PIC18F1220/1320
18/20/28-Pin High-Performance, Enhanced Flash MCUs
with 10-bit A/D
Low-Power Features
Peripheral Highlights
• Power Managed modes:
- Run: CPU on, peripherals on
- Idle: CPU off, peripherals on
- Sleep: CPU off, peripherals off
• Power Consumption modes:
- PRI_RUN: 150 A, 1 MHz, 2V
- PRI_IDLE: 37 A, 1 MHz, 2V
- SEC_RUN: 14 A, 32 kHz, 2V
- SEC_IDLE: 5.8 A, 32 kHz, 2V
- RC_RUN: 110 A, 1 MHz, 2V
- RC_IDLE: 52 A, 1 MHz, 2V
- Sleep: 0.1 A, 1 MHz, 2V
• Timer1 Oscillator: 1.1 A, 32 kHz, 2V
• Watchdog Timer: 2.1 A
• Two-Speed Oscillator Start-up
• High Current Sink/Source 25 mA/25 mA
• Three External Interrupts
• Enhanced Capture/Compare/PWM (ECCP) module:
- One, two or four PWM outputs
- Selectable polarity
- Programmable dead time
- Auto-Shutdown and Auto-Restart
- Capture is 16-bit, max resolution 6.25 ns (TCY/16)
- Compare is 16-bit, max resolution 100 ns (TCY)
• Compatible 10-bit, up to 13-Channel Analog-toDigital Converter module (A/D) with Programmable
Acquisition Time
• Enhanced USART module:
- Supports RS-485, RS-232 and LIN 1.2
- Auto-Wake-up on Start bit
- Auto-Baud Detect
Oscillators
Special Microcontroller Features
• Four Crystal modes:
- LP, XT, HS: up to 25 MHz
- HSPLL: 4-10 MHz (16-40 MHz internal)
• Two External RC modes, up to 4 MHz
• Two External Clock modes, up to 40 MHz
• Internal Oscillator Block:
- 8 user-selectable frequencies: 31 kHz, 125 kHz,
250 kHz, 500 kHz, 1 MHz, 2 MHz, 4 MHz, 8 MHz
- 125 kHz to 8 MHz calibrated to 1%
- Two modes select one or two I/O pins
- OSCTUNE – Allows user to shift frequency
• Secondary Oscillator using Timer1 @ 32 kHz
• Fail-Safe Clock Monitor
- Allows for safe shutdown if peripheral clock stops
Program Memory
• 100,000 Erase/Write Cycle Enhanced Flash
Program Memory, typical
• 1,000,000 Erase/Write Cycle Data EEPROM
Memory, typical
• Flash/Data EEPROM Retention: > 40 years
• Self-Programmable under Software Control
• Priority Levels for Interrupts
• 8 x 8 Single-Cycle Hardware Multiplier
• Extended Watchdog Timer (WDT):
- Programmable period from 41 ms to 131s
- 2% stability over VDD and Temperature
• 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
Data Memory
Flash
(bytes)
# Single-Word
Instructions
SRAM
(bytes)
EEPROM
(bytes)
I/O
10-bit
A/D (ch)
ECCP
(PWM)
EUSART
Timers
8/16-bit
PIC18F1220
4K
2048
256
256
16
7
1
Y
1/3
PIC18F1320
8K
4096
256
256
16
7
1
Y
1/3
Device
2002-2015 Microchip Technology Inc.
DS30009605G-page 1
PIC18F1220/1320
Pin Diagrams
20-Pin SSOP
18-Pin PDIP, SOIC
16
OSC1/CLKI/RA7
15
OSC2/CLKO/RA6
14
VDD/AVDD
3
18
OSC1/CLKI/RA7
MCLR/VPP/RA5
4
17
OSC2/CLKO/RA6
16
VDD
15
AVDD
VSS
5
RB7/PGD/T1OSI/
P1D/KBI3
RB6/PGC/T1OSO/
T13CKI/P1C/KBI2
AVSS
6
RA2/AN2/VREF-
7
RA3/AN3/VREF+
8
13
RB0/AN4/INT0
9
12
RB5/PGM/KBI1
10
11
RB4/AN6/RX/
DT/KBI0
RA2/AN2/VREF-
6
RA3/AN3/VREF+
7
12
RB0/AN4/INT0
8
11
RB5/PGM/KBI1
RB1/AN5/TX/
CK/INT1
9
10
RB4/AN6/RX/
DT/KBI0
RA1/AN1/LVDIN
RA0/AN0
NC
26
25
RA4/T0CKI
28
RB1/AN5/TX/
CK/INT1
27
13
28-Pin QFN
DS30009605G-page 2
RB2/P1B/INT2
RA4/T0CKI
PIC18F1X20
RB2/P1B/INT2
17
NC
5
RB3/CCP1/P1A
19
22
4
20
2
RB3/CCP1/P1A
VSS/AVSS
3
1
RB2/P1B/INT2
MCLR/VPP/RA5
2
RA0/AN0
RA1/AN1/LVDIN
RB3/CCP1/P1A
23
RA4/T0CKI
18
24
RA1/AN1/LVDIN
1
PIC18F1X20
RA0/AN0
14
RB7/PGD/T1OSI/
P1D/KBI3
RB6/PGC/T1OSO/
T13CKI/P1C/KBI2
MCLR/VPP/RA5
1
21
OSC1/CLKI/RA7
NC
VSS
2
20
OSC2/CLKO/RA6
3
19
VDD
NC
4
18
NC
AVSS
5
17
AVDD
NC
6
16
RB7/PGD/T1OSI/P1D/KBI3
RA2/AN2/VREF-
7
15
RB6/PGC/T1OSO/T13CKI/P1C/KBI2
10
11
12
13
14
NC
RB4/AN6/RX/DT/KBI0
RB5/PGM/KBI1
NC
9
RB0/AN4/INT0
RB1/AN5/TX/CK/INT1
8
RA3/AN3/VREF+
PIC18F1X20
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
Table of Contents
1.0 Device Overview .......................................................................................................................................................................... 5
2.0 Oscillator Configurations ............................................................................................................................................................ 10
3.0 Power Managed Modes ............................................................................................................................................................. 18
4.0 Reset .......................................................................................................................................................................................... 31
5.0 Memory Organization ................................................................................................................................................................. 39
6.0 Flash Program Memory.............................................................................................................................................................. 55
7.0 Data EEPROM Memory ............................................................................................................................................................. 64
8.0 8 x 8 Hardware Multiplier............................................................................................................................................................ 68
9.0 Interrupts .................................................................................................................................................................................... 70
10.0 I/O Ports ..................................................................................................................................................................................... 83
11.0 Timer0 Module ........................................................................................................................................................................... 95
12.0 Timer1 Module ........................................................................................................................................................................... 98
13.0 Timer2 Module ......................................................................................................................................................................... 104
14.0 Timer3 Module ......................................................................................................................................................................... 106
15.0 Enhanced Capture/Compare/PWM (ECCP) Module................................................................................................................ 109
16.0 Enhanced Addressable Universal Synchronous Asynchronous Receiver Transmitter (EUSART) .......................................... 126
17.0 10-Bit Analog-to-Digital Converter (A/D) Module ..................................................................................................................... 149
18.0 Low-Voltage Detect .................................................................................................................................................................. 160
19.0 Special Features of the CPU.................................................................................................................................................... 165
20.0 Instruction Set Summary .......................................................................................................................................................... 184
21.0 Development Support............................................................................................................................................................... 226
22.0 Electrical Characteristics .......................................................................................................................................................... 230
23.0 DC and AC Characteristics Graphs and Tables....................................................................................................................... 262
24.0 Packaging Information.............................................................................................................................................................. 280
Appendix A: Revision History............................................................................................................................................................. 290
Appendix B: Device Differences ........................................................................................................................................................ 290
Appendix C: Conversion Considerations ........................................................................................................................................... 291
Appendix D: Migration from Baseline to Enhanced Devices.............................................................................................................. 291
Appendix E: Migration from Mid-Range to Enhanced Devices .......................................................................................................... 292
Appendix F: Migration from High-End to Enhanced Devices ............................................................................................................. 292
The Microchip Web Site ..................................................................................................................................................................... 293
Customer Change Notification Service .............................................................................................................................................. 293
Customer Support .............................................................................................................................................................................. 293
PIC18F1220/1320 Product Identification System .............................................................................................................................. 294
2002-2015 Microchip Technology Inc.
DS30009605G-page 3
PIC18F1220/1320
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. We welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision
of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
• Microchip’s Worldwide Web site; http://www.microchip.com
• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are
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DS30009605G-page 4
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
1.0
DEVICE OVERVIEW
This document contains device specific information for
the following devices:
• PIC18F1220
• PIC18F1320
This family offers the advantages of all PIC18 microcontrollers – namely, high computational performance at an
economical price – with the addition of high endurance
Enhanced Flash program memory. On top of these features, the PIC18F1220/1320 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
POWER MODES
All of the devices in the PIC18F1220/1320 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 are
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.
• Lower Consumption in Key Modules: The power
requirements for both Timer1 and the Watchdog
Timer have been reduced by up to 80%, with typical
values of 1.1 and 2.1 A, respectively.
1.1.2
MULTIPLE OSCILLATOR OPTIONS
AND FEATURES
All of the devices in the PIC18F1220/1320 family offer
nine 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.
• An internal oscillator block, which provides an
8 MHz clock (±2% accuracy) and an INTRC source
(approximately 31 kHz, stable over temperature and
VDD), as well as a range of six user-selectable clock
frequencies (from 125 kHz to 4 MHz) for a total of
8 clock frequencies.
2002-2015 Microchip Technology Inc.
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 Poweron Reset, or wake-up from Sleep mode, until the
primary clock source is available. This allows for
code execution during what would otherwise be the
clock start-up interval and can even allow an application to perform routine background activities and
return to Sleep without returning to full-power
operation.
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.
• 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 USART: This serial communication
module features automatic wake-up on Start bit and
automatic baud rate detection and supports RS-232,
RS-485 and LIN 1.2 protocols, making it ideally
suited for use in Local Interconnect Network (LIN)
bus applications.
• 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, reduce code overhead.
• Extended Watchdog Timer (WDT): This enhanced
version incorporates a 16-bit prescaler, allowing a
time-out range from 4 ms to over two minutes that is
stable across operating voltage and temperature.
DS30009605G-page 5
PIC18F1220/1320
1.3
Details on Individual Family
Members
A block diagram of the PIC18F1220/1320 device
architecture is provided in Figure 1-1. The pinouts for
this device family are listed in Table 1-2.
Devices in the PIC18F1220/1320 family are available
in 18-pin, 20-pin and 28-pin packages. A block diagram
for this device family is shown in Figure 1-1.
The devices are differentiated from each other only in
the amount of on-chip Flash program memory
(4 Kbytes for the PIC18F1220 device, 8 Kbytes for the
PIC18F1320 device). These and other features are
summarized in Table 1-1.
TABLE 1-1:
DEVICE FEATURES
Features
Operating Frequency
PIC18F1220
PIC18F1320
DC – 40 MHz
DC – 40 MHz
Program Memory (Bytes)
4096
8192
Program Memory (Instructions)
2048
4096
Data Memory (Bytes)
256
256
Data EEPROM Memory (Bytes)
256
256
Interrupt Sources
15
15
Ports A, B
Ports A, B
Timers
4
4
Enhanced Capture/Compare/PWM Modules
1
1
Enhanced USART
Enhanced USART
7 input channels
7 input channels
I/O Ports
Serial Communications
10-bit Analog-to-Digital Module
Resets (and Delays)
POR, BOR,
POR, BOR,
RESET Instruction, Stack Full,
RESET Instruction, Stack Full,
Stack Underflow (PWRT, OST), Stack Underflow (PWRT, OST),
MCLR (optional), WDT
MCLR (optional), WDT
Programmable Low-Voltage Detect
Yes
Yes
Programmable Brown-out Reset
Yes
Yes
75 Instructions
75 Instructions
18-pin SDIP
18-pin SOIC
20-pin SSOP
28-pin QFN
18-pin SDIP
18-pin SOIC
20-pin SSOP
28-pin QFN
Instruction Set
Packages
DS30009605G-page 6
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 1-1:
PIC18F1220/1320 BLOCK DIAGRAM
Data Bus
21 Table Pointer
21
8
8
8
PORTA
Data Latch
8
RA0/AN0
Data RAM
inc/dec logic
RA1/AN1/LVDIN
21
Address Latch
20
Address Latch
Program Memory
(4 Kbytes)
PIC18F1220
(8 Kbytes)
PIC18F1320
RA2/AN2/VREF-
PCLATU PCLATH
12(2)
Address
PCU PCH PCL
Program Counter
4
BSR
31 Level Stack
Data Latch
16
Decode
Table Latch
RA3/AN3/VREF+
12
4
FSR0 Bank0, F
FSR1
FSR2
12
RA4/T0CKI
MCLR/VPP/RA5(1)
OSC2/CLKO/RA6(2)
inc/dec
logic
OSC2/CLKI/RA7(2)
8
ROM Latch
PORTB
RB0/AN4/INT0
Instruction
Register
RB1/AN5/TX/CK/INT1
8
Instruction
Decode &
Control
RB2/P1B/INT2
PRODH PRODL
3
RB3/CCP1/P1A
8 x 8 Multiply
RB4/AN6/RX/DT/KBI0
8
OSC1(2)
OSC2(2)
T1OSI
Timing
Generation
INTRC
Oscillator
T1OSO
BIT OP
8
Power-up
Timer
Oscillator
Start-up Timer
MCLR(1)
VDD, VSS
Timer0
In-Circuit
Debugger
Fail-Safe
Clock Monitor
Timer1
RB7/PGD/T1OSI/
P1D/KBI3
8
Precision
Voltage
Reference
Timer2
Enhanced
CCP
Note
RB6/PGC/T1OSO/
T13CKI/P1C/KBI2
ALU
Watchdog
Timer
Brown-out
Reset
RB5/PGM/KBI1
8
8
Power-on
Reset
Low-Voltage
Programming
WREG
8
Timer3
Enhanced
USART
A/D Converter
Data EEPROM
1:RA5 is available only when the MCLR Reset is disabled.
2: OSC1, OSC2, CLKI and CLKO are only available in select oscillator modes and when these pins are not being used as digital
I/O. Refer to Section 2.0 “Oscillator Configurations” for additional information.
2002-2015 Microchip Technology Inc.
DS30009605G-page 7
PIC18F1220/1320
TABLE 1-2:
PIC18F1220/1320 PINOUT I/O DESCRIPTIONS
Pin Number
Pin Name
PDIP/
SSOP
SOIC
MCLR/VPP/RA5
MCLR
4
4
QFN
16
18
Buffer
Type
I
ST
P
I
—
ST
1
VPP
RA5
OSC1/CLKI/RA7
OSC1
Pin
Type
21
I
CLKI
I
RA7
I/O
OSC2/CLKO/RA6
OSC2
15
17
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,
CMOS otherwise.
CMOS
External clock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
ST
General purpose I/O pin.
ST
20
O
—
CLKO
O
—
RA6
I/O
ST
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or
resonator in Crystal Oscillator mode.
In RC, EC and INTRC modes, OSC2 pin outputs
CLKO, which has 1/4 the frequency of OSC1 and
denotes instruction cycle rate.
General purpose I/O pin.
PORTA is a bidirectional I/O port.
RA0/AN0
RA0
AN0
1
RA1/AN1/LVDIN
RA1
AN1
LVDIN
2
RA2/AN2/VREFRA2
AN2
VREF-
6
RA3/AN3/VREF+
RA3
AN3
VREF+
7
RA4/T0CKI
RA4
T0CKI
3
1
2
7
8
3
26
I/O
I
ST
Analog
Digital I/O.
Analog input 0.
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 1.
Low-Voltage Detect input.
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 2.
A/D reference voltage (low) input.
I/O
I
I
ST
Analog
Analog
Digital I/O.
Analog input 3.
A/D reference voltage (high) input.
I/O
I
ST/OD
ST
Digital I/O. Open-drain when configured as output.
Timer0 external clock input.
27
7
8
28
RA5
See the MCLR/VPP/RA5 pin.
RA6
See the OSC2/CLKO/RA6 pin.
RA7
Legend:
See the OSC1/CLKI/RA7 pin.
TTL
ST
O
OD
=
=
=
=
TTL compatible input
Schmitt Trigger input with CMOS levels
Output
Open-drain (no P diode to VDD)
DS30009605G-page 8
CMOS
I
P
= CMOS compatible input or output
= Input
= Power
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 1-2:
PIC18F1220/1320 PINOUT I/O DESCRIPTIONS (CONTINUED)
Pin Number
Pin Name
PDIP/
SSOP
SOIC
QFN
Pin
Type
Buffer
Type
Description
PORTB is a bidirectional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.
RB0/AN4/INT0
RB0
AN4
INT0
8
RB1/AN5/TX/CK/INT1
RB1
AN5
TX
CK
INT1
9
RB2/P1B/INT2
RB2
P1B
INT2
17
RB3/CCP1/P1A
RB3
CCP1
P1A
18
RB4/AN6/RX/DT/KBI0
RB4
AN6
RX
DT
KBI0
10
RB5/PGM/KBI1
RB5
PGM
KBI1
11
RB6/PGC/T1OSO/
T13CKI/P1C/KBI2
RB6
PGC
T1OSO
T13CKI
P1C
KBI2
12
RB7/PGD/T1OSI/
P1D/KBI3
RB7
PGD
T1OSI
P1D
KBI3
13
VSS
5
VDD
14
NC
—
Legend:
TTL
ST
O
OD
=
=
=
=
9
10
19
20
11
12
13
14
5, 6
9
TTL
Analog
ST
Digital I/O.
Analog input 4.
External interrupt 0.
I/O
I
O
I/O
I
TTL
Analog
—
ST
ST
Digital I/O.
Analog input 5.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).
External interrupt 1.
I/O
O
I
TTL
—
ST
Digital I/O.
Enhanced CCP1/PWM output.
External interrupt 2.
I/O
I/O
O
TTL
ST
—
Digital I/O.
Capture 1 input/Compare 1 output/PWM 1 output.
Enhanced CCP1/PWM output.
I/O
I
I
I/O
I
TTL
Analog
ST
ST
TTL
Digital I/O.
Analog input 6.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).
Interrupt-on-change pin.
I/O
I/O
I
TTL
ST
TTL
Digital I/O.
Low-Voltage ICSP™ Programming enable pin.
Interrupt-on-change pin.
I/O
I/O
O
I
O
I
TTL
ST
—
ST
—
TTL
Digital I/O.
In-Circuit Debugger and ICSP programming clock pin.
Timer1 oscillator output.
Timer1/Timer3 external clock output.
Enhanced CCP1/PWM output.
Interrupt-on-change pin.
I/O
I/O
I
O
I
TTL
ST
CMOS
—
TTL
Digital I/O.
In-Circuit Debugger and ICSP programming data pin.
Timer1 oscillator input.
Enhanced CCP1/PWM output.
Interrupt-on-change pin.
10
23
24
12
13
15
16
3, 5
15, 16 17, 19
—
I/O
I
I
18
P
—
Ground reference for logic and I/O pins.
P
—
Positive supply for logic and I/O pins.
—
—
No connect.
TTL compatible input
Schmitt Trigger input with CMOS levels
Output
Open-drain (no P diode to VDD)
2002-2015 Microchip Technology Inc.
CMOS
I
P
= CMOS compatible input or output
= Input
= Power
DS30009605G-page 9
PIC18F1220/1320
2.0
OSCILLATOR
CONFIGURATIONS
2.1
Oscillator Types
The PIC18F1220 and PIC18F1320 devices can be
operated in ten different oscillator modes. The user can
program the Configuration bits, FOSC3:FOSC0, in
Configuration Register 1H to select one of these ten
modes:
1.
2.
3.
4.
LP
XT
HS
HSPLL
5.
RC
6.
RCIO
7.
INTIO1
8.
INTIO2
9. EC
10. ECIO
2.2
Low-Power Crystal
Crystal/Resonator
High-Speed Crystal/Resonator
High-Speed Crystal/Resonator
with PLL enabled
External Resistor/Capacitor with
FOSC/4 output on RA6
External Resistor/Capacitor with
I/O on RA6
Internal Oscillator with FOSC/4
output on RA6 and I/O on RA7
Internal Oscillator with I/O on RA6
and RA7
External Clock with FOSC/4 output
External Clock with I/O on RA6
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 2-1 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 2-1:
CRYSTAL/CERAMIC
RESONATOR OPERATION
(XT, LP, HS OR HSPLL
CONFIGURATION)
C1(1)
OSC1
XTAL
To
Internal
Logic
RF(3)
Sleep
RS(2)
C2(1)
PIC18FXXXX
OSC2
Note 1: See Table 2-1 and Table 2-2 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 2-1:
CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Typical Capacitor Values Used:
Mode
Freq.
OSC1
OSC2
XT
455 kHz
2.0 MHz
4.0 MHz
56 pF
47 pF
33 pF
56 pF
47 pF
33 pF
HS
8.0 MHz
16.0 MHz
27 pF
22 pF
27 pF
22 pF
Capacitor values are for design guidance only.
These capacitors were tested with the resonators
listed below for basic start-up and operation. These
values are not optimized.
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.
See the notes following Table 2-2 for additional
information.
Resonators Used:
455 kHz
4.0 MHz
2.0 MHz
8.0 MHz
16.0 MHz
DS30009605G-page 10
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
Osc Type
LP
XT
HS
CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Crystal
Freq.
Typical Capacitor Values
Tested:
C1
C2
32 kHz
33 pF
33 pF
200 kHz
15 pF
15 pF
1 MHz
33 pF
33 pF
4 MHz
27 pF
27 pF
4 MHz
27 pF
27 pF
8 MHz
22 pF
22 pF
20 MHz
15 pF
15 pF
Capacitor values are for design guidance only.
These capacitors were tested with the crystals listed
below for basic start-up and operation. These values
are not optimized.
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.
See the notes following this table for additional
information.
Crystals Used:
32 kHz
4 MHz
200 kHz
8 MHz
1 MHz
20 MHz
An external clock source may also be connected to the
OSC1 pin in the HS mode, as shown in Figure 2-2.
FIGURE 2-2:
EXTERNAL CLOCK INPUT
OPERATION (HS OSC
CONFIGURATION)
OSC1
Clock from
Ext. System
PIC18FXXXX
OSC2
Open
2.3
HSPLL
A Phase Locked Loop (PLL) circuit is provided as an
option for users who wish to use a lower frequency
crystal 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.
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 PLL is enabled only when the oscillator Configuration bits are programmed for HSPLL mode. If
programmed for any other mode, the PLL is not
enabled.
FIGURE 2-3:
Note 1: Higher capacitance increases the stability
of oscillator, but also increases the startup 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.
PLL BLOCK DIAGRAM
HS Oscillator Enable
PLL Enable
(from Configuration Register 1H)
OSC2
OSC1
Crystal FIN
Osc FOUT
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.
2002-2015 Microchip Technology Inc.
(HS Mode)
Phase
Comparator
Loop
Filter
4
VCO
MUX
TABLE 2-2:
SYSCLK
DS30009605G-page 11
PIC18F1220/1320
2.4
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.
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 2-4 shows the pin connections for the EC
Oscillator mode.
FIGURE 2-4:
EXTERNAL CLOCK INPUT
OPERATION
(EC CONFIGURATION)
OSC1/CLKI
Clock from
Ext. System
PIC18FXXXX
FOSC/4
OSC2/CLKO
2.5
RC Oscillator
For timing insensitive applications, the “RC” and
“RCIO” device options offer additional cost savings.
The RC oscillator frequency is a function of the supply
voltage, the resistor (REXT) and capacitor (CEXT) values and the operating temperature. In addition to this,
the oscillator frequency will vary from unit to unit due to
normal manufacturing variation. Furthermore, the difference in lead frame capacitance between package
types will also affect the oscillation frequency, especially for low CEXT values. The user also needs to take
into account variation, due to tolerance of external
R and C components used. Figure 2-6 shows how the
R/C combination is connected.
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 2-6:
RC OSCILLATOR MODE
VDD
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 2-5 shows the pin connections
for the ECIO Oscillator mode.
FIGURE 2-5:
EXTERNAL CLOCK INPUT
OPERATION
(ECIO CONFIGURATION)
REXT
OSC1
Internal
Clock
CEXT
PIC18FXXXX
VSS
FOSC/4
OSC2/CLKO
Recommended values: 3 k REXT 100 k
CEXT > 20 pF
OSC1/CLKI
Clock from
Ext. System
PIC18FXXXX
RA6
I/O (OSC2)
The RCIO Oscillator mode (Figure 2-7) 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).
FIGURE 2-7:
RCIO OSCILLATOR MODE
VDD
REXT
OSC1
Internal
Clock
CEXT
PIC18FXXXX
VSS
RA6
I/O (OSC2)
Recommended values: 3 k REXT 100 k
CEXT > 20 pF
DS30009605G-page 12
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
2.6
Internal Oscillator Block
The PIC18F1220/1320 devices include an internal
oscillator block, which generates two different clock
signals; either can be used as the system’s clock
source. This can 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 system clock. It
also drives a postscaler, which can provide a range of
clock frequencies from 125 kHz to 4 MHz. The
INTOSC output is enabled when a system clock
frequency from 125 kHz to 8 MHz is selected.
The other clock source is the internal RC oscillator
(INTRC), which provides a 31 kHz output. The INTRC
oscillator is enabled by selecting the internal oscillator
block as the system clock source, or when any of the
following are enabled:
•
•
•
•
Power-up Timer
Fail-Safe Clock Monitor
Watchdog Timer
Two-Speed Start-up
These features are discussed in greater detail in
Section 19.0 “Special Features of the CPU”.
The clock source frequency (INTOSC direct, INTRC
direct or INTOSC postscaler) is selected by configuring
the IRCF bits of the OSCCON register (Register 2-2).
2.6.1
INTIO MODES
2.6.2
INTRC OUTPUT FREQUENCY
The internal oscillator block is calibrated at the factory
to produce an INTOSC output frequency of 8.0 MHz
(see Table 22-6). This changes the frequency of the
INTRC source from its nominal 31.25 kHz. Peripherals
and features that depend on the INTRC source will be
affected by this shift in frequency.
Once set during factory calibration, the INTRC
frequency will remain within ±2% as temperature and
VDD change across their full specified operating
ranges.
2.6.3
OSCTUNE REGISTER
The internal oscillator’s output has been calibrated at
the factory, but can be adjusted in the user’s application. This is done by writing to the OSCTUNE register
(Register 2-1). The tuning sensitivity is constant
throughout the tuning range.
When the OSCTUNE register is modified, the INTOSC
and INTRC frequencies will begin shifting to the new
frequency. The INTRC clock will reach the new
frequency within 8 clock cycles (approximately
8 * 32 s = 256 s). The INTOSC clock will stabilize
within 1 ms. Code execution continues during this shift.
There is no indication that the shift has occurred.
Operation of features that depend on the INTRC clock
source frequency, such as the WDT, Fail-Safe Clock
Monitor and peripherals, will also be affected by the
change in frequency.
Using the internal oscillator as the clock source can
eliminate 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 for digital input and
output.
• In INTIO2 mode, OSC1 functions as RA7 and
OSC2 functions as RA6, both for digital input and
output.
2002-2015 Microchip Technology Inc.
DS30009605G-page 13
PIC18F1220/1320
REGISTER 2-1:
OSCTUNE: OSCILLATOR TUNING REGISTER
U-0
U-0
—
—
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
TUN
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-6
Unimplemented: Read as ‘0’
bit 5-0
TUN: Frequency Tuning bits
100000 = Minimum frequency
•
•
•
111111 =
000000 = Oscillator module is running at the factory-calibrated frequency
000001 =
•
•
•
011110 =
011111 = Maximum frequency
2.7
Clock Sources and Oscillator
Switching
Like previous PIC18 devices, the PIC18F1220/1320
devices include a feature that allows the system clock
source to be switched from the main oscillator to an
alternate low-frequency clock source. PIC18F1220/
1320 devices offer two alternate clock sources. When
enabled, these give additional options for switching to
the various power managed operating modes.
Essentially, there are three clock sources for these
devices:
• Primary oscillators
• Secondary oscillators
• Internal oscillator block
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 on POR by the contents
of Configuration Register 1H. The details of these
modes are covered earlier in this chapter.
PIC18F1220/1320 devices offer only 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 RB6/T1OSO and RB7/T1OSI pins. Like
the LP mode oscillator circuit, loading capacitors are
also connected from each pin to ground. These pins
are also used during ICSP operations.
The Timer1 oscillator is discussed in greater detail in
Section 12.2 “Timer1 Oscillator”.
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 PIC18F1220/1320 devices
are shown in Figure 2-8. See Section 12.0 “Timer1
Module” for further details of the Timer1 oscillator. See
Section 19.1 “Configuration Bits” for Configuration
register details.
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.
DS30009605G-page 14
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
2.7.1
OSCILLATOR CONTROL REGISTER
when the internal oscillator block has stabilized and is
providing the system clock in RC Clock modes or
during Two-Speed Start-ups. The T1RUN bit
(T1CON) indicates when the Timer1 oscillator is
providing the system 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 system clock, or the internal
oscillator block has just started and is not yet stable.
The OSCCON register (Register 2-2) controls several
aspects of the system clock’s operation, both in fullpower operation and in power managed modes.
The System Clock Select bits, SCS1:SCS0, select the
clock source that is used when the device is operating in
power managed modes. The available clock sources are
the primary clock (defined in Configuration Register 1H),
the secondary clock (Timer1 oscillator) and the internal
oscillator block. The clock selection has no effect until a
SLEEP instruction is executed and the device enters a
power managed mode of operation. The SCS bits are
cleared on all forms of Reset.
The IDLEN bit controls the selective shutdown of the
controller’s CPU in power managed modes. The uses
of these bits are discussed in more detail in
Section 3.0 “Power Managed Modes”.
The Internal Oscillator Select bits, IRCF2:IRCF0, select
the frequency output of the internal oscillator block that
is used to drive the system clock. The choices are the
INTRC source, the INTOSC source (8 MHz), or one of
the six frequencies derived from the INTOSC postscaler (125 kHz to 4 MHz). If the internal oscillator block
is supplying the system clock, changing the states of
these bits will have an immediate change on the internal oscillator’s output.
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 when
executing a SLEEP instruction will be
ignored.
The OSTS, IOFS and T1RUN bits indicate which clock
source is currently providing the system clock. The
OSTS indicates that the Oscillator Start-up Timer has
timed out and the primary clock is providing the system
clock in Primary Clock modes. The IOFS bit indicates
2: It is recommended that the Timer1 oscillator be operating and stable before executing the SLEEP instruction or a very
long delay may occur while the Timer1
oscillator starts.
PIC18F1220/1320 CLOCK DIAGRAM
PIC18F1220/1320
CONFIG1H
Primary Oscillator
OSC2
LP, XT, HS, RC, EC
OSC1
Secondary Oscillator
T1OSC
T1OSO
T1OSI
OSCCON
HSPLL
4 x PLL
Sleep
Clock
Control
Clock Source Option
for Other Modules
T1OSCEN
Enable
Oscillator
OSCCON
8
OSCCON
MUX
FIGURE 2-8:
Peripherals
Internal Oscillator
CPU
111
4 MHz
110
Internal
Oscillator
Block
100
500 kHz
250 kHz
125 kHz
31 kHz
2002-2015 Microchip Technology Inc.
IDLEN
101
1 MHz
011
MUX
8 MHz
(INTOSC)
Postscaler
INTRC
Source
2 MHz
010
001
000
WDT, FSCM
DS30009605G-page 15
PIC18F1220/1320
REGISTER 2-2:
R/W-0/0
OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0/0
IDLEN
R/W-1/1
R/W-1/1
IRCF
R(1)
R-0/0
OSTS
IOFS
R/W-0/0
bit 7
R/W-0/0
SCS
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
IDLEN: Idle Enable bits
1 = Idle mode enabled; CPU core is not clocked in power managed modes
0 = Run mode enabled; CPU core is clocked in Run modes, but not Sleep mode
bit 6-4
IRCF: Internal Oscillator Frequency Select bits
111 = 8 MHz (8 MHz source drives clock directly)
110 = 4 MHz
101 = 2 MHz
100 = 1 MHz
011 = 500 kHz
010 = 250 kHz
001 = 125 kHz
000 = 31 kHz (INTRC source drives clock directly)
bit 3
OSTS: Oscillator Start-up Time-out Status bit
1 = Oscillator Start-up Timer time-out has expired; primary oscillator is running
0 = Oscillator Start-up Timer 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(1)
1x = Internal oscillator block (RC modes)
01 =Timer1 oscillator (Secondary modes)
00 = Primary oscillator (Sleep and PRI_IDLE modes)
Note 1:
Depends on state of the IESO bit in Configuration Register 1H.
DS30009605G-page 16
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
2.7.2
OSCILLATOR TRANSITIONS
The PIC18F1220/1320 devices contain circuitry to
prevent clocking “glitches” when switching between
clock sources. A short pause in the system clock
occurs during the clock switch. The length of this pause
is between eight and nine clock periods of the new
clock source. This ensures that the new clock source is
stable and that its pulse width will not be less than the
shortest pulse width of the two clock sources.
Clock transitions are discussed in greater detail in
Section 3.1.2 “Entering Power Managed Modes”.
2.8
Effects of Power Managed Modes
on the Various Clock Sources
When the device executes a SLEEP instruction, the
system is switched to one of the power managed
modes, depending on the state of the IDLEN and
SCS1:SCS0 bits of the OSCCON register. See
Section 3.0 “Power Managed Modes” for details.
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, if used by the oscillator) will stop oscillating.
In Secondary Clock modes (SEC_RUN and SEC_IDLE), the Timer1 oscillator is operating and providing
the system 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 system clock
source. The INTRC output can be used directly to
provide the system clock and may be enabled to
support various special features, regardless of the
power managed mode (see Section 19.2 “Watchdog
Timer (WDT)” through Section 19.4 “Fail-Safe Clock
Monitor”). The INTOSC output at 8 MHz may be used
directly to clock the system, or may be divided down
first. The INTOSC output is disabled if the system clock
is provided directly from the INTRC output.
TABLE 2-3:
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).
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 system clock source (i.e., INTn pins, A/D
conversions and others).
2.9
Power-up Delays
Power-up delays are controlled by two 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 Sections 4.1 through 4.5.
The first timer is the Power-up Timer (PWRT), which
provides a fixed delay on power-up (parameter 33,
Table 22-8) if enabled in Configuration Register 2L.
The second timer is the Oscillator Start-up Timer
(OST), intended to keep the chip in Reset 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, the
device is kept in Reset for an additional 2 ms following
the HS mode OST delay, so the PLL can lock to the
incoming clock frequency.
There is a delay of 5 to 10 s following POR while 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.
OSC1 AND OSC2 PIN STATES IN SLEEP MODE
Oscillator Mode
OSC1 Pin
OSC2 Pin
RC, INTIO1
Floating, external resistor should pull high
At logic low (clock/4 output)
RCIO, INTIO2
Floating, external resistor should pull high
Configured as PORTA, bit 6
ECIO
Floating, pulled by external clock
Configured as PORTA, bit 6
EC
Floating, pulled 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 4-1 in Section 4.0 “Reset” for time-outs due to Sleep and MCLR Reset.
2002-2015 Microchip Technology Inc.
DS30009605G-page 17
PIC18F1220/1320
3.0
POWER MANAGED MODES
For PIC18F1220/1320 devices, the power managed
modes are invoked by using the existing SLEEP
instruction. All modes exit to PRI_RUN mode when triggered by an interrupt, a Reset or a WDT time-out
(PRI_RUN mode is the normal full-power execution
mode; the CPU and peripherals are clocked by the primary oscillator source). In addition, power managed
Run modes may also exit to Sleep mode, or their
corresponding Idle mode.
The PIC18F1220/1320 devices offer a total of six operating modes for more efficient power management
(see Table 3-1). These provide a variety of options for
selective power conservation in applications where
resources may be limited (i.e., battery powered
devices).
There are three categories of power managed modes:
• Sleep mode
• Idle modes
• Run modes
3.1
Selecting a power managed mode requires deciding if
the CPU is to be clocked or not and selecting a clock
source. The IDLEN bit controls CPU clocking, while the
SCS1:SCS0 bits select a clock source. The individual
modes, bit settings, clock sources and affected
modules are summarized in Table 3-1.
These categories define which portions of the device
are clocked and sometimes, what speed. The Run and
Idle modes may use any of the three available clock
sources (primary, secondary or INTOSC multiplexer);
the Sleep mode does not use a clock source.
The clock switching feature offered in other PIC18
devices (i.e., using the Timer1 oscillator in place of the
primary oscillator) and the Sleep mode offered by all
PIC® devices (where all system clocks are stopped) are
both offered in the PIC18F1220/1320 devices
(SEC_RUN and Sleep modes, respectively). However,
additional power managed modes are available that
allow the user greater flexibility in determining what
portions of the device are operating. The power managed modes are event driven; that is, some specific
event must occur for the device to enter or (more
particularly) exit these operating modes.
TABLE 3-1:
3.1.1
CLOCK SOURCES
The clock source is selected by setting the SCS bits of
the OSCCON register (Register 2-2). Three clock
sources are available for use in power managed Idle
modes: the primary clock (as configured in Configuration
Register 1H), the secondary clock (Timer1 oscillator)
and the internal oscillator block. The secondary and
internal oscillator block sources are available for the
power managed modes (PRI_RUN mode is the normal
full-power execution mode; the CPU and peripherals are
clocked by the primary oscillator source).
POWER MANAGED MODES
OSCCON Bits
Mode
Selecting Power Managed Modes
Module Clocking
Available Clock and Oscillator Source
IDLEN
SCS1:SCS0
Sleep
0
00
Off
Off
PRI_RUN
0
00
Clocked
Clocked
SEC_RUN
0
01
Clocked
Clocked
Secondary – Timer1 Oscillator
RC_RUN
0
1x
Clocked
Clocked
Internal Oscillator Block(1)
PRI_IDLE
1
00
Off
Clocked
Primary – LP, XT, HS, HSPLL, RC, EC
SEC_IDLE
1
01
Off
Clocked
Secondary – Timer1 Oscillator
RC_IDLE
1
1x
Off
Clocked
Internal Oscillator Block(1)
Note 1:
CPU
Peripherals
None – All clocks are disabled
Primary – LP, XT, HS, HSPLL, RC, EC, INTRC(1)
This is the normal full-power execution mode.
Includes INTOSC and INTOSC postscaler, as well as the INTRC source.
DS30009605G-page 18
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
3.1.2
ENTERING POWER MANAGED
MODES
In general, entry, exit and switching between power
managed clock sources requires clock source
switching. In each case, the sequence of events is the
same.
Any change in the power managed mode begins with
loading the OSCCON register and executing a SLEEP
instruction. The SCS1:SCS0 bits select one of three
power managed clock sources; the primary clock (as
defined in Configuration Register 1H), the secondary
clock (the Timer1 oscillator) and the internal oscillator
block (used in RC modes). Modifying the SCS bits will
have no effect until a SLEEP instruction is executed.
Entry to the power managed mode is triggered by the
execution of a SLEEP instruction.
Figure 3-5 shows how the system is clocked while
switching from the primary clock to the Timer1 oscillator. When the SLEEP instruction is executed, clocks to
the device are stopped at the beginning of the next
instruction cycle. Eight clock cycles from the new clock
source are counted to synchronize with the new clock
source. After eight clock pulses from the new clock
source are counted, clocks from the new clock source
resume clocking the system. The actual length of the
pause is between eight and nine clock periods from the
new clock source. This ensures that the new clock
source is stable and that its pulse width will not be less
than the shortest pulse width of the two clock sources.
Three bits indicate the current clock source: OSTS and
IOFS in the OSCCON register and T1RUN in the
T1CON register. Only one of these bits will be set while
in a power managed mode. When the OSTS bit is set,
the primary clock is providing the system clock. When
the IOFS bit is set, the INTOSC output is providing a
stable 8 MHz clock source and is providing the system
clock. When the T1RUN bit is set, the Timer1 oscillator
is providing the system clock. If none of these bits are
set, then either the INTRC clock source is clocking the
system, or the INTOSC source is not yet stable.
If the internal oscillator block is configured as the primary clock source in Configuration Register 1H, then
both the OSTS and IOFS bits may be set when in
PRI_RUN or PRI_IDLE modes. This indicates that the
primary clock (INTOSC output) is generating a stable
8 MHz output. Entering an RC power managed mode
(same frequency) would clear the OSTS bit.
2002-2015 Microchip Technology Inc.
Note 1: Caution should be used when modifying
a single IRCF bit. If VDD is less than 3V, it
is possible to select a higher clock speed
than is supported by the low VDD.
Improper device operation may result if
the VDD/FOSC specifications are violated.
2: Executing a SLEEP instruction does not
necessarily place the device into Sleep
mode; executing a SLEEP instruction is
simply a trigger to place the controller into
a power managed mode selected by the
OSCCON register, one of which is Sleep
mode.
3.1.3
MULTIPLE SLEEP COMMANDS
The power managed mode that is invoked with the
SLEEP instruction is determined by the settings of the
IDLEN and SCS bits at the time the instruction is executed. If another SLEEP instruction is executed, the
device will enter the power managed mode specified by
these same bits at that time. If the bits have changed,
the device will enter the new power managed mode
specified by the new bit settings.
3.1.4
COMPARISONS BETWEEN RUN
AND IDLE MODES
Clock source selection for the Run modes is identical to
the corresponding Idle modes. When a SLEEP instruction is executed, the SCS bits in the OSCCON register
are used to switch to a different clock source. As a
result, if there is a change of clock source at the time a
SLEEP instruction is executed, a clock switch will occur.
In Idle modes, the CPU is not clocked and is not running. In Run modes, the CPU is clocked and executing
code. This difference modifies the operation of the
WDT when it times out. In Idle modes, a WDT time-out
results in a wake from power managed modes. In Run
modes, a WDT time-out results in a WDT Reset (see
Table 3-2).
During a wake-up from an Idle mode, the CPU starts
executing code by entering the corresponding Run
mode until the primary clock becomes ready. When the
primary clock becomes ready, the clock source is automatically switched to the primary clock. The IDLEN and
SCS bits are unchanged during and after the wake-up.
Figure 3-2 shows how the system is clocked during the
clock source switch. The example assumes the device
was in SEC_IDLE or SEC_RUN mode when a wake is
triggered (the primary clock was configured in HSPLL
mode).
DS30009605G-page 19
PIC18F1220/1320
TABLE 3-2:
Power
Managed
Mode
COMPARISON BETWEEN POWER MANAGED MODES
CPU is Clocked by ...
WDT Time-out
causes a ...
Peripherals are
Clocked by ...
Clock during Wake-up
(while primary becomes
ready)
Sleep
Not clocked (not running) Wake-up
Not clocked
Any Idle mode
Not clocked (not running) Wake-up
Primary, Secondary or Unchanged from Idle mode
INTOSC multiplexer
(CPU operates as in
corresponding Run mode)
Any Run mode
Primary or secondary
clocks or INTOSC
multiplexer
Primary or secondary
clocks or INTOSC
multiplexer
3.2
Reset
Sleep Mode
The power managed Sleep mode in the PIC18F1220/
1320 devices is identical to that offered in all other PIC
microcontrollers. It is entered by clearing the IDLEN
and SCS1:SCS0 bits (this is the Reset state) and
executing the SLEEP instruction. This shuts down the
primary oscillator and the OSTS bit is cleared (see
Figure 3-1).
When a wake event occurs in Sleep mode (by interrupt,
Reset or WDT time-out), the system will not be clocked
until the primary clock source becomes ready (see
Figure 3-2), or it will be clocked from the internal
oscillator block if either the Two-Speed Start-up or the
Fail-Safe Clock Monitor are enabled (see Section 19.0
“Special Features of the CPU”). In either case, the
OSTS bit is set when the primary clock is providing the
system clocks. The IDLEN and SCS bits are not
affected by the wake-up.
3.3
Idle Modes
The IDLEN bit allows the microcontroller’s CPU to be
selectively shut down while the peripherals continue to
operate. Clearing IDLEN allows the CPU to be clocked.
Setting IDLEN disables clocks to the CPU, effectively
stopping program execution (see Register 2-2). The
peripherals continue to be clocked regardless of the
setting of the IDLEN bit.
None or INTOSC multiplexer
if Two-Speed Start-up or
Fail-Safe Clock Monitor are
enabled
Unchanged from Run mode
If the Idle Enable bit, IDLEN (OSCCON), is set to a
‘1’ when a SLEEP instruction is executed, the
peripherals will be clocked from the clock source
selected using the SCS1:SCS0 bits; however, the CPU
will not be clocked. Since the CPU is not executing
instructions, the only exits from any of the Idle modes
are by interrupt, WDT time-out or a Reset.
When a wake event occurs, CPU execution is delayed
approximately 10 s while it becomes ready to execute
code. When the CPU begins executing code, it is
clocked by the same clock source as was selected in
the power managed mode (i.e., when waking from
RC_IDLE mode, the internal oscillator block will clock
the CPU and peripherals until the primary clock source
becomes ready – this is essentially RC_RUN mode).
This continues until the primary clock source becomes
ready. When the primary clock becomes ready, the
OSTS bit is set and the system clock source is
switched to the primary clock (see Figure 3-4). The
IDLEN and SCS bits are not affected by the wake-up.
While in any Idle mode or the Sleep mode, a WDT
time-out will result in a WDT wake-up to full-power
operation.
There is one exception to how the IDLEN bit functions.
When all the low-power OSCCON bits are cleared
(IDLEN:SCS1:SCS0 = 000), the device enters Sleep
mode upon the execution of the SLEEP instruction. This
is both the Reset state of the OSCCON register and the
setting that selects Sleep mode. This maintains
compatibility with other PIC devices that do not offer
power managed modes.
DS30009605G-page 20
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 3-1:
TIMING TRANSITION FOR ENTRY TO SLEEP MODE
Q1 Q2 Q3 Q4 Q1
OSC1
CPU
Clock
Peripheral
Clock
Sleep
Program
Counter
PC
FIGURE 3-2:
PC + 2
TRANSITION TIMING FOR WAKE FROM SLEEP (HSPLL)
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
TOST(1)
PLL Clock
Output
TPLL(1)
CPU Clock
Peripheral
Clock
Program
Counter
PC
Wake Event
Note 1:
PC + 2
PC + 4
PC + 6
PC + 8
OSTS bit Set
TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
2002-2015 Microchip Technology Inc.
DS30009605G-page 21
PIC18F1220/1320
3.3.1
PRI_IDLE MODE
This mode is unique among the three Low-Power Idle
modes, in that it does not disable the primary system
clock. For timing sensitive applications, this allows for
the fastest resumption of device operation with its more
accurate primary clock source, since the clock source
does not have to “warm up” or transition from another
oscillator.
When a wake event occurs, the CPU is clocked from
the primary clock source. A delay of approximately
10 s is required between the wake event and code
execution starts. This is required to allow the CPU to
become ready to execute instructions. After the wakeup, the OSTS bit remains set. The IDLEN and SCS bits
are not affected by the wake-up (see Figure 3-4).
PRI_IDLE mode is entered by setting the IDLEN bit,
clearing the SCS bits and executing a SLEEP instruction. Although the CPU is disabled, the peripherals
continue to be clocked from the primary clock source
specified in Configuration Register 1H. The OSTS bit
remains set in PRI_IDLE mode (see Figure 3-3).
FIGURE 3-3:
TRANSITION TIMING TO PRI_IDLE MODE
Q1
Q3
Q2
Q4
Q1
OSC1
CPU Clock
Peripheral
Clock
Program
Counter
FIGURE 3-4:
PC
PC + 2
TRANSITION TIMING FOR WAKE FROM PRI_IDLE MODE
Q1
Q2
Q3
Q4
OSC1
CPU Start-up Delay
CPU Clock
Peripheral
Clock
Program
Counter
PC
PC + 2
Wake Event
DS30009605G-page 22
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
3.3.2
SEC_IDLE MODE
When a wake event occurs, the peripherals continue to
be clocked from the Timer1 oscillator. After a 10 s
delay following the wake event, the CPU begins executing code, being clocked by the Timer1 oscillator. The
microcontroller operates in SEC_RUN mode until the
primary clock becomes ready. When the primary clock
becomes ready, a clock switchback to the primary clock
occurs (see Figure 3-6). When the clock switch is complete, the T1RUN bit is cleared, the OSTS bit is set and
the primary clock is providing the system clock. The
IDLEN and SCS bits are not affected by the wake-up.
The Timer1 oscillator continues to run.
In SEC_IDLE mode, the CPU is disabled, but the
peripherals continue to be clocked from the Timer1
oscillator. This mode is entered by setting the Idle bit,
modifying bits, SCS1:SCS0 = 01 and executing a
SLEEP instruction. When the clock source is switched
(see Figure 3-5) to the Timer1 oscillator, the primary
oscillator is shut down, the OSTS bit is cleared and the
T1RUN bit is set.
Note:
The Timer1 oscillator should already be
running prior to entering SEC_IDLE
mode. If the T1OSCEN bit is not set when
the SLEEP instruction is executed, the
SLEEP instruction will be ignored and
entry to SEC_IDLE mode will not occur. If
the Timer1 oscillator is enabled, but not
yet running, peripheral clocks will be
delayed until the oscillator has started; in
such situations, initial oscillator operation
is far from stable and unpredictable operation may result.
