≤ k ≤ 63
Operands:
0 ≤ k ≤ 63
f ∈ [ 0, 1, 2 ]
Operation:
Operation:
FSR(f – k) → FSR(f)
Status Affected:
None
Encoding:
1110
Description:
1001
ffkk
1
Cycles:
1
FSR2 – k → FSR2,
(TOS) → PC
kkkk
The 6-bit literal ‘k’ is subtracted from
the contents of the FSR specified
by ‘f’.
Words:
Status
Affected:
None
Encoding:
1110
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
SUBFSR 2, 23h
Before Instruction
FSR2
=
03FFh
After Instruction
FSR2
=
03DCh
11kk
kkkk
The 6-bit literal ‘k’ is subtracted from the
contents of the FSR2. A RETURN is then
executed by loading the PC with the TOS.
The instruction takes two cycles to
execute; a NOP is performed during the
second cycle.
This may be thought of as a special case of
the SUBFSR instruction, where f = 3 (binary
‘11’); it operates only on FSR2.
Words:
1
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
No
Operation
No
Operation
No
Operation
No
Operation
Example:
© 2009 Microchip Technology Inc.
1001
Description:
Q Cycle Activity:
Example:
Subtract Literal from FSR2 and Return
SUBULNK 23h
Before Instruction
FSR2
=
PC
=
03FFh
0100h
After Instruction
FSR2
=
PC
=
03DCh
(TOS)
DS39689F-page 325
PIC18F2221/2321/4221/4321 FAMILY
25.2.3
Note:
BYTE-ORIENTED AND
BIT-ORIENTED INSTRUCTIONS IN
INDEXED LITERAL OFFSET MODE
Enabling the PIC18 instruction set
extension may cause legacy applications
to behave erratically or fail entirely.
In addition to eight new commands in the extended set,
enabling the extended instruction set also enables
Indexed Literal Offset Addressing mode (Section 6.5.1
“Indexed Addressing with Literal Offset”). This has
a significant impact on the way that many commands of
the standard PIC18 instruction set are interpreted.
When the extended set is disabled, addresses embedded in opcodes are treated as literal memory locations:
either as a location in the Access Bank (‘a’ = 0) or in a
GPR bank designated by the BSR (‘a’ = 1). When the
extended instruction set is enabled and ‘a’ = 0,
however, a file register argument of 5Fh or less is
interpreted as an offset from the pointer value in FSR2
and not as a literal address. For practical purposes, this
means that all instructions that use the Access RAM bit
as an argument – that is, all byte-oriented and bitoriented instructions, or almost half of the core PIC18
instructions – may behave differently when the
extended instruction set is enabled.
When the content of FSR2 is 00h, the boundaries of the
Access RAM are essentially remapped to their original
values. This may be useful in creating backward
compatible code. If this technique is used, it may be
necessary to save the value of FSR2 and restore it
when moving back and forth between C and assembly
routines in order to preserve the Stack Pointer. Users
must also keep in mind the syntax requirements of the
extended instruction set (see Section 25.2.3.1
“Extended Instruction Syntax with Standard PIC18
Commands”).
25.2.3.1
Extended Instruction Syntax with
Standard PIC18 Commands
When the extended instruction set is enabled, the file
register argument, ‘f’, in the standard byte-oriented and
bit-oriented commands is replaced with the literal offset
value, ‘k’. As already noted, this occurs only when ‘f’ is
less than or equal to 5Fh. When an offset value is used,
it must be indicated by square brackets (“[ ]”). As with
the extended instructions, the use of brackets indicates
to the compiler that the value is to be interpreted as an
index or an offset. Omitting the brackets, or using a
value greater than 5Fh within brackets, will generate an
error in the MPASM Assembler.
If the index argument is properly bracketed for Indexed
Literal Offset Addressing mode, the Access RAM
argument is never specified; it will automatically be
assumed to be ‘0’. This is in contrast to standard
operation (extended instruction set disabled) when ‘a’
is set on the basis of the target address. Declaring the
Access RAM bit in this mode will also generate an error
in the MPASM Assembler.
The destination argument, ‘d’, functions as before.
In the latest versions of the MPASM Assembler,
language support for the extended instruction set must
be explicitly invoked. This is done with either the
command line option, /y, or the PE directive in the
source listing.
25.2.4
CONSIDERATIONS WHEN
ENABLING THE EXTENDED
INSTRUCTION SET
It is important to note that the extensions to the instruction set may not be beneficial to all users. In particular,
users who are not writing code that uses a software
stack may not benefit from using the extensions to the
instruction set.
Although the Indexed Literal Offset Addressing mode
can be very useful for dynamic stack and pointer
manipulation, it can also be very annoying if a simple
arithmetic operation is carried out on the wrong
register. Users who are accustomed to the PIC18
programming must keep in mind that, when the
extended instruction set is enabled, register addresses
of 5Fh or less are used for Indexed Literal Offset
Addressing mode.
Additionally, the Indexed Literal Offset Addressing
mode may create issues with legacy applications
written to the PIC18 assembler. This is because
instructions in the legacy code may attempt to address
registers in the Access Bank below 5Fh. Since these
addresses are interpreted as literal offsets to FSR2
when the instruction set extension is enabled, the
application may read or write to the wrong data
addresses.
Representative examples of typical byte-oriented and
bit-oriented instructions in the Indexed Literal Offset
Addressing mode are provided on the following page to
show how execution is affected. The operand
conditions shown in the examples are applicable to all
instructions of these types.
When porting an application to the PIC18F2221/2321/
4221/4321 family, it is very important to consider the
type of code. A large, re-entrant application that is
written in ‘C’ and would benefit from efficient
compilation will do well when using the instruction set
extensions. Legacy applications that heavily use the
Access Bank will most likely not benefit from using the
extended instruction set.
DS39689F-page 326
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
ADDWF
ADD W to Indexed
(Indexed Literal Offset mode)
BSF
Bit Set Indexed
(Indexed Literal Offset mode)
Syntax:
ADDWF
Syntax:
BSF [k], b
Operands:
0 ≤ k ≤ 95
d ∈ [0,1]
Operands:
0 ≤ f ≤ 95
0≤b≤7
Operation:
(W) + ((FSR2) + k) → dest
Operation:
1 → ((FSR2) + k)
Status Affected:
N, OV, C, DC, Z
Status Affected:
None
Encoding:
[k] {,d}
0010
Description:
01d0
kkkk
kkkk
The contents of W are added to the
contents of the register indicated by
FSR2, offset by the value ‘k’.
If ‘d’ is ‘0’, the result is stored in W. If ‘d’
is ‘1’, the result is stored back in
register ‘f’ (default).
Encoding:
1000
bbb0
kkkk
kkkk
Description:
Bit ‘b’ of the register indicated by FSR2,
offset by the value ‘k’, is set.
Words:
1
Cycles:
1
Q Cycle Activity:
Words:
1
Q1
Q2
Q3
Q4
Cycles:
1
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read ‘k’
Process
Data
Write to
destination
Example:
ADDWF
[OFST] , 0
Before Instruction
W
OFST
FSR2
Contents
of 0A2Ch
After Instruction
W
Contents
of 0A2Ch
=
=
=
17h
2Ch
0A00h
=
20h
=
37h
=
20h
Example:
BSF
Before Instruction
FLAG_OFST
FSR2
Contents
of 0A0Ah
After Instruction
Contents
of 0A0Ah
[FLAG_OFST], 7
=
=
0Ah
0A00h
=
55h
=
D5h
SETF
Set Indexed
(Indexed Literal Offset mode)
Syntax:
SETF [k]
Operands:
0 ≤ k ≤ 95
Operation:
FFh → ((FSR2) + k)
Status Affected:
None
Encoding:
0110
1000
kkkk
kkkk
Description:
The contents of the register indicated
by FSR2, offset by ‘k’, are set to FFh.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read ‘k’
Process
Data
Write
register
Example:
SETF
Before Instruction
OFST
FSR2
Contents
of 0A2Ch
After Instruction
Contents
of 0A2Ch
© 2009 Microchip Technology Inc.
[OFST]
=
=
2Ch
0A00h
=
00h
=
FFh
DS39689F-page 327
PIC18F2221/2321/4221/4321 FAMILY
25.2.5
SPECIAL CONSIDERATIONS WITH
MICROCHIP MPLAB® IDE TOOLS
The latest versions of Microchip’s software tools have
been designed to fully support the extended instruction
set of the PIC18F2221/2321/4221/4321 family family of
devices. This includes the MPLAB C18 C Compiler,
MPASM Assembly language and MPLAB Integrated
Development Environment (IDE).
When selecting a target device for software
development, MPLAB IDE will automatically set default
Configuration bits for that device. The default setting for
the XINST Configuration bit is ‘0’, disabling the
extended instruction set and Indexed Literal Offset
Addressing mode. For proper execution of applications
developed to take advantage of the extended
instruction set, XINST must be set during
programming.
DS39689F-page 328
To develop software for the extended instruction set,
the user must enable support for the instructions and
the Indexed Addressing mode in their language tool(s).
Depending on the environment being used, this may be
done in several ways:
• A menu option, or dialog box within the
environment, that allows the user to configure the
language tool and its settings for the project
• A command line option
• A directive in the source code
These options vary between different compilers,
assemblers and development environments. Users are
encouraged to review the documentation accompanying their development systems for the appropriate
information.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
26.0
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
26.1
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.
© 2009 Microchip Technology Inc.
DS39689F-page 329
PIC18F2221/2321/4221/4321 FAMILY
26.2
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.
26.3
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.
26.4
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:
26.5
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
26.6
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
DS39689F-page 330
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
26.7
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.
26.8
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.
© 2009 Microchip Technology Inc.
26.9
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.
26.10 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.
DS39689F-page 331
PIC18F2221/2321/4221/4321 FAMILY
26.11 PICkit 2 Development
Programmer/Debugger and
PICkit 2 Debug Express
26.13 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.
26.12 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.
DS39689F-page 332
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.
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.0
ELECTRICAL CHARACTERISTICS
Absolute Maximum Ratings(†)
Ambient temperature under bias.............................................................................................................-40°C to +125°C
Storage temperature .............................................................................................................................. -65°C to +150°C
Voltage on any pin with respect to VSS (except VDD and MCLR) ................................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ......................................................................................................... -0.3V to +7.5V
Voltage on MCLR with respect to VSS (Note 2) ......................................................................................... 0V to +13.25V
Total power dissipation (Note 1) ...............................................................................................................................1.0W
Maximum current out of VSS pin ...........................................................................................................................300 mA
Maximum current into VDD pin ..............................................................................................................................250 mA
Input clamp current, IIK (VI < 0 or VI > VDD)...................................................................................................................... ±20 mA
Output clamp current, IOK (VO < 0 or VO > 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
Maximum current sunk by all ports .......................................................................................................................200 mA
Maximum current sourced by all ports ..................................................................................................................200 mA
Note 1: Power dissipation is calculated as follows:
Pdis = VDD x {IDD – ∑ IOH} + ∑ {(VDD – VOH) x IOH} + ∑(VOL x IOL)
2: Voltage spikes below VSS at the MCLR/VPP/RE3 pin, inducing currents greater than 80 mA, may cause
latch-up. Thus, a series resistor of 50-100Ω should be used when applying a “low” level to the MCLR/VPP/
RE3 pin, rather than pulling this pin directly to VSS.
† 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 to maximum rating conditions for
extended periods may affect device reliability.
© 2009 Microchip Technology Inc.
DS39689F-page 333
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-1:
PIC18F2221/2321/4221/4321 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
Voltage
5.0V
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
40 MHz
Frequency
FIGURE 27-2:
PIC18F2221/2321/4221/4321 VOLTAGE-FREQUENCY GRAPH (EXTENDED)
6.0V
5.5V
Voltage
5.0V
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
25 MHz
Frequency
DS39689F-page 334
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-3:
PIC18LF2221/2321/4221/4321 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
Voltage
5.0V
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
4 MHz
25 MHz
40 MHz
Frequency
FMAX = (9.54 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz
Note: VDDAPPMIN is the minimum voltage of the PIC® device in the application.
© 2009 Microchip Technology Inc.
DS39689F-page 335
PIC18F2221/2321/4221/4321 FAMILY
27.1
DC Characteristics:
Supply Voltage
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
Symbol
No.
D001
VDD
Characteristic
Min
Typ
Max
Units
Conditions
Supply Voltage
PIC18LF2X21/4X21
2.0
—
5.5
V
PIC18F2X21/4X21
4.2
—
5.5
V
D001C AVDD
Analog Supply Voltage VDD – 0.3V —
VDD + 0.3V
V
D001D AVSS
Analog Ground Voltage VSS – 0.3V —
VSS + 0.3V
V
D002
VDR
RAM Data Retention
1.5
—
—
V
Voltage(1)
VDD Start Voltage
—
—
0.7
V
See section on Power-on Reset for
D003
VPOR
to Ensure Internal
details
Power-on Reset Signal
VDD Rise Rate
0.05
—
—
V/ms See section on Power-on Reset for
D004
SVDD
to Ensure Internal
details
Power-on Reset Signal
VBOR
Brown-out Reset Voltage
D005
PIC18LF2X21/4X21
BORV = 11
2.00
2.11
2.22
V
BORV = 10
2.65
2.79
2.93
V
D005
All devices
BORV = 01(2)
4.11
4.33
4.55
V
BORV = 00
4.36
4.59
4.82
V
Legend: Shading of rows is to assist in readability of the table.
Note 1: This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM data.
2: With BOR enabled, full-speed operation (FOSC = 40 MHz) is supported until a BOR occurs. This is valid although
VDD may be below the minimum voltage for this frequency.
DS39689F-page 336
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Units
Conditions
Power-Down Current (IPD)(1)
0.5
0.7
μA
-40°C
VDD = 2.0V
0.5
0.7
μA
+25°C
(Sleep mode)
0.5
1.7
μA
+85°C
PIC18LF2X21/4X21 0.6
0.9
μA
-40°C
VDD = 3.0V
0.6
0.9
μA
+25°C
(Sleep mode)
0.6
1.9
μA
+85°C
All Devices 0.9
2.0
μA
-40°C
0.9
2.0
μA
+25°C
VDD = 5.0V
(Sleep mode)
0.9
6.5
μA
+85°C
Extended Devices Only 7.5
70
μA
+125°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
PIC18LF2X21/4X21
Legend:
Note 1:
2:
3:
4:
5:
© 2009 Microchip Technology Inc.
DS39689F-page 337
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Units
13
13
13
41
34
27
104
86
67
68
0.31
19
19
17
45
38
30
115
95
75
100
0.35
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
mA
Conditions
Supply Current (IDD)(2)
PIC18LF2X21/4X21
PIC18LF2X21/4X21
All Devices
Extended Devices Only
PIC18LF2X21/4X21
Legend:
Note 1:
2:
3:
4:
5:
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
+125°C
-40°C
VDD = 2.0V
VDD = 3.0V
FOSC = 31 kHz
(RC_RUN mode,
INTRC source)
VDD = 5.0V
VDD = 2.0V
0.31 0.35
mA
+25°C
0.31 0.35
mA
+85°C
PIC18LF2X21/4X21 0.55 0.60
mA
-40°C
FOSC = 1 MHz
0.51 0.60
mA
+25°C
VDD = 3.0V
(RC_RUN mode,
0.47 0.60
mA
+85°C
INTOSC source)
All Devices 1.0
1.3
mA
-40°C
0.94
1.3
mA
+25°C
VDD = 5.0V
0.88
1.2
mA
+85°C
Extended Devices Only 0.88
1.2
mA
+125°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
DS39689F-page 338
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No.
Legend:
Note 1:
2:
3:
4:
5:
Device
Typ
Max
Units
Supply Current (IDD)(2)
PIC18LF2X21/4X21 0.69
0.9
mA
Conditions
-40°C
VDD = 2.0V
0.70
0.9
mA
+25°C
0.71
0.9
mA
+85°C
PIC18LF2X21/4X21 1.17 1.45
mA
-40°C
FOSC = 4 MHz
1.15 1.45
mA
+25°C
VDD = 3.0V
(RC_RUN mode,
1.14 1.45
mA
+85°C
INTOSC source)
All Devices 2.24
2.9
mA
-40°C
2.20
2.9
mA
+25°C
VDD = 5.0V
2.16
2.8
mA
+85°C
Extended Devices Only 2.18
2.8
mA
+125°C
PIC18LF2X21/4X21
3
5
μA
-40°C
VDD = 2.0V
3
5
μA
+25°C
3
5.6
μA
+85°C
PIC18LF2X21/4X21
4
7
μA
-40°C
FOSC = 31 kHz
5
7
μA
+25°C
VDD = 3.0V
(RC_IDLE mode,
5
10
μA
+85°C
INTRC source)
All Devices 10
12
μA
-40°C
10
12
μA
+25°C
VDD = 5.0V
10
16
μA
+85°C
Extended Devices Only 17
50
μA
+125°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
© 2009 Microchip Technology Inc.
DS39689F-page 339
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Units
Conditions
160
230
μA
170
230
μA
+25°C
170
230
μA
+85°C
220
330
μA
-40°C
240
330
μA
+25°C
250
330
μA
+85°C
410
500
μA
-40°C
420
500
μA
+25°C
430
500
μA
+85°C
450
500
μA
310
440
μA
+125°C
-40°C
330
440
μA
+25°C
340
440
μA
+85°C
480
750
μA
-40°C
500
750
μA
+25°C
520
750
μA
+85°C
All Devices 0.91
1.3
mA
-40°C
0.93
1.3
mA
+25°C
0.96
1.3
mA
+85°C
Supply Current (IDD)(2)
PIC18LF2X21/4X21
PIC18LF2X21/4X21
All Devices
Extended Devices Only
PIC18LF2X21/4X21
PIC18LF2X21/4X21
Legend:
Note 1:
2:
3:
4:
5:
-40°C
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHz
(RC_IDLE mode,
INTOSC source)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 4 MHz
(RC_IDLE mode,
INTOSC source)
VDD = 5.0V
Extended Devices Only 0.98
1.3
mA
+125°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
DS39689F-page 340
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Units
Conditions
PIC18LF2X21/4X21 0.22
0.22
0.21
PIC18LF2X21/4X21 0.51
0.45
0.39
All Devices 1.14
0.99
0.83
Extended Devices Only 0.80
PIC18LF2X21/4X21 610
0.35
0.35
0.3
0.55
0.50
0.45
1.15
1.1
1.1
1.1
870
mA
mA
mA
mA
mA
mA
mA
mA
mA
mA
μA
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
+125°C
-40°C
610
610
1.16
1.10
1.07
2.35
2.24
2.14
2.14
9
12
870
870
1.83
1.83
1.83
2.85
2.85
2.85
2.85
15
20
μA
μA
mA
mA
mA
mA
mA
mA
mA
mA
mA
+25°C
+85°C
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
+125°C
+125°C
+125°C
Supply Current (IDD)(2)
PIC18LF2X21/4X21
All Devices
Extended Devices Only
Extended Devices Only
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHz
(PRI_RUN mode,
EC oscillator)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 4 MHz
(PRI_RUN mode,
EC oscillator)
VDD = 5.0V
VDD = 4.2V
VDD = 5.0V
FOSC = 25 MHz
(PRI_RUN mode,
EC oscillator)
All Devices
Legend:
Note 1:
2:
3:
4:
5:
16
19
mA
-40°C
VDD = 4.2V
14
19
mA
+25°C
FOSC = 40 MHz
14
19
mA
+85°C
(PRI_RUN mode,
All Devices 17
22.7
mA
-40°C
EC oscillator)
VDD = 5.0V
17
22.7
mA
+25°C
17
22.7
mA
+85°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
© 2009 Microchip Technology Inc.