FIGURE 3-5:
TIMING TRANSITION FOR ENTRY TO SEC_IDLE MODE
Q1 Q2 Q3 Q4 Q1
1
T1OSI
2
3
4
5
6
Clock Transition
7
8
OSC1
CPU
Clock
Peripheral
Clock
Program
Counter
PC
FIGURE 3-6:
PC + 2
TIMING TRANSITION FOR WAKE FROM SEC_RUN MODE (HSPLL)
Q1
Q2
Q3
Q4
Q2 Q3 Q4 Q1 Q2 Q3
Q1
T1OSI
OSC1
TOST(1)
TPLL(1)
PLL Clock
Output
1
2
3 4 5 6
Clock Transition
7
8
CPU Clock
Peripheral
Clock
Program
Counter
PC
Wake from Interrupt Event
Note 1:
PC + 2
PC + 4
PC + 6
OSTS bit Set
TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
2002-2015 Microchip Technology Inc.
DS30009605G-page 23
PIC18F1220/1320
3.3.3
RC_IDLE MODE
instruction was executed and the INTOSC source was
already stable, the IOFS bit will remain set. If the IRCF
bits are all clear, the INTOSC output is not enabled and
the IOFS bit will remain clear; there will be no indication
of the current clock source.
In RC_IDLE mode, the CPU is disabled, but the peripherals continue to be clocked from the internal oscillator
block using the INTOSC multiplexer. This mode allows
for controllable power conservation during Idle periods.
When a wake event occurs, the peripherals continue to
be clocked from the INTOSC multiplexer. After a 10 s
delay following the wake event, the CPU begins executing code, being clocked by the INTOSC multiplexer.
The microcontroller operates in RC_RUN mode until
the primary clock becomes ready. When the primary
clock becomes ready, a clock switchback to the primary
clock occurs (see Figure 3-8). When the clock switch is
complete, the IOFS bit is cleared, the OSTS bit is set
and the primary clock is providing the system clock.
The IDLEN and SCS bits are not affected by the wakeup. The INTRC source will continue to run if either the
WDT or the Fail-Safe Clock Monitor is enabled.
This mode is entered by setting the IDLEN bit, setting
SCS1 (SCS0 is ignored) and executing a SLEEP
instruction. The INTOSC multiplexer may be used to
select a higher clock frequency by modifying the IRCF
bits before executing the SLEEP instruction. When the
clock source is switched to the INTOSC multiplexer
(see Figure 3-7), the primary oscillator is shut down
and the OSTS bit is cleared.
If the IRCF bits are set to a non-zero value (thus,
enabling the INTOSC output), the IOFS bit becomes
set after the INTOSC output becomes stable, in about
1 ms. Clocks to the peripherals continue while the
INTOSC source stabilizes. If the IRCF bits were
previously at a non-zero value before the SLEEP
FIGURE 3-7:
TIMING TRANSITION TO RC_IDLE MODE
Q1 Q2 Q3 Q4 Q1
1
INTRC
2
3
4
5
6
7
8
Clock Transition
OSC1
CPU
Clock
Peripheral
Clock
Program
Counter
PC
FIGURE 3-8:
PC + 2
TIMING TRANSITION FOR WAKE FROM RC_RUN MODE (RC_RUN TO PRI_RUN)
Q4
Q1
Q2
Q3
Q4
Q2 Q3 Q4 Q1 Q2 Q3
Q1
INTOSC
Multiplexer
OSC1
TOST(1)
TPLL(1)
PLL Clock
Output
1
2
3 4 5 6
Clock Transition
7
8
CPU Clock
Peripheral
Clock
Program
Counter
PC
Wake from Interrupt Event
Note 1:
PC + 2
PC + 4
PC + 6
OSTS bit Set
TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
DS30009605G-page 24
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
3.4
Run Modes
SEC_RUN mode is entered by clearing the IDLEN bit,
setting SCS1:SCS0 = 01 and executing a SLEEP
instruction. The system clock source is switched to the
Timer1 oscillator (see Figure 3-9), the primary oscillator is shut down, the T1RUN bit (T1CON) is set and
the OSTS bit is cleared.
If the IDLEN bit is clear when a SLEEP instruction is
executed, the CPU and peripherals are both clocked
from the source selected using the SCS1:SCS0 bits.
While these operating modes may not afford the power
conservation of Idle or Sleep modes, they do allow the
device to continue executing instructions by using a
lower frequency clock source. RC_RUN mode also
offers the possibility of executing code at a frequency
greater than the primary clock.
Note:
The Timer1 oscillator should already be
running prior to entering SEC_RUN
mode. If the T1OSCEN bit is not set when
the SLEEP instruction is executed, the
SLEEP instruction will be ignored and
entry to SEC_RUN mode will not occur. If
the Timer1 oscillator is enabled, but not
yet running, system clocks will be delayed
until the oscillator has started; in such
situations, initial oscillator operation is far
from stable and unpredictable operation
may result.
When a wake event occurs, the peripherals and CPU
continue to be clocked from the Timer1 oscillator while
the primary clock is started. When the primary clock
becomes ready, a clock switchback to the primary clock
occurs (see Figure 3-6). When the clock switch is complete, the T1RUN bit is cleared, the OSTS bit is set and
the primary clock is providing the system clock. The
IDLEN and SCS bits are not affected by the wake-up.
The Timer1 oscillator continues to run.
Wake-up from a power managed Run mode can be
triggered by an interrupt, or any Reset, to return to fullpower operation. As the CPU is executing code in Run
modes, several additional exits from Run modes are
possible. They include exit to Sleep mode, exit to a corresponding Idle mode and exit by executing a RESET
instruction. While the device is in any of the power
managed Run modes, a WDT time-out will result in a
WDT Reset.
3.4.1
PRI_RUN MODE
The PRI_RUN mode is the normal full-power execution
mode. If the SLEEP instruction is never executed, the
microcontroller operates in this mode (a SLEEP instruction is executed to enter all other power managed
modes). All other power managed modes exit to
PRI_RUN mode when an interrupt or WDT time-out
occur.
Firmware can force an exit from SEC_RUN mode. By
clearing the T1OSCEN bit (T1CON), an exit from
SEC_RUN back to normal full-power operation is triggered. The Timer1 oscillator will continue to run and
provide the system clock, even though the T1OSCEN
bit is cleared. The primary clock is started. When the
primary clock becomes ready, a clock switchback to the
primary clock occurs (see Figure 3-6). When the clock
switch is complete, the Timer1 oscillator is disabled, the
T1RUN bit is cleared, the OSTS bit is set and the primary clock is providing the system clock. The IDLEN
and SCS bits are not affected by the wake-up.
There is no entry to PRI_RUN mode. The OSTS bit is
set. The IOFS bit may be set if the internal oscillator
block is the primary clock source (see Section 2.7.1
“Oscillator Control Register”).
3.4.2
SEC_RUN MODE
The SEC_RUN mode is the compatible mode to the
“clock switching” feature offered in other PIC18
devices. In this mode, the CPU and peripherals are
clocked from the Timer1 oscillator. This gives users the
option of lower power consumption while still using a
high accuracy clock source.
FIGURE 3-9:
TIMING TRANSITION FOR ENTRY TO SEC_RUN MODE
Q1 Q2 Q3 Q4 Q1
Q2
1
T1OSI
2
3
4
5
6
Clock Transition
7
Q3
Q4
Q1
Q2
Q3
8
OSC1
CPU
Clock
Peripheral
Clock
Program
Counter
PC
2002-2015 Microchip Technology Inc.
PC + 2
PC + 2
DS30009605G-page 25
PIC18F1220/1320
3.4.3
RC_RUN MODE
Note:
In RC_RUN mode, the CPU and peripherals are
clocked from the internal oscillator block using the
INTOSC multiplexer and the primary clock is shut
down. When using the INTRC source, this mode provides the best power conservation of all the Run
modes, while still executing code. It works well for user
applications which are not highly timing sensitive, or do
not require high-speed clocks at all times.
If the IRCF bits are all clear, the INTOSC output is not
enabled and the IOFS bit will remain clear; there will be
no indication of the current clock source. The INTRC
source is providing the system clocks.
If the primary clock source is the internal oscillator
block (either of the INTIO1 or INTIO2 oscillators), there
are no distinguishable differences between PRI_RUN
and RC_RUN modes during execution. However, a
clock switch delay will occur during entry to and exit
from RC_RUN mode. Therefore, if the primary clock
source is the internal oscillator block, the use of
RC_RUN mode is not recommended.
If the IRCF bits are changed from all clear (thus,
enabling the INTOSC output), the IOFS bit becomes
set after the INTOSC output becomes stable. Clocks to
the system continue while the INTOSC source
stabilizes, in approximately 1 ms.
If the IRCF bits were previously at a non-zero value
before the SLEEP instruction was executed and the
INTOSC source was already stable, the IOFS bit will
remain set.
This mode is entered by clearing the IDLEN bit, setting
SCS1 (SCS0 is ignored) and executing a SLEEP
instruction. The IRCF bits may select the clock
frequency before the SLEEP instruction is executed.
When the clock source is switched to the INTOSC
multiplexer (see Figure 3-10), the primary oscillator is
shut down and the OSTS bit is cleared.
When a wake event occurs, the system continues to be
clocked from the INTOSC multiplexer while the primary
clock is started. When the primary clock becomes
ready, a clock switch to the primary clock occurs (see
Figure 3-8). When the clock switch is complete, the
IOFS bit is cleared, the OSTS bit is set and the primary
clock is providing the system clock. The IDLEN and
SCS bits are not affected by the wake-up. The INTRC
source will continue to run if either the WDT or the
Fail-Safe Clock Monitor is enabled.
The IRCF bits may be modified at any time to immediately change the system clock speed. Executing a
SLEEP instruction is not required to select a new clock
frequency from the INTOSC multiplexer.
FIGURE 3-10:
Caution should be used when modifying a
single IRCF bit. If VDD is less than 3V, it is
possible to select a higher clock speed
than is supported by the low VDD.
Improper device operation may result if
the VDD/FOSC specifications are violated.
TIMING TRANSITION TO RC_RUN MODE
Q4 Q1 Q2 Q3 Q4
Q1
1
INTRC
Q2
2
3
4
5
6
7
Q3
Q4
Q1
Q2
Q3
8
Clock Transition
OSC1
CPU
Clock
Peripheral
Clock
Program
Counter
PC
DS30009605G-page 26
PC + 2
PC + 4
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
3.4.4
EXIT TO IDLE MODE
An exit from a power managed Run mode to its
corresponding Idle mode is executed by setting the
IDLEN bit and executing a SLEEP instruction. The CPU
is halted at the beginning of the instruction following the
SLEEP instruction. There are no changes to any of the
clock source status bits (OSTS, IOFS or T1RUN).
While the CPU is halted, the peripherals continue to be
clocked from the previously selected clock source.
3.4.5
3.5
An exit from any of the power managed modes is triggered by an interrupt, a Reset or a WDT time-out. This
section discusses the triggers that cause exits from
power managed modes. The clocking subsystem
actions are discussed in each of the power managed
modes (see Sections 3.2 through 3.4).
Note:
EXIT TO SLEEP MODE
An exit from a power managed Run mode to Sleep
mode is executed by clearing the IDLEN and
SCS1:SCS0 bits and executing a SLEEP instruction.
The code is no different than the method used to invoke
Sleep mode from the normal operating (full-power)
mode.
The primary clock and internal oscillator block are
disabled. The INTRC will continue to operate if the
WDT is enabled. The Timer1 oscillator will continue to
run, if enabled in the T1CON register (Register 12-1).
All clock source Status bits are cleared (OSTS, IOFS
and T1RUN).
2002-2015 Microchip Technology Inc.
Wake from Power Managed Modes
If application code is timing sensitive, it
should wait for the OSTS bit to become
set before continuing. Use the interval
during the low-power exit sequence
(before OSTS is set) to perform timing
insensitive “housekeeping” tasks.
Device behavior during Low-Power mode exits is
summarized in Table 3-3.
3.5.1
EXIT BY INTERRUPT
Any of the available interrupt sources can cause the
device to exit a power managed mode and resume fullpower operation. To enable this functionality, an interrupt source must be enabled by setting its enable bit in
one of the INTCON or PIE registers. The exit sequence
is initiated when the corresponding interrupt flag bit is
set. On all exits from Low-Power mode by interrupt,
code execution branches to the interrupt vector if the
GIE/GIEH bit (INTCON) is set. Otherwise, code
execution continues or resumes without branching
(see Section 9.0 “Interrupts”).
DS30009605G-page 27
PIC18F1220/1320
TABLE 3-3:
Clock in Power
Managed Mode
ACTIVITY AND EXIT DELAY ON WAKE FROM SLEEP MODE OR ANY IDLE MODE
(BY CLOCK SOURCES)
Primary System
Clock
LP, XT, HS
Primary System
HSPLL
Clock
(1)
(PRI_IDLE mode) EC, RC, INTRC
(2)
INTOSC
T1OSC or
INTRC(1)
5-10 s(5)
—
OST
EC, RC, INTRC(1)
5-10 s(5)
—
1 ms(4)
IOFS
(2)
OSTS
LP, XT, HS
OST
HSPLL
OST + 2 ms
EC, RC, INTRC(1)
5-10 s(5)
—
None
IOFS
(2)
Activity during Wake-up from
Power Managed Mode
Exit by Interrupt
CPU and peripherals
clocked by primary
clock and executing
instructions.
Exit by Reset
Not clocked or
Two-Speed Start-up
(if enabled)(3).
IOFS
OST + 2 ms
LP, XT, HS
OST
HSPLL
OST + 2 ms
EC, RC, INTRC(1)
5-10 s(5)
INTOSC(2)
Note 1:
2:
3:
4:
5:
OSTS
HSPLL
INTOSC
Sleep mode
Clock Ready
Status Bit
(OSCCON)
LP, XT, HS
INTOSC
INTOSC(2)
Power
Managed
Mode Exit
Delay
1
ms(4)
OSTS
OSTS
—
IOFS
CPU and peripherals
clocked by selected
power managed mode
clock and executing
instructions until
primary clock source
becomes ready.
Not clocked or
Two-Speed Start-up (if
enabled) until primary
clock source becomes
ready(3).
In this instance, refers specifically to the INTRC clock source.
Includes both the INTOSC 8 MHz source and postscaler derived frequencies.
Two-Speed Start-up is covered in greater detail in Section 19.3 “Two-Speed Start-up”.
Execution continues during the INTOSC stabilization period.
Required delay when waking from Sleep and all Idle modes. This delay runs concurrently with any other
required delays (see Section 3.3 “Idle Modes”).
DS30009605G-page 28
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
3.5.2
EXIT BY RESET
Normally, the device is held in Reset by the Oscillator
Start-up Timer (OST) until the primary clock (defined in
Configuration Register 1H) becomes ready. At that
time, the OSTS bit is set and the device begins
executing code.
Code execution can begin before the primary clock
becomes ready. If either the Two-Speed Start-up (see
Section 19.3 “Two-Speed Start-up”) or Fail-Safe
Clock Monitor (see Section 19.4 “Fail-Safe Clock
Monitor”) are enabled in Configuration Register 1H,
the device may begin execution as soon as the Reset
source has cleared. Execution is clocked by the
INTOSC multiplexer driven by the internal oscillator
block. Since the OSCCON register is cleared following
all Resets, the INTRC clock source is selected. A
higher speed clock may be selected by modifying the
IRCF bits in the OSCCON register. Execution is
clocked by the internal oscillator block until either the
primary clock becomes ready, or a power managed
mode is entered before the primary clock becomes
ready; the primary clock is then shut down.
3.5.3
EXIT BY WDT TIME-OUT
A WDT time-out will cause different actions, depending
on which power managed mode the device is in when
the time-out occurs.
If the device is not executing code (all Idle modes and
Sleep mode), the time-out will result in a wake from the
power managed mode (see Sections 3.2 through 3.4).
If the device is executing code (all Run modes), the
time-out will result in a WDT Reset (see Section 19.2
“Watchdog Timer (WDT)”).
The WDT timer and postscaler are cleared by
executing a SLEEP or CLRWDT instruction, the loss of a
currently selected clock source (if the Fail-Safe Clock
Monitor is enabled) and modifying the IRCF bits in the
OSCCON register if the internal oscillator block is the
system clock source.
2002-2015 Microchip Technology Inc.
3.5.4
EXIT WITHOUT AN OSCILLATOR
START-UP DELAY
Certain exits from power managed modes do not
invoke the OST at all. These are:
• PRI_IDLE mode, where the primary clock source
is not stopped; or
• the primary clock source is not any of LP, XT, HS
or HSPLL modes.
In these cases, the primary clock source either does
not require an oscillator start-up delay, since it is
already running (PRI_IDLE), or normally does not
require an oscillator start-up delay (RC, EC and INTIO
Oscillator modes).
However, a fixed delay (approximately 10 s) following
the wake event is required when leaving Sleep and Idle
modes. This delay is required for the CPU to prepare
for execution. Instruction execution resumes on the first
clock cycle following this delay.
3.6
INTOSC Frequency Drift
The factory calibrates the internal oscillator block
output (INTOSC) for 8 MHz (see Table 22-6). However,
this frequency may drift as VDD or temperature
changes, which 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
(Register 2-1). This has the side effect that the INTRC
clock source frequency is also affected. However, the
features that use the INTRC source often do not require
an exact frequency. These features include the Fail-Safe
Clock Monitor, the Watchdog Timer and the RC_RUN/
RC_IDLE modes when the INTRC clock source is
selected.
Being able to adjust the INTOSC requires knowing
when an adjustment is required, in which direction it
should be made and in some cases, how large a
change is needed. Three examples follow but other
techniques may be used.
DS30009605G-page 29
PIC18F1220/1320
3.6.1
EXAMPLE – EUSART
An adjustment may be indicated when the EUSART
begins to generate framing errors, or receives data with
errors while in Asynchronous mode. Framing errors
indicate that the system clock frequency is too high –
try decrementing the value in the OSCTUNE register to
reduce the system clock frequency. Errors in data may
suggest that the system clock speed is too low –
increment OSCTUNE.
3.6.2
EXAMPLE – TIMERS
This technique compares system 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 greater than expected, then the internal oscillator
block is running too fast – decrement OSCTUNE.
DS30009605G-page 30
3.6.3
EXAMPLE – CCP 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 – decrement OSCTUNE. If the measured time
is much less than the calculated time, the internal
oscillator block is running too slow–increment
OSCTUNE.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
4.0
RESET
The PIC18F1220/1320 devices differentiate between
various kinds of Reset:
a)
b)
c)
d)
e)
f)
g)
h)
Power-on Reset (POR)
MCLR Reset during normal operation
MCLR Reset during Sleep
Watchdog Timer (WDT) Reset (during
execution)
Programmable Brown-out Reset (BOR)
RESET Instruction
Stack Full Reset
Stack Underflow Reset
Most registers are unaffected by a Reset. Their status
is unknown on POR and unchanged by all other
Resets. The other registers are forced to a “Reset
state”, depending on the type of Reset that occurred.
FIGURE 4-1:
Most registers are not affected by a WDT wake-up,
since this is viewed as the resumption of normal
operation. Status bits from the RCON register
(Register 5-2), RI, TO, PD, POR and BOR, are set or
cleared differently in different Reset situations, as
indicated in Table 4-2. These bits are used in software
to determine the nature of the Reset. See Table 4-3 for
a full description of the Reset states of all registers.
A simplified block diagram of the On-Chip Reset Circuit
is shown in Figure 4-1.
The Enhanced MCU devices have a MCLR noise filter
in the MCLR Reset path. The filter will detect and
ignore small pulses.
The MCLR pin is not driven low by any internal Resets,
including the WDT.
The MCLR input provided by the MCLR pin can be
disabled with the MCLRE bit in Configuration
Register 3H (CONFIG3H).
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT
RESET
Instruction
Stack
Pointer
Stack Full/Underflow Reset
External Reset
MCLRE
MCLR
( )_IDLE
Sleep
WDT
Time-out
VDD Rise
Detect
POR Pulse
VDD
Brown-out
Reset
BOR
S
OST/PWRT
OST
1024 Cycles
10-bit Ripple Counter
Chip_Reset
R
Q
OSC1
32 s
INTRC(1)
PWRT
65.5 ms
11-bit Ripple Counter
Enable PWRT
Enable OST(2)
Note 1:This is a separate oscillator from the RC oscillator of the CLKI pin.
2: See Table 4-1 for time-out situations.
2002-2015 Microchip Technology Inc.
DS30009605G-page 31
PIC18F1220/1320
4.1
Power-on Reset (POR)
A Power-on Reset pulse is generated on-chip when
VDD rise is detected. To take advantage of the POR
circuitry, just tie the MCLR pin through a resistor (1k to
10 k) to VDD. This will eliminate external RC components usually needed to create a Power-on Reset
delay. A minimum rise rate for VDD is specified
(parameter D004). For a slow rise time, see Figure 4-2.
When the device starts normal operation (i.e., exits the
Reset condition), device operating parameters (voltage, frequency, temperature, etc.) must be met to
ensure operation. If these conditions are not met, the
device must be held in Reset until the operating
conditions are met.
FIGURE 4-2:
EXTERNAL POWER-ON
RESET CIRCUIT (FOR
SLOW VDD POWER-UP)
D
R
R1
MCLR
C
PIC18FXXXX
Note 1:External Power-on Reset circuit is required only
if the VDD power-up slope is too slow. The
diode D helps discharge the capacitor quickly
when VDD powers down.
2: R < 40 k is recommended to make sure that
the voltage drop across R does not violate
the device’s electrical specification.
3: R1 1 k will limit any current flowing into
MCLR from external capacitor C, in the event
of MCLR/VPP pin breakdown due to Electrostatic Discharge (ESD) or Electrical
Overstress (EOS).
4.2
Power-up Timer (PWRT)
The Power-up Timer (PWRT) of the PIC18F1220/1320 is
an 11-bit counter, which uses the INTRC source as the
clock input. This yields a count of 2048 x 32 s = 65.6 ms.
While the PWRT is counting, the device is held in Reset.
The power-up time delay will vary from chip-to-chip due
to VDD, temperature and process variation. See DC
parameter 33 for details.
The PWRT is enabled by clearing Configuration bit,
PWRTEN.
Oscillator Start-up Timer (OST)
The Oscillator Start-up Timer (OST) provides a 1024
oscillator cycle (from OSC1 input) delay after the
PWRT delay is over (parameter 33). This ensures that
the crystal oscillator or resonator has started and
stabilized.
The OST time-out is invoked only for XT, LP, HS and
HSPLL modes and only on Power-on Reset, or on exit
from most low-power modes.
4.4
PLL Lock Time-out
With the PLL enabled in its PLL mode, the time-out
sequence following a Power-on Reset is slightly
different from other oscillator modes. A portion of the
Power-up Timer is used to provide a fixed time-out that
is sufficient for the PLL to lock to the main oscillator frequency. This PLL lock time-out (TPLL) is typically 2 ms
and follows the Oscillator Start-up Time-out.
4.5
VDD
VDD
4.3
Brown-out Reset (BOR)
A Configuration bit, BOR, can disable (if clear/
programmed), or enable (if set) the Brown-out Reset
circuitry. If VDD falls below VBOR (parameter D005) for
greater than TBOR (parameter 35), the brown-out situation will reset the chip. A Reset may not occur if VDD
falls below VBOR for less than TBOR. The chip will
remain in Brown-out Reset until VDD rises above VBOR.
If the Power-up Timer is enabled, it will be invoked after
VDD rises above VBOR; it then will keep the chip in
Reset for an additional time delay, TPWRT
(parameter 33). If VDD drops below VBOR while the
Power-up Timer is running, the chip will go back into a
Brown-out Reset and the Power-up Timer will be initialized. Once VDD rises above VBOR, the Power-up Timer
will execute the additional time delay. Enabling BOR
Reset does not automatically enable the PWRT.
4.6
Time-out Sequence
On power-up, the time-out sequence is as follows:
First, after the POR pulse has cleared, PWRT time-out
is invoked (if enabled). Then, the OST is activated. The
total time-out will vary based on oscillator configuration
and the status of the PWRT. For example, in RC mode
with the PWRT disabled, there will be no time-out at all.
Figure 4-3, Figure 4-4, Figure 4-5, Figure 4-6 and
Figure 4-7 depict time-out sequences on power-up.
Since the time-outs occur from the POR pulse, if MCLR
is kept low long enough, all time-outs will expire. Bringing MCLR high will begin execution immediately
(Figure 4-5). This is useful for testing purposes or to
synchronize more than one PIC18FXXXX device
operating in parallel.
Table 4-2 shows the Reset conditions for some Special
Function Registers, while Table 4-3 shows the Reset
conditions for all the registers.
DS30009605G-page 32
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 4-1:
TIME-OUT IN VARIOUS SITUATIONS
Power-up(2) and Brown-out
Oscillator
Configuration
PWRTEN = 1
Exit from
Low-Power Mode
1024 TOSC + 2 ms(2)
1024 TOSC + 2 ms(2)
PWRTEN = 0
HSPLL
66 ms
(1)
+ 1024 TOSC + 2 ms
(2)
HS, XT, LP
66 ms(1) + 1024 TOSC
1024 TOSC
1024 TOSC
EC, ECIO
66 ms(1)
5-10 s(3)
5-10 s(3)
RC, RCIO
66 ms(1)
5-10 s(3)
5-10 s(3)
INTIO1, INTIO2
66 ms(1)
5-10 s(3)
5-10 s(3)
Note 1: 66 ms (65.5 ms) is the nominal Power-up Timer (PWRT) delay.
2: 2 ms is the nominal time required for the 4x PLL to lock.
3: The program memory bias start-up time is always invoked on POR, wake-up from Sleep, or on any exit
from power managed mode that disables the CPU and instruction execution.
REGISTER 4-1:
OSCCON: OSCILLATOR CONTROL REGISTER
R/W-0/0
U-0
U-0
R/W-1/1
R/W-1/1
U-0
R/W-1/1
R/W-1/1
IPEN
—
—
RI
TO
PD
POR
BOR
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
Note:
Refer to Section 5.14 “RCON Register” for bit definitions.
TABLE 4-2:
STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR
RCON REGISTER
Program
Counter
RCON
Register
RI
TO
PD
POR
BOR
STKFUL
STKUNF
Power-on Reset
0000h
0--1 1100
1
1
1
0
0
0
0
RESET Instruction
0000h
0--0 uuuu
0
u
u
u
u
u
u
Brown-out
0000h
0--1 11u-
1
1
1
u
0
u
u
MCLR during Power Managed Run
modes
0000h
0--u 1uuu
u
1
u
u
u
u
u
MCLR during Power Managed Idle
modes and Sleep
0000h
0--u 10uu
u
1
0
u
u
u
u
WDT Time-out during Full-Power or
Power Managed Run
0000h
0--u 0uuu
u
0
u
u
u
u
u
u
u
1
u
u
1
Condition
MCLR during Full-Power
Execution
Stack Full Reset (STVR = 1)
0000h
0--u uuuu
u
u
u
u
u
Stack Underflow Reset
(STVR = 1)
Stack Underflow Error (not an actual
Reset, STVR = 0)
0000h
u--u uuuu
u
u
u
u
u
u
1
WDT Time-out during Power Managed Idle or Sleep
PC + 2
u--u 00uu
u
0
0
u
u
u
u
Interrupt Exit from Power Managed
modes
PC + 2
u--u u0uu
u
u
0
u
u
u
u
Legend:
Note 1:
u = unchanged, x = unknown, – = unimplemented bit, read as ‘0’
When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the
interrupt vector (0x000008h or 0x000018h).
2002-2015 Microchip Technology Inc.
DS30009605G-page 33
PIC18F1220/1320
TABLE 4-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS
Applicable
Devices
Register
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
TOSU
1220
1320
---0 0000
---0 0000
---0 uuuu(3)
TOSH
1220
1320
0000 0000
0000 0000
uuuu uuuu(3)
TOSL
1220
1320
0000 0000
0000 0000
uuuu uuuu(3)
STKPTR
1220
1320
00-0 0000
00-0 0000
uu-u uuuu(3)
PCLATU
1220
1320
---0 0000
---0 0000
---u uuuu
PCLATH
1220
1320
0000 0000
0000 0000
uuuu uuuu
PCL
1220
1320
0000 0000
0000 0000
TBLPTRU
1220
1320
--00 0000
--00 0000
--uu uuuu
TBLPTRH
1220
1320
0000 0000
0000 0000
uuuu uuuu
PC + 2(2)
TBLPTRL
1220
1320
0000 0000
0000 0000
uuuu uuuu
TABLAT
1220
1320
0000 0000
0000 0000
uuuu uuuu
PRODH
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
PRODL
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
INTCON
1220
1320
0000 000x
0000 000u
uuuu uuuu(1)
INTCON2
1220
1320
1111 -1-1
1111 -1-1
uuuu -u-u(1)
INTCON3
1220
1320
11-0 0-00
11-0 0-00
uu-u u-uu(1)
INDF0
1220
1320
N/A
N/A
N/A
POSTINC0
1220
1320
N/A
N/A
N/A
POSTDEC0
1220
1320
N/A
N/A
N/A
PREINC0
1220
1320
N/A
N/A
N/A
PLUSW0
1220
1320
N/A
N/A
N/A
FSR0H
1220
1320
---- 0000
---- 0000
---- uuuu
FSR0L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
uuuu uuuu
WREG
1220
1320
xxxx xxxx
uuuu uuuu
INDF1
1220
1320
N/A
N/A
N/A
POSTINC1
1220
1320
N/A
N/A
N/A
POSTDEC1
1220
1320
N/A
N/A
N/A
PREINC1
1220
1320
N/A
N/A
N/A
PLUSW1
1220
1320
N/A
N/A
N/A
FSR1H
1220
1320
---- 0000
---- 0000
---- uuuu
FSR1L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 5 of PORTA is enabled if MCLR is disabled.
DS30009605G-page 34
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 4-3:
Register
BSR
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable
Devices
1220
1320
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
---- 0000
---- 0000
---- uuuu
INDF2
1220
1320
N/A
N/A
N/A
POSTINC2
1220
1320
N/A
N/A
N/A
POSTDEC2
1220
1320
N/A
N/A
N/A
PREINC2
1220
1320
N/A
N/A
N/A
PLUSW2
1220
1320
N/A
N/A
N/A
FSR2H
1220
1320
---- 0000
---- 0000
---- uuuu
FSR2L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
STATUS
1220
1320
---x xxxx
---u uuuu
---u uuuu
TMR0H
1220
1320
0000 0000
0000 0000
uuuu uuuu
TMR0L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
T0CON
1220
1320
1111 1111
1111 1111
uuuu uuuu
OSCCON
1220
1320
0000 q000
0000 q000
uuuu qquu
LVDCON
1220
1320
--00 0101
--00 0101
--uu uuuu
WDTCON
1220
1320
---- ---0
---- ---0
---- ---u
(4)
RCON
1220
1320
0--1 11q0
0--q qquu
u--u qquu
TMR1H
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
TMR1L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
T1CON
1220
1320
0000 0000
u0uu uuuu
uuuu uuuu
TMR2
1220
1320
0000 0000
0000 0000
uuuu uuuu
PR2
1220
1320
1111 1111
1111 1111
1111 1111
T2CON
1220
1320
-000 0000
-000 0000
-uuu uuuu
ADRESH
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADRESL
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
ADCON0
1220
1320
00-0 0000
00-0 0000
uu-u uuuu
ADCON1
1220
1320
-000 0000
-000 0000
-uuu uuuu
ADCON2
1220
1320
0-00 0000
0-00 0000
u-uu uuuu
CCPR1H
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCPR1L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
CCP1CON
1220
1320
0000 0000
0000 0000
uuuu uuuu
PWM1CON
1220
1320
0000 0000
0000 0000
uuuu uuuu
ECCPAS
1220
1320
0000 0000
0000 0000
uuuu uuuu
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 5 of PORTA is enabled if MCLR is disabled.
2002-2015 Microchip Technology Inc.
DS30009605G-page 35
PIC18F1220/1320
TABLE 4-3:
INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)
Applicable
Devices
Register
Power-on Reset,
Brown-out Reset
MCLR Resets
WDT Reset
RESET Instruction
Stack Resets
Wake-up via WDT
or Interrupt
TMR3H
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
TMR3L
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
T3CON
1220
1320
0-00 0000
u-uu uuuu
u-uu uuuu
SPBRGH
1220
1320
0000 0000
0000 0000
uuuu uuuu
SPBRG
1220
1320
0000 0000
0000 0000
uuuu uuuu
RCREG
1220
1320
0000 0000
0000 0000
uuuu uuuu
TXREG
1220
1320
0000 0000
0000 0000
uuuu uuuu
TXSTA
1220
1320
0000 0010
0000 0010
uuuu uuuu
RCSTA
1220
1320
0000 000x
0000 000x
uuuu uuuu
BAUDCTL
1220
1320
-1-1 0-00
-1-1 0-00
-u-u u-uu
EEADR
1220
1320
0000 0000
0000 0000
uuuu uuuu
EEDATA
1220
1320
0000 0000
0000 0000
uuuu uuuu
EECON2
1220
1320
0000 0000
0000 0000
0000 0000
EECON1
1220
1320
xx-0 x000
uu-0 u000
uu-0 u000
IPR2
1220
1320
1--1 -11-
1--1 -11-
u--u -uu-
PIR2
1220
1320
0--0 -00-
0--0 -00-
u--u -uu-(1)
PIE2
1220
1320
0--0 -00-
0--0 -00-
u--u -uu-
IPR1
1220
1320
-111 -111
-111 -111
-uuu -uuu
PIR1
1220
1320
-000 -000
-000 -000
-uuu -uuu(1)
PIE1
1220
1320
-000 -000
-000 -000
-uuu -uuu
OSCTUNE
1220
1320
--00 0000
--00 0000
--uu uuuu
TRISB
1220
1320
1111 1111
1111 1111
uuuu uuuu
TRISA(5)
1220
1320
11-1 1111(5)
11-1 1111(5)
uu-u uuuu(5)
LATB
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
LATA(5)
1220
1320
xx-x xxxx(5)
uu-u uuuu(5)
uu-u uuuu(5)
PORTB
1220
1320
xxxx xxxx
uuuu uuuu
uuuu uuuu
PORTA(5,6)
1220
1320
xx0x 0000(5,6)
uu0u 0000(5,6)
uuuu uuuu(5,6)
Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.
Shaded cells indicate conditions do not apply for the designated device.
Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).
2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the
interrupt vector (0008h or 0018h).
3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are
updated with the current value of the PC. The STKPTR is modified to point to the next location in the
hardware stack.
4: See Table 4-2 for Reset value for specific condition.
5: Bits 6 and 7 of PORTA, LATA and TRISA are enabled, depending on the Oscillator mode selected. When
not enabled as PORTA pins, they are disabled and read ‘0’.
6: Bit 5 of PORTA is enabled if MCLR is disabled.
DS30009605G-page 36
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 4-3:
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD, VDD RISE < TPWRT)
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 4-4:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
FIGURE 4-5:
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
2002-2015 Microchip Technology Inc.
DS30009605G-page 37
PIC18F1220/1320
FIGURE 4-6:
SLOW RISE TIME (MCLR TIED TO VDD, VDD RISE > TPWRT)
5V
VDD
1V
0V
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
TOST
OST TIME-OUT
INTERNAL RESET
TIME-OUT SEQUENCE ON POR W/PLL ENABLED (MCLR TIED TO VDD)
FIGURE 4-7:
VDD
MCLR
INTERNAL POR
TPWRT
PWRT TIME-OUT
OST TIME-OUT
TOST
TPLL
PLL TIME-OUT
INTERNAL RESET
Note:
TOST = 1024 clock cycles.
TPLL 2 ms max. First three stages of the PWRT timer.
DS30009605G-page 38
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
5.0
MEMORY ORGANIZATION
There are three memory types in Enhanced MCU
devices. These memory types are:
• Program Memory
• Data RAM
• Data EEPROM
Data and program memory use separate busses,
which allows for concurrent access of these types.
Additional detailed information for Flash program memory and data EEPROM is provided in Section 6.0
“Flash Program Memory” and Section 7.0 “Data
EEPROM Memory”, respectively.
5.1
Program Memory Organization
A 21-bit program counter is capable of addressing the
2-Mbyte program memory space. Accessing a location
between the physically implemented memory and the
2-Mbyte address will cause a read of all ‘0’s (a NOP
instruction).
The PIC18F1220 has 4 Kbytes of Flash memory and
can store up to 2,048 single-word instructions.
The PIC18F1320 has 8 Kbytes of Flash memory and
can store up to 4,096 single-word instructions.
The Reset vector address is at 0000h and the interrupt
vector addresses are at 0008h and 0018h.
The program memory maps for the PIC18F1220 and
PIC18F1320 devices are shown in Figure 5-1 and
Figure 5-2, respectively.
FIGURE 5-2:
FIGURE 5-1:
PROGRAM MEMORY MAP
AND STACK FOR
PIC18F1220
PC
21
CALL,RCALL,RETURN
RETFIE,RETLW
Stack Level 1
PROGRAM MEMORY MAP
AND STACK FOR
PIC18F1320
PC
21
CALL,RCALL,RETURN
RETFIE,RETLW
Stack Level 1
Stack Level 31
Stack Level 31
Reset Vector
0000h
0000h
High Priority Interrupt Vector 0008h
High Priority Interrupt Vector 0008h
Low Priority Interrupt Vector 0018h
Reset Vector
Low Priority Interrupt Vector 0018h
On-Chip
Program Memory
0FFFh
1000h
1FFFh
User Memory Space
2000h
User Memory Space
On-Chip
Program Memory
Read ‘0’
Read ‘0’
1FFFFFh
200000h
2002-2015 Microchip Technology Inc.
1FFFFFh
200000h
DS30009605G-page 39
PIC18F1220/1320
5.2
5.2.2
Return Address Stack
The return address stack allows any combination of up
to 31 program calls and interrupts to occur. The PC
(Program Counter) is pushed onto the stack when a
CALL or RCALL instruction is executed, or an interrupt
is Acknowledged. The PC value is pulled off the stack
on a RETURN, RETLW or a RETFIE instruction. PCLATU
and PCLATH are not affected by any of the RETURN or
CALL instructions.
The STKPTR register (Register 5-1) contains the Stack
Pointer value, the STKFUL (Stack Full) Status bit and
the STKUNF (Stack Underflow) Status bits. The value
of the Stack Pointer can be 0 through 31. The Stack
Pointer increments before values are pushed onto the
stack and decrements after values are popped off the
stack. At Reset, the Stack Pointer value will be zero.
The user may read and write the Stack Pointer value.
This feature can be used by a Real-Time Operating
System for return stack maintenance.
The stack operates as a 31-word by 21-bit RAM and a
5-bit Stack Pointer, with the Stack Pointer initialized to
00000B after all Resets. There is no RAM associated
with Stack Pointer, 00000B. This is only a Reset value.
During a CALL type instruction, causing a push onto the
stack, the Stack Pointer is first incremented and the
RAM location pointed to by the Stack Pointer
(STKPTR) register is written with the contents of the
PC (already pointing to the instruction following the
CALL). During a RETURN type instruction, causing a
pop from the stack, the contents of the RAM location
pointed to by the STKPTR are transferred to the PC
and then the Stack Pointer is decremented.
After the PC is pushed onto the stack 31 times (without
popping any values off the stack), the STKFUL bit is
set. The STKFUL bit is cleared by software or by a
POR.
The action that takes place when the stack becomes
full depends on the state of the STVR (Stack Overflow
Reset Enable) Configuration bit. (Refer to
Section 19.1 “Configuration Bits” for a description of
the device Configuration bits.) If STVR is set (default),
the 31st push will push the (PC + 2) value onto the
stack, set the STKFUL bit and reset the device. The
STKFUL bit will remain set and the Stack Pointer will be
set to zero.
The stack space is not part of either program or data
space. The Stack Pointer is readable and writable and
the address on the top of the stack is readable and
writable through the top-of-stack Special File Registers.
Data can also be pushed to or popped from the stack
using the top-of-stack SFRs. Status bits indicate if the
stack is full, has overflowed or underflowed.
5.2.1
If STVR is cleared, the STKFUL bit will be set on the
31st push and the Stack Pointer will increment to 31.
Any additional pushes will not overwrite the 31st push
and STKPTR will remain at 31.
When the stack has been popped enough times to
unload the stack, the next pop will return a value of zero
to the PC and sets the STKUNF bit, while the Stack
Pointer remains at zero. The STKUNF bit will remain
set until cleared by software or a POR occurs.
TOP-OF-STACK ACCESS
The top of the stack is readable and writable. Three
register locations, TOSU, TOSH and TOSL, hold the
contents of the stack location pointed to by the
STKPTR register (Figure 5-3). This allows users to
implement a software stack if necessary. After a CALL,
RCALL or interrupt, the software can read the pushed
value by reading the TOSU, TOSH and TOSL registers.
These values can be placed on a user defined software
stack. At return time, the software can replace the
TOSU, TOSH and TOSL and do a return.
Note:
The user must disable the Global Interrupt Enable bits
while accessing the stack to prevent inadvertent stack
corruption.
FIGURE 5-3:
RETURN STACK POINTER
(STKPTR)
Returning a value of zero to the PC on an
underflow has the effect of vectoring the
program to the Reset vector, where the
stack conditions can be verified and
appropriate actions can be taken. This is
not the same as a Reset, as the contents
of the SFRs are not affected.
RETURN ADDRESS STACK AND ASSOCIATED REGISTERS
Return Address Stack
11111
11110
11101
TOSU
00h
TOSH
1Ah
Top-of-Stack
DS30009605G-page 40
STKPTR
00010
TOSL
34h
00011
001A34h 00010
000D58h 00001
00000
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 5-1:
STKPTR: STACK POINTER REGISTER
R/C-0/0
R/C-0/0
U-0
STKFUL(1)
STKUNF(1)
—
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
SP
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
C = Clearable only bit
bit 7
STKFUL: Stack Full Flag bit(1)
1 = Stack became full or overflowed
0 = Stack has not become full or overflowed
bit 6
STKUNF: Stack Underflow Flag bit(1)
1 = Stack Underflow occurred
0 = Stack Underflow did not occur
bit 5
Unimplemented: Read as ‘0’
bit 4-0
SP: Stack Pointer Location bits
Note 1:
5.2.3
Bit 7 and bit 6 are cleared by user software or by a POR.
PUSH AND POP INSTRUCTIONS
Since the Top-of-Stack (TOS) is readable and writable,
the ability to push values onto the stack and pull values
off the stack, without disturbing normal program execution, is a desirable option. To push the current PC value
onto the stack, a PUSH instruction can be executed.
This will increment the Stack Pointer and load the current PC value onto the stack. TOSU, TOSH and TOSL
can then be modified to place data or a return address
on the stack.
5.2.4
STACK FULL/UNDERFLOW RESETS
These Resets are enabled by programming the STVR
bit in Configuration Register 4L. When the STVR bit is
cleared, a full or underflow condition will set the appropriate STKFUL or STKUNF bit, but not cause a device
Reset. When the STVR bit is set, a full or underflow
condition will set the appropriate STKFUL or STKUNF
bit and then cause a device Reset. The STKFUL or
STKUNF bits are cleared by the user software or a
Power-on Reset.
The ability to pull the TOS value off of the stack and
replace it with the value that was previously pushed
onto the stack, without disturbing normal execution, is
achieved by using the POP instruction. The POP instruction discards the current TOS by decrementing the
Stack Pointer. The previous value pushed onto the
stack then becomes the TOS value.
2002-2015 Microchip Technology Inc.
DS30009605G-page 41
PIC18F1220/1320
5.3
Fast Register Stack
A “fast return” option is available for interrupts. A fast
register stack is provided for the Status, WREG and
BSR registers and is only one in depth. The stack is not
readable or writable and is loaded with the current
value of the corresponding register when the processor
vectors for an interrupt. The values in the registers are
then loaded back into the working registers, if the
RETFIE, FAST instruction is used to return from the
interrupt.
All interrupt sources will push values into the stack
registers. If both low and high priority interrupts are
enabled, the stack registers cannot be used reliably to
return from low priority interrupts. If a high priority interrupt occurs while servicing a low priority interrupt, the
stack register values stored by the low priority interrupt
will be overwritten. Users must save the key registers
in software during a low priority interrupt.
If interrupt priority is not used, all interrupts may use the
fast register stack for returns from interrupt.
If no interrupts are used, the fast register stack can be
used to restore the Status, WREG and BSR registers at
the end of a subroutine call. To use the fast register
stack for a subroutine call, a CALL LABEL, FAST
instruction must be executed to save the Status,
WREG and BSR registers to the fast register stack. A
RETURN, FAST instruction is then executed to restore
these registers from the fast register stack.
5.4
PCL, PCLATH and PCLATU
The Program Counter (PC) specifies the address of the
instruction to fetch for execution. The PC is 21 bits
wide. The low byte, known as the PCL register, is both
readable and writable. The high byte, or PCH register,
contains the PC bits and is not directly readable
or writable. Updates to the PCH register may be performed through the PCLATH register. The upper byte is
called PCU. This register contains the PC bits
and is not directly readable or writable. Updates to the
PCU register may be performed through the PCLATU
register.
The contents of PCLATH and PCLATU will be
transferred to the program counter by any operation
that writes PCL. Similarly, the upper two bytes of the
program counter will be transferred to PCLATH and
PCLATU by an operation that reads PCL. This is useful
for computed offsets to the PC (see Section 5.8.1
“Computed GOTO”).
The PC addresses bytes in the program memory. To
prevent the PC from becoming misaligned with word
instructions, the LSB of PCL is fixed to a value of ‘0’.
The PC increments by two to address sequential
instructions in the program memory.
The CALL, RCALL, GOTO and program branch instructions write to the program counter directly. For these
instructions, the contents of PCLATH and PCLATU are
not transferred to the program counter.
Example 5-1 shows a source code example that uses
the fast register stack during a subroutine call and
return.
EXAMPLE 5-1:
CALL SUB1, FAST
FAST REGISTER STACK
CODE EXAMPLE
;STATUS, WREG, BSR
;SAVED IN FAST REGISTER
;STACK
RETURN, FAST
SUB1
DS30009605G-page 42
;RESTORE VALUES SAVED
;IN FAST REGISTER STACK
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
5.5
Clocking Scheme/Instruction
Cycle
5.6
Instruction Flow/Pipelining
An “Instruction Cycle” consists of four Q cycles (Q1,
Q2, Q3 and Q4). The instruction fetch and execute are
pipelined such that fetch takes one instruction cycle,
while decode and execute takes another instruction
cycle. However, due to the pipelining, each instruction
effectively executes in one cycle. If an instruction
causes the program counter to change (e.g., GOTO),
then two cycles are required to complete the instruction
(Example 5-2).
The clock input (from OSC1) is internally divided by
four to generate four non-overlapping quadrature
clocks, namely Q1, Q2, Q3 and Q4. Internally, the
Program Counter (PC) is incremented every Q1, the
instruction is fetched from the program memory and
latched into the instruction register in Q4. The instruction is decoded and executed during the following Q1
through Q4. The clocks and instruction execution flow
are shown in Figure 5-4.
A fetch cycle begins with the Program Counter (PC)
incrementing in Q1.
In the execution cycle, the fetched instruction is latched
into the “Instruction Register” (IR) in cycle Q1. This
instruction is then decoded and executed during the
Q2, Q3 and Q4 cycles. Data memory is read during Q2
(operand read) and written during Q4 (destination
write).
FIGURE 5-4:
CLOCK/INSTRUCTION CYCLE
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
Q1
Q2
Q3
Q4
OSC1
Q1
Q2
Internal
Phase
Clock
Q3
Q4
PC
OSC2/CLKO
(RC Mode)
EXAMPLE 5-2:
1. MOVLW 55h
PC
Execute INST (PC – 2)
Fetch INST (PC)
4. BSF
PC + 4
Execute INST (PC)
Fetch INST (PC + 2)
Execute INST (PC + 2)
Fetch INST (PC + 4)
INSTRUCTION PIPELINE FLOW
TCY0
TCY1
Fetch 1
Execute 1
2. MOVWF PORTB
3. BRA
PC + 2
SUB_1
PORTA, BIT3 (Forced NOP)
5. Instruction @ address SUB_1
Fetch 2
TCY2
TCY3
TCY4
TCY5
Execute 2
Fetch 3
Execute 3
Fetch 4
Flush (NOP)
Fetch SUB_1 Execute SUB_1
All instructions are single cycle, except for any program branches. These take two cycles, since the fetch instruction
is “flushed” from the pipeline, while the new instruction is being fetched and then executed.
2002-2015 Microchip Technology Inc.
DS30009605G-page 43
PIC18F1220/1320
5.7
Instructions in Program Memory
The program memory is addressed in bytes. Instructions are stored as two bytes or four bytes in program
memory. The Least Significant Byte of an instruction
word is always stored in a program memory location
with an even address (LSB = 0). Figure 5-5 shows an
example of how instruction words are stored in the program memory. To maintain alignment with instruction
boundaries, the PC increments in steps of 2 and the
LSB will always read ‘0’ (see Section 5.4 “PCL,
PCLATH and PCLATU”).
FIGURE 5-5:
The CALL and GOTO instructions have the absolute
program memory address embedded into the instruction. Since instructions are always stored on word
boundaries, the data contained in the instruction is a
word address. The word address is written to
PC, which accesses the desired byte address in
program memory. Instruction #2 in Figure 5-5 shows
how the instruction ‘GOTO 000006h’ is encoded in the
program memory. Program branch instructions, which
encode a relative address offset, operate in the same
manner. The offset value stored in a branch instruction
represents the number of single-word instructions that
the PC will be offset by. Section 20.0 “Instruction Set
Summary” provides further details of the instruction
set.