DS39689F-page 341
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Units
7
6
6
6
10
10
10
10
10
12
mA
mA
mA
mA
mA
Conditions
Supply Current (IDD)(2)
All Devices
Extended Devices Only
All Devices
Legend:
Note 1:
2:
3:
4:
5:
-40°C
+25°C
+85°C
+125°C
-40°C
VDD = 4.2V
FOSC = 4 MHz,
16 MHz internal
(PRI_RUN HS+PLL)
FOSC = 4 MHz,
9
12
mA
+25°C
16 MHz internal
VDD = 5.0V
9
12
mA
+85°C
(PRI_RUN HS+PLL)
Extended Devices Only
9
12
mA
+125°C
All Devices 17
19
mA
-40°C
FOSC = 10 MHz,
VDD = 4.2V
15
19
mA
+25°C
40 MHz internal
(PRI_RUN
HS+PLL)
15
19
mA
+85°C
All Devices 18
23
mA
-40°C
FOSC = 10 MHz,
18
23
mA
+25°C
40 MHz internal
VDD = 5.0V
(PRI_RUN HS+PLL)
18
23
mA
+85°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
DS39689F-page 342
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Supply Current (IDD)(2)
PIC18LF2X21/4X21
51
75
μA
-40°C
54
60
83
88
93
180
180
180
190
210
220
230
350
360
370
0.69
0.70
0.72
0.74
3.7
4.6
75
75
123
123
123
260
260
260
260
290
290
290
480
480
480
1
1
1
1
4.0
5.0
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
mA
mA
mA
mA
mA
mA
+25°C
+85°C
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
+125°C
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
-40°C
+25°C
+85°C
+125°C
+125°C
+125°C
6.0
6.2
6.6
6.8
7.3
7.3
7.3
9.2
mA
mA
mA
mA
-40°C
+25°C
+85°C
-40°C
PIC18LF2X21/4X21
All Devices
Extended Devices Only
PIC18LF2X21/4X21
PIC18LF2X21/4X21
All Devices
Extended Devices Only
Extended Devices Only
All Devices
All Devices
Legend:
Note 1:
2:
3:
4:
5:
Units
Conditions
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHz
(PRI_IDLE mode,
EC oscillator)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 4 MHz
(PRI_IDLE mode,
EC oscillator)
VDD = 5.0V
VDD = 4.2V
VDD = 5.0V
VDD = 4.2V
FOSC = 25 MHz
(PRI_IDLE mode,
EC oscillator)
FOSC = 40 MHz
(PRI_IDLE mode,
EC oscillator)
VDD = 5.0V
7.0
9.2
mA
+25°C
7.1
9.2
mA
+85°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
© 2009 Microchip Technology Inc.
DS39689F-page 343
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
Typ
Max
Units
Supply Current (IDD)(2)
PIC18LF2X21/4X21
12
19
μA
-40°C(5)
—
13
13
40
—
33
27
101
—
83
65
2.5
19
19
19
45
45
45
45
115
110
110
88
5
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
-10°C
+25°C
+85°C
-40°C(5)
-10°C
+25°C
+85°C
-40°C(5)
-10°C
+25°C
+85°C
-40°C(5)
PIC18LF2X21/4X21
All Devices
PIC18LF2X21/4X21
Legend:
Note 1:
2:
3:
4:
5:
Conditions
VDD = 2.0V
VDD = 3.0V
FOSC = 32 kHz
(SEC_RUN mode,
Timer1 as clock)(3)
VDD = 5.0V
—
5
μA
-10°C
VDD = 2.0V
3.0
5
μA
+25°C
3.5
8
μA
+85°C
PIC18LF2X21/4X21 3.9
7
μA
-40°C(5)
FOSC = 32 kHz
—
7
μA
-10°C
VDD = 3.0V
(SEC_IDLE mode,
4.5
7
μA
+25°C
Timer1 as clock)(3)
5.2
10.7
μA
+85°C
All Devices 7.5
10
μA
-40°C(5)
—
10
μA
-10°C
VDD = 5.0V
8.0
10
μA
+25°C
8.6
15
μA
+85°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
DS39689F-page 344
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
No.
D022
(ΔIWDT)
D022A
(ΔIBOR)
D022B
(ΔILVD)
Legend:
Note 1:
2:
3:
4:
5:
Device
Typ
Max
Units
Conditions
Module Differential Currents (ΔIWDT, ΔIBOR, ΔILVD, ΔIOSCB, ΔIAD)
Watchdog Timer 1.6
2.5
μA
-40°C
1.6
2.5
μA
+25°C
VDD = 2.0V
1.5
2.5
μA
+85°C
2.3
3.5
μA
-40°C
VDD = 3.0V
2.2
3.5
μA
+25°C
2.1
3
μA
+85°C
3.4
7.4
μA
-40°C
3.9
7.4
μA
+25°C
VDD = 5.0V
4.4
7.4
μA
+85°C
4.5
7.4
μA
+125°C
45
μA
-40°C to +85°C
VDD = 3.0V
Brown-out Reset(4) 34
40
62.6
μA
-40°C to +85°C
VDD = 5.0V
42
62.6
μA -40°C to +125°C
0
2
μA
-40°C to +85°C
VDD = 3.0V
Sleep mode,
BOREN = 10
0
5
μA -40°C to +125°C
VDD = 5.0V
High/Low-Voltage 23
35
μA
-40°C to +85°C
VDD = 2.0V
Detect(4) 23
35
μA
-40°C to +85°C
VDD = 3.0V
28
35
μA
-40°C to +85°C
VDD = 5.0V
30
40
μA -40°C to +125°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
© 2009 Microchip Technology Inc.
DS39689F-page 345
PIC18F2221/2321/4221/4321 FAMILY
27.2
DC Characteristics:
Power-Down and Supply Current
PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
PIC18LF2221/2321/4221/4321
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
PIC18F2221/2321/4221/4321
(Industrial, Extended)
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
D025
(ΔIOSCB)
D026
(ΔIAD)
Timer1 Oscillator
Typ
Max
Units
2.1
—
1.8
2.1
2.2
—
2.6
2.9
3.0
—
3.2
3.4
4.5
4.5
4.5
4.5
6.0
6
6.0
6.0
8.0
8
8.0
8.0
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
μA
Conditions
-40°C(5)
-10°C
+25°C
+85°C
-40°C(5)
-10°C
+25°C
+85°C
-40°C(5)
-10°C
+25°C
+85°C
VDD = 2.0V
VDD = 3.0V
32 kHz Tuning Fork,
Crystal on Timer1
Oscillator(3)
VDD = 5.0V
1.0
2.0
μA
-40°C to +85°C
VDD = 2.0V
1.0
2.0
μA
-40°C to +85°C
VDD = 3.0V
A/D on, Not Converting
1.0
2.0
μA
-40°C to +85°C
VDD = 5.0V
2.0
8.0
μA -40°C to +125°C
Shading of rows is to assist in readability of the table.
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 in high-impedance state and tied to VDD or VSS, and all features that
add delta current disabled (such as WDT, Timer1 Oscillator, BOR, etc.).
The supply current is mainly a function of operating voltage, frequency and mode. Other factors, such as I/O pin
loading and switching rate, oscillator type and circuit, internal code execution pattern and temperature, also have
an impact on the current consumption.
The test conditions for all IDD measurements in active operation mode are:
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD or VSS;
MCLR = VDD; WDT enabled/disabled as specified.
Low-power, Timer1 oscillator is selected unless otherwise indicated, where LPT1OSC (CONFIG3H) = 1.
BOR and HLVD enable internal band gap reference. With both modules enabled, current consumption will be less
than the sum of both specifications.
When operation below -10°C is expected, use T1OSC High-Power mode, where LPT1OSC (CONFIG3H) = 0.
A/D Converter
Legend:
Note 1:
2:
3:
4:
5:
DS39689F-page 346
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.3
DC Characteristics: PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
DC CHARACTERISTICS
Param
Symbol
No.
VIL
Characteristic
Min
Max
Units
Conditions
VSS
0.15 VDD
V
VDD < 4.5V
—
0.8
V
4.5V ≤ VDD ≤ 5.5V
VSS
0.2 VDD
V
VSS
0.3 VDD
V
I2C™ enabled
SMBus enabled
Input Low Voltage
I/O Ports:
D030
with TTL Buffer
D030A
D031
with Schmitt Trigger Buffer
D031A
RC3 and RC4
VSS
0.8
V
D032
D031B
MCLR
VSS
0.2 VDD
V
D033
OSC1
VSS
0.3 VDD
V
HS, HSPLL modes
D033A
D033B
D034
OSC1
OSC1
T13CKI
VSS
VSS
VSS
0.2 VDD
0.3
0.3
V
V
V
RC, EC modes(1)
XT, LP modes
0.25 VDD +
0.8V
VDD
V
VDD < 4.5V
4.5V ≤ VDD ≤ 5.5V
VIH
Input High Voltage
I/O Ports:
D040
with TTL Buffer
D040A
D041
with Schmitt Trigger Buffer
D041A
RC3 and RC4
D041B
2.0
VDD
V
0.8 VDD
VDD
V
0.7 VDD
VDD
V
I2C™ enabled
2.1
VDD
V
SMBus enabled,
VSS ≥ 3V
D042
MCLR
0.8 VDD
VDD
V
D043
OSC1
0.7 VDD
VDD
V
HS, HSPLL modes
D043A
D043B
D043C
D044
OSC1
OSC1
OSC1
T13CKI
0.8 VDD
0.9 VDD
1.6
1.6
VDD
VDD
VDD
VDD
V
V
V
V
EC mode
RC mode(1)
XT, LP modes
—
±200
nA
VDD < 5.5V,
VSS ≤ VPIN ≤ VDD,
Pin at High-Impedance
—
±50
nA
VDD < 3V,
VSS ≤ VPIN ≤ VDD,
Pin at High-Impedance
MCLR
—
±1
μA
Vss ≤ VPIN ≤ VDD
OSC1
—
±1
μA
Vss ≤ VPIN ≤ VDD
IIL
D060
Input Leakage Current(2,3)
I/O Ports
D061
D063
Note 1:
2:
3:
In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PIC® device be driven with an external clock while in RC mode.
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.
Negative current is defined as current sourced by the pin.
© 2009 Microchip Technology Inc.
DS39689F-page 347
PIC18F2221/2321/4221/4321 FAMILY
27.3
DC Characteristics: PIC18F2221/2321/4221/4321 (Industrial)
PIC18LF2221/2321/4221/4321 (Industrial) (Continued)
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
DC CHARACTERISTICS
Param
Symbol
No.
D070
Characteristic
IPU
Weak Pull-up Current
IPURB
PORTB Weak Pull-up Current
VOL
Output Low Voltage
Min
Max
Units
Conditions
50
400
μA
VDD = 5V, VPIN = VSS
D080
I/O Ports
—
0.6
V
IOL = 8.5 mA, VDD = 4.5V,
-40°C to +85°C
D083
OSC2/CLKO
(RC, RCIO, EC, ECIO modes)
—
0.6
V
IOL = 1.6 mA, VDD = 4.5V,
-40°C to +85°C
VOH
Output High Voltage(3)
D090
I/O Ports
VDD – 0.7
—
V
IOH = -3.0 mA, VDD = 4.5V,
-40°C to +85°C
D092
OSC2/CLKO
(RC, RCIO, EC, ECIO modes)
VDD – 0.7
—
V
IOH = -1.3 mA, VDD = 4.5V,
-40°C to +85°C
—
15
pF
In XT, HS and LP modes
when external clock is used
to drive OSC1
Capacitive Loading Specs
on Output Pins
D100
COSC2 OSC2 Pin
D101
CIO
All I/O Pins and OSC2
(in RC mode)
—
50
pF
Maximum that allows the
AC Timing Specifications to
be met
D102
CB
SCL, SDA
—
400
pF
Maximum bus capacitance
permitted by I2C™
Specification
Note 1:
2:
3:
In RC oscillator configuration, the OSC1/CLKI pin is a Schmitt Trigger input. It is not recommended that the
PIC® device be driven with an external clock while in RC mode.
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.
Negative current is defined as current sourced by the pin.
DS39689F-page 348
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 27-1:
MEMORY PROGRAMMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
DC CHARACTERISTICS
Param
No.
Sym
Characteristic
Min
Typ†
Max
Units
Conditions
Data EEPROM Memory
D120
ED
Byte Endurance
D121
VDRW
VDD for Read/Write
1M
10M
—
VMIN
—
5.5
D122
TDEW
E/W -40°C to +85°C
V
Erase/Write Cycle Time
—
4
—
ms
D123
TRETD Characteristic Retention
40
—
—
Year Provided no other
specifications are violated
D124
TREF
Number of Total Erase/Write
Cycles before Refresh(1)
100K
1M
—
E/W -40°C to +85°C
D125
IDDP
Supply Current during
Programming
—
10
—
mA
D130
EP
Cell Endurance
10K
100K
—
E/W -40°C to +85°C
D131
VPR
VDD for Read
VMIN
—
5.5
D132
VIE
VDD for Block Erase
Using EECON to read/write,
VMIN = Minimum operating
voltage
Program Flash Memory
D132B VPEW
VDD for Self-Timed Write
D133A TIW
Self-Timed Write Cycle Time
D134
TRETD Characteristic Retention
D135
IDDP
Supply Current during
Programming
V
VMIN = Minimum operating
voltage
3.0
—
5.5
V
Using ICSP™ port, 25°C
VMIN
—
5.5
V
VMIN = Minimum operating
voltage
—
2
—
40
100
—
Year Provided no other
specifications are violated
ms
—
10
—
mA
† Data in “Typ” column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
Note 1: Refer to Section 8.7 “Using the Data EEPROM” for a more detailed discussion on data EEPROM
endurance.
© 2009 Microchip Technology Inc.
DS39689F-page 349
PIC18F2221/2321/4221/4321 FAMILY
TABLE 27-2:
COMPARATOR SPECIFICATIONS
Operating Conditions: 3.0V < VDD < 5.5V, -40°C < TA < +85°C for industrial (unless otherwise stated)
-40°C < TA < +125°C for extended (unless otherwise stated)
Param
No.
Sym
Characteristics
Min
Typ
Max
Units
Comments
D300
VIOFF
Input Offset Voltage
—
±5.0
±10
mV
D301
VICM
Input Common Mode Voltage
0
—
VDD – 1.5
V
D302
CMRR
Common Mode Rejection Ratio
55
—
—
dB
D303
TRESP
Response Time(1)
—
150
400
ns
PIC18FXXXX
—
150
600
ns
PIC18LFXXXX,
VDD = 2.0V
—
—
10
μs
D303A
D304
Note 1:
TMC2OV
Comparator Mode Change to
Output Valid
Response time measured with one comparator input at (VDD – 1.5)/2, while the other input transitions
from VSS to VDD.
TABLE 27-3:
VOLTAGE REFERENCE SPECIFICATIONS
Operating Conditions: 3.0V < VDD < 5.5V, -40°C < TA < +85°C for industrial (unless otherwise stated)
-40°C < TA < +125°C for extended (unless otherwise stated)
Param
No.
Sym
Characteristics
Min
Typ
Max
Units
D310
VRES
Resolution
VDD/24
—
VDD/32
LSb
D311
VRAA
Absolute Accuracy
—
—
1/2
LSb
D312
VRUR
Unit Resistor Value (R)
—
2k
—
Ω
D310
TSET
Settling Time(1)
—
—
10
μs
Note 1:
Comments
Settling time measured while CVRR = 1 and CVR transitions from ‘0000’ to ‘1111’.
DS39689F-page 350
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-4:
HIGH/LOW-VOLTAGE DETECT CHARACTERISTICS
VDD
(HLVDIF can be
cleared in software)
VLVD
(HLVDIF set by hardware)
HLVDIF(1)
Note 1: VDIRMAG = 0.
TABLE 27-4:
HIGH/LOW-VOLTAGE DETECT CHARACTERISTICS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Param
Symbol
No.
D420
Characteristic
Min
Typ
Max
Units
HLVD Voltage on VDD LVV = 0000
Transition High-to-Low LVV = 0001
2.06
2.17
2.28
V
2.12
2.23
2.34
V
LVV = 0010
2.24
2.36
2.48
V
LVV = 0011
2.32
2.44
2.56
V
LVV = 0100
2.47
2.60
2.73
V
LVV = 0101
2.65
2.79
2.93
V
© 2009 Microchip Technology Inc.
LVV = 0110
2.74
2.89
3.04
V
LVV = 0111
2.96
3.12
3.28
V
LVV = 1000
3.22
3.39
3.56
V
LVV = 1001
3.37
3.55
3.73
V
LVV = 1010
3.52
3.71
3.90
V
LVV = 1011
3.70
3.90
4.10
V
LVV = 1100
3.90
4.11
4.32
V
LVV = 1101
4.11
4.33
4.55
V
LVV = 1110
4.36
4.59
4.82
V
LVV = 1111
1.10
1.20
1.30
V
Conditions
HLVDIN Input/Internal
Reference Voltage
DS39689F-page 351
PIC18F2221/2321/4221/4321 FAMILY
27.4
27.4.1
AC (Timing) Characteristics
TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created
using one of the following formats:
1. TppS2ppS
2. TppS
T
F
Frequency
Lowercase letters (pp) and their meanings:
pp
cc
CCP1
ck
CLKO
cs
CS
di
SDI
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
I2C only
AA
output access
BUF
Bus free
TCC:ST (I2C specifications only)
CC
HD
Hold
ST
DAT
DATA input hold
STA
Start condition
DS39689F-page 352
3. TCC:ST
4. Ts
(I2C specifications only)
(I2C specifications only)
T
Time
osc
rd
rw
sc
ss
t0
t1
wr
OSC1
RD
RD or WR
SCK
SS
T0CKI
T13CKI
WR
P
R
V
Z
Period
Rise
Valid
High-impedance
High
Low
High
Low
SU
Setup
STO
Stop condition
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
27.4.2
TIMING CONDITIONS
Note:
The temperature and voltages specified in Table 27-5
apply to all timing specifications unless otherwise
noted. Figure 27-5 specifies the load conditions for the
timing specifications.