INSTRUCTIONS IN PROGRAM MEMORY
LSB = 1
LSB = 0
0Fh
EFh
F0h
C1h
F4h
55h
03h
00h
23h
56h
Program Memory
Byte Locations
5.7.1
Instruction 1:
Instruction 2:
MOVLW
GOTO
055h
000006h
Instruction 3:
MOVFF
123h, 456h
TWO-WORD INSTRUCTIONS
PIC18F1220/1320 devices have four two-word
instructions: MOVFF, CALL, GOTO and LFSR. The second
word of these instructions has the 4 MSBs set to ‘1’s and
is decoded as a NOP instruction. The lower 12 bits of the
second word contain data to be used by the instruction.
If the first word of the instruction is executed, the data in
the second word is accessed. If the second word of the
EXAMPLE 5-3:
Word Address
000000h
000002h
000004h
000006h
000008h
00000Ah
00000Ch
00000Eh
000010h
000012h
000014h
instruction is executed by itself (first word was skipped),
it will execute as a NOP. This action is necessary when
the two-word instruction is preceded by a conditional
instruction that results in a skip operation. A program
example that demonstrates this concept is shown in
Example 5-3. Refer to Section 20.0 “Instruction Set
Summary” for further details of the instruction set.
TWO-WORD INSTRUCTIONS
CASE 1:
Object Code
Source Code
0110 0110 0000 0000
TSTFSZ
REG1
1100 0001 0010 0011
MOVFF
REG1, REG2 ; No, skip this word
1111 0100 0101 0110
0010 0100 0000 0000
; is RAM location 0?
; Execute this word as a NOP
ADDWF
REG3
; continue code
CASE 2:
Object Code
Source Code
0110 0110 0000 0000
TSTFSZ
REG1
1100 0001 0010 0011
MOVFF
REG1, REG2 ; Yes, execute this word
ADDWF
REG3
1111 0100 0101 0110
0010 0100 0000 0000
DS30009605G-page 44
; is RAM location 0?
; 2nd word of instruction
; continue code
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
5.8
Look-up Tables
Look-up tables are implemented two ways:
• Computed GOTO
• Table Reads
5.8.1
COMPUTED GOTO
A computed GOTO is accomplished by adding an offset
to the program counter (see Example 5-4).
A look-up table can be formed with an ADDWF PCL
instruction and a group of RETLW 0xnn instructions.
WREG is loaded with an offset into the table before
executing a call to that table. The first instruction of the
called routine is the ADDWF PCL instruction. The next
instruction executed will be one of the RETLW 0xnn
instructions, that returns the value 0xnn to the calling
function.
The offset value (in WREG) specifies the number of
bytes that the program counter should advance and
should be multiples of 2 (LSB = 0).
In this method, only one data byte may be stored in
each instruction location and room on the return
address stack is required.
EXAMPLE 5-4:
ORG
TABLE
5.8.2
MOVFW
CALL
0xnn00
ADDWF
RETLW
RETLW
RETLW
.
.
.
COMPUTED GOTO USING
AN OFFSET VALUE
OFFSET
TABLE
PCL
0xnn
0xnn
0xnn
TABLE READS/TABLE WRITES
A better method of storing data in program memory
allows two bytes of data to be stored in each instruction
location.
Look-up table data may be stored two bytes per program word by using table reads and writes. The Table
Pointer (TBLPTR) register specifies the byte address
and the Table Latch (TABLAT) register contains the
data that is read from or written to program memory.
Data is transferred to/from program memory, one byte
at a time.
The table read/table write operation is discussed
further in Section 6.1 “Table Reads and Table
Writes”.
2002-2015 Microchip Technology Inc.
5.9
Data Memory Organization
The data memory is implemented as static RAM. Each
register in the data memory has a 12-bit address,
allowing up to 4096 bytes of data memory. Figure 5-6
shows the data memory organization for the
PIC18F1220/1320 devices.
The data memory map is divided into as many as
16 banks that contain 256 bytes each. The lower four
bits of the Bank Select Register (BSR) select
which bank will be accessed. The upper four bits for the
BSR are not implemented.
The data memory contains Special Function Registers
(SFR) and General Purpose Registers (GPR). The
SFRs are used for control and status of the controller
and peripheral functions, while GPRs are used for data
storage and scratch pad operations in the user’s application. The SFRs start at the last location of Bank 15
(FFFh) and extend towards F80h. Any remaining space
beyond the SFRs in the Bank may be implemented as
GPRs. GPRs start at the first location of Bank 0 and
grow upwards. Any read of an unimplemented location
will read as ‘0’s.
The entire data memory may be accessed directly or
indirectly. Direct addressing may require the use of the
BSR register. Indirect addressing requires the use of a
File Select Register (FSRn) and a corresponding Indirect File Operand (INDFn). Each FSR holds a 12-bit
address value that can be used to access any location
in the Data Memory map without banking. See
Section 5.12 “Indirect Addressing, INDF and FSR
Registers” for indirect addressing details.
The instruction set and architecture allow operations
across all banks. This may be accomplished by indirect
addressing or by the use of the MOVFF instruction. The
MOVFF instruction is a two-word/two-cycle instruction
that moves a value from one register to another.
To ensure that commonly used registers (SFRs and
select GPRs) can be accessed in a single cycle,
regardless of the current BSR values, an Access Bank
is implemented. A segment of Bank 0 and a segment of
Bank 15 comprise the Access RAM. Section 5.10
“Access Bank” provides a detailed description of the
Access RAM.
5.9.1
GENERAL PURPOSE
REGISTER FILE
Enhanced MCU devices may have banked memory in
the GPR area. GPRs are not initialized by a Power-on
Reset and are unchanged on all other Resets.
Data RAM is available for use as GPR registers by all
instructions. The second half of Bank 15 (F80h to
FFFh) contains SFRs. All other banks of data memory
contain GPRs, starting with Bank 0.
DS30009605G-page 45
PIC18F1220/1320
FIGURE 5-6:
DATA MEMORY MAP FOR PIC18F1220/1320 DEVICES
BSR
= 0000
Data Memory Map
00h
Access RAM
FFh
GPR
Bank 0
000h
07Fh
080h
0FFh
Access Bank
Access RAM Low
= 0001
= 1110
Bank 1
to
Bank 14
00h
7Fh
Access RAM High 80h
(SFRs)
FFh
Unused
Read ‘00h’
When a = 0,
The BSR is ignored and the
Access Bank is used.
= 1111
00h
Unused
FFh
SFR
Bank 15
EFFh
F00h
F7Fh
F80h
FFFh
The first 128 bytes are
General Purpose RAM
(from Bank 0).
The second 128 bytes are
Special Function Registers
(from Bank 15).
When a = 1,
The BSR specifies the Bank
used by the instruction.
DS30009605G-page 46
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
5.9.2
SPECIAL FUNCTION REGISTERS
The Special Function Registers (SFRs) are registers
used by the CPU and peripheral modules for controlling
the desired operation of the device. These registers are
implemented as static RAM. A list of these registers is
given in Table 5-1 and Table 5-2.
The SFRs can be classified into two sets: those associated with the “core” function and those related to the
peripheral functions. Those registers related to the
“core” are described in this section, while those related
to the operation of the peripheral features are
described in the section of that peripheral feature.
The SFRs are typically distributed among the peripherals
whose functions they control.
The unused SFR locations will be unimplemented and
read as ‘0’s.
TABLE 5-1:
Address
SPECIAL FUNCTION REGISTER MAP FOR PIC18F1220/1320 DEVICES
Name
Address
Name
FFFh
TOSU
FDFh
INDF2(2)
FFEh
TOSH
FDEh
POSTINC2(2)
FFDh
TOSL
FDDh POSTDEC2(2)
FFCh
STKPTR
Address
Name
Address
Name
FBFh
CCPR1H
F9Fh
IPR1
FBEh
CCPR1L
F9Eh
PIR1
FBDh
CCP1CON
F9Dh
PIE1
FDCh
PREINC2(2)
FBCh
—
F9Ch
—
FFBh
PCLATU
FDBh
PLUSW2(2)
FBBh
—
F9Bh
OSCTUNE
FFAh
PCLATH
FDAh
FSR2H
FBAh
—
F9Ah
—
FF9h
PCL
FD9h
FSR2L
FB9h
—
F99h
—
FF8h
TBLPTRU
FD8h
STATUS
FB8h
—
F98h
—
FF7h
TBLPTRH
FD7h
TMR0H
FB7h
PWM1CON
F97h
—
FF6h
TBLPTRL
FD6h
TMR0L
FB6h
ECCPAS
F96h
—
FF5h
TABLAT
FD5h
T0CON
FB5h
—
F95h
—
FF4h
PRODH
FD4h
—
FB4h
—
F94h
—
FF3h
PRODL
FD3h
OSCCON
FB3h
TMR3H
F93h
TRISB
FF2h
INTCON
FD2h
LVDCON
FB2h
TMR3L
F92h
TRISA
FF1h
INTCON2
FD1h
WDTCON
FB1h
T3CON
F91h
—
FF0h
INTCON3
FD0h
RCON
FB0h
SPBRGH
F90h
—
FEFh
FEEh
INDF0
(2)
POSTINC0(2)
FEDh POSTDEC0(2)
FCFh
TMR1H
FAFh
SPBRG
F8Fh
—
FCEh
TMR1L
FAEh
RCREG
F8Eh
—
FCDh
T1CON
FADh
TXREG
F8Dh
—
FCCh
TMR2
FACh
TXSTA
F8Ch
—
FECh
PREINC0(2)
FEBh
PLUSW0(2)
FCBh
PR2
FABh
RCSTA
F8Bh
—
FEAh
FSR0H
FCAh
T2CON
FAAh
BAUDCTL
F8Ah
LATB
FE9h
FSR0L
FC9h
—
FA9h
EEADR
F89h
LATA
FE8h
WREG
FC8h
—
FA8h
EEDATA
F88h
—
FC7h
—
FA7h
EECON2
F87h
—
FC6h
—
FA6h
EECON1
F86h
—
FC5h
—
FA5h
—
F85h
—
FC4h
ADRESH
FA4h
—
F84h
—
FE7h
FE6h
INDF1
(2)
POSTINC1(2)
(2)
FE5h POSTDEC1
FE4h
PREINC1(2)
FE3h
PLUSW1(2)
FC3h
ADRESL
FA3h
—
F83h
—
FE2h
FSR1H
FC2h
ADCON0
FA2h
IPR2
F82h
—
FE1h
FSR1L
FC1h
ADCON1
FA1h
PIR2
F81h
PORTB
FE0h
BSR
FC0h
ADCON2
FA0h
PIE2
F80h
PORTA
Note 1:
2:
Unimplemented registers are read as ‘0’.
This is not a physical register.
2002-2015 Microchip Technology Inc.
DS30009605G-page 47
PIC18F1220/1320
TABLE 5-2:
File Name
REGISTER FILE SUMMARY (PIC18F1220/1320)
Bit 7
Bit 6
Bit 5
—
—
—
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Details on
Page:
---0 0000
34, 40
TOSH
Top-of-Stack High Byte (TOS)
0000 0000
34, 40
TOSL
Top-of-Stack Low Byte (TOS)
0000 0000
34, 40
Return Stack Pointer
00-0 0000
34, 41
Holding Register for PC
TOSU
STKPTR
PCLATU
STKFUL
STKUNF
—
—
—
bit 21(3)
Top-of-Stack Upper Byte (TOS)
Value on
POR, BOR
---0 0000
34, 42
PCLATH
Holding Register for PC
0000 0000
34, 42
PCL
PC Low Byte (PC)
0000 0000
34, 42
--00 0000
34, 58
TBLPTRU
—
—
bit 21
Program Memory Table Pointer Upper Byte (TBLPTR)
TBLPTRH
Program Memory Table Pointer High Byte (TBLPTR)
0000 0000
34, 58
TBLPTRL
Program Memory Table Pointer Low Byte (TBLPTR)
0000 0000
34, 58
TABLAT
Program Memory Table Latch
0000 0000
34, 58
PRODH
Product Register High Byte
xxxx xxxx
34, 68
PRODL
Product Register Low Byte
xxxx xxxx
34, 68
RBIF
0000 000x
34, 72
34, 73
INTCON
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INTCON2
RBPU
INTEDG0
INTEDG1
INTCON3
INT2IP
INT1IP
—
INTEDG2
—
TMR0IP
—
RBIP
1111 -1-1
INT2IE
INT1IE
—
INT2IF
INT1IF
11-0 0-00
34, 74
Uses contents of FSR0 to address data memory – value of FSR0 not changed (not a physical register)
N/A
34, 51
POSTINC0
Uses contents of FSR0 to address data memory – value of FSR0 post-incremented (not a physical register)
N/A
34, 51
POSTDEC0
Uses contents of FSR0 to address data memory– value of FSR0 post-decremented (not a physical register)
N/A
34, 51
PREINC0
Uses contents of FSR0 to address data memory – value of FSR0 pre-incremented (not a physical register)
N/A
34, 51
PLUSW0
Uses contents of FSR0 to address data memory – value of FSR0 offset by W (not a physical register)
INDF0
FSR0H
—
—
—
—
INT0IF
Indirect Data Memory Address Pointer 0 High
N/A
34, 51
---- 0000
34, 51
34, 51
FSR0L
Indirect Data Memory Address Pointer 0 Low Byte
xxxx xxxx
WREG
Working Register
xxxx xxxx
34
INDF1
Uses contents of FSR1 to address data memory – value of FSR1 not changed (not a physical register)
N/A
34, 51
POSTINC1
Uses contents of FSR1 to address data memory – value of FSR1 post-incremented (not a physical register)
N/A
34, 51
POSTDEC1
Uses contents of FSR1 to address data memory – value of FSR1 post-decremented (not a physical register)
N/A
34, 51
PREINC1
Uses contents of FSR1 to address data memory – value of FSR1 pre-incremented (not a physical register)
N/A
34, 51
PLUSW1
Uses contents of FSR1 to address data memory – value of FSR1 offset by W (not a physical register)
N/A
34, 51
---- 0000
34, 51
FSR1H
FSR1L
BSR
—
—
—
—
Indirect Data Memory Address Pointer 1 High
Indirect Data Memory Address Pointer 1 Low Byte
—
—
—
—
Bank Select Register
xxxx xxxx
34, 51
---- 0000
35, 50
35, 51
INDF2
Uses contents of FSR2 to address data memory – value of FSR2 not changed (not a physical register)
N/A
POSTINC2
Uses contents of FSR2 to address data memory – value of FSR2 post-incremented (not a physical register)
N/A
35, 51
POSTDEC2
Uses contents of FSR2 to address data memory – value of FSR2 post-decremented (not a physical register)
N/A
35, 51
PREINC2
Uses contents of FSR2 to address data memory – value of FSR2 pre-incremented (not a physical register)
N/A
35, 51
PLUSW2
Uses contents of FSR2 to address data memory – value of FSR2 offset by W (not a physical register)
N/A
35, 51
---- 0000
35, 51
FSR2H
FSR2L
STATUS
—
—
—
—
Indirect Data Memory Address Pointer 2 High
Indirect Data Memory Address Pointer 2 Low Byte
—
—
—
N
OV
Z
DC
C
xxxx xxxx
35, 51
---x xxxx
35, 53
TMR0H
Timer0 Register High Byte
0000 0000
35, 97
TMR0L
Timer0 Register Low Byte
xxxx xxxx
35, 97
35, 95
T0CON
TMR0ON
T08BIT
T0CS
T0SE
PSA
T0PS2
T0PS1
T0PS0
1111 1111
OSCCON
IDLEN
IRCF2
IRCF1
IRCF0
OSTS
IOFS
SCS1
SCS0
0000 q000
35, 16
LVDCON
—
—
IVRST
LVDEN
LVDL3
LVDL2
LVDL1
LVDL0
--00 0101
35, 162
—
—
—
—
—
—
—
SWDTEN
--- ---0
35, 174
IPEN
—
—
RI
TO
PD
POR
BOR
0--1 11q0
33, 54, 81
WDTCON
RCON
Legend: x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
Note 1:RA6 and associated bits are configured as port pins in RCIO, ECIO and INTIO2 (with port function on RA6) Oscillator mode only and read ‘0’ in
all other oscillator modes.
2: RA7 and associated bits are configured as port pins in INTIO2 Oscillator mode only and read ‘0’ in all other modes.
3: Bit 21 of the PC is only available in Test mode and Serial Programming modes.
4: The RA5 port bit is only available when MCLRE fuse (CONFIG3H) is programmed to ‘0’. Otherwise, RA5 reads ‘0’. This bit is read-only.
DS30009605G-page 48
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 5-2:
File Name
REGISTER FILE SUMMARY (PIC18F1220/1320) (CONTINUED)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Details on
Page:
TMR1H
Timer1 Register High Byte
xxxx xxxx
35, 103
TMR1L
Timer1 Register Low Byte
xxxx xxxx
35, 103
T1CON
RD16
T1RUN
TMR2
Timer2 Register
PR2
Timer2 Period Register
T2CON
—
TOUTPS3
T1CKPS1
T1CKPS0
TOUTPS2
TOUTPS1
T1OSCEN
TOUTPS0
T1SYNC
TMR2ON
TMR1CS
T2CKPS1
TMR1ON
T2CKPS0
0000 0000
35, 98
0000 0000
35, 104
1111 1111
35, 104
-000 0000
35, 104
35, 159
ADRESH
A/D Result Register High Byte
xxxx xxxx
ADRESL
A/D Result Register Low Byte
xxxx xxxx
35, 159
00-0 0000
35, 150
ADCON0
VCFG1
VCFG0
ADCON1
—
ADCON2
ADFM
—
CHS2
CHS1
CHS0
GO/DONE
ADON
PCFG6
PCFG5
PCFG4
PCFG3
PCFG2
PCFG1
PCFG0
-000 0000
35, 151
—
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
0-00 0000
35, 152
35. 110
CCPR1H
Capture/Compare/PWM Register 1 High Byte
xxxx xxxx
CCPR1L
Capture/Compare/PWM Register 1 Low Byte
xxxx xxxx
35, 110
CCP1M0
0000 0000
35, 109
CCP1CON
PWM1CON
ECCPAS
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
PRSEN
PDC6
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
0000 0000
35, 121
ECCPASE
ECCPAS2
ECCPAS1
ECCPAS0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
0000 0000
35, 122
36, 108
TMR3H
Timer3 Register High Byte
xxxx xxxx
TMR3L
Timer3 Register Low Byte
xxxx xxxx
36, 108
0-00 0000
36, 106
T3CON
RD16
—
T3CKPS1
T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
SPBRGH
EUSART Baud Rate Generator High Byte
0000 0000
36
SPBRG
EUSART Baud Rate Generator Low Byte
0000 0000
36, 130
RCREG
EUSART Receive Register
0000 0000
36, 138,
137
TXREG
EUSART Transmit Register
0000 0000
36, 135,
137
36, 127
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
36, 128
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
36, 129
36, 64
BAUDCTL
EEADR
EEPROM Address Register
0000 0000
EEDATA
EEPROM Data Register
0000 0000
36, 67
EECON2
EEPROM Control Register 2 (not a physical register)
0000 0000
36, 56, 64
EECON1
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
RD
xx-0 x000
36, 57, 65
IPR2
OSCFIP
—
—
EEIP
—
LVDIP
TMR3IP
—
1--1 -11-
36, 80
PIR2
OSCFIF
—
—
EEIF
—
LVDIF
TMR3IF
—
0--0 -00-
36, 76
PIE2
OSCFIE
—
—
EEIE
—
LVDIE
TMR3IE
—
0--0 -00-
36, 78
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
36, 79
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
36, 75
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
36, 77
OSCTUNE
—
—
TUN5
TUN4
TUN3
TUN2
TUN1
TUN0
--00 0000
36, 14
TRISB
TRISA
Data Direction Control Register for PORTB
TRISA7(2)
TRISA6(1)
Data Direction Control Register for PORTA
11-1 1111
xxxx xxxx
36, 94
—
Read/Write PORTA Data Latch
xx-x xxxx
36, 85
Read/Write PORTB Data Latch
LATA
LATA(2) LATA(1)
PORTB
Read PORTB pins, Write PORTB Data Latch
RA7(2)
RA6(1)
36, 94
36, 85
—
LATB
PORTA
1111 1111
RA5(4)
Read PORTA pins, Write PORTA Data Latch
xxxx xxxx
36, 94
xx0x 0000
36, 85
Legend: x = unknown, u = unchanged, – = unimplemented, q = value depends on condition
Note 1:RA6 and associated bits are configured as port pins in RCIO, ECIO and INTIO2 (with port function on RA6) Oscillator mode only and read ‘0’ in
all other oscillator modes.
2: RA7 and associated bits are configured as port pins in INTIO2 Oscillator mode only and read ‘0’ in all other modes.
3: Bit 21 of the PC is only available in Test mode and Serial Programming modes.
4: The RA5 port bit is only available when MCLRE fuse (CONFIG3H) is programmed to ‘0’. Otherwise, RA5 reads ‘0’. This bit is read-only.
2002-2015 Microchip Technology Inc.
DS30009605G-page 49
PIC18F1220/1320
5.10
Access Bank
5.11
The Access Bank is an architectural enhancement
which is very useful for C compiler code optimization.
The techniques used by the C compiler may also be
useful for programs written in assembly.
The need for a large general purpose memory space
dictates a RAM banking scheme. The data memory is
partitioned into as many as sixteen banks. When using
direct addressing, the BSR should be configured for the
desired bank.
This data memory region can be used for:
•
•
•
•
•
BSR holds the upper four bits of the 12-bit RAM
address. The BSR bits will always read ‘0’s and
writes will have no effect (see Figure 5-7).
Intermediate computational values
Local variables of subroutines
Faster context saving/switching of variables
Common variables
Faster evaluation/control of SFRs (no banking)
A MOVLB instruction has been provided in the instruction
set to assist in selecting banks.
If the currently selected bank is not implemented, any
read will return all ‘0’s and all writes are ignored. The
Status register bits will be set/cleared as appropriate for
the instruction performed.
The Access Bank is comprised of the last 128 bytes in
Bank 15 (SFRs) and the first 128 bytes in Bank 0.
These two sections will be referred to as Access RAM
High and Access RAM Low, respectively. Figure 5-6
indicates the Access RAM areas.
Each Bank extends up to FFh (256 bytes). All data
memory is implemented as static RAM.
A bit in the instruction word specifies if the operation is
to occur in the bank specified by the BSR register or in
the Access Bank. This bit is denoted as the ‘a’ bit (for
access bit).
A MOVFF instruction ignores the BSR, since the 12-bit
addresses are embedded into the instruction word.
Section 5.12 “Indirect Addressing, INDF and FSR
Registers” provides a description of indirect addressing, which allows linear addressing of the entire RAM
space.
When forced in the Access Bank (a = 0), the last
address in Access RAM Low is followed by the first
address in Access RAM High. Access RAM High maps
the Special Function Registers, so these registers can
be accessed without any software overhead. This is
useful for testing status flags and modifying control bits.
FIGURE 5-7:
Bank Select Register (BSR)
DIRECT ADDRESSING
Direct Addressing
BSR
0
0
0
BSR
7
From Opcode(3)
0
0
Bank Select(2)
Location Select(3)
00h
01h
0Eh
0Fh
000h
100h
E00h
F00h
0FFh
1FFh
EFFh
FFFh
Bank 14
Bank 15
Data
Memory(1)
Bank 0
Bank 1
Note 1: For register file map detail, see Table 5-1.
2: The access bit of the instruction can be used to force an override of the selected bank (BSR) to the registers
of the Access Bank.
3: The MOVFF instruction embeds the entire 12-bit address in the instruction.
DS30009605G-page 50
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
5.12
Indirect Addressing, INDF and
FSR Registers
Indirect addressing is a mode of addressing data memory, where the data memory address in the instruction
is not fixed. An FSR register is used as a pointer to the
data memory location that is to be read or written. Since
this pointer is in RAM, the contents can be modified by
the program. This can be useful for data tables in the
data memory and for software stacks. Figure 5-8
shows how the fetched instruction is modified prior to
being executed.
Indirect addressing is possible by using one of the
INDF registers. Any instruction, using the INDF register, actually accesses the register pointed to by the File
Select Register, FSR. Reading the INDF register itself,
indirectly (FSR = 0), will read 00h. Writing to the INDF
register indirectly, results in a no operation (NOP). The
FSR register contains a 12-bit address, which is shown
in Figure 5-9.
The INDFn register is not a physical register. Addressing INDFn actually addresses the register whose
address is contained in the FSRn register (FSRn is a
pointer). This is indirect addressing.
Example 5-5 shows a simple use of indirect addressing
to clear the RAM in Bank 1 (locations 100h-1FFh) in a
minimum number of instructions.
EXAMPLE 5-5:
NEXT
HOW TO CLEAR RAM
(BANK 1) USING
INDIRECT ADDRESSING
LFSR
CLRF
FSR0,0x100
POSTINC0
BTFSS
FSR0H, 1
GOTO
CONTINUE
NEXT
;
;
;
;
;
;
;
;
Clear INDF
register then
inc pointer
All done with
Bank1?
NO, clear next
YES, continue
There are three indirect addressing registers. To
address the entire data memory space (4096 bytes),
these registers are 12-bit wide. To store the 12 bits of
addressing information, two 8-bit registers are required:
1.
2.
3.
FSR0: composed of FSR0H:FSR0L
FSR1: composed of FSR1H:FSR1L
FSR2: composed of FSR2H:FSR2L
In addition, there are registers INDF0, INDF1 and
INDF2, which are not physically implemented. Reading
or writing to these registers activates indirect addressing, with the value in the corresponding FSR register
being the address of the data. If an instruction writes a
value to INDF0, the value will be written to the address
pointed to by FSR0H:FSR0L. A read from INDF1 reads
the data from the address pointed to by
FSR1H:FSR1L. INDFn can be used in code anywhere
an operand can be used.
2002-2015 Microchip Technology Inc.
If INDF0, INDF1 or INDF2 are read indirectly via an
FSR, all ‘0’s are read (zero bit is set). Similarly, if
INDF0, INDF1 or INDF2 are written to indirectly, the
operation will be equivalent to a NOP instruction and the
Status bits are not affected.
5.12.1
INDIRECT ADDRESSING
OPERATION
Each FSR register has an INDF register associated with
it, plus four additional register addresses. Performing an
operation using one of these five registers determines
how the FSR will be modified during indirect addressing.
When data access is performed using one of the five
INDFn locations, the address selected will configure
the FSRn register to:
• Do nothing to FSRn after an indirect access (no
change) – INDFn
• Auto-decrement FSRn after an indirect access
(post-decrement) – POSTDECn
• Auto-increment FSRn after an indirect access
(post-increment) – POSTINCn
• Auto-increment FSRn before an indirect access
(pre-increment) – PREINCn
• Use the value in the WREG register as an offset
to FSRn. Do not modify the value of the WREG or
the FSRn register after an indirect access (no
change) – PLUSWn
When using the auto-increment or auto-decrement
features, the effect on the FSR is not reflected in the
Status register. For example, if the indirect address
causes the FSR to equal ‘0’, the Z bit will not be set.
Auto-incrementing or auto-decrementing an FSR affects
all 12 bits. That is, when FSRnL overflows from an
increment, FSRnH will be incremented automatically.
Adding these features allows the FSRn to be used as a
stack pointer, in addition to its uses for table operations
in data memory.
Each FSR has an address associated with it that
performs an indexed indirect access. When a data
access to this INDFn location (PLUSWn) occurs, the
FSRn is configured to add the signed value in the
WREG register and the value in FSR to form the
address before an indirect access. The FSR value is
not changed. The WREG offset range is -128 to +127.
If an FSR register contains a value that points to one of
the INDFn, an indirect read will read 00h (zero bit is
set), while an indirect write will be equivalent to a NOP
(Status bits are not affected).
If an indirect addressing write is performed when the target address is an FSRnH or FSRnL register, the data is
written to the FSR register, but no pre- or post-increment/
decrement is performed.
DS30009605G-page 51
PIC18F1220/1320
FIGURE 5-8:
INDIRECT ADDRESSING OPERATION
RAM
0h
Instruction
Executed
Opcode
Address
FFFh
12
File Address = Access of an Indirect Addressing Register
BSR
Instruction
Fetched
4
12
8
Opcode
FIGURE 5-9:
12
File
FSR
INDIRECT ADDRESSING
Indirect Addressing
FSRnH:FSRnL
3
0
7
0
11
0
Location Select
0000h
Data
Memory(1)
0FFFh
Note 1: For register file map detail, see Table 5-1.
DS30009605G-page 52
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
5.13
Status Register
The STATUS register, shown in Register 5-2, contains
the arithmetic status of the ALU. As with any other SFR,
it can be the operand for any instruction.
If the STATUS register is the destination for an instruction that affects the Z, DC, C, OV or N bits, the results
of the instruction are not written; instead, the status is
updated according to the instruction performed. Therefore, the result of an instruction with the STATUS
register as its destination may be different than
REGISTER 5-2:
intended. As an example, CLRF STATUS will set the Z
bit and leave the remaining Status bits unchanged
(‘000u u1uu’).
It is recommended that only BCF, BSF, SWAPF, MOVFF
and MOVWF instructions are used to alter the STATUS
register, because these instructions do not affect the Z,
C, DC, OV or N bits in the STATUS register.
For other instructions that do not affect Status bits, see
the instruction set summaries in Table 20-1.
Note:
The C and DC bits operate as the borrow
and digit borrow bits, respectively, in
subtraction.
STATUS: STATUS REGISTER
U-0
U-0
U-0
R-1/q
R-1/q
R/W-0/u
R/W-0/u
R/W-0/u
—
—
—
N
OV
Z
DC
C
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7-5
Unimplemented: Read as ‘0’
bit 4
N: Negative bit
This bit is used for signed arithmetic (2’s complement). It indicates whether the result was
negative (ALU MSB = 1).
1 = Result was negative
0 = Result was positive
bit 3
OV: Overflow bit
This bit is used for signed arithmetic (2’s complement). It indicates an overflow of the
7-bit magnitude, which causes the sign bit (bit 7) to change state.
1 = Overflow occurred for signed arithmetic (in this arithmetic operation)
0 = No overflow occurred
bit 2
Z: Zero bit
1 = The result of an arithmetic or logic operation is zero
0 = The result of an arithmetic or logic operation is not zero
bit 1
DC: Digit Carry/Digit Borrow bit (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1)
1 = A carry-out from the 4th low-order bit of the result occurred
0 = No carry-out from the 4th low-order bit of the result
bit 0
C: Carry/Borrow bit(1) (ADDWF, ADDLW, SUBLW, SUBWF instructions)(1)
1 = A carry-out from the Most Significant bit of the result occurred
0 = No carry-out from the Most Significant bit of the result occurred
Note 1:
For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order
bit of the source register.
2002-2015 Microchip Technology Inc.
DS30009605G-page 53
PIC18F1220/1320
5.14
RCON Register
The Reset Control (RCON) register contains flag bits
that allow differentiation between the sources of a
device Reset. These flags include the TO, PD, POR,
BOR and RI bits. This register is readable and writable.
Note 1: If the BOR Configuration bit is set
(Brown-out Reset enabled), the BOR bit
is ‘1’ on a Power-on Reset. After a
Brown-out Reset has occurred, the BOR
bit will be cleared and must be set by
firmware to indicate the occurrence of the
next Brown-out Reset.
2: It is recommended that the POR bit be
set after a Power-on Reset has been
detected, so that subsequent Power-on
Resets may be detected.
REGISTER 5-3:
RCON: RESET CONTROL REGISTER
R/W-0
U-0
U-0
R/W-1
R-1
R-1
R/W-0
R/W-0
IPEN
—
—
RI
TO
PD
POR
BOR
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
q = Value depends on condition
bit 7
IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (PIC16CXXX Compatibility mode)
bit 6-5
Unimplemented: Read as ‘0’
bit 4
RI: RESET Instruction Flag bit
1 = The RESET instruction was not executed (set by firmware only)
0 = The RESET instruction was executed causing a device Reset
(must be set in software after a Brown-out Reset occurs)
bit 3
TO: Watchdog Time-out Flag bit
1 = Set by power-up, CLRWDT instruction or SLEEP instruction
0 = A WDT time-out occurred
bit 2
PD: Power-down Detection Flag bit
1 = Set by power-up or by the CLRWDT instruction
0 = Cleared by execution of the SLEEP instruction
bit 1
POR: Power-on Reset Status bit
1 = A Power-on Reset has not occurred (set by firmware only)
0 = A Power-on Reset occurred (must be set in software after a Power-on Reset occurs)
bit 0
BOR: Brown-out Reset Status bit
1 = A Brown-out Reset has not occurred (set by firmware only)
0 = A Brown-out Reset occurred (must be set in software after a Brown-out Reset occurs)
Note 1:
For Borrow, the polarity is reversed. A subtraction is executed by adding the two’s complement of the
second operand. For rotate (RRF, RLF) instructions, this bit is loaded with either the high-order or low-order
bit of the source register.
DS30009605G-page 54
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PIC18F1220/1320
6.0
FLASH PROGRAM MEMORY
The program memory space is 16 bits wide, while the
data RAM space is eight bits wide. Table reads and
table writes move data between these two memory
spaces through an 8-bit register (TABLAT).
The Flash program memory is readable, writable and
erasable during normal operation over the entire VDD
range.
Table read operations retrieve data from program
memory and place it into TABLAT in the data RAM
space. Figure 6-1 shows the operation of a table read
with program memory and data RAM.
A read from program memory is executed on one byte
at a time. A write to program memory is executed on
blocks of 8 bytes at a time. Program memory is erased
in blocks of 64 bytes at a time. A “Bulk Erase” operation
may not be issued from user code.
Table write operations store data from TABLAT in the
data memory space into holding registers in program
memory. The procedure to write the contents of the
holding registers into program memory is detailed in
Section 6.5 “Writing to Flash Program Memory”.
Figure 6-2 shows the operation of a table write with
program memory and data RAM.
While writing or erasing program memory, instruction
fetches cease until the operation is complete. The
program memory cannot be accessed during the write
or erase, therefore, code cannot execute. An internal
programming timer terminates program memory writes
and erases.
Table operations work with byte entities. A table block
containing data, rather than program instructions, is not
required to be word aligned. Therefore, a table block
can start and end at any byte address. If a table write is
being used to write executable code into program
memory, program instructions will need to be word
aligned (TBLPTRL = 0).
A value written to program memory does not need to be
a valid instruction. Executing a program memory
location that forms an invalid instruction results in a
NOP.
6.1
Table Reads and Table Writes
The EEPROM on-chip timer controls the write and
erase times. The write and erase voltages are generated by an on-chip charge pump rated to operate over
the voltage range of the device for byte or word
operations.
In order to read and write program memory, there are
two operations that allow the processor to move bytes
between the program memory space and the data
RAM:
• Table Read (TBLRD)
• Table Write (TBLWT)
FIGURE 6-1:
TABLE READ OPERATION
Instruction: TBLRD*
Program Memory
Table Pointer(1)
TBLPTRU
TBLPTRH
Table Latch (8-bit)
TBLPTRL
TABLAT
Program Memory
(TBLPTR)
Note 1: Table Pointer points to a byte in program memory.
2002-2015 Microchip Technology Inc.
DS30009605G-page 55
PIC18F1220/1320
FIGURE 6-2:
TABLE WRITE OPERATION
Instruction: TBLWT*
Program Memory
Holding Registers
Table Pointer(1)
TBLPTRU
TBLPTRH
Table Latch (8-bit)
TBLPTRL
TABLAT
Program Memory
(TBLPTR)
Note 1: Table Pointer actually points to one of eight holding registers, the address of which is determined by
TBLPTRL. The process for physically writing data to the program memory array is discussed
in Section 6.5 “Writing to Flash Program Memory”.
6.2
Control Registers
Several control registers are used in conjunction with
the TBLRD and TBLWT instructions. These include the:
•
•
•
•
EECON1 register
EECON2 register
TABLAT register
TBLPTR registers
6.2.1
EECON1 AND EECON2 REGISTERS
EECON1 is the control register for memory accesses.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the memory write and erase sequences.
Control bit, EEPGD, determines if the access will be to
program or data EEPROM memory. When clear,
operations will access the data EEPROM memory.
When set, program memory is accessed.
Control bit, CFGS, determines if the access will be to
the Configuration registers, or to program memory/data
EEPROM memory. When set, subsequent operations
access Configuration registers. When CFGS is clear,
the EEPGD bit selects either program Flash or data
EEPROM memory.
The FREE bit controls program memory erase operations. When the FREE bit is set, the erase operation is
initiated on the next WR command. When FREE is
clear, only writes are enabled.
DS30009605G-page 56
The WREN bit enables and disables erase and write
operations. When set, erase and write operations are
allowed. When clear, erase and write operations are
disabled – the WR bit cannot be set while the WREN bit
is clear. This process helps to prevent accidental writes
to memory due to errant (unexpected) code execution.
Firmware should keep the WREN bit clear at all times,
except when starting erase or write operations. Once
firmware has set the WR bit, the WREN bit may be
cleared. Clearing the WREN bit will not affect the
operation in progress.
The WRERR bit is set when a write operation is
interrupted by a Reset. In these situations, the user can
check the WRERR bit and rewrite the location. It will be
necessary to reload the data and address registers
(EEDATA and EEADR) as these registers have cleared
as a result of the Reset.
Control bits, RD and WR, start read and erase/write
operations, respectively. These bits are set by firmware
and cleared by hardware at the completion of the
operation.
The RD bit cannot be set when accessing program
memory (EEPGD = 1). Program memory is read using
table read instructions. See Section 6.3 “Reading the
Flash Program Memory” regarding table reads.
Note:
Interrupt flag bit, EEIF in the PIR2 register,
is set when the write is complete. It must
be cleared in software.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 6-1:
R/W-x
EECON1: EEPROM CONTROL 1 REGISTER
R/W-x
EEPGD
U-0
CFGS
R/W-0
—
FREE
R/W-x
(1)
WRERR
R/W-0
R/S-0
R/S-0
WREN
WR
RD
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
S = Bit can only be set
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
HC = Bit is cleared by hardware
bit 7
EEPGD: Flash Program or Data EEPROM Memory Select bit
1 = Access program Flash memory
0 = Access data EEPROM memory
bit 6
CFGS: Flash Program/Data EEPROM or Configuration Select bit
1 = Accesses Configuration, User ID and Device ID Registers
0 = Accesses Flash Program or data EEPROM Memory
bit 5
Unimplemented: Read as ‘0’
bit 4
FREE: Flash Row Erase Enable bit
1 = Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation – TBLPTR are ignored)
0 = Perform write only
bit 3
WRERR: EEPROM Error Flag bit(1)
1 = A write operation was prematurely terminated (any Reset during self-timed programming)
0 = The write operation completed normally
bit 2
WREN: Program/Erase Enable bit
1 = Allows program/erase cycles
0 = Inhibits programming/erasing of program Flash and data EEPROM
bit 1
WR: Write Control bit
1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write cycle.
(The operation is self-timed and the bit is cleared by hardware once write is complete. The WR
bit can only be set (not cleared) in software.)
0 = Write cycle completed
bit 0
RD: Read Control bit
1 = Initiates a memory read
(Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared) in
software. RD bit cannot be set when EEPGD = 1.)
0 = Read completed
Note 1:
When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows
tracing of the error condition.
2002-2015 Microchip Technology Inc.
DS30009605G-page 57
PIC18F1220/1320
6.2.2
TABLAT – TABLE LATCH REGISTER
6.2.4
The Table Latch (TABLAT) is an 8-bit register mapped
into the SFR space. The table latch is used to hold 8-bit
data during data transfers between program memory
and data RAM.
6.2.3
TBLPTR is used in reads, writes and erases of the
Flash program memory.
When a TBLRD is executed, all 22 bits of the Table
Pointer determine which byte is read from program or
configuration memory into TABLAT.
TBLPTR – TABLE POINTER
REGISTER
When a TBLWT is executed, the three LSbs of the Table
Pointer (TBLPTR) determine which of the eight
program memory holding registers is written to. When
the timed write to program memory (long write) begins,
the 19 MSbs of the Table Pointer (TBLPTR) will
determine which program memory block of 8 bytes is
written to (TBLPTR are ignored). For more detail,
see Section 6.5 “Writing to Flash Program Memory”.
The Table Pointer (TBLPTR) addresses a byte within
the program memory. The TBLPTR is comprised of
three SFR registers: Table Pointer Upper Byte, Table
Pointer High Byte and Table Pointer Low Byte
(TBLPTRU:TBLPTRH:TBLPTRL). These three registers join to form a 22-bit wide pointer. The low-order
21 bits allow the device to address up to 2 Mbytes of
program memory space. Setting the 22nd bit allows
access to the device ID, the user ID and the
configuration bits.
When an erase of program memory is executed, the
16 MSbs of the Table Pointer (TBLPTR) point to
the 64-byte block that will be erased. The Least
Significant bits (TBLPTR) are ignored.
The Table Pointer (TBLPTR) register is used by the
TBLRD and TBLWT instructions. These instructions can
update the TBLPTR in one of four ways based on the
table operation. These operations are shown in
Table 6-1. These operations on the TBLPTR only affect
the low-order 21 bits.
TABLE 6-1:
TABLE POINTER BOUNDARIES
Figure 6-3 describes the relevant boundaries of
TBLPTR based on Flash program memory operations.
TABLE POINTER OPERATIONS WITH TBLRD AND TBLWT INSTRUCTIONS
Example
Operation on Table Pointer
TBLRD*
TBLWT*
TBLPTR is not modified
TBLRD*+
TBLWT*+
TBLPTR is incremented after the read/write
TBLRD*TBLWT*-
TBLPTR is decremented after the read/write
TBLRD+*
TBLWT+*
TBLPTR is incremented before the read/write
FIGURE 6-3:
21
TABLE POINTER BOUNDARIES BASED ON OPERATION
TBLPTRU
16
15
TBLPTRH
8
7
TBLPTRL
0
ERASE – TBLPTR
LONG WRITE – TBLPTR
READ or WRITE – TBLPTR
DS30009605G-page 58
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PIC18F1220/1320
6.3
Reading the Flash Program
Memory
The TBLRD instruction is used to retrieve data from
program memory and place it into data RAM. Table
reads from program memory are performed one byte at
a time.
The internal program memory is typically organized by
words. The Least Significant bit of the address selects
between the high and low bytes of the word. Figure 6-4
shows the interface between the internal program
memory and the TABLAT.
TBLPTR points to a byte address in program space.
Executing a TBLRD instruction places the byte pointed
to into TABLAT. In addition, TBLPTR can be modified
automatically for the next table read operation.
FIGURE 6-4:
READS FROM FLASH PROGRAM MEMORY
Program Memory
Odd (High) Byte
Even (Low) Byte
TBLPTR
LSB = 0
TBLPTR
LSB = 1
Instruction Register
(IR)
EXAMPLE 6-1:
TABLAT
Read Register
READING A FLASH PROGRAM MEMORY WORD
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
; Load TBLPTR with the base
; address of the word
READ_WORD
TBLRD*+
MOVFW
MOVWF
TBLRD*+
MOVFW
MOVWF
TABLAT
WORD_EVEN
TABLAT
WORD_ODD
2002-2015 Microchip Technology Inc.
; read into TABLAT and increment TBLPTR
; get data
; read into TABLAT and increment TBLPTR
; get data
DS30009605G-page 59
PIC18F1220/1320
6.4
6.4.1
Erasing Flash Program Memory
The minimum erase block size is 32 words or 64 bytes
under firmware control. Only through the use of an
external programmer, or through ICSP control, can
larger blocks of program memory be bulk erased. Word
erase in Flash memory is not supported.
FLASH PROGRAM MEMORY
ERASE SEQUENCE
The sequence of events for erasing a block of internal
program memory location is:
1.
When initiating an erase sequence from the microcontroller itself, a block of 64 bytes of program memory
is erased. The Most Significant 16 bits of the
TBLPTR point to the block being erased.
TBLPTR are ignored.
2.
The EECON1 register commands the erase operation.
The EEPGD bit must be set to point to the Flash
program memory. The CFGS bit must be clear to
access program Flash and data EEPROM memory.
The WREN bit must be set to enable write operations.
The FREE bit is set to select an erase operation. The
WR bit is set as part of the required instruction
sequence (as shown in Example 6-2) and starts the
actual erase operation. It is not necessary to load the
TABLAT register with any data as it is ignored.
3.
4.
5.
6.
7.
8.
9.
For protection, the write initiate sequence using
EECON2 must be used.
Load Table Pointer with address of row being
erased.
Set the EECON1 register for the erase operation:
•set EEPGD bit to point to program memory;
•clear the CFGS bit to access program
memory;
•set WREN bit to enable writes;
•set FREE bit to enable the erase.
Disable interrupts.
Write 55h to EECON2.
Write AAh to EECON2.
Set the WR bit. This will begin the row erase
cycle.
The CPU will stall for duration of the erase
(about 2 ms using internal timer).
Execute a NOP.
Re-enable interrupts.
A long write is necessary for erasing the internal Flash.
Instruction execution is halted while in a long write
cycle. The long write will be terminated by the internal
programming timer.
EXAMPLE 6-2:
ERASING A FLASH PROGRAM MEMORY ROW
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
; load TBLPTR with the base
; address of the memory block
BSF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
BSF
EECON1,
EECON1,
EECON1,
INTCON,
55h
EECON2
AAh
EECON2
EECON1,
;
;
;
;
ERASE_ROW
Required
Sequence
DS30009605G-page 60
EEPGD
WREN
FREE
GIE
point to FLASH program memory
enable write to memory
enable Row Erase operation
disable interrupts
; write 55H
WR
INTCON, GIE
; write AAH
; start erase (CPU stall)
; re-enable interrupts
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
6.5
Writing to Flash Program Memory
The programming block size is 4 words or 8 bytes.
Word or byte programming is not supported.
Table writes are used internally to load the holding
registers needed to program the Flash memory. There
are eight holding registers used by the table writes for
programming.
FIGURE 6-5:
Since the Table Latch (TABLAT) is only a single byte,
the TBLWT instruction must be executed eight times for
each programming operation. All of the table write
operations will essentially be short writes, because only
the holding registers are written. At the end of updating
eight registers, the EECON1 register must be written
to, to start the programming operation with a long write.
The long write is necessary for programming the
internal Flash. Instruction execution is halted while in a
long write cycle. The long write will be terminated by
the internal programming timer.
TABLE WRITES TO FLASH PROGRAM MEMORY
TABLAT
Write Register
8
8
TBLPTR = xxxxx0
8
TBLPTR = xxxxx2
TBLPTR = xxxxx1
Holding Register
Holding Register
Holding Register
8
TBLPTR = xxxxx7
Holding Register
Program Memory
6.5.1
FLASH PROGRAM MEMORY WRITE
SEQUENCE
The sequence of events for programming an internal
program memory location should be:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Read 64 bytes into RAM.
Update data values in RAM as necessary.
Load Table Pointer with address being erased.
Do the row erase procedure (see Section 6.4.1
“Flash Program Memory Erase Sequence”).
Load Table Pointer with address of first byte
being written.
Write the first 8 bytes into the holding registers
with auto-increment.
Set the EECON1 register for the write operation:
•set EEPGD bit to point to program memory;
•clear the CFGS bit to access program
memory;
•set WREN bit to enable byte writes.
Disable interrupts.
Write 55h to EECON2.
2002-2015 Microchip Technology Inc.
10. Write AAh to EECON2.
11. Set the WR bit. This will begin the write cycle.
12. The CPU will stall for duration of the write (about
2 ms using internal timer).
13. Execute a NOP.
14. Re-enable interrupts.
15. Repeat steps 6-14 seven times to write
64 bytes.
16. Verify the memory (table read).
This procedure will require about 18 ms to update one
row of 64 bytes of memory. An example of the required
code is given in Example 6-3.
DS30009605G-page 61
PIC18F1220/1320
EXAMPLE 6-3:
WRITING TO FLASH PROGRAM MEMORY
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
D'64
COUNTER
BUFFER_ADDR_HIGH
FSR0H
BUFFER_ADDR_LOW
FSR0L
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
; number of bytes in erase block
TBLRD*+
MOVF
MOVWF
DECFSZ
GOTO
TABLAT, W
POSTINC0
COUNTER
READ_BLOCK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
DATA_ADDR_HIGH
FSR0H
DATA_ADDR_LOW
FSR0L
NEW_DATA_LOW
POSTINC0
NEW_DATA_HIGH
INDF0
; point to buffer
CODE_ADDR_UPPER
TBLPTRU
CODE_ADDR_HIGH
TBLPTRH
CODE_ADDR_LOW
TBLPTRL
EECON1, CFGS
EECON1, EEPGD
EECON1, WREN
EECON1, FREE
INTCON, GIE
55h
EECON2
AAh
EECON2
EECON1, WR
; load TBLPTR with the base
; address of the memory block
INTCON, GIE
; re-enable interrupts
8
COUNTER_HI
BUFFER_ADDR_HIGH
FSR0H
BUFFER_ADDR_LOW
FSR0L
; number of write buffer groups of 8 bytes
; point to buffer
; Load TBLPTR with the base
; address of the memory block
; 6 LSB = 0
READ_BLOCK
;
;
;
;
;
read into TABLAT, and inc
get data
store data and increment FSR0
done?
repeat
MODIFY_WORD
; update buffer word and increment FSR0
; update buffer word
ERASE_BLOCK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BSF
BSF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
NOP
BSF
WRITE_BUFFER_BACK
MOVLW
MOVWF
MOVLW
MOVWF
MOVLW
MOVWF
PROGRAM_LOOP
MOVLW
MOVWF
DS30009605G-page 62
8
COUNTER
; 6 LSB = 0
;
;
;
;
;
;
;
point to PROG/EEPROM memory
point to FLASH program memory
enable write to memory
enable Row Erase operation
disable interrupts
Required sequence
write 55H
; write AAH
; start erase (CPU stall)
; point to buffer
; number of bytes in holding register
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
EXAMPLE 6-3:
WRITING TO FLASH PROGRAM MEMORY (CONTINUED)
WRITE_WORD_TO_HREGS
MOVF
POSTINC0, W
MOVWF
TABLAT
TBLWT+*
;
;
;
;
get low byte of buffer data and increment FSR0
present data to table latch
short write
to internal TBLWT holding register, increment
TBLPTR
; loop until buffers are full
DECFSZ COUNTER
GOTO
WRITE_WORD_TO_HREGS
PROGRAM_MEMORY
BCF
INTCON, GIE
MOVLW
55h
MOVWF
EECON2
MOVLW
AAh
MOVWF
EECON2
BSF
EECON1, WR
NOP
BSF
INTCON, GIE
DECFSZ COUNTER_HI
GOTO PROGRAM_LOOP
BCF
EECON1, WREN
6.5.2
; disable interrupts
; required sequence
; write 55H
; write AAH
; start program (CPU stall)
; re-enable interrupts
; loop until done
; disable write to memory
6.6
WRITE VERIFY
Depending on the application, good programming
practice may dictate that the value written to the memory should be verified against the original value. This
should be used in applications where excessive writes
can stress bits near the specification limit.
6.5.3
Flash Program Operation During
Code Protection
See Section 19.0 “Special Features of the CPU” for
details on code protection of Flash program memory.
UNEXPECTED TERMINATION OF
WRITE OPERATION
If a write is terminated by an unplanned event, such as
loss of power or an unexpected Reset, the memory
location just programmed should be verified and reprogrammed if needed. The WRERR bit is set when a
write operation is interrupted by a MCLR Reset, or a
WDT Time-out Reset during normal operation. In these
situations, users can check the WRERR bit and rewrite
the location.
TABLE 6-2:
REGISTERS ASSOCIATED WITH PROGRAM FLASH MEMORY
Name
Bit 7
Bit 6
Bit 5
TBLPTRU
—
—
bit 21
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
Value on
all other
Resets
Program Memory Table Pointer Upper Byte (TBLPTR) --00 0000 --00 0000
TBPLTRH Program Memory Table Pointer High Byte (TBLPTR)
0000 0000 0000 0000
TBLPTRL Program Memory Table Pointer High Byte (TBLPTR)
0000 0000 0000 0000
TABLAT
Program Memory Table Latch
INTCON
GIE/GIEH PEIE/GIEL TMR0IE
EECON2
EEPROM Control Register 2 (not a physical register)
0000 0000 0000 0000
INTE
RBIE
TMR0IF
INTF
RBIF
0000 000x 0000 000u
—
—
EECON1
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
RD
xx-0 x000 uu-0 u000
IPR2
OSCFIP
—
—
EEIP
—
LVDIP
TMR3IP
—
1--1 -11- 1--1 -11-
PIR2
OSCFIF
—
—
EEIF
—
LVDIF
TMR3IF
—
0--0 -00- 0--0 -00-
PIE2
OSCFIE
—
—
EEIE
—
LVDIE
TMR3IE
—
0--0 -00- 0--0 -00-
Legend:
x = unknown, u = unchanged, – = unimplemented, read as ‘0’.
Shaded cells are not used during Flash/EEPROM access.
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7.0
DATA EEPROM MEMORY
The data EEPROM is readable and writable during
normal operation over the entire VDD range. The data
memory is not directly mapped in the register file
space. Instead, it is indirectly addressed through the
Special Function Registers (SFR).
There are four SFRs used to read and write the
program and data EEPROM memory. These registers
are:
•
•
•
•
EECON1
EECON2
EEDATA
EEADR
The EEPROM data memory allows byte read and write.
When interfacing to the data memory block, EEDATA
holds the 8-bit data for read/write and EEADR holds the
address of the EEPROM location being accessed.
These devices have 256 bytes of data EEPROM with
an address range from 00h to FFh.
The EEPROM data memory is rated for high erase/
write cycle endurance. A byte write automatically
erases the location and writes the new data (erasebefore-write). The write time is controlled by an on-chip
timer. The write time will vary with voltage and
temperature, as well as from chip to chip. Please
refer to parameter D122 (Table 22-1 in Section 22.0
“Electrical Characteristics”) for exact limits.
7.1
EEADR
The address register can address 256 bytes of data
EEPROM.
7.2
EECON1 and EECON2 Registers
Control bit, CFGS, determines if the access will be to
the Configuration registers or to program memory/data
EEPROM memory. When set, subsequent operations
access Configuration registers. When CFGS is clear,
the EEPGD bit selects either program Flash or data
EEPROM memory.
The WREN bit enables and disables erase and write
operations. When set, erase and write operations are
allowed. When clear, erase and write operations are
disabled – the WR bit cannot be set while the WREN bit
is clear. This mechanism helps to prevent accidental
writes to memory due to errant (unexpected) code
execution.
Firmware should keep the WREN bit clear at all times,
except when starting erase or write operations. Once
firmware has set the WR bit, the WREN bit may be
cleared. Clearing the WREN bit will not affect the
operation in progress.
The WRERR bit is set when a write operation is
interrupted by a Reset. In these situations, the user can
check the WRERR bit and rewrite the location. It is
necessary to reload the data and address registers
(EEDATA and EEADR), as these registers have
cleared as a result of the Reset.
Control bits, RD and WR, start read and erase/write
operations, respectively. These bits are set by firmware
and cleared by hardware at the completion of the
operation.
The RD bit cannot be set when accessing program
memory (EEPGD = 1). Program memory is read using
table read instructions. See Section 6.1 “Table Reads
and Table Writes” regarding table reads.
Note:
Interrupt flag bit, EEIF in the PIR2 register,
is set when write is complete. It must be
cleared in software.
EECON1 is the control register for memory accesses.
EECON2 is not a physical register. Reading EECON2
will read all ‘0’s. The EECON2 register is used
exclusively in the memory write and erase sequences.
Control bit, EEPGD, determines if the access will be to
program or data EEPROM memory. When clear,
operations will access the data EEPROM memory.
When set, program memory is accessed.
DS30009605G-page 64
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 7-1:
R/W-x
EECON1: EEPROM CONTROL 1 REGISTER
R/W-x
EEPGD
U-0
CFGS
R/W-0
—
FREE
R/W-x
(1)
WRERR
R/W-0
R/S-0
R/S-0
WREN
WR
RD
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
S = Bit can only be set
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
HC = Bit is cleared by hardware
bit 7
EEPGD: Flash Program or Data EEPROM Memory Select bit
1 = Access program Flash memory
0 = Access data EEPROM memory
bit 6
CFGS: Flash Program/Data EEPROM or Configuration Select bit
1 = Accesses Configuration, User ID and Device ID Registers
0 = Accesses Flash Program or data EEPROM Memory
bit 5
Unimplemented: Read as ‘0’
bit 4
FREE: Flash Row Erase Enable bit
1 = Erase the program memory row addressed by TBLPTR on the next WR command
(cleared by completion of erase operation – TBLPTR are ignored)
0 = Perform write only
bit 3
WRERR: EEPROM Error Flag bit(1)
1 = A write operation was prematurely terminated (any Reset during self-timed programming)
0 = The write operation completed normally
bit 2
WREN: Program/Erase Enable bit
1 = Allows program/erase cycles
0 = Inhibits programming/erasing of program Flash and data EEPROM
bit 1
WR: Write Control bit
1 = Initiates a data EEPROM erase/write cycle or a program memory erase cycle or write cycle.
(The operation is self-timed and the bit is cleared by hardware once write is complete. The WR
bit can only be set (not cleared) in software.)
0 = Write cycle completed
bit 0
RD: Read Control bit
1 = Initiates a memory read
(Read takes one cycle. RD is cleared in hardware. The RD bit can only be set (not cleared) in
software. RD bit cannot be set when EEPGD = 1.)
0 = Read completed
Note 1:
When a WRERR occurs, the EEPGD and CFGS bits are not cleared. This allows
tracing of the error condition.
2002-2015 Microchip Technology Inc.
DS30009605G-page 65
PIC18F1220/1320
7.3
Reading the Data EEPROM
Memory
To read a data memory location, the user must write the
address to the EEADR register, clear the EEPGD
control bit (EECON1) and then set control bit, RD
(EECON1). The data is available for the very next
instruction cycle; therefore, the EEDATA register can
be read by the next instruction. EEDATA will hold this
value until another read operation, or until it is written to
by the user (during a write operation).
7.4
Writing to the Data EEPROM
Memory
To write an EEPROM data location, the address must
first be written to the EEADR register and the data
written to the EEDATA register. The sequence in
Example 7-2 must be followed to initiate the write cycle.
The write will not begin if this sequence is not exactly
followed (write 55h to EECON2, write AAh to EECON2,
then set WR bit) for each byte. It is strongly recommended that interrupts be disabled during this
code segment.
Additionally, the WREN bit in EECON1 must be set to
enable writes. This mechanism prevents accidental
writes to data EEPROM due to unexpected code execution (i.e., runaway programs). The WREN bit should
be kept clear at all times, except when updating the
EEPROM. The WREN bit is not cleared by hardware.
EXAMPLE 7-1:
MOVLW
MOVWF
BCF
BSF
MOVF
At the completion of the write cycle, the WR bit is
cleared in hardware and the EEPROM Interrupt Flag bit
(EEIF) is set. The user may either enable this interrupt
or poll this bit. EEIF must be cleared by software.
7.5
Write Verify
Depending on the application, good programming
practice may dictate that the value written to the
memory should be verified against the original value.
This should be used in applications where excessive
writes can stress bits near the specification limit.
7.6
Protection Against Spurious Write
There are conditions when the device may not want to
write to the data EEPROM memory. To protect against
spurious EEPROM writes, various mechanisms have
been built-in. On power-up, the WREN bit is cleared.
Also, the Power-up Timer (72 ms duration) prevents
EEPROM write.
The write initiate sequence and the WREN bit together
help prevent an accidental write during brown-out,
power glitch or software malfunction.
DATA EEPROM READ
DATA_EE_ADDR;
EEADR
; Data Memory Address to read
EECON1, EEPGD; Point to DATA memory
EECON1, RD ; EEPROM Read
EEDATA, W ; W = EEDATA
EXAMPLE 7-2:
Required
Sequence
After a write sequence has been initiated, EECON1,
EEADR and EEDATA cannot be modified. The WR bit
will be inhibited from being set unless the WREN bit is
set. The WREN bit must be set on a previous instruction. Both WR and WREN cannot be set with the same
instruction.
DATA EEPROM WRITE
MOVLW
MOVWF
MOVLW
MOVWF
BCF
BSF
BCF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BSF
DATA_EE_ADDR;
EEADR
; Data Memory Address to write
DATA_EE_DATA;
EEDATA
; Data Memory Value to write
EECON1, EEPGD; Point to DATA memory
EECON1, WREN; Enable writes
INTCON, GIE ; Disable Interrupts
55h
;
EECON2
; Write 55h
AAh
;
EECON2
; Write AAh
EECON1, WR ; Set WR bit to begin write
INTCON, GIE ; Enable Interrupts
SLEEP
BCF
; Wait for interrupt to signal write complete
EECON1, WREN; Disable writes
DS30009605G-page 66
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
7.7
Operation During Code-Protect
7.8
Data EEPROM memory has its own code-protect bits in
Configuration Words. External read and write
operations are disabled if either of these mechanisms
are enabled.
Using the Data EEPROM
The data EEPROM is a high endurance, byte addressable array that has been optimized for the storage of frequently changing information (e.g., program variables or
other data that are updated often). Frequently changing
values will typically be updated more often than specification D124. If this is not the case, an array refresh must
be performed. For this reason, variables that change
infrequently (such as constants, IDs, calibration, etc.)
should be stored in Flash program memory.
The microcontroller itself can both read and write to the
internal data EEPROM, regardless of the state of the
code-protect Configuration bit. Refer to Section 19.0
“Special Features of the CPU” for additional
information.
A simple data EEPROM refresh routine is shown in
Example 7-3.
Note:
EXAMPLE 7-3:
DATA EEPROM REFRESH ROUTINE
CLRF
BCF
BCF
BCF
BSF
EEADR
EECON1,
EECON1,
INTCON,
EECON1,
BSF
MOVLW
MOVWF
MOVLW
MOVWF
BSF
BTFSC
BRA
INCFSZ
BRA
EECON1, RD
55h
EECON2
AAh
EECON2
EECON1, WR
EECON1, WR
$-2
EEADR, F
Loop
BCF
BSF
EECON1, WREN
INTCON, GIE
;
;
;
;
;
;
;
;
;
;
;
;
;
CFGS
EEPGD
GIE
WREN
Loop
TABLE 7-1:
Name
INTCON
If data EEPROM is only used to store
constants and/or data that changes rarely,
an array refresh is likely not required. See
specification D124.
Start at address 0
Set for memory
Set for Data EEPROM
Disable interrupts
Enable writes
Loop to refresh array
Read current address
Write 55h
Write AAh
Set WR bit to begin write
Wait for write to complete
; Increment address
; Not zero, do it again
; Disable writes
; Enable interrupts
REGISTERS ASSOCIATED WITH DATA EEPROM MEMORY
Value on
all other
Resets
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on:
POR, BOR
GIE/GIEH
PEIE/GIEL
TMR0IE
INTE
RBIE
TMR0IF
INTF
RBIF
0000 000x 0000 000u
EEADR
EEPROM Address Register
0000 0000 0000 0000
EEDATA
EEPROM Data Register
0000 0000 0000 0000
EECON2
EEPROM Control Register 2 (not a physical register)
—
—
EECON1
EEPGD
CFGS
—
FREE
WRERR
WREN
WR
RD
xx-0 x000 uu-0 u000
IPR2
OSCFIP
—
—
EEIP
—
LVDIP
TMR3IP
—
1--1 -11- 1--1 -11-
PIR2
OSCFIF
—
—
EEIF
—
LVDIF
TMR3IF
—
0--0 -00- 0--0 -00-
PIE2
OSCFIE
—
—
EEIE
—
LVDIE
TMR3IE
—
0--0 -00- 0--0 -00-
Legend: x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used during Flash/EEPROM access.
2002-2015 Microchip Technology Inc.
DS30009605G-page 67
PIC18F1220/1320
8.0
8 x 8 HARDWARE MULTIPLIER
Making the 8 x 8 multiplier execute in a single cycle
gives the following advantages:
8.1
Introduction
• Higher computational throughput
• Reduces code size requirements for multiply
algorithms
An 8 x 8 hardware multiplier is included in the ALU of
the PIC18F1220/1320 devices. By making the multiply
a hardware operation, it completes in a single instruction cycle. This is an unsigned multiply that gives a
16-bit result. The result is stored into the 16-bit product
register pair (PRODH:PRODL). The multiplier does not
affect any flags in the Status register.
TABLE 8-1:
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
13
69
6.9 s
27.6 s
69 s
Without hardware multiply
Time
Hardware multiply
1
1
100 ns
400 ns
1 s
Without hardware multiply
33
91
9.1 s
36.4 s
91 s
Hardware multiply
6
6
600 ns
2.4 s
6 s
Without hardware multiply
21
242
24.2 s
96.8 s
242 s
Hardware multiply
28
28
2.8 s
11.2 s
28 s
Without hardware multiply
52
254
25.4 s
102.6 s
254 s
Hardware multiply
35
40
4 s
16 s
40 s
EXAMPLE 8-2:
Operation
Example 8-1 shows the sequence to do an 8 x 8
unsigned multiply. Only one instruction is required
when one argument of the multiply is already loaded in
the WREG register.
Example 8-2 shows the sequence to do an 8 x 8 signed
multiply. To account for the sign bits of the arguments,
each argument’s Most Significant bit (MSb) is tested
and the appropriate subtractions are done.
EXAMPLE 8-1:
MOVF
MULWF
Table 8-1 shows a performance comparison between
Enhanced devices using the single-cycle hardware
multiply and performing the same function without the
hardware multiply.
PERFORMANCE COMPARISON
Routine
8.2
The performance increase allows the device to be used
in applications previously reserved for Digital Signal
Processors.
ARG1, W
ARG2
DS30009605G-page 68
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
;
;
;
;
;
ARG1 * ARG2 ->
PRODH:PRODL
Test Sign Bit
PRODH = PRODH
- ARG1
; Test Sign Bit
; PRODH = PRODH
;
- ARG2
;
; ARG1 * ARG2 ->
; PRODH:PRODL
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
Example 8-3 shows the sequence to do a 16 x 16
unsigned multiply. Equation 8-1 shows the algorithm
that is used. The 32-bit result is stored in four registers,
RES3:RES0.
EQUATION 8-1:
16 x 16 UNSIGNED
MULTIPLICATION
ALGORITHM
RES3:RES0
=
ARG1H:ARG1L ARG2H:ARG2L
=
(ARG1H ARG2H 216) +
(ARG1H ARG2L 28) +
(ARG1L ARG2H 28) +
(ARG1L ARG2L)
EXAMPLE 8-3:
EQUATION 8-2:
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 8-4:
16 x 16 UNSIGNED
MULTIPLY ROUTINE
MOVFARG1L, W
MULWFARG2L
MOVFFPRODH, RES1
MOVFFPRODL, RES0
; ARG1L * ARG2L ->
; PRODH:PRODL
;
;
MOVFFPRODH, RES3
MOVFFPRODL, RES2
; ARG1H * ARG2H ->
; PRODH:PRODL
;
;
MOVFPRODL, W
ADDWFRES1, F
MOVFPRODH, W
ADDWFCRES2, F
CLRFWREG
ADDWFCRES3,F
;
;
;
;
;
;
;
;
ARG1L * ARG2H ->
PRODH:PRODL
Add cross
products
MOVFPRODL, W
ADDWFRES1, F
MOVFPRODH, W
ADDWFCRES2, F
CLRFWREG
ADDWFCRES3, F
;
;
;
;
;
;
;
;
;
ARG1H * ARG2L ->
PRODH:PRODL
Add cross
products
Example 8-4 shows the sequence to do a 16 x 16
signed multiply. Equation 8-2 shows the algorithm
used. The 32-bit result is stored in four registers,
RES3:RES0. To account for the sign bits of the arguments, each argument pairs’ Most Significant bit (MSb)
is tested and the appropriate subtractions are done.
2002-2015 Microchip Technology Inc.
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
;
;
MOVFARG1H, W
MULWFARG2L
MOVF
MULWF
;
;
MOVFARG1L, W
MULWFARG2H
16 x 16 SIGNED
MULTIPLY ROUTINE
;
;
MOVFARG1H, W
MULWFARG2H
16 x 16 SIGNED
MULTIPLICATION
ALGORITHM
;
;
;
;
;
;
;
;
;
ARG1H * ARG2L ->
PRODH:PRODL
Add cross
products
;
;
SIGN_ARG1
BTFSS
BRA
MOVF
SUBWF
MOVF
SUBWFB
;
CONT_CODE
:
DS30009605G-page 69
PIC18F1220/1320
9.0
INTERRUPTS
The PIC18F1220/1320 devices have multiple interrupt
sources and an interrupt priority feature that allows
each interrupt source to be assigned a high priority
level or a low priority level. The high priority interrupt
vector is at 000008h and the low priority interrupt vector
is at 000018h. 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, each interrupt source has three bits to
control its operation. The functions of these bits 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
(INT0 has no priority bit and is always high 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 000008h or 000018h,
depending on the priority bit setting. Individual
interrupts can be disabled through their corresponding
enable bits.
DS30009605G-page 70
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
000008h 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 low
priority 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
(000008h or 000018h). 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 INT 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 2-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.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 9-1:
INTERRUPT LOGIC
TMR0IF
TMR0IE
TMR0IP
RBIF
RBIE
RBIP
INT0IF
INT0IE
Wake-up if in Low-Power Mode
Interrupt to CPU
Vector to Location
0008h
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
INT0IF
INT0IE
GIEH/GIE
ADIF
ADIE
ADIP
IPEN
IPEN
RCIF
RCIE
RCIP
GIEL/PEIE
IPEN
Additional Peripheral Interrupts
High Priority Interrupt Generation
Low Priority Interrupt Generation
INT0IF
INT0IE
Interrupt to CPU
Vector to Location
0018h
TMR0IF
TMR0IE
TMR0IP
ADIF
ADIE
ADIP
RBIF
RBIE
RBIP
RCIF
RCIE
RCIP
INT0IF
INT0IE
Additional Peripheral Interrupts
2002-2015 Microchip Technology Inc.
GIEL\PEIE
GIE\GIEH
INT1IF
INT1IE
INT1IP
INT2IF
INT2IE
INT2IP
DS30009605G-page 71
PIC18F1220/1320
9.1
INTCON Registers
Note:
The INTCON registers are readable and writable
registers, which contain various enable, priority and
flag bits.
REGISTER 9-1:
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. User software should
ensure the appropriate interrupt flag bits
are clear prior to enabling an interrupt.
This feature allows for software polling.
INTCON: INTERRUPT CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R-0/0
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF(1)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
GIE/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: Timer0 Overflow Interrupt Flag bit
1 = TMR0 register has overflowed
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)
1 = At least one of the RB pins changed state (must be cleared in software)
0 = None of the RB pins have changed state
Note 1:
A mismatch condition will continue to set this bit. Reading PORTB will end the
mismatch condition and allow the bit to be cleared.
DS30009605G-page 72
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 9-2:
INTCON2: INTERRUPT CONTROL REGISTER 2
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
U-0
R/W-1/1
U-0
R/W-1/1
RBPU
INTEDG0
INTEDG1
INTEDG2
—
TMR0IP
—
RBIP
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
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
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.
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REGISTER 9-3:
INTCON3: INTERRUPT CONTROL REGISTER 3
R/W-1/1
R/W-1/1
U-0
R/W-0/0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
INT2IP
INT1IP
—
INT2IE
INT1IE
—
INT2IF
INT1IF
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
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
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.
DS30009605G-page 74
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PIC18F1220/1320
9.2
PIR Registers
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, PIR2).
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).
2: User software should ensure the appropriate interrupt flag bits are cleared prior
to enabling an interrupt and after servicing
that interrupt.
REGISTER 9-4:
PIR1: PERIPHERAL INTERRUPT REQUEST REGISTER 1
U-0
R/W-0/0
R-0/0
R-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
Unimplemented: 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
Unimplemented: Read as ‘0’
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
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PIC18F1220/1320
REGISTER 9-5:
PIR2: PERIPHERAL INTERRUPT REQUEST REGISTER 2
R/W-0/0
U-0
U-0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
U-0
OSCFIF
—
—
EEIF
—
LVDIF
TMR3IF
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
OSCFIF: Oscillator Fail Interrupt Flag bit
1 = System oscillator failed, clock input has changed to INTOSC (must be cleared in software)
0 = System clock operating
bit 6-5
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
Unimplemented: Read as ‘0’
bit 2
LVDIF: Low-Voltage Detect Interrupt Flag bit
1 = A low-voltage condition occurred (must be cleared in software)
0 = The device voltage is above the Low-Voltage Detect trip point
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
Unimplemented: Read as ‘0’
DS30009605G-page 76
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
9.3
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, PIE2). When
IPEN = 0, the PEIE bit must be set to enable any of
these peripheral interrupts.
REGISTER 9-6:
PIE1: PERIPHERAL INTERRUPT ENABLE REGISTER 1
U-0
R/W-0/0
R/W-0/0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
Unimplemented: 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
Unimplemented: Read as ‘0’
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
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REGISTER 9-7:
PIE2: PERIPHERAL INTERRUPT ENABLE REGISTER 2
R/W-0/0
U-0
U-0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
U-0
OSCFIE
—
—
EEIE
—
LVDIE
TMR3IE
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
OSCFIE: Oscillator Fail Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 6-5
Unimplemented: Read as ‘0’
bit 4
EEIE: Data EEPROM/Flash Write Operation Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 3
Unimplemented: Read as ‘0’
bit 2
LVDIE: Low-Voltage Detect Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 1
TMR3IE: TMR3 Overflow Interrupt Enable bit
1 = Enabled
0 = Disabled
bit 0
Unimplemented: Read as ‘0’
DS30009605G-page 78
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
9.4
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, IPR2). Using the
priority bits requires that the Interrupt Priority Enable
(IPEN) bit be set.
REGISTER 9-8:
IPR1: PERIPHERAL INTERRUPT PRIORITY REGISTER 1
U-0
R/W-1/1
R/W-1/1
R/W-1/1
U-0
R/W-1/1
R/W-1/1
R/W-1/1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
Unimplemented: Read as ‘0’
bit 6
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
Unimplemented: Read as ‘0’
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
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
REGISTER 9-9:
IPR2: PERIPHERAL INTERRUPT PRIORITY REGISTER 2
R/W-1/1
U-0
U-0
R/W-1/1
U-0
R/W-1/1
R/W-1/1
U-0
OSCFIP
—
—
EEIP
—
LVDIP
TMR3IP
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
OSCFIP: Oscillator Fail Interrupt Priority bit
1 = High priority
0 = Low priority
bit 6-5
Unimplemented: Read as ‘0’
bit 4
EEIP: Data EEPROM/Flash Write Operation Interrupt Priority bit
1 = High priority
0 = Low priority
bit 3
Unimplemented: Read as ‘0’
bit 2
LVDIP: 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
Unimplemented: Read as ‘0’
DS30009605G-page 80
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
9.5
RCON Register
The RCON register contains bits used to determine the
cause of the last Reset or wake-up from a low-power
mode. RCON also contains the bit that enables
interrupt priorities (IPEN).
REGISTER 9-10:
RCON: RESET CONTROL REGISTER
R/W-0
U-0
U-0
R/W-1
R-1
R-1
R/W-0
R/W-0
IPEN
—
—
RI
TO
PD
POR
BOR
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
IPEN: Interrupt Priority Enable bit
1 = Enable priority levels on interrupts
0 = Disable priority levels on interrupts (PIC16CXXX Compatibility mode)
bit 6-5
Unimplemented: Read as ‘0’
bit 4
RI: RESET Instruction Flag bit
For details of bit operation, see Register 5-3.
bit 3
TO: Watchdog Time-out Flag bit
For details of bit operation, see Register 5-3.
bit 2
PD: Power-down Detection Flag bit
For details of bit operation, see Register 5-3.
bit 1
POR: Power-on Reset Status bit
For details of bit operation, see Register 5-3.
bit 0
BOR: Brown-out Reset Status bit
For details of bit operation, see Register 5-3.
2002-2015 Microchip Technology Inc.
DS30009605G-page 81
PIC18F1220/1320
9.6
INTn Pin Interrupts
9.7
External interrupts on the RB0/INT0, RB1/INT1 and
RB2/INT2 pins are edge-triggered: either rising if the
corresponding INTEDGx bit is set in the INTCON2 register, or falling if the INTEDGx bit is clear. 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 wake-up
the processor from low-power modes if bit INTxE was
set prior to going into low-power 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
(FFh 00h) in the TMR0 register will set flag bit,
TMR0IF. In 16-bit mode, an overflow (FFFFh 0000h)
in the TMR0H:TMR0L registers will set flag bit,
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 11.0 “Timer0 Module”
for further details on the Timer0 module.
9.8
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).
9.9
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 5.3 “Fast Register
Stack”), 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 9-1
saves and restores the WREG, Status and BSR
registers during an Interrupt Service Routine.
EXAMPLE 9-1:
MOVWF
MOVFF
MOVFF
;
; USER
;
MOVFF
MOVF
MOVFF
SAVING STATUS, WREG AND BSR REGISTERS IN RAM
W_TEMP
STATUS, STATUS_TEMP
BSR, BSR_TEMP
; W_TEMP is in virtual bank
; STATUS_TEMP located anywhere
; BSR_TMEP located anywhere
ISR CODE
BSR_TEMP, BSR
W_TEMP, W
STATUS_TEMP, STATUS
DS30009605G-page 82
; Restore BSR
; Restore WREG
; Restore STATUS
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
10.0
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 (output latch)
The Data Latch (LATA) register is useful for readmodify-write operations on the value that the I/O pins
are driving.
The Data Latch register (LATA) 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 to become the RA4/T0CKI pin.
The sixth pin of PORTA (MCLR/VPP/RA5) is an input
only pin. Its operation is controlled by the MCLRE
configuration bit in Configuration Register 3H
(CONFIG3H). 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, RA5 also
functions as the programming voltage input during
programming.
Note:
A simplified model of a generic I/O port without the
interfaces to other peripherals is shown in Figure 10-1.
FIGURE 10-1:
GENERIC I/O PORT
OPERATION
RD LAT
Data
Bus
D
WR LAT
or Port
Q
I/O pin(1)
CK
Data Latch
D
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 Configuration
Register 1H (see Section 19.1 “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 LVD
input. The operation of pins RA3:RA0 as A/D converter
inputs is selected by clearing/setting the control bits in
the ADCON1 register (A/D Control Register 1).
Q
Note:
WR TRIS
CK
TRIS Latch
Input
Buffer
RD TRIS
Q
D
ENEN
RD Port
Note 1:
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).
Reading the PORTA register reads the status of the
pins, whereas writing to it will write to the port latch.
2002-2015 Microchip Technology Inc.
On a Power-on Reset, RA3:RA0 are
configured as analog inputs and read as
‘0’. RA4 is always a digital pin.
The RA4/T0CKI pin is a Schmitt Trigger input and an
open-drain output. All other PORTA pins have TTL
input levels and full CMOS output drivers.
The TRISA register controls the direction of the RA
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 10-1:
CLRF
10.1
On a Power-on Reset, RA5 is enabled as a
digital input only if Master Clear functionality
is disabled.
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
PORTA
;
;
;
LATA
;
;
;
0x7F
;
ADCON1 ;
0xD0
;
;
;
TRISA
;
;
INITIALIZING PORTA
Initialize PORTA 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 RA as outputs
RA as inputs
DS30009605G-page 83
PIC18F1220/1320
FIGURE 10-2:
BLOCK DIAGRAM OF
RA3:RA0 PINS
FIGURE 10-4:
BLOCK DIAGRAM OF
RA4/T0CKI PIN
RD LATA
RD LATA
Data
Bus
D
WR LATA
or
PORTA
Q
VDD
CK
Q
P
Data
Bus
D
Q
WR LATA
or
PORTA
CK
Q
Data Latch
D
Q
CK
Q
Data Latch
N
(1)
I/O pin
WR TRISA
WR TRISA
Analog
Input
Mode
I/O pin(1)
N
VSS
D
Q
CK
Q
VSS
Schmitt
Trigger
Input
Buffer
TRIS Latch
TRIS Latch
RD TRISA
RD TRISA
Q
Schmitt
Trigger
Input
Buffer
D
Q
D
ENEN
EN
RD PORTA
RD PORTA
TMR0 Clock Input
To A/D Converter and LVD Modules
Note 1:
Note 1:
I/O pins have protection diodes to VDD and VSS.
FIGURE 10-3:
I/O pins have protection diodes to VDD and VSS.
FIGURE 10-5:
BLOCK DIAGRAM OF
OSC2/CLKO/RA6 PIN
RA6 Enable
Data
Bus
RA7 Enable
RD LATA
RD LATA
WR LATA
or
PORTA
D
Q
CK
Q
VDD
WR LATA
or
PORTA
P
D
Q
CK
Q
D
Q
CK
Q
VDD
P
Data Latch
N
(1)
I/O pin
WR
TRISA
VSS
D
Q
CK
Q
N
Schmitt
Trigger
Input
Buffer
RD
TRISA
ECIO or
RCIO
Enable
VSS
RD
TRISA
Schmitt
Trigger
Input
Buffer
RA7
Enable
Q
Q
D
RD PORTA
I/O pins have protection diodes to VDD and VSS.
D
EN
EN
DS30009605G-page 84
I/O pin(1)
TRIS Latch
TRIS Latch
Note 1:
To Oscillator
Data
Bus
Data Latch
WR
TRISA
BLOCK DIAGRAM OF
OSC1/CLKI/RA7 PIN
RD PORTA
Note 1:
I/O pins have protection diodes to VDD and VSS.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 10-6:
MCLR/VPP/RA5 PIN BLOCK DIAGRAM
MCLRE
Data Bus
MCLR/VPP/RA5
RD TRISA
Schmitt
Trigger
RD LATA
Latch
Q
D
EN
RD PORTA
High-Voltage Detect
HV
Internal MCLR
Filter
Low-Level
MCLR Detect
TABLE 10-1:
PORTA FUNCTIONS
Name
RA0/AN0
Bit#
Buffer
bit 0
ST
Function
Input/output port pin or analog input.
RA1/AN1/LVDIN
bit 1
ST
Input/output port pin, analog input or Low-Voltage Detect input.
RA2/AN2/VREF-
bit 2
ST
Input/output port pin, analog input or VREF-.
RA3/AN3/VREF+
bit 3
ST
Input/output port pin, analog input or VREF+.
RA4/T0CKI
bit 4
ST
Input/output port pin or external clock input for Timer0.
Output is open-drain type.
MCLR/VPP/RA5
bit 5
ST
Master Clear input or programming voltage input (if MCLR is enabled); input
only port pin or programming voltage input (if MCLR is disabled).
OSC2/CLKO/RA6
bit 6
ST
OSC2, clock output or I/O pin.
OSC1/CLKI/RA7
bit 7
ST
OSC1, clock input or I/O pin.
Legend: TTL = TTL input, ST = Schmitt Trigger input
TABLE 10-2:
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA
Value on
all other
Resets
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
RA7(1)
RA6(1)
RA5(2)
RA4
RA3
RA2
RA1
RA0
xx0x 0000 uu0u 0000
LATA
LATA7
LATA6(1)
—
LATA Data Output Register
xx-x xxxx uu-u uuuu
TRISA
TRISA7(1) TRISA6(1)
—
PORTA Data Direction Register
11-1 1111 11-1 1111
Name
PORTA
ADCON1
Legend:
Note 1:
2:
—
(1)
PCFG6
PCFG5 PCFG4 PCFG3 PCFG2 PCFG1 PCFG0 -000 0000 -000 0000
x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by PORTA.
RA7:RA6 and their associated latch and data direction bits are enabled as I/O pins based on oscillator
configuration; otherwise, they are read as ‘0’.
RA5 is an input only if MCLR is disabled.
2002-2015 Microchip Technology Inc.
DS30009605G-page 85
PIC18F1220/1320
10.2
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 10-2:
CLRF
CLRF
MOVLW
MOVWF
MOVLW
MOVWF
PORTB
;
;
;
LATB
;
;
;
0x70
;
ADCON1 ;
;
0xCF
;
;
TRISB
;
;
;
INITIALIZING PORTB
Initialize PORTB by
clearing output
data latches
Alternate method
to clear output
data latches
Set RB0, RB1, RB4 as
digital I/O pins
Value used to
initialize data
direction
Set RB as inputs
RB as outputs
RB as inputs
This interrupt can wake the device from Sleep. The
user, in the Interrupt Service Routine, can clear the
interrupt in the following manner:
a)
b)
Any read or write of PORTB (except with the
MOVFF instruction). This will end the mismatch
condition.
Clear flag bit, RBIF.
A mismatch condition will continue to set flag bit, RBIF.
Reading PORTB will end the mismatch condition and
allow flag bit, RBIF, to 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.
FIGURE 10-7:
VDD
RBPU(2)
Analog Input Mode
Data Bus
D
WR LATB
or PORTB
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.
On a Power-on Reset, RB4:RB0 are
configured as analog inputs by default and
read as ‘0’; RB7:RB5 are configured as
digital inputs.
Four of the PORTB pins (RB7:RB4) have an interrupton-change feature. Only pins configured as inputs can
cause this interrupt to occur (i.e., any RB7:RB4 pin
configured as an output is excluded from the interrupton-change comparison). The input pins (of RB7:RB4)
are compared with the old value latched on the last
read of PORTB. The “mismatch” outputs of RB7:RB4
are OR’ed together to generate the RB Port Change
Interrupt with Flag bit, RBIF (INTCON).
DS30009605G-page 86
Q
I/O
pin(1)
CK
D
Q
CK
TTL
Input
Buffer
TRIS Latch
RD TRISB
RD LATB
Q
D
ENEN
RD PORTB
Schmitt Trigger
Buffer
INTx
Note:
Weak
P Pull-up
Data Latch
WR TRISB
Pins RB0-RB2 are multiplexed with INT0-INT2; pins
RB0, RB1 and RB4 are multiplexed with A/D inputs;
pins RB1 and RB4 are multiplexed with EUSART; and
pins RB2, RB3, RB6 and RB7 are multiplexed with
ECCP.
BLOCK DIAGRAM OF
RB0/AN4/INT0 PIN
To A/D Converter
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS
bit(s) and clear the RBPU bit (INTCON2).
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 10-8:
BLOCK DIAGRAM OF RB1/AN5/TX/CK/INT1 PIN
EUSART Enable
1
TX/CK Data
0
TX/CK TRIS
VDD
RBPU(2)
Analog Input Mode
Data Bus
WR LATB
or
PORTB
WR TRISB
Weak
P Pull-up
Data Latch
D
Q
RB1 pin(1)
CK
TRIS Latch
D
Q
CK
TTL
Input
Buffer
RD TRISB
RD LATB
Q
D
RD PORTB
EN
RD PORTB
Schmitt
Trigger
Input
Buffer
INT1/CK Input
Analog Input
Mode
To A/D Converter
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
2002-2015 Microchip Technology Inc.
DS30009605G-page 87
PIC18F1220/1320
FIGURE 10-9:
BLOCK DIAGRAM OF RB2/P1B/INT2 PIN
VDD
RBPU(2)
P Weak
Pull-up
P1B Enable
P1B Data
1
P1B/D Tri-State
Auto-Shutdown
0
Data Bus
WR LATB or
PORTB
Data Latch
D
Q
RB2 pin(1)
CK
TRIS Latch
D
Q
WR TRISB
TTL
Input
Buffer
CK
RD TRISB
RD LATB
Q
D
RD PORTB
EN
INT2 Input
Note 1:
2:
Schmitt
Trigger
RD PORTB
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
DS30009605G-page 88
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 10-10:
BLOCK DIAGRAM OF RB3/CCP1/P1A PIN
ECCP1(3) pin Output Enable
ECCP1(4) pin Input Enable
VDD
RBPU(2)
Weak
P Pull-up
P1A/C Tri-State Auto-Shutdown
ECCP1/P1A Data Out
VDD
1
P
0
RD LATB
Data Bus
WR LATB or
PORTB
D
Q
RB3 pin
CK
Q
Data Latch
D
WR TRISB
N
Q
VSS
CK
Q
TTL Input
Buffer
TRIS Latch
RD TRISB
Q
D
EN
RD PORTB
ECCP1 Input
Schmitt
Trigger
Note 1:
I/O pins have diode protection to VDD and VSS.
2:
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
3:
ECCP1 pin output enable active for any PWM mode and Compare mode, where CCP1M = 1000 or 1001.
4:
ECCP1 pin input enable active for Capture mode only.
2002-2015 Microchip Technology Inc.
DS30009605G-page 89
PIC18F1220/1320
FIGURE 10-11:
BLOCK DIAGRAM OF RB4/AN6/RX/DT/KBI0 PIN
EUSART Enabled
VDD
RBPU(2)
Analog Input Mode
P Weak
Pull-up
DT TRIS
DT Data
1
0
RD LATB
Data Bus
WR LATB or
PORTB
D
Q
RB4 pin
CK
Q
Data Latch
D
WR TRISB
CK
Q
Q
TRIS Latch
TTL
Input
Buffer
RD TRISB
Q
Set RBIF
EN
RD PORTB
From other
RB7:RB4 pins
D
Q
D
RD PORTB
EN
RX/DT Input
To A/D Converter
Note 1:
2:
Q1
Q3
Schmitt
Trigger
Analog Input
Mode
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
DS30009605G-page 90
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 10-12:
BLOCK DIAGRAM OF RB5/PGM/KBI1 PIN
VDD
RBPU(2)
Weak
P Pull-up
Data Latch
Data Bus
D
WR LATB
or PORTB
Q
I/O pin(1)
CK
TRIS Latch
D
Q
WR TRISB
TTL
Input
Buffer
CK
ST
Buffer
RD TRISB
RD LATB
Latch
Q
D
RD PORTB
EN
Set RBIF
Q
Q1
D
RD PORTB
From other
RB7:RB5 and
RB4 pins
EN
Q3
RB7:RB5 in Serial Programming Mode
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit
(INTCON2).
2002-2015 Microchip Technology Inc.
DS30009605G-page 91
PIC18F1220/1320
FIGURE 10-13:
BLOCK DIAGRAM OF RB6/PGC/T1OSO/T13CKI/P1C/KBI2 PIN
ECCP1 P1C/D Enable
VDD
RBPU(2)
P Weak
Pull-up
P1B/D Tri-State Auto-Shutdown
P1C Data
1
0
RD LATB
Data Bus
WR LATB or
PORTB
D
CK
Q
RB6 pin
Q
Data Latch
D
WR TRISB
CK
Q
Q
Timer1
Oscillator
TRIS Latch
From RB7 pin
T1OSCEN
TTL
Buffer
RD TRISB
Q
Set RBIF
From other
RB7:RB4 pins
D
EN
RD PORTB
Q
Schmitt
Trigger
Q1
D
RD PORTB
EN
Q3
PGC
T13CKI
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
DS30009605G-page 92
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 10-14:
BLOCK DIAGRAM OF RB7/PGD/T1OSI/P1D/KBI3 PIN
VDD
ECCP1 P1C/D Enable
RBPU(2)
Weak
P Pull-up
P1B/D Tri-State Auto-Shutdown
P1D Data
To RB6 pin
1
0
RD LATB
Data Bus
WR LATB or
PORTB
D
Q
RB7 pin
CK
Q
Data Latch
D
WR TRISB
CK
Q
Q
TRIS Latch
T1OSCEN
TTL
Input
Buffer
RD TRISB
Q
Set RBIF
From other
RB7:RB4 pins
D
EN
RD PORTB
Q
Schmitt
Trigger
Q1
D
RD PORTB
EN
Q3
PGD
Note 1:
2:
I/O pins have diode protection to VDD and VSS.
To enable weak pull-ups, set the appropriate TRIS bit(s) and clear the RBPU bit (INTCON2).
2002-2015 Microchip Technology Inc.
DS30009605G-page 93
PIC18F1220/1320
TABLE 10-3:
PORTB FUNCTIONS
Name
Bit#
Buffer
RB0/AN4/INT0
bit 0
TTL(1)/ST(2)
Input/output port pin, analog input or external interrupt
input 0.
RB1/AN5/TX/CK/INT1
bit 1
TTL(1)/ST(2)
Input/output port pin, analog input, Enhanced USART
Asynchronous Transmit, Addressable USART
Synchronous Clock or external interrupt input 1.
RB2/P1B/INT2
bit 2
TTL(1)/ST(2)
Input/output port pin or external interrupt input 2.
Internal software programmable weak pull-up.
RB3/CCP1/P1A
bit 3
TTL(1)/ST(3)
Input/output port pin or Capture1 input/Compare1 output/
PWM output. Internal software programmable weak pull-up.
RB4/AN6/RX/DT/KBI0
bit 4
TTL(1)/ST(4)
Input/output port pin (with interrupt-on-change), analog input,
Enhanced USART Asynchronous Receive or Addressable
USART Synchronous Data.
RB5/PGM/KBI1
bit 5
TTL(1)/ST(5)
Input/output port pin (with interrupt-on-change).
Internal software programmable weak pull-up.
Low-Voltage ICSP™ enable pin.
RB6/PGC/T1OSO/T13CKI/
P1C/KBI2
bit 6
RB7/PGD/T1OSI/P1D/KBI3
bit 7
Legend:
Note 1:
2:
3:
4:
5:
6:
PORTB
TTL(1)/ST(5,6) Input/output port pin (with interrupt-on-change), Timer1/
Timer3 clock input or Timer1oscillator output.
Internal software programmable weak pull-up.
Serial programming clock.
TTL(1)/ST(5)
Input/output port pin (with interrupt-on-change) or Timer1
oscillator input. Internal software programmable weak pull-up.
Serial programming data.
TTL = TTL input, ST = Schmitt Trigger input
This buffer is a TTL input when configured as a port input pin.
This buffer is a Schmitt Trigger input when configured as the external interrupt.
This buffer is a Schmitt Trigger input when configured as the CCP1 input.
This buffer is a Schmitt Trigger input when used as EUSART receive input.
This buffer is a Schmitt Trigger input when used in Serial Programming mode.
This buffer is a TTL input when used as the T13CKI input.
TABLE 10-4:
Name
Function
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
RB7
RB6
RB5
RB4
RB3
RB2
RB1
RB0
xxxq qqqq
uuuu uuuu
LATB
LATB Data Output Register
xxxx xxxx
uuuu uuuu
TRISB
PORTB Data Direction Register
1111 1111
1111 1111
INTCON
GIE/GIEH PEIE/GIEL TMR0IE
RBIF
0000 000x
0000 000u
1111 -1-1
INT0IE
RBIE
TMR0IF
INTEDG0 INTEDG1 INTEDG2
INT0IF
INTCON2
RBPU
—
TMR0IP
—
RBIP
1111 -1-1
INTCON3
INT2IP
INT1IP
—
INT2IE
INT1IE
—
INT2IF
INT1IF
11-0 0-00
11-0 0-00
ADCON1
—
PCFG6
PCFG5
PCFG4
PCFG3
PCFG2
PCFG1
PCFG0
-000 0000
-000 0000
Legend:
x = unknown, u = unchanged, q = value depends on condition. Shaded cells are not used by PORTB.
DS30009605G-page 94
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
11.0
TIMER0 MODULE
The Timer0 module has the following features:
• Software selectable as an 8-bit or 16-bit timer/
counter
• Readable and writable
• Dedicated 8-bit software programmable prescaler
• Clock source selectable to be external or internal
• Interrupt-on-overflow from FFh to 00h in 8-bit
mode and FFFFh to 0000h in 16-bit mode
• Edge select for external clock
REGISTER 11-1:
Figure 11-1 shows a simplified block diagram of the
Timer0 module in 8-bit mode and Figure 11-2 shows a
simplified block diagram of the Timer0 module in 16-bit
mode.
The T0CON register (Register 11-1) is a readable and
writable register that controls all the aspects of Timer0,
including the prescale selection.
T0CON: TIMER0 CONTROL REGISTER
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
R/W-1/1
TMR0ON
T08BIT
T0CS
T0SE
PSA
T0PS2
T0PS1
T0PS0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
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
2002-2015 Microchip Technology Inc.
DS30009605G-page 95
PIC18F1220/1320
FIGURE 11-1:
TIMER0 BLOCK DIAGRAM IN 8-BIT MODE
Data Bus
FOSC/4
RA4/T0CKI
pin
0
8
1
Sync with
Internal
Clocks
1
Programmable
Prescaler
TMR0
0
(2 TCY Delay)
T0SE
3
PSA
Set Interrupt
Flag bit TMR0IF
on Overflow
T0PS2, T0PS1, T0PS0
T0CS
Note:
Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI maximum prescale.
FIGURE 11-2:
RA4/T0CKI
pin
TIMER0 BLOCK DIAGRAM IN 16-BIT MODE
FOSC/4
0
1
1
Programmable
Prescaler
0
T0SE
Sync with
Internal
Clocks
TMR0L
TMR0
High Byte
8
(2 TCY Delay)
3
Set Interrupt
Flag bit TMR0IF
on Overflow
Read TMR0L
T0PS2, T0PS1, T0PS0
T0CS
PSA
Write TMR0L
8
8
TMR0H
8
Data Bus
Note:
Upon Reset, Timer0 is enabled in 8-bit mode with clock input from T0CKI maximum prescale.
DS30009605G-page 96
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
11.1
11.2.1
Timer0 Operation
SWITCHING PRESCALER
ASSIGNMENT
Timer0 can operate as a timer or as a counter.
The prescaler assignment is fully under software
control (i.e., it can be changed “on-the-fly” during
program execution).
Timer mode is selected by clearing the T0CS bit. In
Timer mode, the Timer0 module will increment every
instruction cycle (without prescaler). If the TMR0 register is written, 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.
11.3
The TMR0 interrupt is generated when the TMR0 register overflows from FFh to 00h in 8-bit mode, or FFFFh
to 0000h in 16-bit mode. This overflow sets the TMR0IF
bit. The interrupt can be masked by clearing the
TMR0IE bit. The TMR0IF bit must be cleared in software by the Timer0 module Interrupt Service Routine
before re-enabling this interrupt. The TMR0 interrupt
cannot awaken the processor from Low-Power Sleep
mode, since the timer requires clock cycles even when
T0CS is set.
Counter mode is selected by setting the T0CS bit. In
Counter mode, Timer0 will increment either on every
rising or falling edge of pin RA4/T0CKI. The incrementing edge is determined by the Timer0 Source Edge
Select bit (T0SE). Clearing the T0SE bit selects the
rising edge.
When an external clock input is used for Timer0, it must
meet certain requirements. The requirements ensure
the external clock can be synchronized with the internal
phase clock (TOSC). Also, there is a delay in the actual
incrementing of Timer0 after synchronization.
11.2
11.4
Prescaler
The PSA and T0PS2:T0PS0 bits determine the
prescaler assignment and prescale ratio.
Clearing bit PSA will assign the prescaler to the Timer0
module. When the prescaler is assigned to the Timer0
module, prescale values of 1:2, 1:4, ..., 1:256 are
selectable.