TABLE 27-5:
TEMPERATURE AND VOLTAGE SPECIFICATIONS – AC
AC CHARACTERISTICS
FIGURE 27-5:
Because of space limitations, the generic
terms “PIC18FXXXX” and “PIC18LFXXXX”
are used throughout this section to refer to
the PIC18F2221/2321/4221/4321 and
PIC18LF2221/2321/4221/4321 families of
devices specifically and only those devices.
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C ≤ TA ≤ +85°C for industrial
-40°C ≤ TA ≤ +125°C for extended
Operating voltage VDD range as described in DC spec Section 27.1 and
Section 27.3.
LF parts operate for industrial temperatures only.
LOAD CONDITIONS FOR DEVICE TIMING SPECIFICATIONS
Load Condition 1
Load Condition 2
VDD/2
RL
CL
Pin
VSS
CL
Pin
RL = 464Ω
VSS
© 2009 Microchip Technology Inc.
CL = 50 pF
for all pins except OSC2/CLKO
and including D and E outputs as ports
DS39689F-page 353
PIC18F2221/2321/4221/4321 FAMILY
27.4.3
TIMING DIAGRAMS AND SPECIFICATIONS
FIGURE 27-6:
EXTERNAL CLOCK TIMING (ALL MODES EXCEPT PLL)
Q4
Q1
Q2
Q3
Q4
Q1
OSC1
1
3
4
3
4
2
CLKO
TABLE 27-6:
Param.
No.
1A
EXTERNAL CLOCK TIMING REQUIREMENTS
Symbol
FOSC
Characteristic
Min
Max
Units
External CLKI Frequency(1)
DC
1
MHz
XT, RC Oscillator mode
DC
25
MHz
HS Oscillator mode
DC
40
MHz
EC Oscillator mode
Oscillator Frequency(1)
1
TOSC
External CLKI Period(1)
Oscillator
Period(1)
2
TCY
Instruction Cycle Time(1)
3
TOSL,
TOSH
External Clock in (OSC1)
High or Low Time
4
Note 1:
TOSR,
TOSF
External Clock in (OSC1)
Rise or Fall Time
Conditions
4
10
MHz
HS+PLL Oscillator mode
DC
50
kHz
LP Oscillator mode
DC
4
MHz
RC Oscillator mode
0.1
4
MHz
XT Oscillator mode
4
25
MHz
HS Oscillator mode
5
200
kHz
LP Oscillator mode
1000
—
ns
XT, RC Oscillator mode
40
—
ns
HS Oscillator mode
25
—
ns
EC Oscillator mode
100
250
ns
HS+PLL Oscillator mode
32
—
μs
LP Oscillator mode
250
—
ns
RC Oscillator mode
250
1
μs
XT Oscillator mode
40
250
ns
HS Oscillator mode
5
209
μs
LP Oscillator mode
100
—
ns
TCY = 4/FOSC, Industrial
160
—
ns
TCY = 4/FOSC, Extended
30
—
ns
XT Oscillator mode
2.5
—
μs
LP Oscillator mode
10
—
ns
HS Oscillator mode
—
20
ns
XT Oscillator mode
—
50
ns
LP Oscillator mode
—
7.5
ns
HS Oscillator mode
Instruction cycle period (TCY) equals four times the input oscillator time base period for all configurations
except PLL. 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/CLKI pin. When an external clock
input is used, the “max.” cycle time limit is “DC” (no clock) for all devices.
DS39689F-page 354
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
TABLE 27-7:
Param
No.
PLL CLOCK TIMING SPECIFICATIONS (VDD = 4.2V TO 5.5V)
Sym
Characteristic
Min
Typ†
Max
4
16
—
—
10
40
Units
F10
F11
FOSC Oscillator Frequency Range
FSYS On-Chip VCO System Frequency
F12
trc
PLL Start-up Time (Lock Time)
—
—
2
ms
ΔCLK
CLKO Stability (Jitter)
-2
—
+2
%
F13
Conditions
MHz HS mode only
MHz HS mode only
† Data in “Typ” column is at 5V, 25°C unless otherwise stated. These parameters are for design guidance
only and are not tested.
TABLE 27-8:
AC CHARACTERISTICS: INTERNAL RC ACCURACY
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
Min
Typ
Max
Units
Conditions
INTOSC Accuracy @ Freq = 8 MHz, 4 MHz, 2 MHz, 1 MHz, 500 kHz, 250 kHz, 125 kHz, 31 kHz(1)
PIC18LF2221/2321/4221/4321
PIC18F2221/2321/4221/4321
-2
+/-1
2
%
+25°C
VDD = 2.0-5.5V
VDD = 2.0-5.5V
-5
—
5
%
-10°C to +85°C
-10
+/-1
10
%
-40°C to +85°C
VDD = 2.0-5.5V
-2
+/-1
2
%
+25°C
VDD = 4.2-5.5V
-5
—
5
%
-10°C to +85°C
VDD = 4.2-5.5V
-10
+/-1
10
%
-40°C to +85°C
VDD = 4.2-5.5V
PIC18LF2221/2321/4221/4321 26.562
—
35.938
kHz
-40°C to +85°C
VDD = 2.0-5.5V
PIC18F2221/2321/4221/4321 26.562
—
35.938
kHz
-40°C to +85°C
VDD = 4.2-5.5V
INTRC Accuracy @ Freq = 31 kHz
Note 1:
Frequency calibrated at 25°C. OSCTUNE register can be used to compensate for temperature drift.
© 2009 Microchip Technology Inc.
DS39689F-page 355
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-7:
CLKO AND I/O TIMING
Q1
Q4
Q2
Q3
OSC1
11
10
CLKO
13
14
19
12
18
16
I/O pin
(Input)
15
17
I/O pin
(Output)
20, 21
Refer to Figure 27-5 for load conditions.
Note:
TABLE 27-9:
Param
No.
10
New Value
Old Value
CLKO AND I/O TIMING REQUIREMENTS
Symbol
Characteristic
TosH2ckL OSC1 ↑ to CLKO ↓
Min
Typ
Max
—
75
200
Units Conditions
ns
(Note 1)
11
TosH2ckH OSC1 ↑ to CLKO ↑
—
75
200
ns
(Note 1)
12
TckR
CLKO Rise Time
—
35
100
ns
(Note 1)
13
TckF
CLKO Fall Time
—
35
100
ns
(Note 1)
14
TckL2ioV
CLKO ↓ to Port Out Valid
—
—
0.5 TCY + 20
ns
(Note 1)
15
TioV2ckH Port In Valid before CLKO ↑
16
TckH2ioI
17
TosH2ioV OSC1 ↑ (Q1 cycle) to Port Out Valid
18
TosH2ioI
18A
Port In Hold after CLKO ↑
OSC1 ↑ (Q2 cycle) to
Port Input Invalid
(I/O in hold time)
0.25 TCY + 25
—
—
ns
(Note 1)
0
—
—
ns
(Note 1)
—
50
150
ns
PIC18FXXXX
100
—
—
ns
PIC18LFXXXX
200
—
—
ns
19
TioV2osH Port Input Valid to OSC1 ↑ (I/O in setup time)
0
—
—
ns
20
TioR
Port Output Rise Time
20A
21
TioF
21A
Port Output Fall Time
PIC18FXXXX
—
10
25
ns
PIC18LFXXXX
—
—
60
ns
PIC18FXXXX
—
10
25
ns
PIC18LFXXXX
—
—
60
ns
22†
TINP
INTx Pin High or Low Time
TCY
—
—
ns
23†
TRBP
RB Change INTx High or Low Time
TCY
—
—
ns
VDD = 2.0V
VDD = 2.0V
VDD = 2.0V
† These parameters are asynchronous events not related to any internal clock edges.
Note 1: Measurements are taken in RC mode, where CLKO output is 4 x TOSC.
DS39689F-page 356
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-8:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND
POWER-UP TIMER TIMING
VDD
MCLR
30
Internal
POR
33
PWRT
Time-out
32
OSC
Time-out
Internal
Reset
Watchdog
Timer
Reset
31
34
34
I/O pins
FIGURE 27-9:
BROWN-OUT RESET TIMING
BVDD
VDD
35
VIRVST
Enable Internal
Reference Voltage
Internal Reference
Voltage Stable
36
TABLE 27-10: RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Param.
Symbol
No.
Characteristic
Min
Typ
Max
Units
30
TmcL
MCLR Pulse Width (low)
2
—
—
μs
31
TWDT
Watchdog Timer Time-out Period
(no postscaler)
3.56
4.19
4.82
ms
32
TOST
Oscillation Start-up Timer Period
1024 TOSC
—
1024 TOSC
—
33
TPWRT
Power-up Timer Period
57
67
77
ms
34
TIOZ
I/O High-Impedance from MCLR
Low or Watchdog Timer Reset
—
2
—
μs
35
TBOR
Brown-out Reset Pulse Width
200
—
—
μs
36
TIRVST
Time for Internal Reference
Voltage to become Stable
—
20
50
μs
37
TLVD
High/Low-Voltage Detect Pulse Width
200
—
—
μs
38
TCSD
CPU Start-up Time
—
10
—
μs
39
TIOBST
Time for INTOSC to Stabilize
—
1
—
μs
© 2009 Microchip Technology Inc.