A write to the high byte of Timer0 must also take place
through the TMR0H Buffer register. Timer0 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.
When assigned to the Timer0 module, all instructions
writing to the TMR0 register (e.g., CLRF TMR0, MOVWF
TMR0, BSF TMR0, x, ..., etc.) will clear the prescaler
count.
Writing to TMR0 when the prescaler is
assigned to Timer0 will clear the prescaler
count, but will not change the prescaler
assignment.
TABLE 11-1:
Name
16-Bit Mode Timer Reads
and Writes
TMR0H is not the high byte of the timer/counter in
16-bit mode, but is actually a buffered version of the
high byte of Timer0 (refer to Figure 11-2). The high byte
of the Timer0 counter/timer is not directly readable nor
writable. 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.
An 8-bit counter is available as a prescaler for the Timer0
module. The prescaler is not readable or writable.
Note:
Timer0 Interrupt
REGISTERS ASSOCIATED WITH TIMER0
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
uuuu uuuu
TMR0L
Timer0 Module Low Byte Register
xxxx xxxx
TMR0H
Timer0 Module High Byte Register
0000 0000
0000 0000
0000 000x
0000 000u
INTCON
GIE/GIEH
PEIE/GIEL
TMR0IE
T0CON
TMR0ON
T08BIT
T0CS
TRISA
RA7(1)
RA6(1)
—
Legend:
Note 1:
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
T0SE
PSA
T0PS2
T0PS1
T0PS0
PORTA Data Direction Register
1111 1111
1111 1111
11-1 1111
11-1 1111
x = unknown, u = unchanged, – = unimplemented locations read as ‘0’. Shaded cells are not used by Timer0.
RA6 and RA7 are enabled as I/O pins, depending on the oscillator mode selected in Configuration Word 1H.
2002-2015 Microchip Technology Inc.
DS30009605G-page 97
PIC18F1220/1320
12.0
TIMER1 MODULE
The Timer1 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers: TMR1H and TMR1L)
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt-on-overflow from FFFFh to 0000h
• Reset from CCP module special event trigger
• Status of system clock operation
Figure 12-1 is a simplified block diagram of the Timer1
module.
REGISTER 12-1:
Register 12-1 details the Timer1 Control register. This
register controls the operating mode of the Timer1
module and contains the Timer1 Oscillator Enable bit
(T1OSCEN). Timer1 can be enabled or disabled by
setting or clearing control bit, TMR1ON (T1CON).
The Timer1 oscillator can be used as a secondary clock
source in power managed modes. When the T1RUN bit
is set, the Timer1 oscillator is providing the system
clock. If the Fail-Safe Clock Monitor is enabled and the
Timer1 oscillator fails while providing the system clock,
polling the T1RUN bit will indicate whether the clock is
being provided by the Timer1 oscillator or another
source.
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.
T1CON: TIMER1 CONTROL REGISTER
R/W-0/0
R-1/1
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
RD16
T1RUN
T1CKPS1
T1CKPS0
T1OSCEN
T1SYNC
TMR1CS
TMR1ON
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
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 = System clock is derived from Timer1 oscillator
0 = System 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 RB6/PGC/T1OSO/T13CKI/P1C/KBI2 (on the rising edge)
0 = Internal clock (Fosc/4)
bit 0
TMR1ON: Timer1 On bit
1 = Enables Timer1
0 = Stops Timer1
DS30009605G-page 98
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
12.1
Timer1 Operation
When TMR1CS = 0, Timer1 increments every instruction cycle. When TMR1CS = 1, Timer1 increments on
every rising edge of the external clock input, or the Timer1 oscillator, if enabled.
Timer1 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RB7/PGD/T1OSI/P1D/KBI3 and RB6/T1OSO/
T13CKI/P1C/KBI2 pins become inputs. That is, the
TRISB7:TRISB6 values are ignored and the pins read
as ‘0’.
The operating mode is determined by the clock select
bit, TMR1CS (T1CON).
Timer1 also has an internal “Reset input”. This Reset
can be generated by the CCP module (see
Section 15.4.4 “Special Event Trigger”).
FIGURE 12-1:
TIMER1 BLOCK DIAGRAM
CCP Special Event Trigger
TMR1IF
Overflow
Interrupt
Flag bit
TMR1
TMR1H
Synchronized
Clock Input
0
CLR
TMR1L
1
TMR1ON
On/Off
T1OSC
T13CKI/T1OSO
T1OSCEN
Enable
Oscillator(1)
T1OSI
T1SYNC
1
Synchronize
Prescaler
1, 2, 4, 8
FOSC/4
Internal
Clock
det
0
2
T1CKPS1:T1CKPS0
Peripheral Clocks
TMR1CS
Note 1:
When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off. This eliminates
power drain.
FIGURE 12-2:
TIMER1 BLOCK DIAGRAM: 16-BIT READ/WRITE MODE
Data Bus
8
TMR1H
8
8
Write TMR1L
CCP Special Event Trigger
Read TMR1L
TMR1IF
Overflow
Interrupt
Flag bit
TMR1
8
Timer 1
High Byte
Synchronized
Clock Input
0
CLR
TMR1L
1
TMR1ON
on/off
T1OSC
T13CKI/T1OSO
T1OSI
T1SYNC
1
T1OSCEN
Enable
Oscillator(1)
FOSC/4
Internal
Clock
Prescaler
1, 2, 4, 8
Synchronize
det
0
2
TMR1CS
Peripheral Clocks
T1CKPS1:T1CKPS0
Note 1:
When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
2002-2015 Microchip Technology Inc.
DS30009605G-page 99
PIC18F1220/1320
12.2
Timer1 Oscillator
FIGURE 12-3:
A crystal oscillator circuit is built-in between pins T1OSI
(input) and T1OSO (amplifier output). It is enabled by
setting control bit, T1OSCEN (T1CON). The oscillator is a low-power oscillator 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 12-3. Table 12-1 shows the capacitor selection
for the Timer1 oscillator.
C1
22 pF
The Timer1 oscillator shares the T1OSI
and T1OSO pins with the PGD and PGC
pins used for programming and
debugging.
When using the Timer1 oscillator, In-Circuit
Serial Programming (ICSP) may not
function correctly (high voltage or low
voltage), or the In-Circuit Debugger (ICD)
may not communicate with the controller.
As a result of using either ICSP or ICD, the
Timer1 crystal may be damaged.
If ICSP or ICD operations are required,
the crystal should be disconnected from
the circuit (disconnect either lead), or
installed after programming. The oscillator
loading capacitors may remain in-circuit
during ICSP or ICD operation.
PGD
PIC18FXXXX
PGD/T1OSI
XTAL
32.768 kHz
The user must provide a software time delay to ensure
proper start-up of the Timer1 oscillator.
Note:
EXTERNAL
COMPONENTS FOR THE
TIMER1 LP OSCILLATOR
PGC/T1OSO
C2
22 pF
Note:
PGC
See the Notes with Table 12-1 for additional
information about capacitor selection.
TABLE 12-1:
CAPACITOR SELECTION FOR
THE TIMER OSCILLATOR
Osc Type
Freq
C1
C2
LP
32 kHz
22 pF(1)
22 pF(1)
Note 1: Microchip suggests this value as a
starting point in validating the oscillator
circuit. Oscillator operation should then
be
tested
to
ensure
expected
performance
under
all
expected
conditions (VDD and temperature).
2: Higher capacitance increases the stability of the oscillator, but also increases the
start-up time.
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.
DS30009605G-page 100
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
12.3
Timer1 Oscillator Layout
Considerations
12.5
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 12-3, 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 12-4, may be helpful when used on a
single sided PCB, or in addition to a ground plane.
FIGURE 12-4:
OSCILLATOR CIRCUIT
WITH GROUNDED
GUARD RING
RA1
RB2
RA4
OSC1
MCLR
OSC2
C2
X1
C3
VSS
VDD
C1
RA2
RB7
RA3
RB6
C4
X2
C5
RB0
RB5
Note: Not drawn to scale.
12.4
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/disabled by
setting/clearing Timer1 Interrupt Enable bit, TMR1IE
(PIE1).
2002-2015 Microchip Technology Inc.
Resetting Timer1 Using a CCP
Trigger Output
If the CCP module is configured in Compare mode to
generate
a
“special
event
trigger”
(CCP1M3:CCP1M0 = 1011), this signal will reset
Timer1 and start an A/D conversion, if the A/D module is enabled (see Section 15.4.4 “Special Event
Trigger” for more information).
Note:
The special event triggers from the CCP1
module will not set interrupt flag bit,
TMR1IF (PIR1).
Timer1 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature.
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 from CCP1, the write will take
precedence.
In this mode of operation, the CCPR1H:CCPR1L
register pair effectively becomes the period register for
Timer1.
12.6
Timer1 16-Bit Read/Write Mode
Timer1 can be configured for 16-bit reads and writes
(see Figure 12-2). 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, is
valid, due to a rollover between reads.
A write to the high byte of Timer1 must also take place
through the TMR1H Buffer register. 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.
DS30009605G-page 101
PIC18F1220/1320
12.7
Using Timer1 as a
Real-Time Clock
Adding an external LP oscillator to Timer1 (such as the
one described in Section 12.2 “Timer1 Oscillator”,
above), 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.
Since the register pair is 16 bits wide, counting up to
overflow the register directly from a 32.768 kHz clock
would take two 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 error 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.
The application code routine, RTCisr, shown in
Example 12-1, 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.
EXAMPLE 12-1:
IMPLEMENTING A REAL-TIME CLOCK USING A TIMER1 INTERRUPT SERVICE
RTCinit
MOVLW
MOVWF
CLRF
MOVLW
MOVWF
CLRF
CLRF
MOVLW
MOVWF
BSF
RETURN
0x80
TMR1H
TMR1L
b’00001111’
T1OSC
secs
mins
.12
hours
PIE1, TMR1IE
BSF
BCF
INCF
MOVLW
CPFSGT
RETURN
CLRF
INCF
MOVLW
CPFSGT
RETURN
CLRF
INCF
MOVLW
CPFSGT
RETURN
MOVLW
MOVWF
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
DS30009605G-page 102
secs
mins, F
.59
mins
mins
hours, F
.23
hours
.01
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 to 1
; Done
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 12-2:
Name
Bit 7
REGISTERS ASSOCIATED WITH TIMER1 AS A TIMER/COUNTER
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x 0000 000u
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000 -000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000 -000 -000
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111 -111 -111
INTCON
GIE/GIEH PEIE/GIEL
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
T1CON
Legend:
RD16
T1RUN
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC TMR1CS TMR1ON 0000 0000 u0uu uuuu
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Timer1 module.
2002-2015 Microchip Technology Inc.
DS30009605G-page 103
PIC18F1220/1320
13.0
TIMER2 MODULE
13.1
The Timer2 module timer has the following features:
•
•
•
•
•
•
8-bit timer (TMR2 register)
8-bit period register (PR2)
Readable and writable (both registers)
Software programmable prescaler (1:1, 1:4, 1:16)
Software programmable postscaler (1:1 to 1:16)
Interrupt on TMR2 match with PR2
Timer2 has a control register shown in Register 13-1.
TMR2 can be shut off by clearing control bit, TMR2ON
(T2CON), to minimize power consumption.
Figure 13-1 is a simplified block diagram of the Timer2
module. Register 13-1 shows the Timer2 Control
register. The prescaler and postscaler selection of
Timer2 are controlled by this register.
Timer2 Operation
Timer2 can be used as the PWM time base for the
PWM mode of the CCP module. The TMR2 register is
readable and writable and is cleared on any device
Reset. The input clock (FOSC/4) has a prescale option
of 1:1, 1:4 or 1:16, selected by control bits,
T2CKPS1:T2CKPS0 (T2CON). The match output of TMR2 goes through a 4-bit postscaler (which
gives a 1:1 to 1:16 scaling inclusive) to generate a
TMR2 interrupt (latched in flag bit, TMR2IF (PIR1)).
The prescaler and postscaler counters are cleared
when any of the following occurs:
• 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 13-1:
T2CON: TIMER2 CONTROL REGISTER
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
—
TOUTPS3
TOUTPS2
TOUTPS1
TOUTPS0
TMR2ON
T2CKPS1
T2CKPS0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
Unimplemented: Read as ‘0’
bit 6-3
TOUTPS: 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
DS30009605G-page 104
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
13.2
Timer2 Interrupt
13.3
The Timer2 module has an 8-bit period register, PR2.
Timer2 increments from 00h until it matches PR2 and
then resets to 00h on the next increment cycle. PR2 is
a readable and writable register. The PR2 register is
initialized to FFh upon Reset.
FIGURE 13-1:
Output of TMR2
The output of TMR2 (before the postscaler) is fed to the
Synchronous Serial Port module, which optionally uses
it to generate the shift clock.
TIMER2 BLOCK DIAGRAM
Sets Flag
bit TMR2IF
TMR2
Output(1)
Prescaler
1:1, 1:4, 1:16
FOSC/4
TMR2
2
Reset
Comparator
EQ
Postscaler
1:1 to 1:16
T2CKPS1:T2CKPS0
4
PR2
TOUTPS3:TOUTPS0
TABLE 13-1:
Name
Bit 7
REGISTERS ASSOCIATED WITH TIMER2 AS A TIMER/COUNTER
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Value on
all other
Resets
Bit 0
Value on
POR, BOR
0000 000x 0000 000u
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000 -000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000 -000 -000
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111 -111 -111
INTCON GIE/GIEH PEIE/GIEL
TMR2
T2CON
PR2
Legend:
Timer2 Module Register
—
0000 0000 0000 0000
TOUTPS3 TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
Timer2 Period Register
1111 1111 1111 1111
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Timer2 module.
2002-2015 Microchip Technology Inc.
DS30009605G-page 105
PIC18F1220/1320
14.0
TIMER3 MODULE
Figure 14-1 is a simplified block diagram of the Timer3
module.
The Timer3 module timer/counter has the following
features:
• 16-bit timer/counter
(two 8-bit registers; TMR3H and TMR3L)
• Readable and writable (both registers)
• Internal or external clock select
• Interrupt-on-overflow from FFFFh to 0000h
• Reset from CCP module trigger
REGISTER 14-1:
Register 14-1 shows the Timer3 Control register. This
register controls the operating mode of the Timer3
module and sets the CCP clock source.
Register 12-1 shows the Timer1 Control register. This
register controls the operating mode of the Timer1
module, as well as contains the Timer1 Oscillator
Enable bit (T1OSCEN), which can be a clock source for
Timer3.
T3CON: TIMER3 CONTROL REGISTER
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
RD16
—
T3CKPS1
T3CKPS0
T3CCP1
T3SYNC
TMR3CS
TMR3ON
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
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
Unimplemented: Read as ‘0’
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 3
T3CCP1: Timer3 and Timer1 to CCP1 Enable bits
1 = Timer3 is the clock source for compare/capture CCP module
0 = Timer1 is the clock source for compare/capture CCP module
bit 2
T3SYNC: Timer3 External Clock Input Synchronization Control bit
(Not usable if the system 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
DS30009605G-page 106
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
14.1
Timer3 Operation
When TMR3CS = 0, Timer3 increments every instruction cycle. When TMR3CS = 1, Timer3 increments on
every rising edge of the Timer1 external clock input or
the Timer1 oscillator, if enabled.
Timer3 can operate in one of these modes:
• As a timer
• As a synchronous counter
• As an asynchronous counter
When the Timer1 oscillator is enabled (T1OSCEN is
set), the RB7/PGD/T1OSI/P1D/KBI3 and RB6/PGC/
T1OSO/T13CKI/P1C/KBI2 pins become inputs. That
is, the TRISB7:TRISB6 value is ignored and the pins
are read as ‘0’.
The operating mode is determined by the clock select
bit, TMR3CS (T3CON).
Timer3 also has an internal “Reset input”. This Reset
can be generated by the CCP module (see
Section 15.4.4 “Special Event Trigger”).
FIGURE 14-1:
TIMER3 BLOCK DIAGRAM
CCP Special Event Trigger
T3CCPx
TMR3IF
Overflow
Interrupt
Flag bit
TMR3H
Synchronized
Clock Input
0
CLR
TMR3L
1
TMR3ON
On/Off
T3SYNC
T1OSC
T1OSO/
T13CKI
1
T1OSCEN FOSC/4
Enable
Internal
Oscillator(1) Clock
T1OSI
Synchronize
Prescaler
1, 2, 4, 8
det
0
2
Peripheral Clocks
TMR3CS
T3CKPS1:T3CKPS0
Note 1:
When enable bit, T1OSCEN, is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
FIGURE 14-2:
TIMER3 BLOCK DIAGRAM CONFIGURED IN 16-BIT READ/WRITE MODE
Data Bus
8
TMR3H
8
8
Write TMR3L
Read TMR3L
Set TMR3IF Flag bit
on Overflow
8
CCP Special Event Trigger
T3CCPx
Synchronized
TMR3
Timer3
High Byte
0
TMR3L
Clock Input
CLR
1
To Timer1 Clock Input
T1OSO/
T13CKI
T1OSI
TMR3ON
On/Off
T3SYNC
T1OSC
1
T1OSCEN
Enable
Oscillator(1)
FOSC/4
Internal
Clock
Synchronize
Prescaler
1, 2, 4, 8
det
0
2
T3CKPS1:T3CKPS0
Peripheral
Clocks
TMR3CS
Note 1:
When the T1OSCEN bit is cleared, the inverter and feedback resistor are turned off. This eliminates power drain.
2002-2015 Microchip Technology Inc.
DS30009605G-page 107
PIC18F1220/1320
14.2
Timer1 Oscillator
14.4
The Timer1 oscillator may be used as the clock source
for Timer3. The Timer1 oscillator is enabled by setting
the T1OSCEN (T1CON) bit. The oscillator is a lowpower oscillator rated for 32 kHz crystals. See
Section 12.2 “Timer1 Oscillator” for further details.
14.3
If the CCP module is configured in Compare mode
to
generate
a
“special
event
trigger”
(CCP1M3:CCP1M0 = 1011), this signal will reset
Timer3. See Section 15.4.4 “Special Event Trigger”
for more information.
Timer3 Interrupt
Note:
The TMR3 register pair (TMR3H:TMR3L) increments
from 0000h to FFFFh and rolls over to 0000h. The
TMR3 interrupt, if enabled, is generated on overflow,
which is latched in interrupt flag bit, TMR3IF
(PIR2). This interrupt can be enabled/disabled by
setting/clearing TMR3 Interrupt Enable bit, TMR3IE
(PIE2).
TABLE 14-1:
Resetting Timer3 Using a CCP
Trigger Output
The special event triggers from the CCP
module will not set interrupt flag bit,
TMR3IF (PIR1).
Timer3 must be configured for either Timer or Synchronized Counter mode to take advantage of this feature.
If Timer3 is running in Asynchronous Counter mode,
this Reset operation may not work. In the event that a
write to Timer3 coincides with a special event trigger
from CCP1, the write will take precedence. In this mode
of operation, the CCPR1H:CCPR1L register pair
effectively becomes the period register for Timer3.
REGISTERS ASSOCIATED WITH TIMER3 AS A TIMER/COUNTER
Value on
all other
Resets
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
INTCON
GIE/
GIEH
PEIE/
GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x 0000 000u
PIR2
OSCFIF
—
—
EEIF
—
LVDIF
TMR3IF
—
0--0 -00- 0--0 -00-
PIE2
OSCFIE
—
—
EEIE
—
LVDIE
TMR3IE
—
0--0 -00- 0--0 -00-
IPR2
OSCFIP
—
—
EEIP
—
LVDIP
TMR3IP
—
1--1 -11- 1--1 -11-
TMR3L
Holding Register for the Least Significant Byte of the 16-bit TMR3 Register
xxxx xxxx uuuu uuuu
TMR3H
Holding Register for the Most Significant Byte of the 16-bit TMR3 Register
xxxx xxxx uuuu uuuu
T1CON
RD16
T1RUN
T3CON
RD16
—
Legend:
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by the Timer3 module.
DS30009605G-page 108
T1CKPS1 T1CKPS0 T1OSCEN
T1SYNC
TMR1CS TMR1ON 0000 0000 u0uu uuuu
T3CKPS1 T3CKPS0
T3SYNC
TMR3CS TMR3ON 0-00 0000 u-uu uuuu
T3CCP1
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
15.0
ENHANCED CAPTURE/
COMPARE/PWM (ECCP)
MODULE
The control register for CCP1 is shown in Register 15-1.
The Enhanced CCP module is implemented as a
standard CCP module with Enhanced PWM
capabilities. These capabilities allow for two or four
output channels, user-selectable polarity, dead-band
control and automatic shutdown and restart and are
discussed in detail in Section 15.5 “Enhanced PWM
Mode”.
REGISTER 15-1:
In addition to the expanded functions of the CCP1CON
register, the ECCP module has two additional
registers associated with Enhanced PWM operation
and auto-shutdown features:
• PWM1CON
• ECCPAS
CCP1CON REGISTER FOR ENHANCED CCP OPERATION
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
P1M1
P1M0
DC1B1
DC1B0
CCP1M3
CCP1M2
CCP1M1
CCP1M0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-6
P1M: PWM Output Configuration bits
If CCP1M = 00, 01, 10:
xx = P1A assigned as Capture/Compare input; 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 Least Significant bits
Capture mode:
Unused.
Compare mode:
Unused.
PWM mode:
These bits are the two LSbs of the PWM duty cycle. The eight MSbs are found in CCPR1L.
bit 3-0
CCP1M: ECCP1 Mode Select bits
0000 = Capture/Compare/PWM off (resets ECCP module)
0001 = Unused (reserved)
0010 = Compare mode, toggle output on match (ECCP1IF bit is set)
0011 = Unused (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, set output on match (ECCP1IF bit is set)
1001 = Compare mode, clear output on match (ECCP1IF bit is set)
1010 = Compare mode, generate software interrupt on match (ECCP1IF bit is set,
ECCP1 pin returns to port pin operation)
1011 = Compare mode, trigger special event (ECCP1IF bit is set; ECCP resets TMR1 or
TMR3 and starts an A/D conversion if the A/D module is enabled)
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
2002-2015 Microchip Technology Inc.
DS30009605G-page 109
PIC18F1220/1320
15.1
ECCP Outputs
The Enhanced CCP module may have up to four
outputs, depending on the selected operating mode.
These outputs, designated P1A through P1D, are
multiplexed with I/O pins on PORTB. The pin
assignments are summarized in Table 15-1.
TABLE 15-1:
To configure I/O pins as PWM outputs, the proper PWM
mode must be selected by setting the P1Mn and
CCP1Mn
bits
(CCP1CON
and
,
respectively). The appropriate TRISB direction bits for
the port pins must also be set as outputs.
PIN ASSIGNMENTS FOR VARIOUS ECCP MODES
ECCP Mode
CCP1CON
Configuration
RB3
RB2
RB6
RB7
Compatible CCP
00xx 11xx
CCP1
RB2/INT2
RB6/PGC/T1OSO/T13CKI/KBI2
RB7/PGD/T1OSI/KBI3
Dual PWM
10xx 11xx
P1A
P1B
RB6/PGC/T1OSO/T13CKI/KBI2
RB7/PGD/T1OSI/KBI3
x1xx 11xx
P1A
P1B
P1C
P1D
Quad PWM
Legend:
Note 1:
15.2
x = Don’t care. Shaded cells indicate pin assignments not used by ECCP in a given mode.
TRIS register values must be configured appropriately.
CCP Module
15.3.1
Capture/Compare/PWM Register 1 (CCPR1) is comprised of two 8-bit registers: CCPR1L (low byte) and
CCPR1H (high byte). The CCP1CON register controls
the operation of CCP1. All are readable and writable.
TABLE 15-2:
15.3
CCP MODE – TIMER
RESOURCE
CCP Mode
Timer Resource
Capture
Compare
PWM
Timer1 or Timer3
Timer1 or Timer3
Timer2
Capture Mode
In Capture mode, CCPR1H:CCPR1L captures the 16-bit
value of the TMR1 or TMR3 registers when an event
occurs on pin RB3/CCP1/P1A. An event is defined as
one of the following:
•
•
•
•
every falling edge
every rising edge
every 4th rising edge
every 16th rising edge
CCP PIN CONFIGURATION
In Capture mode, the RB3/CCP1/P1A pin should be
configured as an input by setting the TRISB bit.
Note:
15.3.2
If the RB3/CCP1/P1A is configured as an
output, a write to the port can cause a
capture condition.
TIMER1/TIMER3 MODE SELECTION
The timers that are to be used with the capture feature
(either Timer1 and/or Timer3) must be running in Timer
mode or Synchronized Counter mode. In Asynchronous Counter mode, the capture operation may not
work. The timer to be used with the CCP module is
selected in the T3CON register.
15.3.3
SOFTWARE INTERRUPT
When the Capture mode is changed, a false capture
interrupt may be generated. The user should keep bit,
CCP1IE (PIE1), clear while changing capture
modes to avoid false interrupts and should clear the
flag bit, CCP1IF, following any such change in
operating mode.
The event is selected by control bits, CCP1M3:CCP1M0
(CCP1CON). When a capture is made, the interrupt request flag bit, CCP1IF (PIR1), is set; it must
be cleared in software. If another capture occurs before
the value in register CCPR1 is read, the old captured
value is overwritten by the new captured value.
DS30009605G-page 110
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
15.3.4
CCP PRESCALER
There are four prescaler settings, specified by bits
CCP1M3:CCP1M0. Whenever the CCP module is
turned off or the CCP module is not in Capture mode,
the prescaler counter is cleared. This means that any
Reset will clear the prescaler counter.
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 15-1 shows the
FIGURE 15-1:
recommended method for switching between capture
prescalers. This example also clears the prescaler
counter and will not generate the “false” interrupt.
EXAMPLE 15-1:
CHANGING BETWEEN
CAPTURE PRESCALERS
CLRF
MOVLW
CCP1CON
NEW_CAPT_PS
MOVWF
CCP1CON
;
;
;
;
;
;
Turn CCP module off
Load WREG with the
new prescaler mode
value and CCP ON
Load CCP1CON with
this value
CAPTURE MODE OPERATION BLOCK DIAGRAM
TMR3H
TMR3L
Set Flag bit CCP1IF
Prescaler
1, 4, 16
T3CCP1
CCP1 pin
TMR3
Enable
CCPR1H
and
Edge Detect
T3CCP1
CCPR1L
TMR1
Enable
TMR1H
TMR1L
CCP1CON
Q’s
15.4
Compare Mode
15.4.2
TIMER1/TIMER3 MODE SELECTION
In Compare mode, the 16-bit CCPR1 register value is
constantly compared against either the TMR1 register
pair value, or the TMR3 register pair value. When a
match occurs, the RB3/CCP1/P1A pin:
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.
•
•
•
•
15.4.3
Is driven high
Is driven low
Toggles output (high-to-low or low-to-high)
Remains unchanged (interrupt only)
The action on the pin is based on the value of control
bits, CCP1M3:CCP1M0. At the same time, interrupt
flag bit, CCP1IF, is set.
15.4.1
CCP PIN CONFIGURATION
The user must configure the RB3/CCP1/P1A pin as an
output by clearing the TRISB bit.
Note:
Clearing the CCP1CON register will force
the RB3/CCP1/P1A compare output latch
to the default low level. This is not the
PORTB I/O data latch.
2002-2015 Microchip Technology Inc.
SOFTWARE INTERRUPT MODE
When generate software interrupt is chosen, the RB3/
CCP1/P1A pin is not affected. CCP1IF is set and an
interrupt is generated (if enabled).
15.4.4
SPECIAL EVENT TRIGGER
In this mode, an internal hardware trigger is generated,
which may be used to initiate an action.
The special event trigger output of CCP1 resets the
TMR1 register pair. This allows the CCPR1 register to
effectively be a 16-bit programmable period register for
Timer1.
The special event trigger also sets the GO/DONE bit
(ADCON0). This starts a conversion of the
currently selected A/D channel if the A/D is on.
DS30009605G-page 111
PIC18F1220/1320
FIGURE 15-2:
COMPARE MODE OPERATION BLOCK DIAGRAM
Special Event Trigger will:
Reset Timer1 or Timer3, but does not set Timer1 or Timer3 interrupt flag bit
and set bit GO/DONE (ADCON0), which starts an A/D conversion.
Special Event Trigger
Set Flag bit CCP1IF
CCPR1H CCPR1L
Q
RB3/CCP1/P1A pin
S
Output
Logic
R
TRISB
Output Enable
Comparator
Match
CCP1CON
Mode Select
TMR1H
TABLE 15-3:
Name
INTCON
0
T3CCP1
TMR1L
1
TMR3H
TMR3L
REGISTERS ASSOCIATED WITH CAPTURE, COMPARE, TIMER1 AND TIMER3
Bit 7
Bit 6
GIE/GIEH PEIE/GIEL
Value on
all other
Resets
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x 0000 000u
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF -000 -000 -000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE -000 -000 -000 -000
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP -111 -111 -111 -111
IPR1
TRISB
PORTB Data Direction Register
1111 1111 1111 1111
TMR1L
Holding Register for the Least Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
TMR1H
Holding Register for the Most Significant Byte of the 16-bit TMR1 Register
xxxx xxxx uuuu uuuu
T1CON
RD16
T1RUN
T1CKPS1 T1CKPS0 T1OSCEN T1SYNC
CCPR1L
Capture/Compare/PWM Register 1 (LSB)
CCPR1H
Capture/Compare/PWM Register 1 (MSB)
CCP1CON
P1M1
P1M0
DC1B1
DC1B0
TMR1CS TMR1ON 0000 0000 uuuu uuuu
xxxx xxxx uuuu uuuu
xxxx xxxx uuuu uuuu
CCP1M3
CCP1M2
CCP1M1
CCP1M0 0000 0000 0000 0000
TMR3L
Holding Register for the Least Significant Byte of the 16-bit TMR3 Register
xxxx xxxx uuuu uuuu
TMR3H
Holding Register for the Most Significant Byte of the 16-bit TMR3 Register
xxxx xxxx uuuu uuuu
T3CON
ADCON0
Legend:
RD16
—
VCFG1
VCFG0
T3CKPS1 T3CKPS0
—
CHS2
T3CCP1
T3SYNC
CHS1
CHS0
TMR3CS TMR3ON 0-00 0000 u-uu uuuu
GO/DONE
ADON
00-0 0000 00-0 0000
x = unknown, u = unchanged, – = unimplemented, read as ‘0’. Shaded cells are not used by Capture and Timer1.
DS30009605G-page 112
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
15.5
Enhanced PWM Mode
15.5.2
The Enhanced PWM Mode provides additional PWM
output options for a broader range of control applications. The module is an upwardly 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 P1M1:P1M0 and
CCP1M3CCP1M0 bits of the CCP1CON register
(CCP1CON and CCP1CON, respectively).
Figure 15-3 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
Delay register, ECCP1DEL, which is loaded at either the
duty cycle boundary or the boundary period (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).
As before, the user must manually configure the
appropriate TRIS bits for output.
15.5.1
PWM PERIOD
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 equation:
EQUATION 15-2:
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 equation:
EQUATION 15-3:
(
) bits
PWM PERIOD
Note:
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 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
15.5.3
If the PWM duty cycle value is longer than
the PWM period, the CCP1 pin will not be
cleared.
PWM OUTPUT CONFIGURATIONS
The P1M1:P1M0 bits in the CCP1CON register allow
one of four configurations:
•
•
•
•
The Timer2 postscaler (see Section 13.0
“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.
TABLE 15-4:
PWM RESOLUTION
log FOSC
FPWM
PWM Resolution (max) =
log(2)
PWM Period = [(PR2) + 1] • 4 • TOSC •
(TMR2 Prescale Value)
Note:
PWM DUTY CYCLE
PWM Duty Cycle = (CCPR1L:CCP1CON) •
TOSC • (TMR2 Prescale Value)
The PWM period is specified by writing to the PR2
register. The PWM period can be calculated using the
equation:
EQUATION 15-1:
PWM DUTY CYCLE
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 15.5 “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 15-4.
EXAMPLE PWM FREQUENCIES AND RESOLUTIONS AT 40 MHz
PWM Frequency
2.44 kHz
Timer Prescaler (1, 4, 16)
PR2 Value
Maximum Resolution (bits)
2002-2015 Microchip Technology Inc.
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
DS30009605G-page 113
PIC18F1220/1320
FIGURE 15-3:
SIMPLIFIED BLOCK DIAGRAM OF THE ENHANCED PWM MODULE
CCP1CON
Duty Cycle Registers
CCP1M
4
P1M1
2
CCPR1L
CCP1/P1A
RB3/CCP1/P1A
TRISB
CCPR1H (Slave)
P1B
R
Comparator
Output
Controller
Q
RB2/P1B/INT2
TRISB
RB6/PGC/T1OSO/T13CKI/
P1C/KBI2
P1C
TMR2
(Note 1)
TRISB
S
P1D
Comparator
Clear Timer,
set CCP1 pin and
latch D.C.
PR2
Note:
RB7/PGD/T1OSI/P1D/KBI3
TRISB
CCP1DEL
The 8-bit TMR2 register is concatenated with the 2-bit internal Q clock, or two bits of the prescaler to create the
10-bit time base.
FIGURE 15-4:
PWM OUTPUT RELATIONSHIPS (ACTIVE-HIGH STATE)
0
CCP1CON
PR2+1
Duty
Cycle
SIGNAL
Period
00
(Single Output)
P1A Modulated
Delay(1)
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
DS30009605G-page 114
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 15-5:
PWM OUTPUT RELATIONSHIPS (ACTIVE-LOW STATE)
0
CCP1CON
PR2+1
Duty
Cycle
SIGNAL
Period
00
(Single Output)
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 * (PWM1CON)
Note 1: Dead-band delay is programmed using the PWM1CON register (Section 15.5.6 “Programmable Dead-Band
Delay”).
2002-2015 Microchip Technology Inc.
DS30009605G-page 115
PIC18F1220/1320
15.5.4
HALF-BRIDGE MODE
The TRISB and TRISB bits must be cleared to
configure P1A and P1B as outputs.
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 RB3/CCP1/P1A pin, while the
complementary PWM output signal is output on the
RB2/P1B/INT2 pin (Figure 15-6). This mode can be
used for half-bridge applications, as shown in
Figure 15-7, or for full-bridge applications, where four
power switches are being modulated with two PWM
signals.
FIGURE 15-6:
Period
Period
Duty Cycle
P1A
td
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,
PDC6:PDC0 (PWM1CON), 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 15.5.6 “Programmable Dead-Band Delay”
for more details of the dead-band delay operations.
FIGURE 15-7:
HALF-BRIDGE PWM
OUTPUT (ACTIVE-HIGH)
td
P1B
(1)
(1)
(1)
td = Dead-Band Delay
Note 1:At this time, the TMR2 register is equal to the
PR2 register.
EXAMPLES OF HALF-BRIDGE OUTPUT MODE APPLICATIONS
Standard Half-Bridge Circuit (“Push-Pull”)
PIC18F1220/1320
FET
Driver
+
V
-
P1A
Load
FET
Driver
+
V
-
P1B
Half-Bridge Output Driving a Full-Bridge Circuit
V+
PIC18F1220/1320
FET
Driver
FET
Driver
P1A
FET
Driver
Load
FET
Driver
P1B
V-
DS30009605G-page 116
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
15.5.5
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 RB3/CCP1/P1A is continuously active and pin RB7/PGD/T1OSI/P1D/KBI3 is
modulated. In the Reverse mode, pin RB6/PGC/
T1OSO/T13CKI/P1C/KBI2 is continuously active and
pin RB2/P1B/INT2 is modulated. These are illustrated
in Figure 15-8.
FIGURE 15-8:
The TRISB and TRISB bits must be cleared
to make the P1A, P1B, P1C and P1D pins output.
FULL-BRIDGE PWM OUTPUT (ACTIVE-HIGH)
Forward Mode
Period
P1A
Duty Cycle
P1B
P1C
P1D
(1)
(1)
Reverse Mode
Period
Duty Cycle
P1A
P1B
P1C
P1D
(1)
Note 1:
(1)
At this time, the TMR2 register is equal to the PR2 register.
2002-2015 Microchip Technology Inc.
DS30009605G-page 117
PIC18F1220/1320
FIGURE 15-9:
EXAMPLE OF FULL-BRIDGE APPLICATION
V+
PIC18F1220/1320
FET
Driver
QC
QA
FET
Driver
P1A
Load
P1B
FET
Driver
P1C
FET
Driver
QD
QB
VP1D
15.5.5.1
Direction Change in Full-Bridge Mode
In the Full-Bridge Output mode, the P1M1 bit in the
CCP1CON register allows the 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 bit (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 15-10.
Note that in the Full-Bridge Output mode, the ECCP
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 15-11 shows an example where the PWM direction changes from forward to reverse, at a near 100%
duty cycle. At time t1, the output 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 15-9) 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.
DS30009605G-page 118
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 15-10:
PWM DIRECTION CHANGE (ACTIVE-HIGH)
PWM Period(1)
SIGNAL
PWM Period
P1A
P1B
DC
P1C
One Timer2 Count(2)
P1D
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 toggle one Timer2 count before the end of the current PWM cycle.
The modulated P1B and P1D signals are inactive at this time.
FIGURE 15-11:
PWM DIRECTION CHANGE AT NEAR 100% DUTY CYCLE (ACTIVE-HIGH)
Forward Period
t1
Reverse Period
P1A
P1B
DC
P1C
P1D
DC
tON
External Switch C
tOFF
External Switch D
Potential
Shoot-Through
Current
Note 1:
t = tOFF – tON
tON is the turn-on delay of power switch QC and its driver.
2: tOFF is the turn-off delay of power switch QD and its driver.
2002-2015 Microchip Technology Inc.
DS30009605G-page 119
PIC18F1220/1320
15.5.6
PROGRAMMABLE DEAD-BAND
DELAY
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.
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:
Writing to the ECCPASE bit is disabled
while a shutdown condition is active.
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 non-active
state to the active state. See Figure 15-6 for an illustration. The lower seven bits of the PWM1CON register
(Register 15-2) sets the delay period in terms of
microcontroller instruction cycles (TCY or 4 TOSC).
15.5.7
ENHANCED PWM
AUTO-SHUTDOWN
When the ECCP 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.
A shutdown event can be caused by the INT0, INT1 or
INT2 pins (or any combination of these three sources).
The auto-shutdown feature can be disabled by not
selecting any auto-shutdown sources. The autoshutdown sources to be used are selected using the
ECCPAS2:ECCPAS0 bits (bits of the ECCPAS
register).
When a shutdown occurs, the output pins are
asynchronously placed in their shutdown states, specified by the PSSAC1:PSSAC0 and PSSBD1:PSSBD0
bits (ECCPAS). Each pin pair (P1A/P1C and
P1B/P1D) may be set to drive high, drive low or be tristated (not driving). The ECCPASE bit (ECCPAS)
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.
DS30009605G-page 120
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 15-2:
PWM1CON: PWM CONFIGURATION REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
PRSEN
PDC6
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
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
Number of FOSC/4 (4 * TOSC) cycles between the scheduled time when a PWM signal should
transition active and the actual time it transitions active.
2002-2015 Microchip Technology Inc.
DS30009605G-page 121
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REGISTER 15-3:
ECCPAS: ENHANCED CAPTURE/COMPARE/PWM/AUTO-SHUTDOWN
CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
ECCPASE
ECCPAS2
ECCPAS1
ECCPAS0
PSSAC1
PSSAC0
PSSBD1
PSSBD0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
ECCPASE: ECCP Auto-Shutdown Event Status bit
0 = ECCP outputs are operating
1 = A shutdown event has occurred; ECCP outputs are in shutdown state
bit 6
ECCPAS2: ECCP Auto-Shutdown bit 2
0 = INT0 pin has no effect
1 = INT0 pin low causes shutdown
bit 5
ECCPAS1: ECCP Auto-Shutdown bit 1
0 = INT2 pin has no effect
1 = INT2 pin low causes shutdown
bit 4
ECCPAS0: ECCP Auto-Shutdown bit 0
0 = INT1 pin has no effect
1 = INT1 pin low causes shutdown
bit 3-2
PSSACn: Pins A and C Shutdown State Control bits
00 = Drive Pins A and C to ‘0’
01 = Drive Pins A and C to ‘1’
1x = Pins A and C tri-state
bit 1-0
PSSBDn: Pins B and D Shutdown State Control bits
00 = Drive Pins B and D to ‘0’
01 = Drive Pins B and D to ‘1’
1x = Pins B and D tri-state
DS30009605G-page 122
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
15.5.7.1
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
PWM1CON register (PWM1CON).
In Shutdown mode with PRSEN = 1 (Figure 15-12), the
ECCPASE bit will remain set for as long as the cause
of the shutdown continues. When the shutdown
condition clears, the ECCPASE bit is automatically
cleared. If PRSEN = 0 (Figure 15-13), 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, 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 15-12:
15.5.8
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 CCP1M1:CCP1M0 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 Period
PWM Period
PWM Activity
Dead Time
Duty Cycle
Dead Time
Duty Cycle
Dead Time
Duty Cycle
Shutdown Event
ECCPASE bit
FIGURE 15-13:
PWM AUTO-SHUTDOWN (PRSEN = 0, AUTO-RESTART DISABLED)
PWM Period
PWM Period
PWM Period
PWM Activity
Dead Time
Duty Cycle
Dead Time
Duty Cycle
Dead Time
Duty Cycle
Shutdown Event
ECCPASE bit
ECCPASE
Cleared by Firmware
2002-2015 Microchip Technology Inc.
DS30009605G-page 123
PIC18F1220/1320
15.5.9
SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the ECCP1 module for PWM operation:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Configure the PWM pins P1A and P1B (and
P1C and P1D, if used) as inputs by setting the
corresponding TRISB bits.
Set the PWM period by loading the PR2 register.
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
P1M1:P1M0 bits.
• Select the polarities of the PWM output
signals with the CCP1M3:CCP1M0 bits.
Set the PWM duty cycle by loading the CCPR1L
register and CCP1CON bits.
For Half-Bridge Output mode, set the deadband delay by loading PWM1CON with
the appropriate value.
If auto-shutdown operation is required, load the
ECCPAS register:
• Select the auto-shutdown sources using the
ECCPAS bits.
• Select the shutdown states of the PWM
output pins using PSSAC1:PSSAC0 and
PSSBD1:PSSBD0 bits.
• Set the ECCPASE bit (ECCPAS).
If auto-restart operation is required, set the
PRSEN bit (PWM1CON).
Configure and start TMR2:
• Clear the TMR2 interrupt flag bit by clearing
the TMR2IF bit (PIR1).
• Set the TMR2 prescale value by loading the
T2CKPS bits (T2CON).
• Enable Timer2 by setting the TMR2ON bit
(T2CON).
Enable PWM outputs after a new PWM cycle
has started:
• Wait until TMR2 overflows (TMR2IF bit is set).
• Enable the CCP1/P1A, P1B, P1C and/or P1D
pin outputs by clearing the respective TRISB
bits.
• Clear the ECCPASE bit (ECCPAS).
DS30009605G-page 124
15.5.10
OPERATION IN LOW-POWER
MODES
In the Low-Power Sleep mode, all clock sources are
disabled. Timer2 will not increment and the state of the
module will not change. If the ECCP pin is driving a
value, it will continue to drive that value. When the
device wakes up, it will continue from this state. If TwoSpeed Start-ups are enabled, the initial start-up
frequency may not be stable if the INTOSC is being
used.
In PRI_IDLE mode, the primary clock will continue to
clock the ECCP module without change.
In all other low-power modes, the selected low-power
mode clock will clock Timer2. Other low-power mode
clocks will most likely be different than the primary
clock frequency.
15.5.10.1
Operation with Fail-Safe
Clock Monitor
If the Fail-Safe Clock Monitor is enabled
(CONFIG1H is programmed), a clock failure will
force the device into the Low-Power RC_RUN mode
and the OSCFIF bit (PIR2) will be set. The ECCP
will then be clocked from the INTRC clock source,
which may have a different clock frequency than the
primary clock. By loading the IRCF2:IRCF0 bits on
Resets, the user can enable the INTOSC at a high
clock speed in the event of a clock failure.
See the previous section for additional details.
15.5.11
EFFECTS OF A RESET
Both power-on and subsequent Resets will force all
ports to input mode and the CCP registers to their
Reset states.
This forces the Enhanced CCP module to reset to a
state compatible with the standard CCP module.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 15-5:
Name
INTCON
RCON
REGISTERS ASSOCIATED WITH ENHANCED PWM AND TIMER2
Bit 7
Bit 6
GIE/GIEH PEIE/GIEL
IPEN
Value on
POR, BOR
Value on
all other
Resets
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x 0000 000u
—
RI
TO
PD
POR
BOR
0--1 11qq 0--q qquu
-000 -000 -000 -000
—
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE -000 -000 -000 -000
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP -111 -111 -111 -111
IPR1
TMR2
Timer2 Module Register
PR2
Timer2 Module Period Register
T2CON
—
TOUTPS3
0000 0000 0000 0000
1111 1111 1111 1111
TOUTPS2 TOUTPS1 TOUTPS0 TMR2ON T2CKPS1 T2CKPS0 -000 0000 -000 0000
TRISB
PORTB Data Direction Register
1111 1111 1111 1111
CCPR1H
Enhanced Capture/Compare/PWM Register 1 High Byte
xxxx xxxx uuuu uuuu
CCPR1L
Enhanced Capture/Compare/PWM Register 1 Low Byte
CCP1CON
ECCPAS
PWM1CON
OSCCON
Legend:
P1M1
P1M0
DC1B1
DC1B0
xxxx xxxx uuuu uuuu
CCP1M3
CCP1M2
CCP1M1
CCP1M0 0000 0000 0000 0000
ECCPASE ECCPAS2 ECCPAS1 ECCPAS0 PSSAC1
PSSBD0 0000 0000 0000 0000
PSSAC0
PSSBD1
PRSEN
PDC6
PDC5
PDC4
PDC3
PDC2
PDC1
PDC0
0000 0000 uuuu uuuu
IDLEN
IRCF2
IRCF1
IRCF0
OSTS
IOFS
SCS1
SCS0
0000 qq00 0000 qq00
x = unknown, u = unchanged, – = unimplemented, read as ‘0’.
Shaded cells are not used by the ECCP module in Enhanced PWM mode.
2002-2015 Microchip Technology Inc.
DS30009605G-page 125
PIC18F1220/1320
16.0
ENHANCED ADDRESSABLE
UNIVERSAL SYNCHRONOUS
ASYNCHRONOUS RECEIVER
TRANSMITTER (EUSART)
The Enhanced Addressable Universal Synchronous
Asynchronous Receiver Transmitter (EUSART) module can be configured as a full-duplex asynchronous
system that can communicate with peripheral devices,
such as CRT terminals and personal computers. It can
also be configured as a half-duplex synchronous
system that can communicate with peripheral devices,
such as A/D or D/A integrated circuits, serial
EEPROMs, etc.
The Enhanced Addressable USART module
implements additional features, including automatic
baud rate detection and calibration, automatic wake-up
on Sync Break reception and 12-bit Break character
transmit. These features make it ideally suited for use
in Local Interconnect Network (LIN) bus systems.
The EUSART can be configured in the following
modes:
• Asynchronous (full duplex) with:
- Auto-wake-up on character reception
- Auto-baud calibration
- 12-bit Break character transmission
• Synchronous – Master (half duplex) with
selectable clock polarity
• Synchronous – Slave (half duplex) with selectable
clock polarity
16.1
Asynchronous Operation in Power
Managed Modes
The EUSART may operate in Asynchronous mode
while the peripheral clocks are being provided by the
internal oscillator block. This makes it possible to
remove the crystal or resonator that is commonly
connected as the primary clock on the OSC1 and
OSC2 pins.
The factory calibrates the internal oscillator block output (INTOSC) for 8 MHz (see Table 22-6). However,
this frequency may drift as VDD or temperature
changes and this directly affects the asynchronous
baud rate. Two methods may be used to adjust the
baud rate clock, but both require a reference clock
source of some kind.
The first (preferred) method uses the OSCTUNE
register to adjust the INTOSC output back to 8 MHz.
Adjusting the value in the OSCTUNE register allows for
fine resolution changes to the system clock source (see
Section 3.6 “INTOSC Frequency Drift” for more
information).
The other method adjusts the value in the Baud Rate
Generator (BRG). There may not be fine enough
resolution when adjusting the Baud Rate Generator to
compensate for a gradual change in the peripheral
clock frequency.
The RB1/AN5/TX/CK/INT1 and RB4/AN6/RX/DT/KBI0
pins must be configured as follows for use with the
Universal Synchronous Asynchronous Receiver
Transmitter:
•
•
•
•
SPEN (RCSTA) bit must be set ( = 1),
PCFG6:PCFG5 (ADCON1) must be set ( = 1),
TRISB bit must be set ( = 1) and
TRISB bit must be set ( = 1).
Note:
The EUSART control will automatically
reconfigure the pin from input to output as
needed.
The operation of the Enhanced USART module is
controlled through three registers:
• Transmit Status and Control (TXSTA)
• Receive Status and Control (RCSTA)
• Baud Rate Control (BAUDCTL)
These are detailed in on the following pages in
Register 16-1, Register 16-2 and Register 16-3,
respectively.
DS30009605G-page 126
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 16-1:
TXSTA: TRANSMIT STATUS AND CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R-1/1
R/W-0/0
CSRC
TX9
TXEN(1)
SYNC
SENDB
BRGH
TRMT
TX9D
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
CSRC: Clock Source Select bit
Asynchronous mode:
Don’t care.