Conditions
TOSC = OSC1 period
VDD ≤ BVDD (see D005)
VDD ≤ VLVD
DS39689F-page 357
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-10:
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
41
40
42
T1OSO/T13CKI
46
45
47
48
TMR0 or
TMR1
TABLE 27-11: TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
No.
40
Symbol
Tt0H
Characteristic
T0CKI High Pulse Width
No prescaler
With prescaler
41
Tt0L
T0CKI Low Pulse Width
No prescaler
With prescaler
42
45
Tt0P
Tt1H
Tt1L
Tt1P
Ft1
48
0.5 TCY + 20
—
ns
10
—
ns
0.5 TCY + 20
—
ns
10
—
ns
TCY + 10
—
ns
—
ns
T13CKI
Synchronous, no prescaler
High Time Synchronous,
PIC18FXXXX
with prescaler
PIC18LFXXXX
0.5 TCY + 20
—
ns
10
—
ns
25
—
ns
PIC18FXXXX
30
—
ns
PIC18LFXXXX
50
—
ns
0.5 TCY + 5
—
ns
10
—
ns
T13CKI
Low Time
Synchronous, no prescaler
Synchronous,
with prescaler
PIC18FXXXX
PIC18LFXXXX
25
—
ns
Asynchronous
PIC18FXXXX
30
—
ns
T13CKI
Input
Period
N = prescale
value
(1, 2, 4,..., 256)
VDD = 2.0V
VDD = 2.0V
VDD = 2.0V
50
—
ns
VDD = 2.0V
Synchronous
Greater of:
20 ns or
(TCY + 40)/N
—
ns
N = prescale
value (1, 2, 4, 8)
Asynchronous
60
—
ns
DC
50
kHz
2 TOSC
7 TOSC
—
T13CKI Oscillator Input Frequency Range
Tcke2tmrI Delay from External T13CKI Clock Edge to
Timer Increment
DS39689F-page 358
Units Conditions
Greater of:
20 ns or
(TCY + 40)/N
No prescaler
PIC18LFXXXX
47
Max
With prescaler
T0CKI Period
Asynchronous
46
Min
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-11:
CAPTURE/COMPARE/PWM TIMINGS (ALL CCP MODULES)
CCPx
(Capture Mode)
50
51
52
CCPx
(Compare or PWM Mode)
53
54
TABLE 27-12: CAPTURE/COMPARE/PWM REQUIREMENTS (ALL CCP MODULES)
Param
Symbol
No.
50
51
TccL
TccH
Characteristic
Min
Max
Units
CCPx Input Low No prescaler
Time
With
PIC18FXXXX
prescaler PIC18LFXXXX
0.5 TCY + 20
—
ns
10
—
ns
20
—
ns
CCPx Input
High Time
0.5 TCY + 20
—
ns
No prescaler
With
prescaler
52
TccP
CCPx Input Period
53
TccR
CCPx Output Fall Time
54
TccF
CCPx Output Fall Time
© 2009 Microchip Technology Inc.
Conditions
VDD = 2.0V
PIC18FXXXX
10
—
ns
PIC18LFXXXX
20
—
ns
VDD = 2.0V
3 TCY + 40
N
—
ns
N = prescale
value (1, 4 or 16)
—
25
ns
PIC18FXXXX
PIC18LFXXXX
—
45
ns
PIC18FXXXX
—
25
ns
PIC18LFXXXX
—
45
ns
VDD = 2.0V
VDD = 2.0V
DS39689F-page 359
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-12:
PARALLEL SLAVE PORT TIMING (PIC18F4221/4321)
RE2/CS
RE0/RD
RE1/WR
65
RD
62
64
63
Note:
Refer to Figure 27-5 for load conditions.
TABLE 27-13: PARALLEL SLAVE PORT REQUIREMENTS (PIC18F4221/4321)
Param.
No.
Symbol
Characteristic
Min
Max
Units
—
ns
62
TdtV2wrH
Data In Valid before WR ↑ or CS ↑ (setup time)
20
63
TwrH2dtI
WR ↑ or CS ↑ to Data–In
Invalid (hold time)
PIC18FXXXX
20
—
ns
PIC18LFXXXX
35
—
ns
80
ns
ns
TrdL2dtV
RD ↓ and CS ↓ to Data–Out Valid
—
65
TrdH2dtI
RD ↑ or CS ↓ to Data–Out Invalid
10
30
66
TibfINH
Inhibit of the IBF Flag bit being Cleared from
WR ↑ or CS ↑
—
3 TCY
64
DS39689F-page 360
Conditions
VDD = 2.0V
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-13:
EXAMPLE SPI MASTER MODE TIMING (CKE = 0)
SS
SCK
(CKP = 0)
78
79
79
78
SCK
(CKP = 1)
80
bit 6 - - - - - -1
MSb
SDO
LSb
75, 76
SDI
MSb In
bit 6 - - - -1
LSb In
74
73
TABLE 27-14: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 0)
Param
No.
Symbol
Characteristic
73
TdiV2scH,
TdiV2scL
Setup Time of SDI Data Input to SCK Edge
73A
Tb2b
Last Clock Edge of Byte 1 to the 1st Clock Edge
of Byte 2
74
TscH2diL,
TscL2diL
75
Min
Max Units
20
—
ns
1.5 TCY + 40
—
ns
Hold Time of SDI Data Input to SCK Edge
40
—
ns
TdoR
SDO Data Output Rise Time
—
25
ns
76
TdoF
SDO Data Output Fall Time
78
TscR
SCK Output Rise Time
PIC18FXXXX
PIC18LFXXXX
79
TscF
SCK Output Fall Time
80
TscH2doV,
TscL2doV
SDO Data Output Valid after
SCK Edge
© 2009 Microchip Technology Inc.
—
45
ns
—
25
ns
PIC18FXXXX
—
25
ns
PIC18LFXXXX
—
45
ns
—
25
ns
PIC18FXXXX
—
50
ns
PIC18LFXXXX
—
100
ns
Conditions
VDD = 2.0V
VDD = 2.0V
VDD = 2.0V
DS39689F-page 361
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-14:
EXAMPLE SPI MASTER MODE TIMING (CKE = 1)
SS
81
SCK
(CKP = 0)
79
73
SCK
(CKP = 1)
80
78
MSb
SDO
bit 6 - - - - - -1
LSb
bit 6 - - - -1
LSb In
75, 76
SDI
MSb In
74
TABLE 27-15: EXAMPLE SPI MODE REQUIREMENTS (MASTER MODE, CKE = 1)
Param.
No.
Symbol
Characteristic
73
TdiV2scH,
TdiV2scL
Setup Time of SDI Data Input to SCK Edge
73A
Tb2b
Last Clock Edge of Byte 1 to the 1st Clock Edge
of Byte 2
74
TscH2diL,
TscL2diL
75
TdoR
Min
20
—
ns
1.5 TCY + 40
—
ns
Hold Time of SDI Data Input to SCK Edge
40
—
ns
SDO Data Output Rise Time
—
25
ns
45
ns
PIC18FXXXX
PIC18LFXXXX
76
TdoF
SDO Data Output Fall Time
78
TscR
SCK Output Rise Time
79
TscF
SCK Output Fall Time
80
TscH2doV,
TscL2doV
SDO Data Output Valid after
SCK Edge
TdoV2scH,
TdoV2scL
SDO Data Output Setup to SCK Edge
PIC18FXXXX
—
25
ns
—
25
ns
45
ns
—
25
ns
PIC18LFXXXX
81
DS39689F-page 362
Max Units
PIC18FXXXX
—
PIC18LFXXXX
TCY
50
ns
100
ns
—
ns
Conditions
VDD = 2.0V
VDD = 2.0V
VDD = 2.0V
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-15:
EXAMPLE SPI SLAVE MODE TIMING (CKE = 0)
SS
70
SCK
(CKP = 0)
83
71
72
SCK
(CKP = 1)
80
MSb
SDO
bit 6 - - - - - -1
LSb
77
75, 76
MSb In
SDI
bit 6 - - - -1
LSb In
74
73
TABLE 27-16: EXAMPLE SPI MODE REQUIREMENTS (SLAVE MODE TIMING, CKE = 0)
Param
No.
Symbol
Characteristic
70
TssL2scH, SS ↓ to SCK ↓ or SCK ↑ Input
TssL2scL
71
TscH
SCK Input High Time
71A
72
TscL
SCK Input Low Time
72A
Min
3 TCY
Max Units Conditions
—
ns
Continuous
1.25 TCY + 30
—
ns
Single Byte
40
—
ns
Continuous
1.25 TCY + 30
—
ns
Single Byte
40
—
ns
20
—
ns
—
ns
73
TdiV2scH, Setup Time of SDI Data Input to SCK Edge
TdiV2scL
73A
Tb2b
74
TscH2diL, Hold Time of SDI Data Input to SCK Edge
TscL2diL
40
—
ns
75
TdoR
—
25
ns
45
ns
25
ns
Last Clock Edge of Byte 1 to the First Clock Edge of Byte 2 1.5 TCY + 40
SDO Data Output Rise Time
PIC18FXXXX
PIC18LFXXXX
76
TdoF
SDO Data Output Fall Time
—
77
TssH2doZ SS ↑ to SDO Output High-Impedance
10
50
ns
80
TscH2doV, SDO Data Output Valid after SCK Edge PIC18FXXXX
TscL2doV
PIC18LFXXXX
—
50
ns
83
TscH2ssH, SS ↑ after SCK edge
TscL2ssH
Note 1:
2:
1.5 TCY + 40
100
ns
—
ns
(Note 1)
(Note 1)
(Note 2)
VDD = 2.0V
VDD = 2.0V
Requires the use of Parameter #73A.
Only if Parameter #71A and #72A are used.
© 2009 Microchip Technology Inc.
DS39689F-page 363
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-16:
EXAMPLE SPI SLAVE MODE TIMING (CKE = 1)
82
SS
SCK
(CKP = 0)
70
83
71
72
SCK
(CKP = 1)
80
MSb
SDO
bit 6 - - - - - -1
LSb
75, 76
SDI
MSb In
77
bit 6 - - - -1
LSb In
74
TABLE 27-17: EXAMPLE SPI SLAVE MODE REQUIREMENTS (CKE = 1)
Param
No.
Symbol
Characteristic
Min
Max Units Conditions
70
TssL2scH, SS ↓ to SCK ↓ or SCK ↑ Input
TssL2scL
71
TscH
SCK Input High Time
TscL
SCK Input Low Time
73A
Tb2b
Last Clock Edge of Byte 1 to the First Clock Edge of Byte 2 1.5 TCY + 40
74
TscH2diL, Hold Time of SDI Data Input to SCK Edge
TscL2diL
75
TdoR
71A
72
72A
SDO Data Output Rise Time
Continuous
3 TCY
—
ns
1.25 TCY + 30
—
ns
Single Byte
40
—
ns
Continuous
1.25 TCY + 30
—
ns
Single Byte
40
—
ns
(Note 1)
—
ns
(Note 2)
40
—
ns
—
25
ns
45
ns
—
25
ns
PIC18FXXXX
PIC18LFXXXX
76
TdoF
SDO Data Output Fall Time
77
TssH2doZ SS ↑ to SDO Output High-Impedance
10
50
ns
80
TscH2doV, SDO Data Output Valid after SCK
TscL2doV Edge
PIC18FXXXX
—
50
ns
PIC18LFXXXX
—
100
ns
82
TssL2doV SDO Data Output Valid after SS ↓
Edge
PIC18FXXXX
—
50
ns
PIC18LFXXXX
—
100
ns
1.5 TCY + 40
—
ns
83
TscH2ssH, SS ↑ after SCK Edge
TscL2ssH
Note 1:
2:
(Note 1)
VDD = 2.0V
VDD = 2.0V
VDD = 2.0V
Requires the use of Parameter #73A.
Only if Parameter #71A and #72A are used.
DS39689F-page 364
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
I2C™ BUS START/STOP BITS TIMING
FIGURE 27-17:
SCL
91
93
90
92
SDA
Stop
Condition
Start
Condition
TABLE 27-18: I2C™ BUS START/STOP BITS REQUIREMENTS (SLAVE MODE)
Param.
Symbol
No.
90
91
92
93
TSU:STA
THD:STA
TSU:STO
Characteristic
Max
Units
Conditions
ns
Only relevant for Repeated
Start condition
ns
After this period, the first
clock pulse is generated
Start Condition
100 kHz mode
4700
—
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
400 kHz mode
600
—
100 kHz mode
4000
—
400 kHz mode
600
—
THD:STO Stop Condition
Hold Time
FIGURE 27-18:
Min
ns
ns
I2C™ BUS DATA TIMING
103
102
100
101
SCL
90
106
107
91
92
SDA
In
110
109
109
SDA
Out
© 2009 Microchip Technology Inc.
DS39689F-page 365
PIC18F2221/2321/4221/4321 FAMILY
TABLE 27-19: I2C™ BUS DATA REQUIREMENTS (SLAVE MODE)
Param.
Symbol
No.
100
THIGH
101
91
106
107
92
109
110
2:
—
μs
μs
—
—
100 kHz mode
4.7
—
μs
400 kHz mode
1.3
—
μs
MSSP Module
1.5 TCY
—
—
1000
ns
20 + 0.1 CB
300
ns
100 kHz mode
—
300
ns
400 kHz mode
20 + 0.1 CB
300
ns
CB is specified to be from
10 to 400 pF
TSU:STA Start Condition
Setup Time
100 kHz mode
4.7
—
μs
400 kHz mode
0.6
—
μs
Only relevant for Repeated
Start condition
THD:STA Start Condition
Hold Time
100 kHz mode
4.0
—
μs
400 kHz mode
0.6
—
μs
THD:DAT Data Input Hold
Time
100 kHz mode
0
—
ns
400 kHz mode
0
0.9
μs
TSU:DAT Data Input Setup
Time
100 kHz mode
250
—
ns
400 kHz mode
100
—
ns
TSU:STO Stop Condition
Setup Time
100 kHz mode
4.7
—
μs
400 kHz mode
0.6
—
μs
TAA
100 kHz mode
—
3500
ns
400 kHz mode
—
—
ns
CB
Note 1:
4.0
Conditions
0.6
TBUF
D102
Units
1.5 TCY
TF
90
100 kHz mode
Max
MSSP Module
TR
103
Clock High Time
Min
400 kHz mode
TLOW
102
Characteristic
Clock Low Time
SDA and SCL Rise 100 kHz mode
Time
400 kHz mode
SDA and SCL Fall
Time
Output Valid from
Clock
Bus Free Time
100 kHz mode
4.7
—
μs
400 kHz mode
1.3
—
μs
—
400
pF
Bus Capacitive Loading
CB is specified to be from
10 to 400 pF
After this period, the first
clock pulse is generated
(Note 2)
(Note 1)
Time the bus must be free
before a new transmission
can start
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 SCL to avoid unintended generation of Start or Stop conditions.
A Fast mode I2C bus device can be used in a Standard mode 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 SCL signal. If such a device does stretch the LOW period of the SCL signal, it must
output the next data bit to the SDA line, TR max. + TSU:DAT = 1000 + 250 = 1250 ns (according to the
Standard mode I2C bus specification), before the SCL line is released.
DS39689F-page 366
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
MASTER SSP I2C™ BUS START/STOP BITS TIMING WAVEFORMS
FIGURE 27-19:
SCL
93
91
90
92
SDA
Stop
Condition
Start
Condition
TABLE 27-20: MASTER SSP I2C™ BUS START/STOP BITS REQUIREMENTS
Param.
Symbol
No.
90
91
TSU:STA
Characteristic
ns
Only relevant for
Repeated Start
condition
ns
After this period, the
first clock pulse is
generated
100 kHz mode
2(TOSC)(BRG + 1)
—
400 kHz mode
2(TOSC)(BRG + 1)
—
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
100 kHz mode
2(TOSC)(BRG + 1)
—
400 kHz mode
2(TOSC)(BRG + 1)
—
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
100 kHz mode
2(TOSC)(BRG + 1)
—
400 kHz mode
2(TOSC)(BRG + 1)
—
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
100 kHz mode
2(TOSC)(BRG + 1)
—
400 kHz mode
2(TOSC)(BRG + 1)
—
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
THD:STA Start Condition
TSU:STO Stop Condition
THD:STO Stop Condition
Hold Time
Note 1: Maximum pin capacitance = 10 pF for all
FIGURE 27-20:
Units
Setup Time
Setup Time
93
Max
Start Condition
Hold Time
92
Min
I2C
Conditions
ns
ns
pins.
MASTER SSP I2C™ BUS DATA TIMING
103
102
100
101
SCL
90
106
91
107
92
SDA
In
109
109
110
SDA
Out
© 2009 Microchip Technology Inc.
DS39689F-page 367
PIC18F2221/2321/4221/4321 FAMILY
TABLE 27-21: MASTER SSP I2C™ BUS DATA REQUIREMENTS
Param.
Symbol
No.
100
101
THIGH
TLOW
Characteristic
Min
Max
Units
Clock High Time 100 kHz mode
2(TOSC)(BRG + 1)
—
ms
400 kHz mode
2(TOSC)(BRG + 1)
—
ms
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
ms
Clock Low Time 100 kHz mode
2(TOSC)(BRG + 1)
—
ms
400 kHz mode
2(TOSC)(BRG + 1)
—
ms
(1)
2(TOSC)(BRG + 1)
—
ms
100 kHz mode
—
1000
ns
400 kHz mode
20 + 0.1 CB
300
ns
1 MHz mode(1)
—
300
ns
1 MHz mode
102
103
90
91
TR
TF
TSU:STA
SDA and SCL
Rise Time
SDA and SCL
Fall Time
Start Condition
Setup Time
THD:STA Start Condition
Hold Time
100 kHz mode
—
300
ns
400 kHz mode
20 + 0.1 CB
300
ns
1 MHz mode(1)
—
100
ns
100 kHz mode
2(TOSC)(BRG + 1)
—
ms
400 kHz mode
2(TOSC)(BRG + 1)
—
ms
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
ms
100 kHz mode
2(TOSC)(BRG + 1)
—
ms
400 kHz mode
2(TOSC)(BRG + 1)
—
ms
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
ms
0
—
ns
106
THD:DAT Data Input
Hold Time
100 kHz mode
400 kHz mode
0
0.9
ms
107
TSU:DAT
100 kHz mode
250
—
ns
92
TSU:STO Stop Condition
Setup Time
109
110
D102
Note 1:
2:
TAA
TBUF
CB
Data Input
Setup Time
Output Valid
from Clock
Bus Free Time
400 kHz mode
100
—
ns
100 kHz mode
2(TOSC)(BRG + 1)
—
ms
400 kHz mode
2(TOSC)(BRG + 1)
—
ms
1 MHz mode(1)
2(TOSC)(BRG + 1)
—
ms
100 kHz mode
—
3500
ns
400 kHz mode
—
1000
ns
(1)
1 MHz mode
—
—
ns
100 kHz mode
4.7
—
ms
400 kHz mode
1.3
—
ms
—
400
pF
Bus Capacitive Loading
Conditions
CB is specified to be from
10 to 400 pF
CB is specified to be from
10 to 400 pF
Only relevant for
Repeated Start
condition
After this period, the first
clock pulse is generated
(Note 2)
Time the bus must be free
before a new transmission
can start
2C
Maximum pin capacitance = 10 pF for all I pins.