Synchronous mode:
1 = Master mode (clock generated internally from BRG)
0 = Slave mode (clock from external source)
bit 6
TX9: 9-bit Transmit Enable bit
1 = Selects 9-bit transmission
0 = Selects 8-bit transmission
bit 5
TXEN: Transmit Enable bit(1)
1 = Transmit enabled
0 = Transmit disabled
bit 4
SYNC: EUSART Mode Select bit
1 = Synchronous mode
0 = Asynchronous mode
bit 3
SENDB: Send Break Character bit
Asynchronous mode:
1 = Send Sync Break on next transmission (cleared by hardware upon completion)
0 = Sync Break transmission completed
Synchronous mode:
Don’t care.
bit 2
BRGH: High Baud Rate Select bit
Asynchronous mode:
1 = High speed
0 = Low speed
Synchronous mode:
Unused in this mode.
bit 1
TRMT: Transmit Shift Register Status bit
1 = TSR Idle
0 = TSR busy
bit 0
TX9D: 9th bit of Transmit Data
Can be address/data bit or a parity bit.
Note 1:
SREN/CREN overrides TXEN in Sync mode.
2002-2015 Microchip Technology Inc.
DS30009605G-page 127
PIC18F1220/1320
REGISTER 16-2:
RCSTA: RECEIVE STATUS AND CONTROL REGISTER
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R-0/0
R-0/0
R-x
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
SPEN: Serial Port Enable bit
1 = Serial port enabled (configures RX/DT and TX/CK pins as serial port pins)
0 = Serial port disabled (held in Reset)
bit 6
RX9: 9-bit Receive Enable bit
1 = Selects 9-bit reception
0 = Selects 8-bit reception
bit 5
SREN: Single Receive Enable bit
Asynchronous mode:
Don’t care.
Synchronous mode – Master:
1 = Enables single receive
0 = Disables single receive
This bit is cleared after reception is complete.
Synchronous mode – Slave:
Don’t care.
bit 4
CREN: Continuous Receive Enable bit
Asynchronous mode:
1 = Enables receiver
0 = Disables receiver
Synchronous mode:
1 = Enables continuous receive until enable bit, CREN, is cleared (CREN overrides SREN)
0 = Disables continuous receive
bit 3
ADDEN: Address Detect Enable bit
Asynchronous mode 9-bit (RX9 = 1):
1 = Enables address detection, generates RCIF interrupt and loads RCREG when RX9D is set
0 = Disables address detection, all bytes are received and ninth bit can be used as parity bit
Asynchronous mode 8-bit (RX9 = 0):
Don’t care.
bit 2
FERR: Framing Error bit
1 = Framing error (can be updated by reading RCREG register and receiving next valid byte)
0 = No framing error
bit 1
OERR: Overrun Error bit
1 = Overrun error (can be cleared by clearing bit CREN)
0 = No overrun error
bit 0
RX9D: 9th bit of Received Data
This can be address/data bit or a parity bit and must be calculated by user firmware.
DS30009605G-page 128
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 16-3:
BAUDCTL: BAUD RATE CONTROL REGISTER
U-0
R-1
U-0
R/W-0/0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
Unimplemented: Read as ‘0’
bit 6
RCIDL: Receive Operation Idle Status bit
1 = Receiver is Idle
0 = Receiver is busy
bit 5
Unimplemented: Read as ‘0’
bit 4
SCKP: Synchronous Clock Polarity Select bit
Asynchronous mode:
Unused in this mode.
Synchronous mode:
1 = Idle state for clock (CK) is a high level
0 = Idle state for clock (CK) is a low level
bit 3
BRG16: 16-bit Baud Rate Register Enable bit
1 = 16-bit Baud Rate Generator – SPBRGH and SPBRG
0 = 8-bit Baud Rate Generator – SPBRG only (Compatible mode), SPBRGH value ignored
bit 2
Unimplemented: Read as ‘0’
bit 1
WUE: Wake-up Enable bit
Asynchronous mode:
1 = EUSART will continue to sample the RX pin – interrupt generated on falling edge; bit cleared in
hardware on following rising edge
0 = RX pin not monitored or rising edge detected
Synchronous mode:
Unused in this mode.
bit 0
ABDEN: Auto-Baud Detect Enable bit
Asynchronous mode:
1 = Enable baud rate measurement on the next character – requires reception of a Sync byte (55h);
cleared in hardware upon completion
0 = Baud rate measurement disabled or completed
Synchronous mode:
Unused in this mode.
2002-2015 Microchip Technology Inc.
DS30009605G-page 129
PIC18F1220/1320
16.2
16.2.1
EUSART Baud Rate Generator
(BRG)
The BRG is a dedicated 8-bit or 16-bit generator, that
supports both the Asynchronous and Synchronous
modes of the EUSART. By default, the BRG operates
in 8-bit mode; setting the BRG16 bit (BAUDCTL)
selects 16-bit mode.
The SPBRGH:SPBRG register pair controls the period
of a free running timer. In Asynchronous mode, bits
BRGH (TXSTA) and BRG16 also control the baud
rate. In Synchronous mode, bit BRGH is ignored.
Table 16-1 shows the formula for computation of the
baud rate for different EUSART modes which only
apply in Master mode (internally generated clock).
Given the desired baud rate and FOSC, the nearest
integer value for the SPBRGH:SPBRG registers can be
calculated using the formulas in Table 16-1. From this,
the error in baud rate can be determined. An example
calculation is shown in Example 16-1. Typical baud
rates and error values for the various asynchronous
modes are shown in Table 16-2. It may be
advantageous to use the high baud rate (BRGH = 1),
or the 16-bit BRG to reduce the baud rate error, or
achieve a slow baud rate for a fast oscillator frequency.
POWER MANAGED MODE
OPERATION
The system clock is used to generate the desired baud
rate; however, when a power managed mode is
entered, the clock source may be operating at a different frequency than in PRI_RUN mode. In Sleep mode,
no clocks are present and in PRI_IDLE mode, the
primary clock source continues to provide clocks to the
Baud Rate Generator; however, in other power
managed modes, the clock frequency will probably
change. This may require the value in SPBRG to be
adjusted.
If the system clock is changed during an active receive
operation, a receive error or data loss may result. To
avoid this problem, check the status of the RCIDL bit
and make sure that the receive operation is Idle before
changing the system clock.
16.2.2
SAMPLING
The data on the RB4/AN6/RX/DT/KBI0 pin is sampled
three times by a majority detect circuit to determine if a
high or a low level is present at the RX pin.
Writing a new value to the SPBRGH:SPBRG registers
causes the BRG timer to be reset (or cleared). This
ensures the BRG does not wait for a timer overflow
before outputting the new baud rate.
TABLE 16-1:
BAUD RATE FORMULAS
Configuration Bits
BRG/EUSART Mode
Baud Rate Formula
0
8-bit/Asynchronous
FOSC/[64 (n + 1)]
1
8-bit/Asynchronous
1
0
16-bit/Asynchronous
0
1
1
16-bit/Asynchronous
1
0
x
8-bit/Synchronous
1
1
x
16-bit/Synchronous
SYNC
BRG16
BRGH
0
0
0
0
0
FOSC/[16 (n + 1)]
FOSC/[4 (n + 1)]
Legend: x = Don’t care, n = value of SPBRGH:SPBRG register pair
EXAMPLE 16-1:
CALCULATING BAUD RATE ERROR
For a device with FOSC of 16 MHz, desired baud rate of 9600, Asynchronous mode, 8-bit BRG:
Desired Baud Rate= FOSC/(64 ([SPBRGH:SPBRG] + 1))
Solving for SPBRGH:SPBRG:
X
= ((FOSC/Desired Baud Rate)/64) – 1
= ((16000000/9600)/64) – 1
= [25.042] = 25
Calculated Baud Rate=16000000/(64 (25 + 1))
= 9615
Error
= (Calculated Baud Rate – Desired Baud Rate)/Desired Baud Rate
= (9615 – 9600)/9600 = 0.16%
DS30009605G-page 130
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 16-2:
REGISTERS ASSOCIATED WITH BAUD RATE GENERATOR
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on all
other Resets
TXSTA
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 -010
0000 -010
RCSTA
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 -00x
0000 -00x
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
Name
BAUDCTL
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented, read as ‘0’. Shaded cells are not used by the BRG.
TABLE 16-3:
BAUD RATES FOR ASYNCHRONOUS MODES
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
(K)
FOSC = 40.000 MHz
FOSC = 20.000 MHz
SPBRG
value
Actual
Rate
(K)
SPBRG
value
FOSC = 10.000 MHz
Actual
Rate
(K)
SPBRG
value
FOSC = 8.000 MHz
Actual
Rate
(K)
SPBRG
value
Actual
Rate
(K)
%
Error
0.3
—
—
—
—
—
—
—
—
—
—
—
—
1.2
—
—
—
1.221
1.73
255
1.202
0.16
129
1201
-0.16
103
2.4
2.441
1.73
255
2.404
0.16
129
2.404
0.16
64
2403
-0.16
51
9.6
9.615
0.16
64
9.766
1.73
31
9.766
1.73
15
9615
-0.16
12
19.2
19.531
1.73
31
19.531
1.73
15
19.531
1.73
7
—
—
—
57.6
56.818
-1.36
10
62.500
8.51
4
52.083
-9.58
2
—
—
—
115.2
125.000
8.51
4
104.167
-9.58
2
78.125
-32.18
1
—
—
—
(decimal)
%
Error
(decimal)
%
Error
(decimal)
%
Error
(decimal)
SYNC = 0, BRGH = 0, BRG16 = 0
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
207
300
-0.16
0.16
51
1201
2.404
0.16
25
8.929
-6.99
6
19.2
20.833
8.51
57.6
62.500
8.51
115.2
62.500
-45.75
Actual
Rate
(K)
%
Error
0.3
0.300
0.16
1.2
1.202
2.4
9.6
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
103
300
-0.16
51
-0.16
25
1201
-0.16
12
2403
-0.16
12
—
—
—
—
—
—
—
—
—
2
—
—
—
—
—
—
0
—
—
—
—
—
—
0
—
—
—
—
—
—
SPBRG
value
2002-2015 Microchip Technology Inc.
SPBRG
value
SPBRG
value
(decimal)
DS30009605G-page 131
PIC18F1220/1320
TABLE 16-3:
BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
(K)
FOSC = 40.000 MHz
Actual
Rate
(K)
%
Error
FOSC = 20.000 MHz
SPBRG
value
(decimal)
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
FOSC = 10.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
SPBRG
value
(decimal)
2.4
—
—
—
—
—
—
2.441
1.73
255
2403
-0.16
9.6
9.766
1.73
255
9.615
0.16
129
9.615
0.16
64
9615
-0.16
207
51
19.2
19.231
0.16
129
19.231
0.16
64
19.531
1.73
31
19230
-0.16
25
57.6
58.140
0.94
42
56.818
-1.36
21
56.818
-1.36
10
55555
3.55
8
115.2
113.636
-1.36
21
113.636
-1.36
10
125.000
8.51
4
—
—
—
SYNC = 0, BRGH = 1, BRG16 = 0
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
—
—
0.16
207
1201
-0.16
2.404
0.16
103
2403
9.615
0.16
25
9615
19.231
0.16
12
—
—
Actual
Rate
(K)
%
Error
0.3
—
—
1.2
1.202
2.4
9.6
19.2
SPBRG
value
FOSC = 1.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
—
300
-0.16
207
103
1201
-0.16
51
-0.16
51
2403
-0.16
25
-0.16
12
—
—
—
—
—
—
—
SPBRG
value
SPBRG
value
(decimal)
57.6
62.500
8.51
3
—
—
—
—
—
—
115.2
125.000
8.51
1
—
—
—
—
—
—
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
(K)
FOSC = 40.000 MHz
FOSC = 20.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
8332
0.300
0.02
0.02
2082
1.200
-0.03
2.402
0.06
1040
2.399
9.615
0.16
259
9.615
19.2
19.231
0.16
129
57.6
58.140
0.94
42
115.2
113.636
-1.36
21
Actual
Rate
(K)
%
Error
0.3
0.300
0.00
1.2
1.200
2.4
9.6
SPBRG
value
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
4165
0.300
0.02
1041
1.200
-0.03
520
0.16
129
19.231
0.16
56.818
113.636
FOSC = 8.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
2082
300
-0.04
1665
-0.03
520
1201
-0.16
415
2.404
0.16
259
2403
-0.16
207
9.615
0.16
64
9615
-0.16
51
64
19.531
1.73
31
19230
-0.16
25
-1.36
21
56.818
-1.36
10
55555
3.55
8
-1.36
10
125.000
8.51
4
—
—
—
SPBRG
value
SPBRG
value
SPBRG
value
(decimal)
SYNC = 0, BRGH = 0, BRG16 = 1
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 2.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
(decimal)
%
Error
832
207
300
1201
-0.16
-0.16
415
103
300
1201
-0.16
-0.16
207
51
-0.16
51
2403
-0.16
25
-0.16
12
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
%
Error
0.3
1.2
0.300
1.202
0.04
0.16
2.4
2.404
0.16
103
2403
9.6
9.615
0.16
25
9615
19.2
19.231
0.16
12
—
57.6
62.500
8.51
3
115.2
125.000
8.51
1
DS30009605G-page 132
SPBRG
value
FOSC = 1.000 MHz
Actual
Rate
(K)
Actual
Rate
(K)
SPBRG
value
SPBRG
value
(decimal)
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 16-3:
BAUD RATES FOR ASYNCHRONOUS MODES (CONTINUED)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
(K)
FOSC = 40.000 MHz
FOSC = 20.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
0.00
33332
0.300
0.00
8332
1.200
2.400
0.02
4165
9.6
9.606
0.06
19.2
19.193
57.6
57.803
115.2
114.943
FOSC = 10.000 MHz
(decimal)
Actual
Rate
(K)
%
Error
0.00
16665
0.300
0.00
0.02
4165
1.200
0.02
2.400
0.02
2082
2.402
1040
9.596
-0.03
520
-0.03
520
19.231
0.16
0.35
172
57.471
-0.22
-0.22
86
116.279
0.94
Actual
Rate
(K)
%
Error
0.3
0.300
1.2
1.200
2.4
SPBRG
value
FOSC = 8.000 MHz
Actual
Rate
(K)
%
Error
8332
300
-0.01
6665
2082
1200
-0.04
1665
0.06
1040
2400
-0.04
832
9.615
0.16
259
9615
-0.16
207
259
19.231
0.16
129
19230
-0.16
103
86
58.140
0.94
42
57142
0.79
34
42
113.636
-1.36
21
117647
-2.12
16
SPBRG
value
SPBRG
value
(decimal)
SPBRG
value
(decimal)
SYNC = 0, BRGH = 1, BRG16 = 1 or SYNC = 1, BRG16 = 1
BAUD
RATE
(K)
FOSC = 4.000 MHz
FOSC = 2.000 MHz
Actual
Rate
(K)
%
Error
3332
300
-0.04
832
1201
-0.16
0.16
415
2403
9.615
0.16
103
19.231
0.16
Actual
Rate
(K)
%
Error
0.3
0.300
0.01
1.2
1.200
0.04
2.4
2.404
9.6
19.2
FOSC = 1.000 MHz
Actual
Rate
(K)
%
Error
1665
300
-0.04
832
415
1201
-0.16
207
-0.16
207
2403
-0.16
103
9615
-0.16
51
9615
-0.16
25
51
19230
-0.16
25
19230
-0.16
12
SPBRG
value
(decimal)
SPBRG
value
(decimal)
SPBRG
value
(decimal)
57.6
58.824
2.12
16
55555
3.55
8
—
—
—
115.2
111.111
-3.55
8
—
—
—
—
—
—
2002-2015 Microchip Technology Inc.
DS30009605G-page 133
PIC18F1220/1320
16.2.3
AUTO-BAUD RATE DETECT
Note 1: It is up to the user to determine that the
incoming character baud rate is within the
range of the selected BRG clock source.
Some
combinations
of
oscillator
frequency and EUSART baud rates are
not possible due to bit error rates. Overall
system timing and communication baud
rates must be taken into consideration
when using the Auto-Baud Rate Detection
feature.
The Enhanced USART module supports the automatic
detection and calibration of baud rate. This feature is
active only in Asynchronous mode and while the WUE
bit is clear.
The automatic baud rate measurement sequence
(Figure 16-1) begins whenever a Start bit is received and
the ABDEN bit is set. The calculation is self-averaging.
In the Auto-Baud Rate Detect (ABD) mode, the clock to
the BRG is reversed. Rather than the BRG clocking the
incoming RX signal, the RX signal is timing the BRG. In
ABD mode, the internal Baud Rate Generator is used
as a counter to time the bit period of the incoming serial
byte stream.
Once the ABDEN bit is set, the state machine will clear
the BRG and look for a Start bit. The Auto-Baud Detect
must receive a byte with the value 55h (ASCII “U”,
which is also the LIN bus Sync character), in order to
calculate the proper bit rate. The measurement is taken
over both a low and a high bit time in order to minimize
any effects caused by asymmetry of the incoming signal. After a Start bit, the SPBRG begins counting up
using the preselected clock source on the first rising
edge of RX. After eight bits on the RX pin, or the fifth
rising edge, an accumulated value totaling the proper
BRG period is left in the SPBRGH:SPBRG registers.
Once the fifth edge is seen (should correspond to the
Stop bit), the ABDEN bit is automatically cleared.
While calibrating the baud rate period, the BRG
registers are clocked at 1/8th the preconfigured clock
rate. Note that the BRG clock will be configured by the
BRG16 and BRGH bits. Independent of the BRG16 bit
setting, both the SPBRG and SPBRGH will be used as
a 16-bit counter. This allows the user to verify that no
carry occurred for 8-bit modes, by checking for 00h in
the SPBRGH register. Refer to Table 16-4 for counter
clock rates to the BRG.
While the ABD sequence takes place, the EUSART
state machine is held in Idle. The RCIF interrupt is set
once the fifth rising edge on RX is detected. The value
in the RCREG needs to be read to clear the RCIF
interrupt. RCREG content should be discarded.
DS30009605G-page 134
16.2.4
RECEIVING A SYNC (AUTO-BAUD
RATE DETECT)
To receive a Sync (Auto-Baud Rate Detect):
1.
2.
3.
4.
5.
Configure the EUSART for asynchronous receive.
TXEN should remain clear. SPBRGH:SPBRG
may be left as is. The controller should operate in
either PRI_RUN or PRI_IDLE.
Enable RXIF interrupts. Set RCIE, PEIE, GIE.
Enable Auto-Baud Rate Detect. Set ABDEN.
When the next RCIF interrupt occurs, the
received baud rate has been measured. Read
RCREG to clear RCIF and discard. Check
SPBRGH:SPBRG for a valid value. The
EUSART is ready for normal communications.
Return from the interrupt. Allow the primary
clock to run (PRI_RUN or PRI_IDLE).
Process subsequent RCIF interrupts normally
as in asynchronous reception. Remain in
PRI_RUN or PRI_IDLE until communications
are complete.
TABLE 16-4:
BRG16
BRGH
BRG COUNTER CLOCK
RATES
BRG Counter Clock
0
0
FOSC/512
0
1
FOSC/128
1
0
FOSC/128
1
1
FOSC/32
Note: During the ABD sequence, SPBRG and
SPBRGH are both used as a 16-bit counter,
independent of BRG16 setting.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 16-1:
BRG Value
AUTOMATIC BAUD RATE CALCULATION
XXXXh
0000h
RX pin
001Ch
Start
Edge #1
Bit 1
Bit 0
Edge #2
Bit 3
Bit 2
Edge #3
Bit 5
Bit 4
Edge #4
Bit 7
Bit 6
Edge #5
Stop Bit
BRG Clock
Auto-Cleared
Set by User
ABDEN bit
RCIF bit
(Interrupt)
Read
RCREG
SPBRG
XXXXh
1Ch
SPBRGH
XXXXh
00h
Note 1:
16.3
The ABD sequence requires the EUSART module to be configured in Asynchronous mode and WUE = 0.
EUSART Asynchronous Mode
The Asynchronous mode of operation is selected by
clearing the SYNC bit (TXSTA). In this mode, the
EUSART uses standard Non-Return-to-Zero (NRZ) format (one Start bit, eight or nine data bits and one Stop
bit). The most common data format is eight bits. An onchip dedicated 8-bit/16-bit Baud Rate Generator can be
used to derive standard baud rate frequencies from the
oscillator.
The EUSART transmits and receives the LSb first. The
EUSART’s transmitter and receiver are functionally
independent, but use the same data format and baud
rate. The Baud Rate Generator produces a clock, either
x16 or x64 of the bit shift rate, depending on the BRGH
and BRG16 bits (TXSTA and BAUDCTL). Parity
is not supported by the hardware, but can be
implemented in software and stored as the ninth data bit.
Asynchronous mode is available in all low-power
modes; it is available in Sleep mode only when autowake-up on Sync Break is enabled. When in PRI_IDLE
mode, no changes to the Baud Rate Generator values
are required; however, other low-power mode clocks
may operate at another frequency than the primary
clock. Therefore, the Baud Rate Generator values may
need to be adjusted.
When operating in Asynchronous mode, the EUSART
module consists of the following important elements:
•
•
•
•
•
•
•
Baud Rate Generator
Sampling Circuit
Asynchronous Transmitter
Asynchronous Receiver
Auto-Wake-up on Sync Break Character
12-bit Break Character Transmit
Auto-Baud Rate Detection
2002-2015 Microchip Technology Inc.
16.3.1
EUSART ASYNCHRONOUS
TRANSMITTER
The EUSART transmitter block diagram is shown in
Figure 16-2. The heart of the transmitter is the Transmit
(Serial) Shift Register (TSR). The shift register obtains
its data from the Read/Write Transmit Buffer register,
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the Stop
bit has been transmitted from the previous load. As
soon as the Stop bit is transmitted, the TSR is loaded
with new data from the TXREG register (if available).
Once the TXREG register transfers the data to the TSR
register (occurs in one TCY), the TXREG register is
empty and flag bit, TXIF (PIR1), is set. This interrupt
can be enabled/disabled by setting/clearing enable bit,
TXIE (PIE1). Flag bit, TXIF, will be set, regardless of
the state of enable bit, TXIE, and cannot be cleared in
software. Flag bit, TXIF, is not cleared immediately upon
loading the Transmit Buffer register, TXREG. TXIF
becomes valid in the second instruction cycle following
the load instruction. Polling TXIF immediately following a
load of TXREG will return invalid results.
While flag bit, TXIF, indicates the status of the TXREG
register, another bit, TRMT (TXSTA), shows the
status of the TSR register. Status bit, TRMT, is a readonly bit, which is set when the TSR register is empty.
No interrupt logic is tied to this bit, so the user has to
poll this bit in order to determine if the TSR register is
empty.
Note 1: The TSR register is not mapped in data
memory, so it is not available to the user.
2: Flag bit, TXIF, is set when enable bit,
TXEN, is set.
DS30009605G-page 135
PIC18F1220/1320
To set up an Asynchronous Transmission:
1.
2.
3.
4.
5.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
FIGURE 16-2:
6.
7.
Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Load data to the TXREG register (starts
transmission).
If using interrupts, ensure that the GIE and PEIE bits in
the INTCON register (INTCON) are set.
EUSART TRANSMIT BLOCK DIAGRAM
Data Bus
TXIF
TXREG Register
TXIE
8
MSb
RB1/AN5/TX/CK/INT1 pin
LSb
(8)
Pin Buffer
and Control
0
TSR Register
Interrupt
TXEN
Baud Rate CLK
TRMT
BRG16
SPBRGH
SPEN
SPBRG
Baud Rate Generator
TX9
TX9D
FIGURE 16-3:
ASYNCHRONOUS TRANSMISSION
Write to TXREG
BRG Output
(Shift Clock)
RB1/AN5/TX/
CK/INT1 (pin)
TXIF bit
(Transmit Buffer
Reg. Empty Flag)
TRMT bit
(Transmit Shift
Reg. Empty Flag)
DS30009605G-page 136
Word 1
Start bit
bit 0
bit 1
bit 7/8
Stop bit
Word 1
1 TCY
Word 1
Transmit Shift Reg
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 16-4:
ASYNCHRONOUS TRANSMISSION (BACK TO BACK)
Write to TXREG
Word 2
Word 1
BRG Output
(Shift Clock)
RB1/AN5/TX/
CK/INT1 (pin)
Start bit
bit 0
bit 1
Word 1
1 TCY
TXIF bit
(Interrupt Reg. Flag)
bit 7/8
Stop bit
Start bit
Word 2
bit 0
1 TCY
TRMT bit
(Transmit Shift
Reg. Empty Flag)
Note:
INTCON
Word 2
Transmit Shift Reg.
This timing diagram shows two consecutive transmissions.
TABLE 16-5:
Name
Word 1
Transmit Shift Reg.
REGISTERS ASSOCIATED WITH ASYNCHRONOUS TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0000 000u
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
-000 -000
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
-111 -111
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
RCSTA
TXREG
TXSTA
BAUDCTL
EUSART Transmit Register
0000 -00x
0000 -00x
0000 0000
0000 0000
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous transmission.
2002-2015 Microchip Technology Inc.
DS30009605G-page 137
PIC18F1220/1320
16.3.2
EUSART ASYNCHRONOUS
RECEIVER
16.3.3
The receiver block diagram is shown in Figure 16-5.
The data is received on the RB4/AN6/RX/DT/KBI0 pin
and drives the data recovery block. The data recovery
block is actually a high-speed shifter, operating at x16
times the baud rate, whereas the main receive serial
shifter operates at the bit rate or at FOSC. This mode
would typically be used in RS-232 systems.
This mode would typically be used in RS-485 systems.
To set up an Asynchronous Reception with Address
Detect Enable:
1.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
2. Enable the asynchronous serial port by clearing
the SYNC bit and setting the SPEN bit.
3. If interrupts are required, set the RCEN bit and
select the desired priority level with the RCIP bit.
4. Set the RX9 bit to enable 9-bit reception.
5. Set the ADDEN bit to enable address detect.
6. Enable reception by setting the CREN bit.
7. The RCIF bit will be set when reception is
complete. The interrupt will be Acknowledged if
the RCIE and GIE bits are set.
8. Read the RCSTA register to determine if any
error occurred during reception, as well as read
bit 9 of data (if applicable).
9. Read RCREG to determine if the device is being
addressed.
10. If any error occurred, clear the CREN bit.
11. If the device has been addressed, clear the
ADDEN bit to allow all received data into the
receive buffer and interrupt the CPU.
To set up an Asynchronous Reception:
1.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
2. Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
3. If interrupts are desired, set enable bit RCIE.
4. If 9-bit reception is desired, set bit RX9.
5. Enable the reception by setting bit CREN.
6. Flag bit, RCIF, will be set when reception is
complete and an interrupt will be generated if
enable bit RCIE was set.
7. Read the RCSTA register to get the 9th bit (if
enabled) and determine if any error occurred
during reception.
8. Read the 8-bit received data by reading the
RCREG register.
9. If any error occurred, clear the error by clearing
enable bit CREN.
10. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON) are
set.
FIGURE 16-5:
SETTING UP 9-BIT MODE WITH
ADDRESS DETECT
EUSART RECEIVE BLOCK DIAGRAM
CREN
OERR
FERR
x64 Baud Rate CLK
BRG16
SPBRGH
SPBRG
Baud Rate Generator
64
or
16
or
4
RSR Register
MSb
Stop
(8)
7
1
LSb
0
Start
RX9
RB4/AN6/RX/DT/KBI0
Pin Buffer
and Control
Data
Recovery
RX9D
RCREG Register
FIFO
SPEN
8
Interrupt
RCIF
Data Bus
RCIE
DS30009605G-page 138
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
To set up an Asynchronous Transmission:
1.
2.
3.
4.
5.
Initialize the SPBRG register for the appropriate
baud rate. If a high-speed baud rate is desired,
set bit BRGH (see Section 16.2 “EUSART
Baud Rate Generator (BRG)”).
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
FIGURE 16-6:
Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Load data to the TXREG register (starts
transmission).
6.
7.
If using interrupts, ensure that the GIE and PEIE bits in
the INTCON register (INTCON) are set.
ASYNCHRONOUS RECEPTION
Start
bit
bit 0
RX (pin)
bit 1
bit 7/8 Stop
bit
Rcv Shift
Reg
Rcv Buffer Reg
Start
bit
bit 7/8
bit 0
Start
bit
bit 7/8
Stop
bit
Word 2
RCREG
Word 1
RCREG
Read Rcv
Buffer Reg
RCREG
Stop
bit
RCIF
(Interrupt Flag)
OERR bit
CREN
Note:
This timing diagram shows three words appearing on the RX input. The RCREG (receive buffer) is read after
the third word, causing the OERR (overrun) bit to be set.
TABLE 16-6:
Name
REGISTERS ASSOCIATED WITH ASYNCHRONOUS RECEPTION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
0000 000u
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE TMR2IE TMR1IE
-000 -000
-000 -000
—
ADIP
RCIP
TXIP
—
CCP1IP TMR2IP TMR1IP
-111 -111
-111 -111
SPEN
RX9
SREN
CREN
ADDEN
0000 000x
0000 000x
0000 0000
0000 0000
INTCON
IPR1
RCSTA
RCREG
TXSTA
BAUDCTL
FERR
OERR
RX9D
EUSART Receive Register
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented locations read as ‘0’. Shaded cells are not used for asynchronous reception.
2002-2015 Microchip Technology Inc.
DS30009605G-page 139
PIC18F1220/1320
16.3.4
AUTO-WAKE-UP ON SYNC BREAK
CHARACTER
During Sleep mode, all clocks to the EUSART are
suspended. Because of this, the Baud Rate Generator
is inactive and a proper byte reception cannot be performed. The auto-wake-up feature allows the controller
to wake-up due to activity on the RX/DT line while the
EUSART is operating in Asynchronous mode.
The auto-wake-up feature is enabled by setting the
WUE bit (BAUDCTL). Once set, the typical receive
sequence on RX/DT is disabled and the EUSART
remains in an Idle state, monitoring for a wake-up event
independent of the CPU mode. A wake-up event consists of a high-to-low transition on the RX/DT line. (This
coincides with the start of a Sync Break or a Wake-up
Signal character for the LIN protocol.)
Following a wake-up event, the module generates an
RCIF interrupt. The interrupt is generated synchronously to the Q clocks in normal operating modes
(Figure 16-7) and asynchronously if the device is in
Sleep mode (Figure 16-8). The interrupt condition is
cleared by reading the RCREG register.
The WUE bit is automatically cleared once a low-to-high
transition is observed on the RX line, following the wakeup event. At this point, the EUSART module is in Idle
mode and returns to normal operation. This signals to
the user that the Sync Break event is over.
16.3.4.1
Special Considerations Using
Auto-Wake-up
Since auto-wake-up functions by sensing rising edge
transitions on RX/DT, information with any state changes
before the Stop bit may signal a false end-of-character
FIGURE 16-7:
and cause data or framing errors. To work properly,
therefore, the initial character in the transmission must
be all ‘0’s. This can be 00h (8 bytes) for standard RS-232
devices, or 000h (12 bits) for LIN bus.
Oscillator start-up time must also be considered,
especially in applications using oscillators with longer
start-up intervals (i.e., LP, XT or HS/PLL mode). The
Sync Break (or Wake-up Signal) character must be of
sufficient length and be followed by a sufficient period,
to allow enough time for the selected oscillator to start
and provide proper initialization of the EUSART.
16.3.4.2
Special Considerations Using
the WUE Bit
The timing of WUE and RCIF events may cause some
confusion when it comes to determining the validity of
received data. As noted, setting the WUE bit places the
EUSART in an Idle mode. The wake-up event causes
a receive interrupt by setting the RCIF bit. The WUE bit
is cleared after this when a rising edge is seen on RX/
DT. The interrupt condition is then cleared by reading
the RCREG register. Ordinarily, the data in RCREG will
be dummy data and should be discarded.
The fact that the WUE bit has been cleared (or is still
set) and the RCIF flag is set should not be used as an
indicator of the integrity of the data in RCREG. Users
should consider implementing a parallel method in
firmware to verify received data integrity.
To assure that no actual data is lost, check the RCIDL
bit to verify that a receive operation is not in process. If
a receive operation is not occurring, the WUE bit may
then be set just prior to entering the Sleep mode.
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING NORMAL OPERATION
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Cleared by hardware
Bit Set by User
WUE bit
RX/DT Line
RCIF
Cleared due to User Read of RCREG
Note 1:
The EUSART remains in Idle while the WUE bit is set.
FIGURE 16-8:
AUTO-WAKE-UP BIT (WUE) TIMINGS DURING SLEEP
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
OSC1
Bit Set by User
Q1
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
Enters Sleep
Cleared by hardware
WUE bit
RX/DT Line
Note 1
RCIF
Sleep Ends
Note 1:
2:
Cleared due to User Read of RCREG
If the wake-up event requires a long oscillator warm-up time, the WUE bit may be cleared while the primary clock is still starting.
The EUSART remains in Idle while the WUE bit is set.
DS30009605G-page 140
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
16.3.5
BREAK CHARACTER SEQUENCE
The Enhanced USART module has the capability of
sending the special Break character sequences that
are required by the LIN bus standard. The Break character transmit consists of a Start bit, followed by twelve
‘0’ bits and a Stop bit. The Frame Break character is
sent whenever the SENDB and TXEN bits (TXSTA
and TXSTA) are set while the Transmit Shift
register is loaded with data. Note that the value of data
written to TXREG will be ignored and all ‘0’s will be
transmitted.
The SENDB bit is automatically reset by hardware after
the corresponding Stop bit is sent. This allows the user
to preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN specification).
Note that the data value written to the TXREG for the
Break character is ignored. The write simply serves the
purpose of initiating the proper sequence.
The TRMT bit indicates when the transmit operation is
active or Idle, just as it does during normal transmission. See Figure 16-9 for the timing of the Break
character sequence.
16.3.5.1
Transmitting A Break Signal
The Enhanced USART module has the capability of
sending the Break signal that is required by the LIN bus
standard. The Break signal consists of a Start bit,
followed by twelve ‘0’ bits and a Stop bit. The Break signal is sent whenever the SENDB (TXSTA) and
TXEN (TXSTA) bits are set and TXREG is loaded
with data. The data written to TXREG will be ignored
and all ‘0’s will be transmitted.
SENDB is automatically cleared by hardware when the
Break signal has been sent. This allows the user to
preload the transmit FIFO with the next transmit byte
following the Break character (typically, the Sync
character in the LIN specification).
The TRMT bit indicates when the transmit operation is
active or Idle, just as it does during normal
transmission.
To send a Break Signal:
1.
2.
3.
Configure the EUSART for asynchronous transmissions (steps 1-5). Initialize the SPBRG register
for the appropriate baud rate. If a high-speed baud
rate is desired, set bit BRGH (see Section 16.2
“EUSART Baud Rate Generator (BRG)”).
Enable the asynchronous serial port by clearing
bit SYNC and setting bit SPEN.
If interrupts are desired, set enable bit TXIE.
2002-2015 Microchip Technology Inc.
4.
5.
6.
7.
If 9-bit transmission is desired, set transmit bit
TX9. Can be used as address/data bit.
Enable the transmission by setting bit TXEN,
which will also set bit TXIF.
Set the SENDB bit.
Load a byte into TXREG. This triggers sending a
Break signal. The Break signal is complete
when TRMT is set. SENDB will also be cleared.
See Figure 16-9 for the timing of the Break signal
sequence.
16.3.6
RECEIVING A BREAK CHARACTER
The Enhanced USART module can receive a Break
character in two ways.
The first method forces configuration of the baud rate
at a frequency of 9/13 the typical speed. This allows for
the Stop bit transition to be at the correct sampling
location (12 bits for Break versus Start bit and eight
data bits for typical data).
The second method uses the auto-wake-up feature
described in Section 16.3.4 “Auto-Wake-up on Sync
Break Character”. By enabling this feature, the
EUSART will sample the next two transitions on RX/DT,
cause an RCIF interrupt and receive the next data byte
followed by another interrupt.
Note that following a Break character, the user will
typically want to enable the Auto-Baud Rate Detect
feature. For both methods, the user can set the ABD bit
before placing the EUSART in its Sleep mode.
16.3.6.1
Transmitting a Break Sync
The following sequence will send a message frame
header made up of a Break, followed by an auto-baud
Sync byte. This sequence is typical of a LIN bus master.
1.
2.
3.
4.
5.
Configure the EUSART for the desired mode.
Set the TXEN and SENDB bits to set up the
Break character.
Load the TXREG with a dummy character to
initiate transmission (the value is ignored).
Write ‘55h’ to TXREG to load the Sync character
into the transmit FIFO buffer.
After the Break has been sent, the SENDB bit is
reset by hardware. The Sync character now
transmits in the preconfigured mode. When the
TXREG becomes empty, as indicated by the
TXIF, the next data byte can be written to TXREG.
DS30009605G-page 141
PIC18F1220/1320
16.3.6.2
Receiving a Break Sync
7.
8.
To receive a Break Sync:
1.
2.
3.
4.
5.
6.
Configure the EUSART for asynchronous
transmit and receive. TXEN should remain
clear. SPBRGH:SPBRG may be left as is.
Enable auto-wake-up. Set WUE.
Enable RXIF interrupts. Set RCIE, PEIE, GIE.
The controller may be placed in any power
managed mode.
An RCIF will be generated at the beginning of
the Break signal. When the interrupt is received,
read RCREG to clear RCIF and discard. Allow
the controller to return to PRI_RUN mode.
Wait for the RX line to go high at the end of the
Break signal. Wait for any of the following: WUE
to clear automatically (poll), RB4/RX to go high
(poll) or for RBIF to be set (poll or interrupt). If
RBIF is used, check to be sure that RB4/RX is
high before continuing.
FIGURE 16-9:
Write to TXREG
Enable Auto-Baud Rate Detect. Set ABDEN.
Return from the interrupt. Allow the primary
clock to start and stabilize (PRI_RUN or PRI_IDLE).
9. When the next RCIF interrupt occurs, the
received baud rate has been measured. Read
RCREG to clear RCIF and discard. Check
SPBRGH:SPBRG for a valid value. The
EUSART is ready for normal communications.
Return from the interrupt. Allow the primary
clock to run (PRI_RUN or PRI_IDLE).
10. Process subsequent RCIF interrupts normally
as in asynchronous reception. TXEN should
now be set if transmissions are needed. TXIF
and TXIE may be set if transmit interrupts are
desired. Remain in PRI_RUN or PRI_IDLE until
communications are complete. Clear TXEN and
return to step 2.
SEND BREAK CHARACTER SEQUENCE
Dummy Write
BRG Output
(Shift Clock)
TX (pin)
Start Bit
Bit 0
Bit 1
Bit 11
Stop Bit
Break
TXIF bit
TRMT bit
SENDB
DS30009605G-page 142
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
16.4
EUSART Synchronous Master
Mode
Once the TXREG register transfers the data to the TSR
register (occurs in one TCYCLE), the TXREG is empty
and interrupt bit, TXIF (PIR1), is set. The interrupt
can be enabled/disabled by setting/clearing enable bit,
TXIE (PIE1). Flag bit, TXIF, will be set, regardless
of the state of enable bit, TXIE and cannot be cleared
in software. It will reset only when new data is loaded
into the TXREG register.
The Synchronous Master mode is entered by setting
the CSRC bit (TXSTA). In this mode, the data is
transmitted in a half-duplex manner (i.e., transmission
and reception do not occur at the same time). When
transmitting data, the reception is inhibited and vice
versa. Synchronous mode is entered by setting bit,
SYNC (TXSTA). In addition, enable bit, SPEN
(RCSTA), is set in order to configure the RB1/AN5/
TX/CK/INT1 and RB4/AN6/RX/DT/KBI0 I/O pins to CK
(clock) and DT (data) lines, respectively.
While flag bit, TXIF, indicates the status of the TXREG
register, another bit, TRMT (TXSTA), shows the
status of the TSR register. TRMT is a read-only bit,
which is set when the TSR is empty. No interrupt logic is
tied to this bit, so the user has to poll this bit in order to
determine if the TSR register is empty. The TSR is not
mapped in data memory, so it is not available to the user.
The Master mode indicates that the processor transmits the master clock on the CK line. Clock polarity is
selected with the SCKP bit (BAUDCTL); setting
SCKP sets the Idle state on CK as high, while clearing
the bit sets the Idle state as low. This option is provided
to support Microwire devices with this module.
16.4.1
To set up a Synchronous Master Transmission:
1.
EUSART SYNCHRONOUS MASTER
TRANSMISSION
2.
The EUSART transmitter block diagram is shown in
Figure 16-2. The heart of the transmitter is the Transmit
(Serial) Shift Register (TSR). The shift register obtains
its data from the Read/Write Transmit Buffer register,
TXREG. The TXREG register is loaded with data in
software. The TSR register is not loaded until the last
bit has been transmitted from the previous load. As
soon as the last bit is transmitted, the TSR is loaded
with new data from the TXREG (if available).
FIGURE 16-10:
7.
8.
SYNCHRONOUS TRANSMISSION
Q1 Q2 Q3Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4
RB4/AN6/RX/
DT/KBI0 pin
bit 0
bit 1
Word 1
RB1/AN5/TX/
CK/INT1 pin
(SCKP = 0)
RB1/AN5/TX/
CK/INT1 pin
(SCKP = 1)
Write to
TXREG Reg
3.
4.
5.
6.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set bit TX9.
Enable the transmission by setting bit TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON) are
set.
Write Word 1
bit 2
Q3 Q4 Q1 Q2 Q3 Q4 Q1Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
bit 7
bit 0
bit 1
bit 7
Word 2
Write Word 2
TXIF bit
(Interrupt Flag)
TRMT bit
TXEN bit
Note:
‘1’
‘1’
Sync Master mode, SPBRG = 0, continuous transmission of two 8-bit words.
2002-2015 Microchip Technology Inc.
DS30009605G-page 143
PIC18F1220/1320
FIGURE 16-11:
SYNCHRONOUS TRANSMISSION (THROUGH TXEN)
bit 0
RB4/AN6/RX/DT/KBI0 pin
bit 2
bit 1
bit 6
bit 7
RB1/AN5/TX/CK/INT1 pin
Write to
TXREG reg
TXIF bit
TRMT bit
TXEN bit
TABLE 16-7:
Name
INTCON
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER TRANSMISSION
Bit 7
Bit 6
Bit 5
GIE/GIEH PEIE/GIEL TMR0IE
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
0000 000u
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
-000 -000
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
-111 -111
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 -00x
0000 -00x
0000 0000
0000 0000
RCSTA
TXREG
TXSTA
BAUDCTL
EUSART Transmit Register
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for synchronous master transmission.
DS30009605G-page 144
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
16.4.2
EUSART SYNCHRONOUS MASTER
RECEPTION
3.
4.
5.
6.
Ensure bits CREN and SREN are clear.
If interrupts are desired, set enable bit RCIE.
If 9-bit reception is desired, set bit RX9.
If a single reception is required, set bit SREN.
For continuous reception, set bit CREN.
7. Interrupt flag bit, RCIF, will be set when reception
is complete and an interrupt will be generated if
the enable bit, RCIE, was set.
8. Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
9. Read the 8-bit received data by reading the
RCREG register.
10. If any error occurred, clear the error by clearing
bit CREN.
11. If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON) are
set.
Once Synchronous mode is selected, reception is
enabled by setting either the Single Receive Enable bit,
SREN (RCSTA), or the Continuous Receive
Enable bit, CREN (RCSTA). Data is sampled on the
RB4/AN6/RX/DT/KBI0 pin on the falling edge of the
clock.
If enable bit, SREN, is set, only a single word is
received. If enable bit, CREN, is set, the reception is
continuous until CREN is cleared. If both bits are set,
then CREN takes precedence.
To set up a Synchronous Master Reception:
1.
2.
Initialize the SPBRGH:SPBRG registers for the
appropriate baud rate. Set or clear the BRGH
and BRG16 bits, as required, to achieve the
desired baud rate.
Enable the synchronous master serial port by
setting bits SYNC, SPEN and CSRC.
FIGURE 16-12:
SYNCHRONOUS RECEPTION (MASTER MODE, SREN)
Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
RB4/AN6/RX/
DT/KBI0 pin
bit 0
bit 1
bit 2
bit 3
bit 4
bit 5
bit 6
bit 7
RB1/AN5/TX/
CK/INT1 pin
(SCKP = 0)
RB1/AN5/TX/
CK/INT1 pin
(SCKP = 1)
Write to
bit SREN
SREN bit
CREN bit
‘0’
‘0’
RCIF bit
(Interrupt)
Read
RXREG
Note:
Timing diagram demonstrates Sync Master mode with bit SREN = 1 and bit BRGH = 0.
2002-2015 Microchip Technology Inc.
DS30009605G-page 145
PIC18F1220/1320
TABLE 16-8:
Name
REGISTERS ASSOCIATED WITH SYNCHRONOUS MASTER RECEPTION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
0000 000u
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
-000 -000
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
-111 -111
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
INTCON
IPR1
RCSTA
RCREG
TXSTA
BAUDCTL
GIE/GIEH PEIE/GIEL
EUSART Receive Register
0000 0000
0000 0000
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend:
x = unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for synchronous master reception.
DS30009605G-page 146
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
16.5
EUSART Synchronous
Slave Mode
To set up a Synchronous Slave Transmission:
1.
Synchronous Slave mode is entered by clearing bit,
CSRC (TXSTA). This mode differs from the
Synchronous Master mode in that the shift clock is
supplied externally at the RB1/AN5/TX/CK/INT1 pin
(instead of being supplied internally in Master mode).
This allows the device to transfer or receive data while
in any low-power mode.
16.5.1
Enable the synchronous slave serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
Clear bits CREN and SREN.
If interrupts are desired, set enable bit TXIE.
If 9-bit transmission is desired, set bit TX9.
Enable the transmission by setting enable bit
TXEN.
If 9-bit transmission is selected, the ninth bit
should be loaded in bit TX9D.
Start transmission by loading data to the TXREG
register.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON) are
set.
2.
3.
4.
5.
6.
EUSART SYNCHRONOUS
SLAVE TRANSMIT
7.
The operation of the Synchronous Master and Slave
modes are identical, except in the case of the Sleep
mode.
8.
If two words are written to the TXREG and then the
SLEEP instruction is executed, the following will occur:
a)
b)
c)
d)
e)
The first word will immediately transfer to the
TSR register and transmit.
The second word will remain in the TXREG
register.
Flag bit, TXIF, will not be set.
When the first word has been shifted out of TSR,
the TXREG register will transfer the second
word to the TSR and flag bit, TXIF, will now be
set.
If enable bit, TXIE, is set, the interrupt will wake
the chip from Sleep. If the global interrupt is
enabled, the program will branch to the interrupt
vector.
TABLE 16-9:
Name
REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE TRANSMISSION
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
0000 000u
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
-000 -000
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
-111 -111
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
0000 0000
0000 0000
INTCON
IPR1
RCSTA
TXREG
TXSTA
BAUDCTL
EUSART Transmit Register
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend: x = unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave transmission.
2002-2015 Microchip Technology Inc.
DS30009605G-page 147
PIC18F1220/1320
16.5.2
EUSART SYNCHRONOUS SLAVE
RECEPTION
To set up a Synchronous Slave Reception:
1.
The operation of the Synchronous Master and Slave
modes is identical, except in the case of Sleep, or any
Idle mode and bit SREN, which is a “don’t care” in
Slave mode.
2.
3.
4.
5.
If receive is enabled by setting the CREN bit prior to
entering Sleep or any Idle mode, then a word may be
received while in this low-power mode. Once the word
is received, the RSR register will transfer the data to the
RCREG register; if the RCIE enable bit is set, the interrupt generated will wake the chip from low-power
mode. If the global interrupt is enabled, the program will
branch to the interrupt vector.
6.
7.
8.
9.
Enable the synchronous master serial port by
setting bits SYNC and SPEN and clearing bit
CSRC.
If interrupts are desired, set enable bit RCIE.
If 9-bit reception is desired, set bit RX9.
To enable reception, set enable bit CREN.
Flag bit, RCIF, will be set when reception is
complete. An interrupt will be generated if
enable bit, RCIE, was set.
Read the RCSTA register to get the ninth bit (if
enabled) and determine if any error occurred
during reception.
Read the 8-bit received data by reading the
RCREG register.
If any error occurred, clear the error by clearing
bit CREN.
If using interrupts, ensure that the GIE and PEIE
bits in the INTCON register (INTCON) are
set.
TABLE 16-10: REGISTERS ASSOCIATED WITH SYNCHRONOUS SLAVE RECEPTION
Name
INTCON
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
GIE/GIEH
PEIE/GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 000x
0000 000u
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
-000 -000
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
-111 -111
SPEN
RX9
SREN
CREN
ADDEN
FERR
OERR
RX9D
0000 000x
0000 000x
IPR1
RCSTA
RCREG
TXSTA
BAUDCTL
EUSART Receive Register
0000 0000
0000 0000
CSRC
TX9
TXEN
SYNC
SENDB
BRGH
TRMT
TX9D
0000 0010
0000 0010
—
RCIDL
—
SCKP
BRG16
—
WUE
ABDEN
-1-1 0-00
-1-1 0-00
SPBRGH
Baud Rate Generator Register High Byte
0000 0000
0000 0000
SPBRG
Baud Rate Generator Register Low Byte
0000 0000
0000 0000
Legend: x = unknown, – = unimplemented, read as ‘0’. Shaded cells are not used for synchronous slave reception.
DS30009605G-page 148
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
17.0
10-BIT ANALOG-TO-DIGITAL
CONVERTER (A/D) MODULE
The Analog-to-Digital (A/D) converter module has
seven inputs for the PIC18F1220/1320 devices. This
module allows conversion of an analog input signal to
a corresponding 10-bit digital number.
A new feature for the A/D converter is the addition of
programmable acquisition time. This feature allows the
user to select a new channel for conversion and to set
the GO/DONE bit immediately. When the GO/DONE bit
is set, the selected channel is sampled for the programmed acquisition time before a conversion is actually started. This removes the firmware overhead that
may have been required to allow for an acquisition
(sampling) period (see Register 17-3 and Section 17.3
“Selecting and Configuring Automatic Acquisition
Time”).
2002-2015 Microchip Technology Inc.
The module has five registers:
•
•
•
•
•
A/D Result High Register (ADRESH)
A/D Result Low Register (ADRESL)
A/D Control Register 0 (ADCON0)
A/D Control Register 1 (ADCON1)
A/D Control Register 2 (ADCON2)
The ADCON0 register, shown in Register 17-1,
controls the operation of the A/D module. The
ADCON1 register, shown in Register 17-2, configures
the functions of the port pins. The ADCON2 register,
shown in Register 17-3, configures the A/D clock
source, programmed acquisition time and justification.
DS30009605G-page 149
PIC18F1220/1320
REGISTER 17-1:
R/W-0/0
VCFG1
ADCON0: A/D CONTROL REGISTER 0
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
VCFG0
—
CHS2
CHS1
CHS0
GO/DONE
ADON
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-6
VCFG: Voltage Reference Configuration bits
A/D VREF+
A/D VREF-
00
AVDD
AVSS
01
External VREF+
AVSS
10
AVDD
External VREF-
11
External VREF+
External VREF-
bit 5
Unimplemented: Read as ‘0’
bit 4-2
CHS: Analog Channel Select bits
000 = Channel 0 (AN0)
001 = Channel 1 (AN1)
010 = Channel 2 (AN2)
011 = Channel 3 (AN3)
100 = Channel 4 (AN4)
101 = Channel 5 (AN5)
110 = Channel 6 (AN6)
111 = Unimplemented(1)
bit 1
GO/DONE: A/D Conversion Status bit
When ADON = 1:
1 = A/D conversion in progress
0 = A/D Idle
bit 0
ADON: A/D On bit
1 = A/D converter module is enabled
0 = A/D converter module is disabled
Performing a conversion on unimplemented channels returns full-scale results.
Note 1:
Performing a conversion on unimplemented channels returns full-scale results.
DS30009605G-page 150
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 17-2:
ADCON1: A/D CONTROL REGISTER 1
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
—
PCFG6
PCFG5
PCFG4
PCFG3
PCFG2
PCFG1
PCFG0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
Unimplemented: Read as ‘0’
bit 6
PCFG6: A/D Port Configuration bit – AN6
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
bit 5
PCFG5: A/D Port Configuration bit – AN5
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
bit 4
PCFG4: A/D Port Configuration bit – AN4
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
bit 3
PCFG3: A/D Port Configuration bit – AN3
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
bit 2
PCFG2: A/D Port Configuration bit – AN2
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
bit 1
PCFG1: A/D Port Configuration bit – AN1
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
bit 0
PCFG0: A/D Port Configuration bit – AN0
1 = Pin configured as a digital port
0 = Pin configured as an analog channel – digital input disabled and reads ‘0’
2002-2015 Microchip Technology Inc.
DS30009605G-page 151
PIC18F1220/1320
REGISTER 17-3:
ADCON2: A/D CONTROL REGISTER 2
R/W-0/0
U-0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
R/W-0/0
ADFM
—
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7
ADFM: A/D Result Format Select bit
1 = Right justified
0 = Left justified
bit 6
Unimplemented: Read as ‘0’
bit 5-3
ACQT: A/D Acquisition Time Select bits
000 = 0 TAD(1)
001 = 2 TAD
010 = 4 TAD
011 = 6 TAD
100 = 8 TAD
101 = 12 TAD
110 = 16 TAD
111 = 20 TAD)
bit 2-0
ADCS: A/D Conversion Clock Select bits
000 = FOSC/2
001 = FOSC/8
010 = FOSC/32
011 = FRC (clock derived from A/D RC oscillator)(1)
100 = FOSC/4
101 = FOSC/16
110 = FOSC/64
111 = FRC (clock derived from A/D RC oscillator)(1)
Note 1:
If the A/D FRC clock source is selected, a delay of one TCY (instruction cycle) is added before the A/D
clock starts. This allows the SLEEP instruction to be executed before starting a conversion.
DS30009605G-page 152
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
The analog reference voltage is software selectable to
either the device’s positive and negative supply voltage
(AVDD and AVSS), or the voltage level on the RA3/AN3/
VREF+ and RA2/AN2/VREF- pins.
A device Reset forces all registers to their Reset state.
This forces the A/D module to be turned off and any
conversion in progress is aborted.
Each port pin associated with the A/D converter can be
configured as an analog input, or as a digital I/O. The
ADRESH and ADRESL registers contain the result of
the A/D conversion. When the A/D conversion is complete, the result is loaded into the ADRESH/ADRESL
registers, the GO/DONE bit (ADCON0 register) is
cleared and A/D Interrupt Flag bit, ADIF, is set. The block
diagram of the A/D module is shown in Figure 17-1.
The A/D converter has a unique feature of being able
to operate while the device is in Sleep mode. To operate in Sleep, the A/D conversion clock must be derived
from the A/D’s internal RC oscillator.
The output of the sample and hold is the input into the
converter, which generates the result via successive
approximation.
FIGURE 17-1:
A/D BLOCK DIAGRAM
CHS2:CHS0
AVDD
111
110
101
100
VAIN
011
(Input Voltage)
10-bit
Converter
A/D
010
001
VCFG1:VCFG0
000
AVDD
VREFH
Reference
Voltage
VREFL
AN6(1)
AN5
AN4
AN3/VREF+
AN2/VREFAN1
AN0
x0
x1
1x
0x
AVSS
Note 1: I/O pins have diode protection to VDD and VSS.
2002-2015 Microchip Technology Inc.
DS30009605G-page 153
PIC18F1220/1320
The value in the ADRESH/ADRESL registers is not
modified for a Power-on Reset. The ADRESH/ADRESL
registers will contain unknown data after a Power-on
Reset.
After the A/D module has been configured as desired,
the selected channel must be acquired before the conversion is started. The analog input channels must
have their corresponding TRIS bits selected as an
input. To determine acquisition time, see Section 17.1
“A/D Acquisition Requirements”. After this acquisition time has elapsed, the A/D conversion can be
started. An acquisition time can be programmed to
occur between setting the GO/DONE bit and the actual
start of the conversion.
To do an A/D Conversion:
1.
Configure the A/D module:
• Configure analog pins, voltage reference and
digital I/O (ADCON1)
• Select A/D input channel (ADCON0)
• Select A/D acquisition time (ADCON2)
• Select A/D conversion clock (ADCON2)
• Turn on A/D module (ADCON0)
Configure A/D interrupt (if desired):
• Clear ADIF bit
• Set ADIE bit
• Set GIE bit
Wait the required acquisition time (if required).
Start conversion:
• Set GO/DONE bit (ADCON0 register)
Wait for A/D conversion to complete, by either:
• Polling for the GO/DONE bit to be cleared
2.
3.
4.
5.
OR
• Waiting for the A/D interrupt
Read A/D Result registers (ADRESH:ADRESL);
clear bit, ADIF, if required.
For the next conversion, go to step 1 or step 2,
as required. The A/D conversion time per bit is
defined as TAD. A minimum wait of 2 TAD is
required before the next acquisition starts.
6.
7.
FIGURE 17-2:
ANALOG INPUT MODEL
VDD
Sampling
Switch
VT = 0.6V
Rs
VAIN
RIC 1k
ANx
CPIN
5 pF
VT = 0.6V
SS
RSS
ILEAKAGE
± 500 nA
CHOLD = 120 pF
VSS
Legend:
DS30009605G-page 154
CPIN
= input capacitance
= threshold voltage
VT
ILEAKAGE = leakage current at the pin due to
various junctions
RIC
= interconnect resistance
SS
= sampling switch
CHOLD
= sample/hold capacitance (from DAC)
= sampling switch resistance
RSS
VDD
6V
5V
4V
3V
2V
5 6 7 8 9 10 11
Sampling Switch (k)
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
17.1
A/D Acquisition Requirements
For the A/D converter to meet its specified accuracy,
the charge holding capacitor (CHOLD) must be allowed
to fully charge to the input channel voltage level. The
analog input model is shown in Figure 17-2. The
source impedance (RS) and the internal sampling
switch (RSS) impedance directly affect the time
required to charge the capacitor CHOLD. The sampling
switch (RSS) impedance varies over the device voltage
(VDD). The source impedance affects the offset voltage
at the analog input (due to pin leakage current). The
maximum recommended impedance for analog
sources is 2.5 k. After the analog input channel is
selected (changed), the channel must be sampled for
at least the minimum acquisition time before starting a
conversion.
Note:
When the conversion is started, the
holding capacitor is disconnected from the
input pin.
To calculate the minimum acquisition time,
Equation 17-1 may be used. This equation assumes
that 1/2 LSb error is used (1024 steps for the A/D). The
1/2 LSb error is the maximum error allowed for the A/D
to meet its specified resolution.
EQUATION 17-1:
Example 17-1 shows the calculation of the minimum
required acquisition time, TACQ. This calculation is
based on the following application system
assumptions:
CHOLD
Rs
Conversion Error
VDD
Temperature
VHOLD
17.2
=
=
=
=
=
120 pF
2.5 k
1/2 LSb
5V RSS = 7 k
50C (system max.)
0V @ time = 0
A/D VREF+ and VREF- References
If external voltage references are used instead of the
internal AVDD and AVSS sources, the source impedance of the VREF+ and VREF- voltage sources must be
considered. During acquisition, currents supplied by
these sources are insignificant. However, during
conversion, the A/D module sinks and sources current
through the reference sources.
In order to maintain the A/D accuracy, the voltage
reference source impedances should be kept low to
reduce voltage changes. These voltage changes occur
as reference currents flow through the reference
source impedance. The maximum recommended
impedance of the VREF+ and VREF- external
reference voltage sources is 250.
ACQUISITION TIME
TACQ= Amplifier Settling Time + Holding Capacitor Charging Time + Temperature Coefficient
= TAMP + TC + TCOFF
EQUATION 17-2:
A/D MINIMUM CHARGING TIME
VHOLD = (VREF – (VREF/2048)) • (1 – e(-TC/CHOLD(RIC + RSS + RS)))
or
TC = -(CHOLD)(RIC + RSS + RS) ln(1/2048)
EXAMPLE 17-1:
CALCULATING THE MINIMUM REQUIRED ACQUISITION TIME
TACQ =TAMP + TC + TCOFF
TAMP =5 s
TCOFF =(Temp – 25ºC)(0.05 s/ºC)
(50ºC – 25ºC)(0.05 s/ºC)
1.25 s
Temperature coefficient is only required for temperatures > 25ºC. Below 25ºC, TCOFF = 0 s.
TC = -(CHOLD)(RIC + RSS + RS) ln(1/2047) s
-(120 pF) (1 k + 7 k + 2.5 k) ln(0.0004883) s
9.61 s
TACQ =5 s + 1.25 s + 9.61 s
12.86 s
2002-2015 Microchip Technology Inc.
DS30009605G-page 155
PIC18F1220/1320
17.3
Selecting and Configuring
Automatic Acquisition Time
The ADCON2 register allows the user to select an
acquisition time that occurs each time the GO/DONE
bit is set.
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 occurs when the ACQT2:ACQT0
bits (ADCON2) remain in their Reset state (‘000’)
and is compatible with devices that do not offer
programmable acquisition times.
If desired, the ACQT bits can be set to select a
programmable acquisition time for the A/D module.
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.
17.4
Selecting the A/D Conversion
Clock
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:
•
•
•
•
•
•
•
2 TOSC
4 TOSC
8 TOSC
16 TOSC
32 TOSC
64 TOSC
Internal RC oscillator
For correct A/D conversions, the A/D conversion clock
(TAD) must be as short as possible, but greater than the
minimum TAD (approximately 2 s, see parameter 130
for more information).
Table 17-1 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 17-1:
TAD vs. DEVICE OPERATING FREQUENCIES
AD Clock Source (TAD)
4:
PIC18LF1220/1320(4)
Operation
ADCS2:ADCS0
PIC18F1220/1320
2 TOSC
000
1.25 MHz
666 kHz
TOSC
100
2.50 MHz
1.33 MHz
8 TOSC
001
5.00 MHz
2.66 MHz
16 TOSC
101
10.0 MHz
5.33 MHz
32 TOSC
010
20.0 MHz
10.65 MHz
64 TOSC
110
40.0 MHz
21.33 MHz
RC(3)
x11
1.00 MHz(1)
4
Note 1:
2:
3:
Maximum Device Frequency
1.00 MHz(2)
The RC source has a typical TAD time of 4 s.
The RC source has a typical TAD time of 6 s.
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 devices only.
DS30009605G-page 156
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PIC18F1220/1320
17.5
Operation in Low-Power Modes
The selection of the automatic acquisition time and the
A/D conversion clock is determined, in part, by the lowpower mode clock source and frequency while in a
low-power mode.
If the A/D is expected to operate while the device is
in a low-power mode, the ACQT2:ACQT0 and
ADCS2:ADCS0 bits in ADCON2 should be updated in
accordance with the low-power mode clock that will be
used. After the low-power mode is entered (either of
the Run modes), an A/D acquisition or conversion may
be started. Once an acquisition or conversion is
started, the device should continue to be clocked by the
same low-power mode clock source until the conversion has been completed. If desired, the device may be
placed into the corresponding low-power (ANY)_IDLE
mode during the conversion.
If the low-power mode clock frequency is less than
1 MHz, the A/D RC clock source should be selected.
17.6
Configuring Analog Port Pins
The ADCON1, TRISA and TRISB 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
CHS2:CHS0 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 an
analog input. 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.
Operation in the Low-Power Sleep mode requires the A/
D RC clock to be selected. If bits, ACQT2:ACQT0, 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 Low-Power Sleep
mode. The IDLEN and SCS bits in the OSCCON register
must have already been cleared prior to starting the
conversion.
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PIC18F1220/1320
17.7
A/D Conversions
Figure 17-3 shows the operation of the A/D converter
after the GO bit has been set and the ACQT2:ACQT0
bits are cleared. A conversion is started after the following instruction to allow entry into Low-Power Sleep
mode before the conversion begins.
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 17-4 shows the operation of the A/D converter
after the GO bit has been set and the ACQT2:ACQT0
bits are set to ‘010’ and selecting a 4 TAD acquisition
time before the conversion starts.
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.
Note:
FIGURE 17-3:
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
b4
b1
b0
b6
b7
b2
b9
b8
b3
b5
Conversion Starts
Holding capacitor is disconnected from analog input (typically 100 ns)
Set GO bit
Next Q4: ADRESH/ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is connected to analog input.
FIGURE 17-4:
A/D CONVERSION TAD CYCLES (ACQT = 010, TACQ = 4 TAD)
TAD Cycles
TACQT Cycles
1
2
3
Automatic
Acquisition
Time
4
1
3
4
5
6
7
8
9
10
11
b8
b7
b6
b5
b4
b3
b2
b1
b0
Conversion Starts
(Holding capacitor is disconnected)
Set GO bit
(Holding capacitor continues
acquiring input)
DS30009605G-page 158
2
b9
Next Q4: ADRESH:ADRESL is loaded, GO bit is cleared,
ADIF bit is set, holding capacitor is reconnected to analog input.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
17.8
Use of the CCP1 Trigger
software overhead (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).
An A/D conversion can be started by the “special event
trigger” of the CCP1 module. This requires that the
CCP1M3:CCP1M0 bits (CCP1CON) 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
TABLE 17-2:
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.
SUMMARY OF A/D REGISTERS
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Value on
POR, BOR
Value on
all other
Resets
INTCON
GIE/
GIEH
PEIE/
GIEL
TMR0IE
INT0IE
RBIE
TMR0IF
INT0IF
RBIF
0000 0000
0000 0000
PIR1
—
ADIF
RCIF
TXIF
—
CCP1IF
TMR2IF
TMR1IF
-000 -000
-000 -000
PIE1
—
ADIE
RCIE
TXIE
—
CCP1IE
TMR2IE
TMR1IE
-000 -000
-000 -000
IPR1
—
ADIP
RCIP
TXIP
—
CCP1IP
TMR2IP
TMR1IP
-111 -111
-111 -111
PIR2
OSCFIF
—
—
EEIF
—
LVDIF
TMR3IF
—
0--0 -00-
0--0 -00-
PIE2
OSCFIE
—
—
EEIE
—
LVDIE
TMR3IE
—
0--0 -00-
0--0 -00-
IPR2
OSCFIP
—
—
EEIP
—
LVDIP
TMR3IP
—
1--1 -11-
1--1 -11-
ADRESH
A/D Result Register High Byte
xxxx xxxx
uuuu uuuu
ADRESL
A/D Result Register Low Byte
xxxx xxxx
uuuu uuuu
00-0 0000
00-0 0000
ADCON0
VCFG1
VCFG0
ADCON1
—
PCFG6
PCFG5
PCFG4
PCFG3
PCFG2
PCFG1
PCFG0
-000 0000
-000 0000
ADCON2
ADFM
—
ACQT2
ACQT1
ACQT0
ADCS2
ADCS1
ADCS0
0-00 0000
0-00 0000
PORTA
RA7(3)
RA6(2)
RA5(1)
RA4
RA3
RA2
RA1
RA0
qq0x 0000
uu0u 0000
qq-1 1111
11-1 1111
—
CHS2
CHS1
CHS0
GO/DONE
ADON
TRISA
TRISA7(3) TRISA6(2)
PORTB
Read PORTB pins, Write LATB Latch
xxxx xxxx
uuuu uuuu
TRISB
PORTB Data Direction Register
1111 1111
1111 1111
LATB
PORTB Output Data Latch
xxxx xxxx
uuuu uuuu
Legend:
Note 1:
2:
3:
—
PORTA Data Direction Register
x = unknown, u = unchanged, q = depends on CONFIG1H, – = unimplemented, read as ‘0’.
Shaded cells are not used for A/D conversion.
RA5 port bit is available only as an input pin when the MCLRE bit in the Configuration register is ‘0’.
RA6 and TRISA6 are available only when the primary oscillator mode selection offers RA6 as a port pin; otherwise, RA6
always reads ‘0’, TRISA6 always reads ‘1’ and writes to both are ignored (see CONFIG1H).
RA7 and TRISA7 are available only when the internal RC oscillator is configured as the primary oscillator in CONFIG1H; otherwise, RA7 always reads ‘0’, TRISA7 always reads ‘1’ and writes to both are ignored.
2002-2015 Microchip Technology Inc.
DS30009605G-page 159
PIC18F1220/1320
18.0
LOW-VOLTAGE DETECT
In many applications, the ability to determine if the
device voltage (VDD) is below a specified voltage level
is a desirable feature. A window of operation for the
application can be created, where the application software can do “housekeeping tasks”, before the device
voltage exits the valid operating range. This can be
done using the Low-Voltage Detect module.
This module is a software programmable circuitry,
where a device voltage trip point can be specified.
When the voltage of the device becomes lower then the
specified point, 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 that interrupt source.
The Low-Voltage Detect circuitry is completely under
software control. This allows the circuitry to be turned
off by the software, which minimizes the current
consumption for the device.
Voltage
FIGURE 18-1:
Figure 18-1 shows a possible application voltage curve
(typically for batteries). Over time, the device voltage
decreases. When the device voltage equals voltage VA,
the LVD logic generates an interrupt. This occurs at
time TA. The application software then has the time,
until the device voltage is no longer in valid operating
range, to shut down the system. Voltage point VB is the
minimum valid operating voltage specification. This
occurs at time TB. The difference, TB – TA, is the total
time for shutdown.
The block diagram for the LVD module is shown in
Figure 18-2 (following page). A comparator uses an
internally generated reference voltage as the set point.
When the selected tap output of the device voltage
crosses the set point (is lower than), the LVDIF bit is set.
Each node in the resistor divider represents a “trip
point” voltage. The “trip point” voltage is the minimum
supply voltage level at which the device can operate
before the LVD module asserts an interrupt. When the
supply voltage is equal to the trip point, the voltage
tapped off of the resistor array is equal to the 1.2V
internal reference voltage generated by the voltage
reference module. The comparator then generates an
interrupt signal setting the LVDIF bit. This voltage is
software programmable to any one of 16 values (see
Figure 18-2). The trip point is selected by
programming the LVDL3:LVDL0 bits (LVDCON).
TYPICAL LOW-VOLTAGE DETECT APPLICATION
VA
VB
Legend: VA = LVD trip point
VB = Minimum valid device
operating voltage
Time
DS30009605G-page 160
TA
TB
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 18-2:
LOW-VOLTAGE DETECT (LVD) BLOCK DIAGRAM
LVDIN
LVD Control
Register
16-to-1 MUX
VDD
Internally Generated
Reference Voltage
1.2V
LVDEN
The LVD 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,
LVDL3:LVDL0, are set to ‘1111’. In this state, the comparator input is multiplexed from the external input pin,
FIGURE 18-3:
LVDIF
LVDIN (Figure 18-3). This gives users flexibility,
because it allows them to configure the Low-Voltage
Detect interrupt to occur at any voltage in the valid
operating range.
LOW-VOLTAGE DETECT (LVD) WITH EXTERNAL INPUT BLOCK DIAGRAM
VDD
VDD
16-to-1 MUX
LVD Control
Register
LVDIN
Externally Generated
Trip Point
LVDEN
LVD
VxEN
BODEN
EN
BGAP
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DS30009605G-page 161
PIC18F1220/1320
18.1
Control Register
The Low-Voltage Detect Control register controls the
operation of the Low-Voltage Detect circuitry.
REGISTER 18-1:
LVDCON: LOW-VOLTAGE DETECT CONTROL REGISTER
U-0
U-0
R-0/0
R/W-0/0
R/W-0/0
R/W-1/1
R/W-0/0
R/W-1/1
—
—
IRVST
LVDEN
LVDL3
LVDL2
LVDL1
LVDL0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-6
Unimplemented: Read as ‘0’
bit 5
IRVST: Internal Reference Voltage Stable Flag bit
1 = Indicates that the Low-Voltage Detect logic will generate the interrupt flag at the specified voltage
range
0 = Indicates that the Low-Voltage Detect logic will not generate the interrupt flag at the specified voltage range and the LVD interrupt should not be enabled
bit 4
LVDEN: Low-Voltage Detect Power Enable bit
1 = Enables LVD, powers up LVD circuit
0 = Disables LVD, powers down LVD circuit
bit 3-0
LVDL: Low-Voltage Detection Limit bits(1)
1111 = External analog input is used (input comes from the LVDIN pin)
1110 = 4.04V-5.15V
1101 = 3.76V-4.79V
1100 = 3.58V-4.56V
1011 = 3.41V-4.34V
1010 = 3.23V-4.11V
1001 = 3.14V-4.00V
1000 = 2.96V-3.77V
0111 = 2.70V-3.43V
0110 = 2.53V-3.21V
0101 = 2.43V-3.10V
0100 = 2.25V-2.86V
0011 = 2.16V-2.75V
0010 = 1.99V-2.53V
0001 = Reserved
0000 = Reserved
Note 1:
LVDL modes, which result in a trip point below the valid operating voltage of the device, are not
tested.
DS30009605G-page 162
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
18.2
Operation
The following steps are needed to set up the LVD
module:
Depending on the power source for the device voltage,
the voltage normally decreases relatively slowly. This
means that the LVD module does not need to be
constantly operating. To decrease the current requirements, the LVD circuitry only needs to be enabled for
short periods, where the voltage is checked. After
doing the check, the LVD module may be disabled.
1.
2.
3.
Each time that the LVD module is enabled, the circuitry
requires some time to stabilize. After the circuitry has
stabilized, all status flags may be cleared. The module
will then indicate the proper state of the system.
4.
5.
6.
Write the value to the LVDL3:LVDL0 bits
(LVDCON register), which selects the desired
LVD trip point.
Ensure that LVD interrupts are disabled (the
LVDIE bit is cleared or the GIE bit is cleared).
Enable the LVD module (set the LVDEN bit in
the LVDCON register).
Wait for the LVD module to stabilize (the IRVST
bit to become set).
Clear the LVD interrupt flag, which may have
falsely become set, until the LVD module has
stabilized (clear the LVDIF bit).
Enable the LVD interrupt (set the LVDIE and the
GIE bits).
Figure 18-4 shows typical waveforms that the LVD
module may be used to detect.
FIGURE 18-4:
LOW-VOLTAGE DETECT WAVEFORMS
CASE 1:
LVDIF may not be set.
VDD
VLVD
LVDIF
Enable LVD
Internally Generated
Reference Stable
TIVRST
LVDIF cleared in software
CASE 2:
VDD
VLVD
LVDIF
Enable LVD
Internally Generated
Reference Stable
TIVRST
LVDIF cleared in software
LVDIF cleared in software,
LVDIF remains set since LVD condition still exists
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
18.2.1
REFERENCE VOLTAGE SET POINT
The internal reference voltage of the LVD module may
be used by other internal circuitry (the programmable
Brown-out Reset). If these circuits are disabled (lower
current consumption), the reference voltage circuit
requires a time to become stable before a low-voltage
condition can be reliably detected. This time is invariant
of system clock speed. This start-up time is specified in
electrical specification parameter 36. The low-voltage
interrupt flag will not be enabled until a stable reference
voltage is reached. Refer to the waveform in Figure 18-4.
18.2.2
CURRENT CONSUMPTION
18.3
Operation During Sleep
When enabled, the LVD circuitry continues to operate
during Sleep. If the device voltage crosses the trip
point, the LVDIF bit will be set and the device will wakeup from Sleep. Device execution will continue from the
interrupt vector address if interrupts have been globally
enabled.
18.4
Effects of a Reset
A device Reset forces all registers to their Reset state.
This forces the LVD module to be turned off.
When the module is enabled, the LVD comparator and
voltage divider are enabled and will consume static current. The voltage divider can be tapped from multiple
places in the resistor array. Total current consumption,
when enabled, is specified in electrical specification
parameter D022B.
DS30009605G-page 164
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
19.0
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.
PIC18F1220/1320 devices include several features
intended to maximize system reliability, minimize cost
through elimination of external components and offer
code protection. 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.
19.1
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.
Several oscillator options are available to allow the part
to fit the application. The RC oscillator option saves
system cost, while the LP crystal option saves power.
These are discussed in detail in Section 2.0 “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, PIC18F1220/1320 devices
have a Watchdog Timer, which is either permanently
enabled via the Configuration bits, or software
controlled (if configured as disabled).
TABLE 19-1:
Configuration Bits
Programming the Configuration registers is done in a
manner similar to programming the Flash memory. The
EECON1 register WR bit 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 6.5 “Writing
to Flash Program Memory”.
CONFIGURATION BITS AND DEVICE IDS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Default/
Unprogrammed
Value
300001h
CONFIG1H
IESO
FSCM
—
—
FOSC3
FOSC2
FOSC1
FOSC0
11-- 1111
300002h
CONFIG2L
—
—
—
—
BORV1
BORV0
BOR
PWRTEN
---- 1111
300003h
CONFIG2H
—
—
—
WDT
---1 1111
300005h
CONFIG3H
MCLRE
—
—
—
—
—
—
—
1--- ----
300006h
CONFIG4L
DEBUG
—
—
—
—
LVP
—
STVR
1--- -1-1
WDTPS3 WDTPS2 WDTPS1 WDTPS0
300008h
CONFIG5L
—
—
—
—
—
—
CP1
CP0
---- --11
300009h
CONFIG5H
CPD
CPB
—
—
—
—
—
—
11-- ----
30000Ah
CONFIG6L
—
—
—
—
—
—
WRT1
WRT0
---- --11
30000Bh
CONFIG6H
WRTD
WRTB
WRTC
—
—
—
—
—
111- ----
30000Ch
CONFIG7L
—
—
—
—
—
—
EBTR1
EBTR0
---- --11
30000Dh
CONFIG7H
—
EBTRB
—
—
—
—
—
—
-1-- ----
3FFFFEh DEVID1(1)
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
xxxx xxxx(1)
3FFFFFh
DEVID2(1)
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
0000 0111
Legend:
Note 1:
x = unknown, u = unchanged, – = unimplemented. Shaded cells are unimplemented, read as ‘0’.
See Register 19-12 for DEVID1 values. DEVID registers are read-only and cannot be programmed by the user.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
REGISTER 19-1:
CONFIG1H: CONFIGURATION REGISTER 1 HIGH (BYTE ADDRESS 300001h)
R/P-1
R/P-1
U-0
U-0
R/P-1
R/P-1
R/P-1
R/P-1
IESO
FSCM
—
—
FOSC3
FOSC2
FOSC1
FOSC0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7
IESO: Internal External Switchover bit
1 = Internal External Switchover mode enabled
0 = Internal External Switchover mode disabled
bit 6
FSCM: 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
1001 = Internal RC oscillator, CLKO function on RA6 and port function on RA7
1000 = Internal RC oscillator, port function on RA6 and port function on 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
0010 = HS oscillator
0001 = XT oscillator
0000 = LP oscillator
DS30009605G-page 166
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PIC18F1220/1320
REGISTER 19-2:
CONFIG2L: CONFIGURATION REGISTER 2 LOW (BYTE ADDRESS 300002h)
U-0
U-0
U-0
U-0
R/P-1
R/P-1
R/P-1
R/P-1
—
—
—
—
BORV1
BORV0
BOR(1)
PWRTEN(1)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7-4
Unimplemented: Read as ‘0’
bit 3-2
BORV: Brown-out Reset Voltage bits
11 = Reserved
10 = VBOR set to 2.7V
01 = VBOR set to 4.2V
00 = VBOR set to 4.5V
bit 1
BOR: Brown-out Reset Enable bit(1)
1 = Brown-out Reset enabled
0 = Brown-out Reset disabled
bit 0
PWRTEN: Power-up Timer Enable bit(1)
1 = PWRT disabled
0 = PWRT enabled
Note 1:
The Power-up Timer is decoupled from Brown-out Reset, allowing these features to be independently
controlled.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
REGISTER 19-3:
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
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
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
WDT: Watchdog Timer Enable bit
1 = WDT enabled
0 = WDT disabled (control is placed on the SWDTEN bit)
DS30009605G-page 168
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 19-4:
CONFIG3H: CONFIGURATION REGISTER 3 HIGH (BYTE ADDRESS 300005h)
R/P-1
U-0
U-0
U-0
U-0
U-0
U-0
U-0
MCLRE
—
—
—
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7
MCLRE: MCLR Pin Enable bit
1 = MCLR pin enabled, RA5 input pin disabled
0 = RA5 input pin enabled, MCLR disabled
bit 6-0
Unimplemented: Read as ‘0’
REGISTER 19-5:
CONFIG4L: CONFIGURATION REGISTER 4 LOW (BYTE ADDRESS 300006h)
R/P-1
U-0
U-0
U-0
U-0
R/P-1
U-0
R/P-1
DEBUG
—
—
—
—
LVP
—
STVR
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7
DEBUG: Background Debugger Enable bit (see note)
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 6-3
Unimplemented: Read as ‘0’
bit 2
LVP: Low-Voltage ICSP Enable bit
1 = Low-Voltage ICSP enabled
0 = Low-Voltage ICSP disabled
bit 1
Unimplemented: Read as ‘0’
bit 0
STVR: Stack Full/Underflow Reset Enable bit
1 = Stack full/underflow will cause Reset
0 = Stack full/underflow will not cause Reset
Note:
The Timer1 oscillator shares the T1OSI and T1OSO pins with the PGD and PGC pins used for
programming and debugging.
When using the Timer1 oscillator, In-Circuit Serial Programming (ICSP) may not function correctly (high
voltage or low voltage), or the In-Circuit Debugger (ICD) may not communicate with the controller. As a
result of using either ICSP or ICD, the Timer1 crystal may be damaged.
If ICSP or ICD operations are required, the crystal should be disconnected from the circuit (disconnect
either lead) or installed after programming. The oscillator loading capacitors may remain in-circuit during
ICSP or ICD operation.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
REGISTER 19-6:
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
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
C = Clearable bit
bit 7-2
Unimplemented: Read as ‘0’
bit 1
CP1: Code Protection bit (PIC18F1320)
1 = Block 1 (001000-001FFFh) not code-protected
0 = Block 1 (001000-001FFFh) code-protected
bit 0
CP0: Code Protection bit (PIC18F1320)
1 = Block 0 (00200-000FFFh) not code-protected
0 = Block 0 (00200-000FFFh) code-protected
bit 1
CP1: Code Protection bit (PIC18F1220)
1 = Block 1 (000800-000FFFh) not code-protected
0 = Block 1 (000800-000FFFh) code-protected
bit 0
CP0: Code Protection bit (PIC18F1220)
1 = Block 0 (000200-0007FFh) not code-protected
0 = Block 0 (000200-0007FFh) code-protected
REGISTER 19-7:
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
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
C = Clearable bit
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 (000000-0001FFh) not code-protected
0 = Boot Block (000000-0001FFh) code-protected
bit 5-0
Unimplemented: Read as ‘0’
DS30009605G-page 170
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 19-8:
CONFIG6L: CONFIGURATION REGISTER 6 LOW (BYTE ADDRESS 30000Ah)
U-0
U-0
U-0
U-0
U-0
U-0
R/P-1
R/P-1
—
—
—
—
—
—
WRT1
WRT0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7-2
Unimplemented: Read as ‘0’
bit 1
WRT1: Write Protection bit (PIC18F1320)
1 = Block 1 (001000-001FFFh) not write-protected
0 = Block 1 (001000-001FFFh) write-protected
bit 0
WRT0: Write Protection bit (PIC18F1320)
1 = Block 0 (00200-000FFFh) not write-protected
0 = Block 0 (00200-000FFFh) write-protected
bit 1
WRT1: Write Protection bit (PIC18F1220)
1 = Block 1 (000800-000FFFh) not write-protected
0 = Block 1 (000800-000FFFh) write-protected
bit 0
WRT0: Write Protection bit (PIC18F1220)
1 = Block 0 (000200-0007FFh) not write-protected
0 = Block 0 (000200-0007FFh) write-protected
REGISTER 19-9:
R/P-1
CONFIG6H: CONFIGURATION REGISTER 6 HIGH (BYTE ADDRESS 30000Bh)
R/P-1
WRTD
WRTB
R-1
(1)
WRTC
U-0
U-0
U-0
U-0
U-0
—
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
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 (000000-0001FFh) not write-protected
0 = Boot Block (000000-0001FFh) write-protected
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.
2002-2015 Microchip Technology Inc.
DS30009605G-page 171
PIC18F1220/1320
REGISTER 19-10: CONFIG7L: CONFIGURATION REGISTER 7 LOW (BYTE ADDRESS 30000Ch)
U-0
U-0
U-0
U-0
U-0
U-0
R/P-1
R/P-1
—
—
—
—
—
—
EBTR1
EBTR0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7-2
Unimplemented: Read as ‘0’
bit 1
EBTR1: Table Read Protection bit (PIC18F1320)
1 = Block 1 (001000-001FFFh) not protected from table reads executed in other blocks
0 = Block 1 (001000-001FFFh) protected from table reads executed in other blocks
bit 0
EBTR0: Table Read Protection bit (PIC18F1320)
1 = Block 0 (00200-000FFFh) not protected from table reads executed in other blocks
0 = Block 0 (00200-000FFFh) protected from table reads executed in other blocks
bit 1
EBTR1: Table Read Protection bit (PIC18F1220)
1 = Block 1 (000800-000FFFh) not protected from table reads executed in other blocks
0 = Block 1 (000800-000FFFh) protected from table reads executed in other blocks
bit 0
EBTR0: Table Read Protection bit (PIC18F1220)
1 = Block 0 (000200-0007FFh) not protected from table reads executed in other blocks
0 = Block 0 (000200-0007FFh) protected from table reads executed in other blocks
REGISTER 19-11: CONFIG7H: CONFIGURATION REGISTER 7 HIGH (BYTE ADDRESS 30000Dh)
U-0
R/P-1
U-0
U-0
U-0
U-0
U-0
U-0
—
EBTRB
—
—
—
—
—
—
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
P = Programmable bit
bit 7
Unimplemented: Read as ‘0’
bit 6
EBTRB: Boot Block Table Read Protection bit
1 = Boot Block (000000-0001FFh) not protected from table reads executed in other blocks
0 = Boot Block (000000-0001FFh) protected from table reads executed in other blocks
bit 5-0
Unimplemented: Read as ‘0’
DS30009605G-page 172
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
REGISTER 19-12: DEVID1: DEVICE ID REGISTER 1 FOR PIC18F1220/1320 DEVICES
R
R
R
R
R
R
R
R
DEV2
DEV1
DEV0
REV4
REV3
REV2
REV1
REV0
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-5
DEV: Device ID bits
111 = PIC18F1220
110 = PIC18F1320
bit 4-0
REV: Revision ID bits
These bits are used to indicate the device revision.
REGISTER 19-13: DEVID2: DEVICE ID REGISTER 2 FOR PIC18F1220/1320 DEVICES
R
R
R
R
R
R
R
R
DEV10
DEV9
DEV8
DEV7
DEV6
DEV5
DEV4
DEV3
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-n/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-0
Note 1:
DEV: Device ID bits
These bits are used with the DEV bits in the Device ID Register 1 to identify the
part number.
0000 0111 = PIC18F1220/1320 devices
These values for DEV may be shared with other devices. The specific device is always identified by
using the entire DEV bit sequence.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
19.2
Watchdog Timer (WDT)
Note 1: The CLRWDT and SLEEP instructions
clear the WDT and postscaler counts
when executed.
For PIC18F1220/1320 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.
2: Changing the setting of the IRCF bits
(OSCCON) clears the WDT and
postscaler counts.
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:
execute a SLEEP or CLRWDT instruction, the IRCF bits
(OSCCON) are changed or a clock failure has
occurred.
3: When a CLRWDT instruction is executed
the postscaler count will be cleared.
19.2.1
Register 19-14 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, only if the Configuration bit has
disabled the WDT.
Adjustments to the internal oscillator clock period using
the OSCTUNE register also affect the period of the
WDT by the same factor. For example, if the INTRC
period is increased by 3%, then the WDT period is
increased by 3%.
FIGURE 19-1:
CONTROL REGISTER
WDT BLOCK DIAGRAM
Enable WDT
SWDTEN
WDTEN
INTRC Control
WDT Counter
125
INTRC Oscillator
(31 kHz)
Wake-up
from Sleep
CLRWDT
All Device
Resets
Programmable Postscaler
1:1 to 1:32,768
WDT
Reset
Reset
WDT
4
WDTPS
Sleep
REGISTER 19-14: WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0
U-0
U-0
U-0
U-0
U-0
U-0
R/W-0/0
—
—
—
—
—
—
—
SWDTEN(1)
bit 7
bit 0
Legend:
R = Readable bit
W = Writable bit
U = Unimplemented bit, read as ‘0’
u = Bit is unchanged
x = Bit is unknown
-m/n = Value at POR and BOR/Value at all other Resets
‘1’ = Bit is set
‘0’ = Bit is cleared
bit 7-1
Unimplemented: Read as ‘0’
bit 0
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 (CONFIG2H), is enabled.
DS30009605G-page 174
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 19-2:
Name
CONFIG2H
RCON
WDTCON
Legend:
19.3
SUMMARY OF WATCHDOG TIMER REGISTERS
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
—
—
—
WDTPS3
WDTPS2
WDTPS2
WDTPS0
WDTEN
IPEN
—
—
RI
TO
PD
POR
BOR
—
—
—
—
—
—
—
SWDTEN
Shaded cells are not used by the Watchdog Timer.
Two-Speed Start-up
In all other power managed modes, Two-Speed Start-up
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 INTRC oscillator as a clock source until the primary clock source is
available. It is enabled by setting the IESO bit in
Configuration Register 1H (CONFIG1H).
19.3.1
Two-Speed Start-up is available 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 is disabled.
While using the INTRC oscillator in Two-Speed Startup, the device still obeys the normal command
sequences for entering power managed modes, including serial SLEEP instructions (refer to Section 3.1.3
“Multiple Sleep Commands”). In practice, this means
that user code can change the SCS1:SCS0 bit settings
and issue SLEEP commands 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 system clocking by checking the
status of the OSTS bit (OSCCON). If the bit is set,
the primary oscillator is providing the system clock.
Otherwise, the internal oscillator block is providing the
clock during wake-up from Reset or Sleep mode.
Because the OSCCON register is cleared on Reset
events, the INTOSC (or postscaler) clock source is not
initially available after a Reset event; the INTRC clock
is used directly at its base frequency. 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, IFRC2:IFRC0, immediately after
Reset. For wake-ups from Sleep, the INTOSC or postscaler clock sources can be selected by setting
IFRC2:IFRC0 prior to entering Sleep mode.
FIGURE 19-2:
SPECIAL CONSIDERATIONS FOR
USING TWO-SPEED START-UP
TIMING TRANSITION FOR TWO-SPEED START-UP (INTOSC TO HSPLL)
Q1
Q2
Q3
Q4
Q2 Q3 Q4 Q1 Q2 Q3 Q4
Q1
INTOSC
Multiplexer
OSC1
TOST(1)
TPLL(1)
PLL Clock
Output
1
2
3 4 5 6
Clock Transition
7
8
CPU Clock
Peripheral
Clock
Program
Counter
PC
Wake from Interrupt Event
Note
PC + 2
PC + 4
PC + 6
OSTS bit Set
1:TOST = 1024 TOSC; TPLL = 2 ms (approx). These intervals are not shown to scale.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
19.4
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 system clock to the internal oscillator block. The
FSCM function is enabled by setting the Fail-Safe
Clock Monitor Enable bit, FSCM (CONFIG1H).
When FSCM is enabled, the INTRC oscillator runs at
all times to monitor clocks to peripherals and provide
an instant backup clock in the event of a clock failure.
Clock monitoring (shown in Figure 19-3) 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 system 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 system clock source, but cleared on the rising edge
of the sample clock.
FIGURE 19-3:
FSCM BLOCK DIAGRAM
Clock Monitor
Latch (CM)
(edge-triggered)
Peripheral
Clock
INTRC
Source
(32 s)
S
÷ 64
C
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, IFRC2:IFRC0,
immediately after Reset. For wake-ups from Sleep, the
INTOSC or postscaler clock sources can be selected
by setting IFRC2:IFRC0 prior to entering Sleep mode.
Adjustments to the internal oscillator block, using the
OSCTUNE register, also affect the period of the FSCM
by the same factor. This can usually be neglected, as
the clock frequency being monitored is generally much
higher than the sample clock frequency.
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.
Q
19.4.1
Q
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.
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 19-4). This causes the following:
• the FSCM generates an oscillator fail interrupt by
setting bit, OSCFIF (PIR2);
• the system 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.
DS30009605G-page 176
Since the postscaler frequency from the internal oscillator block may not be sufficiently stable, it may be
desirable to select another clock configuration and
enter an alternate power managed mode (see
Section 19.3.1 “Special Considerations for Using
Two-Speed Start-up” and Section 3.1.3 “Multiple
Sleep Commands” for more details). This can be
done to attempt a partial recovery, or execute a
controlled shutdown.
FSCM AND THE WATCHDOG TIMER
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
IRCF2:IRCF0 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.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
19.4.2
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 system clock until the
primary clock source becomes ready (similar to a TwoSpeed Start-up). The clock system source is then
switched to the primary clock (indicated by the OSTS
bit in the OSCCON register becoming set). The FailSafe 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.
Entering a power managed mode by loading the
OSCCON register and executing a SLEEP instruction
will clear the Fail-Safe condition. When the Fail-Safe
condition is cleared, the clock monitor will resume
monitoring the peripheral clock.
FIGURE 19-4:
19.4.3
FSCM INTERRUPTS IN POWER
MANAGED MODES
As previously mentioned, entering a power managed
mode clears the Fail-Safe condition. By entering a
power managed mode, the clock multiplexer selects
the clock source selected by the OSCCON register.
Fail-Safe monitoring of the power managed 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, the device will not exit the
power managed mode on oscillator failure. Instead, the
device will continue to operate as before, but clocked
by the INTOSC multiplexer. While in Idle mode, subsequent interrupts will cause the CPU to begin executing
instructions while being clocked by the INTOSC multiplexer. The device will not transition to a different clock
source until the Fail-Safe condition is cleared.
FSCM TIMING DIAGRAM
Sample Clock
Oscillator
Failure
System
Clock
Output
CM Output
(Q)
Failure
Detected
OSCFIF
CM Test
Note:
CM Test
CM Test
The system clock is normally at a much higher frequency than the sample clock. The relative frequencies in
this example have been chosen for clarity.
2002-2015 Microchip Technology Inc.
DS30009605G-page 177
PIC18F1220/1320
19.4.4
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
system 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 system 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
DS30009605G-page 178
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 19.3.1 “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 system clock to become stable. When the new
powered managed mode is selected, the primary clock
is disabled.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
19.5
Program Verification and
Code Protection
Each of the three blocks has three 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 512 bytes. The remainder of the memory is divided into two blocks on binary
boundaries.
Figure 19-5 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 19-3.
FIGURE 19-5:
CODE-PROTECTED PROGRAM MEMORY FOR PIC18F1220/1320
Block Code
Protection
Controlled By:
CPB, WRTB, EBTRB
MEMORY SIZE/DEVICE
Address
Range
4 Kbytes
(PIC18F1220)
8 Kbytes
(PIC18F1320)
000000h
0001FFh
Boot Block
Boot Block
Address
Range
Block Code
Protection
Controlled By:
000000h
CPB, WRTB, EBTRB
0001FFh
000200h
000200h
Block 0
CP0, WRT0, EBTR0
0007FFh
CP0, WRT0, EBTR0
Block 0
000800h
CP1, WRT1, EBTR1
Block 1
000FFFh
000FFFh
001000h
001000h
Block 1
(Unimplemented
Memory Space)
CP1, WRT1, EBTR1
Unimplemented
Read ‘0’s
001FFFh
002000h
Unimplemented
Read ‘0’s
(Unimplemented
Memory Space)
1FFFFFh
1FFFFFh
TABLE 19-3:
SUMMARY OF CODE PROTECTION REGISTERS
File Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CP1
CP0
300008h
CONFIG5L
—
—
—
—
—
—
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.
2002-2015 Microchip Technology Inc.
DS30009605G-page 179
PIC18F1220/1320
19.5.1
PROGRAM MEMORY
CODE PROTECTION
Note:
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.
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.
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 19-6 through 19-8
illustrate table write and table read protection.
FIGURE 19-6:
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 or an external
programmer.
TABLE WRITE (WRTn) DISALLOWED: PIC18F1320
Register Values
Program Memory
Configuration Bit Settings
000000h
0001FFh
000200h
WRTB, EBTRB = 11
TBLPTR = 0002FFh
WRT0, EBTR0 = 01
PC = 0007FEh
TBLWT *
000FFFh
001000h
PC = 0017FEh
TBLWT *
WRT1, EBTR1 = 11
001FFFh
Results: All table writes disabled to Blockn whenever WRTn = 0.
DS30009605G-page 180
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 19-7:
EXTERNAL BLOCK TABLE READ (EBTRn) DISALLOWED: PIC18F1320
Register Values
Program Memory
Configuration Bit Settings
000000h
WRTB, EBTRB = 11
0001FFh
000200h
TBLPTR = 0002FFh
WRT0, EBTR0 = 10
000FFFh
001000h
PC = 001FFEh
TBLRD *
WRT1, EBTR1 = 11
001FFFh
Results: All table reads from external blocks to Blockn are disabled whenever EBTRn = 0.
TABLAT register returns a value of ‘0’.
FIGURE 19-8:
EXTERNAL BLOCK TABLE READ (EBTRn) ALLOWED: PIC18F1320
Register Values
Program Memory
Configuration Bit Settings
000000h
WRTB, EBTRB = 11
0001FFh
000200h
TBLPTR = 0002FFh
PC = 0007FEh
WRT0, EBTR0 = 10
TBLRD *
000FFFh
001000h
WRT1, EBTR1 = 11
001FFFh
Results: Table reads permitted within Blockn, even when EBTRBn = 0.
TABLAT register returns the value of the data at the location TBLPTR.
2002-2015 Microchip Technology Inc.
DS30009605G-page 181
PIC18F1220/1320
19.5.2
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 external writes to data EEPROM. The
CPU can continue to read and write data EEPROM,
regardless of the protection bit settings.
TABLE 19-4:
Signal
Pin
Notes
PGD
RB7/PGD/T1OSI/
P1D/KBI3
Shared with T1OSC – protect
crystal
PGC
RB6/PGC/T1OSO/
T13CKI/P1C/KBI2
Shared with T1OSC – protect
crystal
MCLR/VPP/RA5
MCLR
VDD
19.5.3
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 or
an external programmer.
19.6
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.
19.7
In-Circuit Serial Programming
PIC18F1220/1320 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 (see Table 19-4).
Note:
The Timer1 oscillator shares the T1OSI
and T1OSO pins with the PGD and PGC
pins used for programming and
debugging.
ICSP/ICD CONNECTIONS
VDD
VSS
VSS
PGM
RB5/PGM/KBI1
19.8
Optional – pull RB5 low is
LVP enabled
In-Circuit Debugger
When the DEBUG bit in Configuration register,
CONFIG4L, 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 19-5 shows which resources are required by
the background debugger.
TABLE 19-5:
DEBUGGER RESOURCES
I/O pins:
RB6, RB7
Stack:
2 levels
Program Memory:
512 bytes
Data Memory:
10 bytes
To use the In-Circuit Debugger function of the
microcontroller, the design must implement In-Circuit
Serial Programming connections to MCLR/VPP, 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 (see the note following Section 19.7 “In-Circuit Serial Programming”
for more information).
When using the Timer1 oscillator, In-Circuit
Serial Programming (ICSP) may not
function correctly (high voltage or low
voltage), or the In-Circuit Debugger (ICD)
may not communicate with the controller.
As a result of using either ICSP or ICD, the
Timer1 crystal may be damaged.
If ICSP or ICD operations are required,
the crystal should be disconnected from
the circuit (disconnect either lead), or
installed after programming. The oscillator
loading capacitors may remain in-circuit
during ICSP or ICD operation.
DS30009605G-page 182
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
19.9
Low-Voltage ICSP Programming
The LVP bit in Configuration register, CONFIG4L,
enables Low-Voltage Programming (LVP). When LVP
is enabled, the microcontroller can be programmed
without requiring high voltage being applied to the
MCLR/VPP/RA5 pin, but the RB5/PGM/KBI1 pin is then
dedicated to controlling Program mode entry and is not
available as a general purpose I/O pin.
LVP is enabled in erased devices.
While programming using LVP, VDD is applied to the
MCLR/VPP/RA5 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.
If Low-Voltage Programming mode will not be used, the
LVP bit can be cleared and RB5/PGM/KBI1 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/RA5 pin).
Once LVP has been disabled, only the standard highvoltage 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
Programming, the device must be supplied with VDD of
4.5V to 5.5V.
2: When Low-Voltage Programming is
enabled, the RB5 pin can no longer be
used as a general purpose I/O pin.
3: When LVP is enabled, externally pull the
PGM pin to VSS to allow normal program
execution.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
20.0
INSTRUCTION SET SUMMARY
The PIC18 instruction set adds many enhancements to
the previous PIC instruction sets, while maintaining an
easy migration from these PIC instruction sets.
Most instructions are a single program memory word
(16 bits), but there are three 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 20-1 lists
byte-oriented, bit-oriented, literal and control
operations. Table 20-1 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 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.
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 ‘—’)
DS30009605G-page 184
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 three
double-word instructions. These three instructions
were made double-word instructions so that all the
required information is available in these 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 s. If a conditional test is
true, or the program counter is changed as a result of
an instruction, the instruction execution time is 2 s.
Two-word branch instructions (if true) would take 3 s.
Figure 20-1 shows the general formats that the
instructions can have.
All examples use the format ‘nnh’ to represent a hexadecimal number, where ‘h’ signifies a hexadecimal
digit.
The Instruction Set Summary, shown in Table 20-1,
lists the instructions recognized by the Microchip
Assembler (MPASMTM). Section 20.2 “Instruction
Set” provides a description of each instruction.
20.1
Read-Modify-Write Operations
Any instruction that specifies a file register as part of
the instruction performs a Read-Modify-Write (R-M-W)
operation. The register is read, the data is modified and
the result is stored according to either the instruction or
the destination designator ‘d’. A read operation is
performed on a register even if the instruction writes to
that register.
For example, a “BCF PORTB,1” instruction will read
PORTB, clear bit 1 of the data, then write the result
back to PORTB. The read operation would have the
unintended result that any condition that sets the RBIF
flag would be cleared. The R-M-W operation may also
copy the level of an input pin to its corresponding output
latch.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 20-1:
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.
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 (0x00 to 0xFF).
fs
12-bit register file address (0x000 to 0xFFF). This is the source address.
fd
12-bit register file address (0x000 to 0xFFF). This is the destination address.
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.
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)
u
Unused or unchanged.
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.
TBLPTR
21-bit Table Pointer (points to a program memory location).
TABLAT
8-bit Table Latch.
TOS
Top-of-Stack.
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.
GIE
Global Interrupt Enable bit.
WDT
Watchdog Timer.
TO
Time-out bit.
PD
Power-down bit.
C, DC, Z, OV, N
ALU Status bits: Carry, Digit Carry, Zero, Overflow, Negative.
[
]
Optional.
(
)
Contents.
Assigned to.
< >
Register bit field.
In the set of.
italics
User defined term (font is Courier).
2002-2015 Microchip Technology Inc.
DS30009605G-page 185
PIC18F1220/1320
FIGURE 20-1:
GENERAL FORMAT FOR INSTRUCTIONS
Byte-oriented file register operations
15
10
9 8 7
OPCODE d
a
Example Instruction
0
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
OPCODE
15
0
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
OPCODE b (BIT #) a
0
BSF MYREG, bit, B
f (FILE #)
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
OPCODE
0
MOVLW 0x7F
k (literal)
k = 8-bit immediate value
Control operations
CALL, GOTO and Branch operations
15
8 7
OPCODE
15
0
GOTO Label
n (literal)
12 11
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)
S = Fast bit
15
OPCODE
15
OPCODE
DS30009605G-page 186
11 10
0
BRA MYFUNC
n (literal)
8 7
n (literal)
0
BC MYFUNC
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 20-1:
Mnemonic,
Operands
PIC18FXXXX INSTRUCTION SET
16-Bit Instruction Word
Description
Cycles
MSb
LSb
Status
Affected
Notes
BYTE-ORIENTED FILE REGISTER OPERATIONS
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
f, d, a
SUBWF
SUBWFB f, d, a
SWAPF
TSTFSZ
XORWF
f, d, a
f, a
f, d, a
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
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
0010
0001
0110
0001
0110
0110
0110
0000
0010
0100
0010
0011
0100
0001
0101
1100
1111
0110
0000
0110
0011
0100
0011
0100
0110
0101
01da
00da
01da
101a
11da
001a
010a
000a
01da
11da
11da
10da
11da
10da
00da
00da
ffff
ffff
111a
001a
110a
01da
01da
00da
00da
100a
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 11da
0101 10da
ffff
ffff
ffff C, DC, Z, OV, N
ffff C, DC, Z, OV, N 1, 2
1
0011 10da
1 (2 or 3) 0110 011a
1
0001 10da
ffff
ffff
ffff
ffff None
ffff None
ffff Z, N
4
1, 2
1
1
1 (2 or 3)
1 (2 or 3)
1
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
ffff
None
None
None
None
None
1, 2
1, 2
3, 4
3, 4
1, 2
None
None
C, DC, Z, OV, N 1, 2
C, Z, N
Z, N
1, 2
C, Z, N
Z, N
None
C, DC, Z, OV, N 1, 2
BIT-ORIENTED FILE REGISTER 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
1001
1000
1011
1010
0111
bbba
bbba
bbba
bbba
bbba
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’.
2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared
if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second
cycle is executed as a NOP.
4: Some instructions are 2-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.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
2002-2015 Microchip Technology Inc.
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PIC18F1220/1320
TABLE 20-1:
PIC18FXXXX INSTRUCTION SET (CONTINUED)
16-Bit Instruction Word
Mnemonic,
Operands
Description
Cycles
MSb
LSb
Status
Affected
Notes
CONTROL OPERATIONS
BC
BN
BNC
BNN
BNOV
BNZ
BOV
BRA
BZ
CALL
n
n
n
n
n
n
n
n
n
n, s
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
CLRWDT —
DAW
—
GOTO
n
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
1 (2)
2
1 (2)
2
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
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
2
2
1
0000 1100
0000 0000
0000 0000
kkkk
0001
0000
1
1
2
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
TO, PD
C
None
None
None
None
None
None
All
GIE/GIEH,
PEIE/GIEL
kkkk None
001s None
0011 TO, PD
4
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’.
2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared
if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second
cycle is executed as a NOP.
4: Some instructions are 2-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.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
DS30009605G-page 188
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 20-1:
PIC18FXXXX INSTRUCTION SET (CONTINUED)
16-Bit Instruction Word
Mnemonic,
Operands
Description
Cycles
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 FSRx
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+*
Table read
2
Table read with post-increment
Table read with post-decrement
Table read with pre-increment
Table write
2 (5)
Table write with post-increment
Table write with post-decrement
Table write with pre-increment
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’.
2: If this instruction is executed on the TMR0 register (and where applicable, d = 1), the prescaler will be cleared
if assigned.
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second
cycle is executed as a NOP.
4: Some instructions are 2-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.
5: If the table write starts the write cycle to internal memory, the write will continue until terminated.
2002-2015 Microchip Technology Inc.
DS30009605G-page 189
PIC18F1220/1320
20.2
Instruction Set
ADDLW
ADD literal to W
Syntax:
[ label ] ADDLW
Operands:
0 k 255
Operation:
(W) + k W
Status Affected:
N, OV, C, DC, Z
Encoding:
0000
Description:
kkkk
kkkk
The contents of W are added to the
8-bit literal ‘k’ and the result is
placed in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
ADDLW
Before Instruction
W
1111
k
=
0x10
0x15
ADDWF
ADD W to f
Syntax:
[ label ] ADDWF
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(W) + (f) dest
Status Affected:
N, OV, C, DC, Z
Encoding:
0010
01da
f [,d [,a]]
ffff
ffff
Description:
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 will be selected. If ‘a’ is ‘1’,
the BSR is used.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
After Instruction
W
=
0x25
Example:
ADDWF
REG, W
Before Instruction
W
REG
=
=
0x17
0xC2
After Instruction
W
REG
DS30009605G-page 190
=
=
0xD9
0xC2
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
ADDWFC
ADD W and Carry bit to f
ANDLW
AND literal with W
Syntax:
[ label ] ADDWFC
Syntax:
[ label ] ANDLW
Operands:
0 f 255
d [0,1]
a [0,1]
f [,d [,a]]
Operation:
(W) + (f) + (C) dest
Status Affected:
N, OV, C, DC, Z
Encoding:
0010
Description:
1
Cycles:
1
0 k 255
Operation:
(W) .AND. k W
Status Affected:
N, Z
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 will be selected. If ‘a’ is ‘1’, the
BSR will not be overridden.
Words:
0000
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
ADDWFC
REG, W
kkkk
kkkk
The contents of W are AND’ed with
the 8-bit literal ‘k’. The result is
placed in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read literal
‘k’
Process
Data
Write to W
ANDLW
0x5F
Before Instruction
W
=
0xA3
After Instruction
W
Example:
1011
Description:
Example:
Q Cycle Activity:
Q1
Decode
00da
Operands:
k
=
0x03
Before Instruction
Carry bit =
REG
=
W
=
1
0x02
0x4D
After Instruction
Carry bit =
REG
=
W
=
0
0x02
0x50
2002-2015 Microchip Technology Inc.
DS30009605G-page 191
PIC18F1220/1320
ANDWF
AND W with f
Syntax:
[ label ] ANDWF
Operands:
0 f 255
d [0,1]
a [0,1]
f [,d [,a]]
Operation:
(W) .AND. (f) dest
Status Affected:
N, Z
Encoding:
0001
ffff
ffff
n
Operands:
-128 n 127
Operation:
if Carry bit is ‘1’
(PC) + 2 + 2n PC
Status Affected:
None
1110
0010
nnnn
nnnn
1
Words:
1
1
Cycles:
1(2)
Cycles:
Q Cycle Activity:
Q1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
ANDWF
Before Instruction
=
=
0x17
0xC2
=
=
REG, W
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
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
If No Jump:
Q1
Decode
After Instruction
W
REG
[ label ] BC
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 2-cycle instruction.
Words:
W
REG
Syntax:
Description:
The contents of W are AND’ed 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 will be
selected. If ‘a’ is ‘1’, the BSR will
not be overridden (default).
Example:
Branch if Carry
Encoding:
01da
Description:
Decode
BC
0x02
0xC2
Example:
HERE
BC
JUMP
Before Instruction
PC
=
address (HERE)
=
=
=
=
1;
address (JUMP)
0;
address (HERE + 2)
After Instruction
If Carry
PC
If Carry
PC
DS30009605G-page 192
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
BCF
Bit Clear f
Syntax:
[ label ] BCF
Operands:
0 f 255
0b7
a [0,1]
Operation:
0 f
Status Affected:
None
Encoding:
Description:
Syntax:
[ label ] BN
Operands:
-128 n 127
Operation:
if Negative bit is ‘1’
(PC) + 2 + 2n PC
Status Affected:
None
bbba
ffff
ffff
1110
1
1
Q Cycle Activity:
Q1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
BCF
FLAG_REG
=
0xC7
=
0x47
After Instruction
FLAG_REG
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 2-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
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
FLAG_REG, 7
Before Instruction
n
Description:
Bit ‘b’ in register ‘f’ is cleared. If ‘a’
is ‘0’, the Access Bank will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Cycles:
Example:
Branch if Negative
Encoding:
1001
Words:
Decode
f,b[,a]
BN
If No Jump:
Q1
Decode
Example:
HERE
BN
Jump
Before Instruction
PC
=
address (HERE)
=
=
=
=
1;
address (Jump)
0;
address (HERE + 2)
After Instruction
If Negative
PC
If Negative
PC
2002-2015 Microchip Technology Inc.
DS30009605G-page 193
PIC18F1220/1320
BNC
Branch if Not Carry
BNN
Branch if Not Negative
Syntax:
[ label ] BNC
Syntax:
[ label ] BNN
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
n
0011
nnnn
nnnn
Encoding:
1110
n
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 2-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 2-cycle instruction.
Words:
1
Words:
1
Cycles:
1(2)
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
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
Q2
Q3
Q4
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
Read literal
‘n’
Process
Data
No
operation
If No Jump:
Q1
Decode
Example:
HERE
BNC
Jump
Before Instruction
PC
DS30009605G-page 194
Decode
Example:
HERE
BNN
Jump
Before Instruction
=
address (HERE)
After Instruction
If Carry
PC
If Carry
PC
If No Jump:
Q1
PC
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
After Instruction
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
If Negative
PC
If Negative
PC
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
BNOV
Branch if Not Overflow
BNZ
Branch if Not Zero
Syntax:
[ label ] BNOV
Syntax:
[ label ] 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:
1110
n
0101
nnnn
nnnn
Encoding:
1110
n
0001
nnnn
nnnn
Description:
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 2-cycle instruction.
Description:
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 2-cycle instruction.
Words:
1
Words:
1
Cycles:
1(2)
Cycles:
1(2)
Q Cycle Activity:
If Jump:
Q1
Q Cycle Activity:
If Jump:
Q1
Q2
Q3
Q4
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
Q2
Q3
Q4
Q2
Q3
Q4
Read literal
‘n’
Process
Data
No
operation
Read literal
‘n’
Process
Data
No
operation
If No Jump:
Q1
Decode
Example:
HERE
BNOV Jump
Before Instruction
PC
Decode
Example:
HERE
BNZ
Jump
Before Instruction
=
address (HERE)
After Instruction
If Overflow
PC
If Overflow
PC
If No Jump:
Q1
PC
=
address (HERE)
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
After Instruction
=
=
=
=
0;
address (Jump)
1;
address (HERE + 2)
2002-2015 Microchip Technology Inc.
If Zero
PC
If Zero
PC
DS30009605G-page 195
PIC18F1220/1320
BRA
Unconditional Branch
BSF
Bit Set f
Syntax:
[ label ] BRA
Syntax:
[ label ] BSF
Operands:
-1024 n 1023
Operands:
Operation:
(PC) + 2 + 2n PC
Status Affected:
None
0 f 255
0b7
a [0,1]
Operation:
1 f
Status Affected:
None
Encoding:
Description:
1101
1
Cycles:
2
Q Cycle Activity:
Q1
No
operation
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 2cycle instruction.
Words:
Decode
n
Q2
Q3
Q4
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
No
operation
Encoding:
HERE
BRA
Jump
PC
=
address (HERE)
=
address (Jump)
After Instruction
PC
DS30009605G-page 196
ffff
ffff
Bit ‘b’ in register ‘f’ is set. If ‘a’ is ‘0’,
the Access Bank will be selected,
overriding the BSR value. If ‘a’ = 1,
then the bank will be selected as
per the BSR value.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
BSF
FLAG_REG, 7
Before Instruction
FLAG_REG
Before Instruction
bbba
Description:
Example:
Example:
1000
f,b[,a]
=
0x0A
=
0x8A
After Instruction
FLAG_REG
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
BTFSC
Bit Test File, Skip if Clear
BTFSS
Bit Test File, Skip if Set
Syntax:
[ label ] BTFSC f,b[,a]
Syntax:
[ label ] BTFSS f,b[,a]
Operands:
0 f 255
0b7
a [0,1]
Operands:
0 f 255
0b (W)
(unsigned comparison)
Operation:
(f) –W),
skip if (f) < (W)
(unsigned comparison)
Status Affected:
None
Status Affected:
None
Encoding:
0110
010a
f [,a]
ffff
ffff
Encoding:
0110
000a
f [,a]
ffff
ffff
Description:
Compares the contents of data
memory location ‘f’ to the contents
of 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 2-cycle instruction. If ‘a’ is ‘0’,
the Access Bank will be selected,
overriding the BSR value. If ‘a’ = 1,
then the bank will be selected as
per the BSR value (default).
Description:
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
2-cycle instruction. If ‘a’ is ‘0’, the
Access Bank will be selected. If ‘a’
is ‘1’, the BSR will not be
overridden (default).
Words:
1
Words:
1
Cycles:
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
Q Cycle Activity:
Q1
Q2
Q3
Q4
Read
register ‘f’
Process
Data
No
operation
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
Decode
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
HERE
NGREATER
GREATER
CPFSGT REG
:
:
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
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
Example:
Before Instruction
PC
W
=
=
Address (HERE)
?
=
=
W;
Address (GREATER)
W;
Address (NGREATER)
After Instruction
If REG
PC
If REG
PC
DS30009605G-page 202
Q4
No
operation
HERE
NLESS
LESS
CPFSLT REG
:
:
Before Instruction
PC
W
=
=
Address (HERE)
?
<
=
=
W;
Address (LESS)
W;
Address (NLESS)
After Instruction
If REG
PC
If REG
PC
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
DAW
Decimal Adjust W Register
DECF
Decrement f
Syntax:
[ label ] DAW
Syntax:
[ label ] 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 > 9] or [C = 1] then
(W) + 6 W;
else
(W) W;
Status Affected:
Encoding:
0000
0000
0000
1
Cycles:
1
Q Cycle Activity:
Q1
Q3
Q4
Read
register W
Process
Data
Write
W
Example 1:
DAW
Before Instruction
=
=
=
0xA5
0
0
ffff
ffff
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 will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
01da
Description:
0111
DAW adjusts the 8-bit value in W,
resulting from the earlier addition of
two variables (each in packed BCD
format) and produces a correct
packed BCD result. The Carry bit
may be set by DAW regardless of its
setting prior to the DAW instruction.
Words:
W
C
DC
0000
C, DC
Description:
Decode
Encoding:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
DECF
CNT
Before Instruction
CNT
Z
=
=
0x01
0
After Instruction
CNT
Z
=
=
0x00
1
After Instruction
W
C
DC
=
=
=
0x05
1
0
Example 2:
Before Instruction
W
C
DC
=
=
=
0xCE
0
0
After Instruction
W
C
DC
=
=
=
0x34
1
0
2002-2015 Microchip Technology Inc.
DS30009605G-page 203
PIC18F1220/1320
DECFSZ
Decrement f, skip if 0
DCFSNZ
Decrement f, skip if not 0
Syntax:
[ label ] DECFSZ f [,d [,a]]
Syntax:
[ label ] 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
11da
ffff
ffff
Encoding:
0100
11da
f [,d [,a]]
ffff
ffff
Description:
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 2-cycle instruction. If ‘a’ is ‘0’, the Access Bank
will be selected, overriding the
BSR value. If ‘a’ = 1, then the bank
will be selected as per the BSR
value (default).
Description:
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 2cycle instruction. If ‘a’ is ‘0’, the
Access Bank will be selected,
overriding the BSR value. If ‘a’ = 1,
then the bank will be selected as
per the BSR value (default).
Words:
1
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
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
No
operation
No
operation
No
operation
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q4
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
If skip:
If skip:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
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
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
HERE
DECFSZ
GOTO
Example:
CNT
LOOP
Example:
CONTINUE
Before Instruction
PC
=
=
=
=
=
DS30009605G-page 204
DCFSNZ TEMP
:
:
Before Instruction
Address (HERE)
After Instruction
CNT
If CNT
PC
If CNT
PC
HERE
ZERO
NZERO
TEMP
=
?
=
=
=
=
TEMP – 1,
0;
Address (ZERO)
0;
Address (NZERO)
After Instruction
CNT – 1
0;
Address (CONTINUE)
0;
Address (HERE + 2)
TEMP
If TEMP
PC
If TEMP
PC
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
GOTO
Unconditional Branch
INCF
Increment f
Syntax:
[ label ]
Syntax:
[ label ]
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)
Description:
1110
1111
GOTO k
1111
k19kkk
k7kkk
kkkk
kkkk0
kkkk8
GOTO allows an unconditional
branch anywhere within the entire
2-Mbyte memory range. The 20-bit
value ‘k’ is loaded into PC.
GOTO is always a 2-cycle
instruction.
Words:
2
Cycles:
2
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read literal
‘k’,
No
operation
Read literal
‘k’,
Write to PC
No
operation
No
operation
No
operation
No
operation
Example:
GOTO THERE
After Instruction
PC =
Address (THERE)
Encoding:
0010
INCF
f [,d [,a]]
10da
ffff
ffff
Description:
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 will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
INCF
CNT
Before Instruction
CNT
Z
C
DC
=
=
=
=
0xFF
0
?
?
After Instruction
CNT
Z
C
DC
2002-2015 Microchip Technology Inc.
=
=
=
=
0x00
1
1
1
DS30009605G-page 205
PIC18F1220/1320
INCFSZ
Increment f, skip if 0
INFSNZ
Increment f, skip if not 0
Syntax:
[ label ]
Syntax:
[ label ]
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:
0011
INCFSZ
11da
f [,d [,a]]
ffff
ffff
Encoding:
0100
INFSNZ
10da
f [,d [,a]]
ffff
ffff
Description:
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 2-cycle instruction. If ‘a’ is ‘0’, the Access Bank
will be selected, overriding the BSR
value. If ‘a’ = 1, then the bank will
be selected as per the BSR value
(default).
Description:
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 2cycle instruction. If ‘a’ is ‘0’, the
Access Bank will be selected, overriding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
1
Words:
1
Cycles:
1(2)
Note: 3 cycles if skip and followed
by a 2-word instruction.
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
No
operation
No
operation
No
operation
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
Read
register ‘f’
Process
Data
Write to
destination
Q4
Q1
Q2
Q3
Q4
No
operation
No
operation
No
operation
No
operation
No
operation
If skip:
If skip:
If skip and followed by 2-word instruction:
Q1
Q2
Q3
Q4
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
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
No
operation
Example:
HERE
NZERO
ZERO
INCFSZ
:
:
Before Instruction
PC
=
=
=
=
=
DS30009605G-page 206
Example:
HERE
ZERO
NZERO
INFSNZ REG
Before Instruction
Address (HERE)
After Instruction
CNT
If CNT
PC
If CNT
PC
CNT
PC
=
Address (HERE)
After Instruction
CNT + 1
0;
Address (ZERO)
0;
Address (NZERO)
REG
If REG
PC
If REG
PC
=
=
=
=
REG + 1
0;
Address (NZERO)
0;
Address (ZERO)
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
IORLW
Inclusive OR literal with W
IORWF
Inclusive OR W with f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(W) .OR. (f) dest
Status Affected:
N, Z
IORLW k
Operands:
0 k 255
Operation:
(W) .OR. k W
Status Affected:
N, Z
Encoding:
0000
Description:
1001
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
IORLW
0x35
Before Instruction
=
0x9A
After Instruction
W
kkkk
The contents of W are OR’ed with
the 8-bit literal ‘k’. The result is
placed in W.
Words:
W
kkkk
=
Encoding:
0001
IORWF
00da
f [,d [,a]]
ffff
ffff
Description:
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 will be selected, overriding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
0xBF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
IORWF RESULT, W
Before Instruction
RESULT =
W
=
0x13
0x91
After Instruction
RESULT =
W
=
2002-2015 Microchip Technology Inc.
0x13
0x93
DS30009605G-page 207
PIC18F1220/1320
LFSR
Load FSR
MOVF
Move f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0f2
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:
LFSR f,k
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
Q Cycle Activity:
Q1
Q2
Q3
Q4
Decode
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:
LFSR 2, 0x3AB
After Instruction
FSR2H
FSR2L
=
=
0x03
0xAB
Encoding:
MOVF
0101
00da
f [,d [,a]]
ffff
ffff
Description:
The contents of register ‘f’ are
moved to a destination dependent
upon the status of ‘d’. If ‘d’ is ‘f’, the
result is placed in W. If ‘d’ is ‘f’, 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 will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write W
MOVF
REG, W
Before Instruction
REG
W
=
=
0x22
0xFF
=
=
0x22
0x22
After Instruction
REG
W
DS30009605G-page 208
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
MOVFF
Move f to f
MOVLB
Move literal to low nibble in BSR
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 fs 4095
0 fd 4095
Operands:
0 k 255
Operation:
k BSR
None
MOVFF fs,fd
Operation:
(fs) fd
Status Affected:
Status Affected:
None
Encoding:
Encoding:
1st word (source)
2nd word (destin.)
Description:
1100
1111
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.
MOVLB k
0000
0001
kkkk
kkkk
Description:
The 8-bit literal ‘k’ is loaded into
the Bank Select Register (BSR).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Read literal
‘k’
Process
Data
Write
literal ‘k’ to
BSR
MOVLB
5
Before Instruction
BSR register
=
0x02
=
0x05
After Instruction
BSR register
The MOVFF instruction should not
be used to modify interrupt settings
while any interrupt is enabled (see
page 70).
Words:
2
Cycles:
2 (3)
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
REG1, REG2
Before Instruction
REG1
REG2
=
=
0x33
0x11
=
=
0x33,
0x33
After Instruction
REG1
REG2
2002-2015 Microchip Technology Inc.
DS30009605G-page 209
PIC18F1220/1320
MOVLW
Move literal to W
MOVWF
Move W to f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 k 255
Operands:
Operation:
kW
0 f 255
a [0,1]
Status Affected:
None
Operation:
(W) f
Status Affected:
None
Encoding:
0000
Description:
1110
kkkk
kkkk
Encoding:
The 8-bit literal ‘k’ is loaded
into W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Process
Data
Write to W
MOVLW
=
0x5A
0x5A
0110
Description:
Read
literal ‘k’
After Instruction
W
MOVLW k
111a
f [,a]
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 will be selected, overriding the BSR value. If ‘a’ = 1, then
the bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
MOVWF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
MOVWF
REG
Before Instruction
W
REG
=
=
0x4F
0xFF
After Instruction
W
REG
DS30009605G-page 210
=
=
0x4F
0x4F
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
MULLW
Multiply Literal with W
MULWF
Multiply W with f
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
0 f 255
a [0,1]
Operation:
(W) x (f) PRODH:PRODL
Status Affected:
None
MULLW
k
Operands:
0 k 255
Operation:
(W) x k PRODH:PRODL
Status Affected:
None
Encoding:
Description:
0000
1
Cycles:
1
Q Cycle Activity:
Q1
Example:
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:
Decode
1101
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write
registers
PRODH:
PRODL
MULLW
0xC4
Before Instruction
W
PRODH
PRODL
=
=
=
0xE2
?
?
=
=
=
0xE2
0xAD
0x08
Encoding:
Description:
0000
001a
1
Cycles:
1
Q Cycle Activity:
Q1
Example:
ffff
ffff
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
registers
PRODH:
PRODL
After Instruction
W
PRODH
PRODL
f [,a]
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 will be selected,
overriding the BSR value. If
‘a’ = 1, then the bank will be
selected as per the BSR value
(default).
Words:
Decode
MULWF
MULWF
REG
Before Instruction
W
REG
PRODH
PRODL
=
=
=
=
0xC4
0xB5
?
?
=
=
=
=
0xC4
0xB5
0x8A
0x94
After Instruction
W
REG
PRODH
PRODL
2002-2015 Microchip Technology Inc.
DS30009605G-page 211
PIC18F1220/1320
NEGF
Negate f
Syntax:
[ label ]
Operands:
0 f 255
a [0,1]
NEGF
Operation:
(f) + 1 f
Status Affected:
N, OV, C, DC, Z
Encoding:
0110
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Syntax:
[ label ]
NOP
Operands:
None
Operation:
No operation
Status Affected:
None
0000
1111
ffff
Description:
1
Cycles:
1
Decode
0000
xxxx
0000
xxxx
No operation.
Words:
Q Cycle Activity:
Q1
0000
xxxx
Q2
Q3
Q4
No
operation
No
operation
No
operation
Example:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
Example:
No Operation
Encoding:
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 will be
selected, overriding the BSR value.
If ‘a’ = 1, then the bank will be
selected as per the BSR value.
Words:
Decode
110a
f [,a]
NOP
NEGF
None.
REG, 1
Before Instruction
REG
=
0011 1010 [0x3A]
After Instruction
REG
=
DS30009605G-page 212
1100 0110 [0xC6]
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
POP
Pop Top of Return Stack
PUSH
Push Top of Return Stack
Syntax:
[ label ]
Syntax:
[ label ]
Operands:
None
Operands:
None
Operation:
(TOS) bit bucket
Operation:
(PC + 2) TOS
Status Affected:
None
Status Affected:
None
Encoding:
0000
POP
0000
0000
0110
Encoding:
0000
PUSH
0000
0000
0101
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.
Description:
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.
Words:
1
Words:
1
Cycles:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q Cycle Activity:
Q1
Q2
Q3
Q4
No
operation
Pop TOS
value
No
operation
POP
GOTO
Example:
NEW
=
=
Q2
Q3
Q4
Push
PC + 2 onto
return stack
No
operation
No
operation
PUSH
Before Instruction
Before Instruction
TOS
Stack (1 level down)
Decode
0x0031A2
0x014332
TOS
PC
=
=
0x00345A
0x000124
=
=
=
0x000126
0x000126
0x00345A
After Instruction
After Instruction
TOS
PC
=
=
2002-2015 Microchip Technology Inc.
0x014332
NEW
PC
TOS
Stack (1 level down)
DS30009605G-page 213
PIC18F1220/1320
RCALL
Relative Call
RESET
Reset
Syntax:
[ label ] RCALL
Syntax:
[ label ]
Operands:
Operation:
-1024 n 1023
Operands:
None
(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:
Description:
1101
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 2-cycle instruction.
Words:
1
Cycles:
2
Encoding:
0000
RESET
0000
1111
1111
Description:
This instruction provides a way to
execute a MCLR Reset in software.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Start
Reset
No
operation
No
operation
RESET
After Instruction
Q Cycle Activity:
Q1
Decode
n
Q2
Q3
Q4
Read literal
‘n’
Process
Data
Write to PC
No
operation
No
operation
Registers =
Flags*
=
Reset Value
Reset Value
Push PC to
stack
No
operation
Example:
No
operation
HERE
RCALL Jump
Before Instruction
PC =
Address (HERE)
After Instruction
PC =
TOS =
Address (Jump)
Address (HERE + 2)
DS30009605G-page 214
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
RETFIE
Return from Interrupt
RETLW
Return Literal to W
Syntax:
[ label ]
Syntax:
[ label ]
RETFIE [s]
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
1
Cycles:
2
Decode
0000
0001
Example:
kkkk
kkkk
W is loaded with the 8-bit literal ‘k’.
The program counter is loaded
from the top of the stack (the return
address). The high address latch
(PCLATH) remains unchanged.
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:
Q2
Q3
Q4
No
operation
No
operation
Pop PC
from stack
Set GIEH or
GIEL
No
operation
1100
Description:
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:
Q Cycle Activity:
Q1
0000
GIE/GIEH, PEIE/GIEL.
Encoding:
Description:
Encoding:
No
operation
RETFIE
No
operation
No
operation
1
CALL TABLE ;
;
;
;
:
TABLE
ADDWF PCL ;
RETLW k0
;
RETLW k1
;
:
:
RETLW kn
;
W contains table
offset value
W now has
table value
W = offset
Begin table
End of table
After Interrupt
PC
W
BSR
Status
GIE/GIEH, PEIE/GIEL
=
=
=
=
=
2002-2015 Microchip Technology Inc.
TOS
WS
BSRS
STATUSS
1
Before Instruction
W
=
0x07
After Instruction
W
=
value of kn
DS30009605G-page 215
PIC18F1220/1320
RETURN
Return from Subroutine
RLCF
Rotate Left f through Carry
Syntax:
[ label ]
Syntax:
[ label ]
RETURN [s]
RLCF
f [,d [,a]]
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
None
Encoding:
Status Affected:
Encoding:
0000
0000
0001
001s
Description:
Return from subroutine. The stack
is popped and the top of the stack
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
Q Cycle Activity:
Q1
0011
Description:
Q3
Q4
Decode
No
operation
Process
Data
Pop PC
from stack
No
operation
No
operation
No
operation
No
operation
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
After Interrupt
PC =
TOS
ffff
register f
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
RETURN
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 will be selected, overriding
the BSR value. If ‘a’ = 1, then the
bank will be selected as per the
BSR value (default).
C
Q2
Example:
01da
RLCF
REG, W
Before Instruction
REG
C
=
=
1110 0110
0
After Instruction
REG
W
C
DS30009605G-page 216
=
=
=
1110 0110
1100 1100
1
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
RLNCF
Rotate Left f (no carry)
RRCF
Rotate Right f through Carry
Syntax:
[ label ]
Syntax:
[ label ]
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:
RLNCF
01da
f [,d [,a]]
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 will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
Encoding:
0011
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
RLNCF
REG
ffff
ffff
register f
C
Q2
Example:
00da
f [,d [,a]]
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 will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
register f
Words:
RRCF
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Before Instruction
REG
=
1010 1011
After Instruction
REG
=
Example:
RRCF
REG, W
Before Instruction
0101 0111
REG
C
=
=
1110 0110
0
After Instruction
REG
W
C
2002-2015 Microchip Technology Inc.
=
=
=
1110 0110
0111 0011
0
DS30009605G-page 217
PIC18F1220/1320
RRNCF
Rotate Right f (no carry)
SETF
Set f
Syntax:
[ label ]
Syntax:
[ label ] SETF
Operands:
0 f 255
d [0,1]
a [0,1]
Operands:
0 f 255
a [0,1]
Operation:
(f) dest,
(f) dest
FFh f
Operation:
Status Affected:
None
Status Affected:
N, Z
Encoding:
0100
Description:
RRNCF
00da
f [,d [,a]]
Encoding:
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).
register f
Words:
1
Cycles:
1
100a
ffff
ffff
Description:
The contents of the specified
register are set to FFh. 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).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Example:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write
register ‘f’
SETF
REG
Before Instruction
Q Cycle Activity:
Q1
Decode
0110
f [,a]
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example 1:
RRNCF
REG
=
0x5A
=
0xFF
After Instruction
REG
REG, 1, 0
Before Instruction
REG
=
1101 0111
After Instruction
REG
=
Example 2:
1110 1011
RRNCF
REG, W
Before Instruction
W
REG
=
=
?
1101 0111
After Instruction
W
REG
=
=
DS30009605G-page 218
1110 1011
1101 0111
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
SLEEP
Enter Sleep mode
SUBFWB
Subtract f from W with borrow
Syntax:
[ label ] SLEEP
Syntax:
[ label ] 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
TO, PD
Encoding:
Status Affected:
Encoding:
0000
0000
0000
0011
Description:
The Power-down Status bit (PD)
is cleared. The Time-out status bit
(TO) is set. The Watchdog Timer
and its postscaler are cleared.
The processor is put into Sleep
mode with the oscillator stopped.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
No
operation
Process
Data
Go to
Sleep
Example:
SLEEP
Description:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
?
?
After Instruction
TO =
1†
0
PD =
01da
ffff
ffff
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 will be
selected, overriding the BSR value.
If ‘a’ is ‘1’, then the bank will be
selected as per the BSR value
(default).
Words:
Before Instruction
TO =
PD =
0101
f [,d [,a]]
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example 1:
SUBFWB REG
Before Instruction
REG
W
C
=
=
=
0x03
0x02
0x01
After Instruction
† If WDT causes wake-up, this bit is cleared.
REG
W
C
Z
N
=
=
=
=
=
Example 2:
0xFF
0x02
0x00
0x00
0x01
SUBFWB
; result is negative
REG, 0, 0
Before Instruction
REG
W
C
=
=
=
2
5
1
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 3:
2
3
1
0
0
SUBFWB
; result is positive
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
1
2
0
After Instruction
REG
W
C
Z
N
2002-2015 Microchip Technology Inc.
=
=
=
=
=
0
2
1
1
0
; result is zero
DS30009605G-page 219
PIC18F1220/1320
SUBLW
Subtract W from literal
SUBWF
Subtract W from f
Syntax:
[ label ] SUBLW k
Syntax:
[ label ] SUBWF
Operands:
0 k 255
Operands:
Operation:
k – (W) W
0 f 255
d [0,1]
a [0,1]
Status Affected:
N, OV, C, DC, Z
Operation:
(f) – (W) dest
Status Affected:
N, OV, C, DC, Z
Encoding:
0000
Description:
1000
kkkk
W is subtracted from the 8-bit
literal ‘k’. The result is placed
in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example 1:
SUBLW
0x02
Before Instruction
W
C
=
=
1
?
=
=
=
=
Example 2:
1
1
0
0
SUBLW
; result is positive
=
=
0
1
1
0
SUBLW
; result is zero
0x02
Before Instruction
W
C
=
=
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 will be selected,
overriding the BSR value. If ‘a’ is
‘1’, then the bank will be selected
as per the BSR value (default).
Words:
1
Cycles:
1
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
SUBWF REG
Before Instruction
=
=
=
3
2
?
=
=
=
=
FF
0
0
1
REG
W
C
Z
N
=
=
=
=
=
Example 2:
1
2
1
0
0
; result is positive
SUBWF REG, W
Before Instruction
3
?
REG
W
C
After Instruction
W
C
Z
N
ffff
After Instruction
=
=
=
=
Example 3:
11da
Description:
REG
W
C
2
?
After Instruction
W
C
Z
N
0101
Example 1:
0x02
Before Instruction
W
C
Encoding:
Q Cycle Activity:
Q1
After Instruction
W
C
Z
N
kkkk
f [,d [,a]]
; (2’s complement)
; result is negative
=
=
=
2
2
?
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 3:
2
0
1
1
0
; result is zero
SUBWF REG
Before Instruction
REG
W
C
=
=
=
0x01
0x02
?
After Instruction
REG
W
C
Z
N
DS30009605G-page 220
=
=
=
=
=
0xFFh ;(2’s complement)
0x02
0x00 ;result is negative
0x00
0x01
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
SUBWFB
Subtract W from f with Borrow
SWAPF
Swap f
Syntax:
[ label ] SUBWFB
Syntax:
[ label ] 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:
Description:
0101
10da
f [,d [,a]]
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 will be
selected, overriding the BSR value. If
‘a’ is ‘1’, then the bank will be
selected as per the BSR value
(default).
Encoding:
0011
Description:
1
Words:
1
Cycles:
1
Cycles:
1
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example 1:
SUBWFB
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
0x19
0x0D
0x01
(0001 1001)
(0000 1101)
0x0C
0x0D
0x01
0x00
0x00
(0000 1011)
(0000 1101)
Example 2:
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
SWAPF
REG
Before Instruction
REG
REG
=
=
=
=
=
ffff
=
0x53
After Instruction
After Instruction
REG
W
C
Z
N
Q Cycle Activity:
Q1
Decode
ffff
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 will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
Words:
Q Cycle Activity:
Q1
10da
=
0x35
; result is positive
SUBWFB REG, 0, 0
Before Instruction
REG
W
C
=
=
=
0x1B
0x1A
0x00
(0001 1011)
(0001 1010)
0x1B
0x00
0x01
0x01
0x00
(0001 1011)
After Instruction
REG
W
C
Z
N
=
=
=
=
=
Example 3:
SUBWFB
; result is zero
REG, 1, 0
Before Instruction
REG
W
C
=
=
=
0x03
0x0E
0x01
(0000 0011)
(0000 1101)
(1111 0100)
; [2’s comp]
(0000 1101)
After Instruction
REG
=
0xF5
W
C
Z
N
=
=
=
=
0x0E
0x00
0x00
0x01
; result is negative
2002-2015 Microchip Technology Inc.
DS30009605G-page 221
PIC18F1220/1320
TBLRD
Table Read
TBLRD
Table Read (Continued)
Syntax:
[ label ] 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;
Before Instruction
Description:
0000
TABLAT
TBLPTR
MEMORY(0x00A356)
=
=
=
0x55
0x00A356
0x34
=
=
0x34
0x00A357
After Instruction
TABLAT
TBLPTR
Example 2:
TBLRD
+* ;
Before Instruction
TABLAT
TBLPTR
MEMORY(0x01A357)
MEMORY(0x01A358)
=
=
=
=
0xAA
0x01A357
0x12
0x34
=
=
0x34
0x01A358
After Instruction
Status Affected: None
Encoding:
*+ ;
0000
0000
10nn
nn = 0*
= 1*+
= 2*= 3+*
TABLAT
TBLPTR
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
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)
DS30009605G-page 222
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TBLWT
Table Write
TBLWT
Syntax:
[ label ] TBLWT ( *; *+; *-; +*)
Words: 1
Operands:
None
Cycles: 2
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;
Q Cycle Activity:
Description:
0000
Q1
Q2
Q3
Q4
Decode
No
operation
No
operation
No
operation
No
operation
No
operation
(Read
TABLAT)
No
operation
No
operation
(Write to
Holding
Register)
Example 1:
TBLWT *+;
Before Instruction
Status Affected: None
Encoding:
Table Write (Continued)
0000
0000
11nn
nn = 0*
= 1*+
= 2*= 3+*
This instruction uses the 3 LSBs of
TBLPTR to determine which of the
eight holding registers the TABLAT is
written to. The holding registers are
used to program the contents of
Program Memory (P.M.). (Refer
to Section 6.0 “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
2002-2015 Microchip Technology Inc.
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
=
=
0x55
0x00A356
=
0xFF
After Instructions (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(0x00A356)
Example 2:
=
=
0x55
0x00A357
=
0x55
TBLWT +*;
Before Instruction
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
=
=
0x34
0x01389A
=
0xFF
=
0xFF
After Instruction (table write completion)
TABLAT
TBLPTR
HOLDING REGISTER
(0x01389A)
HOLDING REGISTER
(0x01389B)
=
=
0x34
0x01389B
=
0xFF
=
0x34
DS30009605G-page 223
PIC18F1220/1320
TSTFSZ
Test f, skip if 0
XORLW
Exclusive OR literal with W
Syntax:
[ label ] TSTFSZ f [,a]
Syntax:
[ label ] 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:
Description:
Encoding:
0110
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 2-cycle instruction. 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).
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
0000
1010
kkkk
kkkk
Description:
The contents of W are XOR’ed
with the 8-bit literal ‘k’. The result
is placed in W.
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
literal ‘k’
Process
Data
Write to W
Example:
XORLW 0xAF
Before Instruction
W
=
0xB5
After Instruction
W
=
0x1A
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
TSTFSZ CNT
:
:
Before Instruction
PC
=
Address (HERE)
=
=
=
0x00,
Address (ZERO)
0x00,
Address (NZERO)
After Instruction
If CNT
PC
If CNT
PC
DS30009605G-page 224
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
XORWF
Exclusive OR W with f
Syntax:
[ label ] XORWF
Operands:
0 f 255
d [0,1]
a [0,1]
Operation:
(W) .XOR. (f) dest
Status Affected:
N, Z
Encoding:
0001
10da
f [,d [,a]]
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 will be selected, overriding
the BSR value. If ‘a’ is ‘1’, then the
bank will be selected as per the
BSR value (default).
Words:
1
Cycles:
1
Q Cycle Activity:
Q1
Decode
Q2
Q3
Q4
Read
register ‘f’
Process
Data
Write to
destination
Example:
XORWF
REG
Before Instruction
REG
W
=
=
0xAF
0xB5
After Instruction
REG
W
=
=
0x1A
0xB5
2002-2015 Microchip Technology Inc.
DS30009605G-page 225
PIC18F1220/1320
21.0
DEVELOPMENT SUPPORT
The PIC® microcontrollers (MCU) and dsPIC® digital
signal controllers (DSC) are supported with a full range
of software and hardware development tools:
• Integrated Development Environment
- MPLAB® X IDE Software
• Compilers/Assemblers/Linkers
- MPLAB XC Compiler
- MPASMTM Assembler
- MPLINKTM Object Linker/
MPLIBTM Object Librarian
- MPLAB Assembler/Linker/Librarian for
Various Device Families
• Simulators
- MPLAB X SIM Software Simulator
• Emulators
- MPLAB REAL ICE™ In-Circuit Emulator
• In-Circuit Debuggers/Programmers
- MPLAB ICD 3
- PICkit™ 3
• Device Programmers
- MPLAB PM3 Device Programmer
• Low-Cost Demonstration/Development Boards,
Evaluation Kits and Starter Kits
• Third-party development tools
21.1
MPLAB X Integrated Development
Environment Software
The MPLAB X IDE is a single, unified graphical user
interface for Microchip and third-party software, and
hardware development tool that runs on Windows®,
Linux and Mac OS® X. Based on the NetBeans IDE,
MPLAB X IDE is an entirely new IDE with a host of free
software components and plug-ins for highperformance application development and debugging.
Moving between tools and upgrading from software
simulators to hardware debugging and programming
tools is simple with the seamless user interface.
With complete project management, visual call graphs,
a configurable watch window and a feature-rich editor
that includes code completion and context menus,
MPLAB X IDE is flexible and friendly enough for new
users. With the ability to support multiple tools on
multiple projects with simultaneous debugging, MPLAB
X IDE is also suitable for the needs of experienced
users.
Feature-Rich Editor:
• Color syntax highlighting
• Smart code completion makes suggestions and
provides hints as you type
• Automatic code formatting based on user-defined
rules
• Live parsing
User-Friendly, Customizable Interface:
• Fully customizable interface: toolbars, toolbar
buttons, windows, window placement, etc.
• Call graph window
Project-Based Workspaces:
•
•
•
•
Multiple projects
Multiple tools
Multiple configurations
Simultaneous debugging sessions
File History and Bug Tracking:
• Local file history feature
• Built-in support for Bugzilla issue tracker
DS30009605G-page 226
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
21.2
MPLAB XC Compilers
The MPLAB XC Compilers are complete ANSI C
compilers for all of Microchip’s 8, 16, and 32-bit MCU
and DSC devices. These compilers provide powerful
integration capabilities, superior code optimization and
ease of use. MPLAB XC Compilers run on Windows,
Linux or MAC OS X.
For easy source level debugging, the compilers provide
debug information that is optimized to the MPLAB X
IDE.
The free MPLAB XC Compiler editions support all
devices and commands, with no time or memory
restrictions, and offer sufficient code optimization for
most applications.
MPLAB XC Compilers include an assembler, linker and
utilities. 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. MPLAB XC Compiler uses the assembler to
produce its object 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 X IDE compatibility
21.3
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.
21.4
MPLINK Object Linker/
MPLIB Object Librarian
The MPLINK Object Linker combines relocatable
objects created by the MPASM Assembler. 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
21.5
MPLAB Assembler, Linker and
Librarian for Various Device
Families
MPLAB Assembler produces relocatable machine
code from symbolic assembly language for PIC24,
PIC32 and dsPIC DSC devices. MPLAB XC 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 X IDE compatibility
The MPASM Assembler features include:
• Integration into MPLAB X IDE projects
• User-defined macros to streamline
assembly code
• Conditional assembly for multipurpose
source files
• Directives that allow complete control over the
assembly process
2002-2015 Microchip Technology Inc.
DS30009605G-page 227
PIC18F1220/1320
21.6
MPLAB X SIM Software Simulator
The MPLAB X 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 X SIM Software Simulator fully supports
symbolic debugging using the MPLAB XC 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.
21.7
MPLAB REAL ICE In-Circuit
Emulator System
The 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 all 8, 16 and 32-bit MCU, and DSC devices
with the easy-to-use, powerful graphical user interface of
the MPLAB X IDE.
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 in-circuit debugger systems (RJ-11)
or with the new high-speed, noise tolerant, LowVoltage Differential Signal (LVDS) interconnection
(CAT5).
The emulator is field upgradable through future firmware
downloads in MPLAB X IDE. MPLAB REAL ICE offers
significant advantages over competitive emulators
including full-speed emulation, run-time variable
watches, trace analysis, complex breakpoints, logic
probes, a ruggedized probe interface and long (up to
three meters) interconnection cables.
DS30009605G-page 228
21.8
MPLAB ICD 3 In-Circuit Debugger
System
The MPLAB ICD 3 In-Circuit Debugger System is
Microchip’s most cost-effective, high-speed hardware
debugger/programmer for Microchip Flash DSC and
MCU devices. It debugs and programs PIC Flash
microcontrollers and dsPIC DSCs with the powerful,
yet easy-to-use graphical user interface of the MPLAB
IDE.
The MPLAB ICD 3 In-Circuit Debugger probe is
connected to the design engineer’s PC using a highspeed 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.
21.9
PICkit 3 In-Circuit Debugger/
Programmer
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 IDE. The MPLAB PICkit 3 is
connected to the design engineer’s PC using a fullspeed USB interface and can be connected to the target via a 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™ (ICSP™).
21.10 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.
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
21.11 Demonstration/Development
Boards, Evaluation Kits, and
Starter Kits
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 boards support a variety of features, including LEDs,
temperature sensors, switches, speakers, RS-232
interfaces, LCD displays, potentiometers and additional
EEPROM memory.
21.12 Third-Party