A Fast mode I2C bus device can be used in a Standard mode I2C bus system, but parameter 107 ≥ 250 ns
must then be met. This will automatically be the case if the device does not stretch the LOW period of the
SCL signal. If such a device does stretch the LOW period of the SCL signal, it must output the next data bit
to the SDA line, parameter 102 + parameter 107 = 1000 + 250 = 1250 ns (for 100 kHz mode), before the
SCL line is released.
DS39689F-page 368
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
FIGURE 27-21:
EUSART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RC6/TX/CK
pin
121
121
RC7/RX/DT
pin
120
122
TABLE 27-22: EUSART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Param
No.
120
Symbol
Characteristic
TckH2dtV SYNC XMIT (MASTER & SLAVE)
Clock High to Data Out Valid
PIC18FXXXX
Min
Max
Units
—
40
ns
PIC18LFXXXX
—
100
ns
121
Tckrf
Clock Out Rise Time and Fall Time
(Master mode)
PIC18FXXXX
—
20
ns
PIC18LFXXXX
—
50
ns
122
Tdtrf
Data Out Rise Time and Fall Time
PIC18FXXXX
—
20
ns
PIC18LFXXXX
—
50
ns
FIGURE 27-22:
Conditions
VDD = 2.0V
VDD = 2.0V
VDD = 2.0V
EUSART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
RC6/TX/CK
pin
125
RC7/RX/DT
pin
126
TABLE 27-23: EUSART SYNCHRONOUS RECEIVE REQUIREMENTS
Param.
No.
125
126
Symbol
TdtV2ckl
TckL2dtl
Characteristic
Min
Max
Units
SYNC RCV (MASTER & SLAVE)
Data Hold before CK ↓ (DT hold time)
10
—
ns
Data Hold after CK ↓ (DT hold time)
15
—
ns
© 2009 Microchip Technology Inc.
Conditions
DS39689F-page 369
PIC18F2221/2321/4221/4321 FAMILY
TABLE 27-24: A/D CONVERTER CHARACTERISTICS
Param
Symbol
No.
Characteristic
Min
Typ
Max
Units
—
—
10
bit
Conditions
ΔVREF ≥ 3.0V
A01
NR
Resolution
A03
EIL
Integral Linearity Error
—
—
#&
.
=
?
## 4 >#&
.
#&
.
: 9&
.$
!# #9&
? 1,
.3
TPWRT) ............................................ 53
SPI Mode (Master Mode) ......................................... 172
SPI Mode (Slave Mode, CKE = 0) ........................... 174
SPI Mode (Slave Mode, CKE = 1) ........................... 174
Synchronous Reception (Master Mode, SREN) ...... 230
Synchronous Transmission ...................................... 228
Synchronous Transmission (Through TXEN) .......... 229
Time-out Sequence on POR w/PLL Enabled
(MCLR Tied to VDD) ........................................... 53
Time-out Sequence on Power-up
(MCLR Not Tied to VDD, Case 1) ....................... 52
Time-out Sequence on Power-up
(MCLR Not Tied to VDD, Case 2) ....................... 52
Time-out Sequence on Power-up
(MCLR Tied to VDD, VDD Rise < TPWRT) ........... 52
Timer0 and Timer1 External Clock .......................... 358
Transition for Entry to Idle Mode ................................ 44
Transition for Entry to SEC_RUN Mode .................... 41
Transition for Entry to Sleep Mode ............................ 43
Transition for Two-Speed Start-up
(INTOSC to HSPLL) ........................................ 271
Transition for Wake from Idle to Run Mode ............... 44
Transition for Wake from Sleep (HSPLL) ................... 43
Transition from RC_RUN Mode to PRI_RUN Mode .. 42
Transition from SEC_RUN Mode to
PRI_RUN Mode (HSPLL) .................................. 41
Transition to RC_RUN Mode ..................................... 42
© 2009 Microchip Technology Inc.
Timing Diagrams and Specifications ............................... 354
Capture/Compare/PWM Requirements
(All CCP Modules) ........................................... 359
CLKO and I/O Requirements ................................... 356
EUSART Synchronous Receive Requirements ....... 369
EUSART Synchronous Transmission Requirements ....
369
Example SPI Mode Requirements
(Master Mode, CKE = 0) .................................. 361
Example SPI Mode Requirements
(Master Mode, CKE = 1) .................................. 362
Example SPI Mode Requirements
(Slave Mode, CKE = 0) .................................... 363
Example SPI Mode Requirements
(Slave Mode, CKE = 1) .................................... 364
External Clock Requirements .................................. 354
I2C Bus Data Requirements (Slave Mode) .............. 366
I2C Bus Start/Stop Requirements (Slave Mode) ..... 365
Master SSP I2C Bus Data Requirements ................ 368
Master SSP I2C Bus Start/Stop Bits
Requirements .................................................. 367
Parallel Slave Port Requirements
(PIC18F4221/4321) ......................................... 360
PLL Clock ................................................................ 355
Reset, Watchdog Timer, Oscillator Start-up
Timer, Power-up Timer and
Brown-out Reset Requirements ...................... 357
Timer0 and Timer1 External Clock
Requirements .................................................. 358
Top-of-Stack Access .......................................................... 60
TRISE Register
PSPMODE Bit ......................................................... 120
TSTFSZ ........................................................................... 319
Two-Speed Start-up ................................................. 259, 271
Two-Word Instructions
Example Cases ......................................................... 64
TXSTA Register
BRGH Bit ................................................................. 215
V
Voltage Reference Specifications .................................... 350
W
Watchdog Timer (WDT) ........................................... 259, 269
Associated Registers ............................................... 270
Control Register ....................................................... 269
During Oscillator Failure .......................................... 272
Programming Considerations .................................. 269
WCOL ...................................................... 199, 200, 201, 204
WCOL Status Flag ................................... 199, 200, 201, 204
WWW Address ................................................................ 399
WWW, On-Line Support ...................................................... 8
X
XORLW ........................................................................... 319
XORWF ........................................................................... 320
DS39689F-page 397
PIC18F2221/2321/4221/4321 FAMILY
NOTES:
DS39689F-page 398
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
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© 2009 Microchip Technology Inc.
DS39689F-page 399
PIC18F2221/2321/4221/4321 FAMILY
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
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Device: PIC18F2221/2321/4221/4321 Family
Literature Number: DS39689F
Questions:
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3. Do you find the organization of this document easy to follow? If not, why?
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DS39689F-page 400
© 2009 Microchip Technology Inc.
PIC18F2221/2321/4221/4321 FAMILY
PIC18F2221/2321/4221/4321 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
PIC18F2221/2321(1), PIC18F4221/4321(1),
PIC18F2221/2321T(2), PIC18F4221/4321T(2);
VDD range 4.2V to 5.5V
PIC18LF2221/2321(1), PIC18LF4221/4321(1),
PIC18LF2221/2321T(2), PIC18LF4221/4321T(2);
VDD range 2.0V to 5.5V
Temperature Range
I
E
=
=
Package
PT
SO
SS
SP
P
ML
=
=
=
=
=
=
Pattern
c)
PIC18F4321-I/P 301 = Industrial temp., PDIP
package, Extended VDD limits, QTP pattern
#301.
PIC18LF2321-I/SO = Industrial temp., SOIC
package, Extended VDD limits.
PIC18LF4321-I/P = Industrial temp., PDIP
package, normal VDD limits.
-40°C to +85°C (Industrial)
-40°C to +125°C (Extended)
TQFP (Thin Quad Flatpack)
SOIC
SSOP
Skinny Plastic DIP
PDIP
QFN
Note 1:
2:
F = Standard Voltage Range
LF = Wide Voltage Range
T = in tape and reel
QTP, SQTP, Code or Special Requirements
(blank otherwise)
© 2009 Microchip Technology Inc.
DS39689F-page 401
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China - Shenzhen
Tel: 86-755-8203-2660
Fax: 86-755-8203-1760
Taiwan - Hsin Chu
Tel: 886-3-6578-300
Fax: 886-3-6578-370
China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
Taiwan - Kaohsiung
Tel: 886-7-536-4818
Fax: 886-7-536-4803
China - Xiamen
Tel: 86-592-2388138
Fax: 86-592-2388130
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 - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049
03/26/09
DS39689F-page 402
© 2009 Microchip Technology Inc.
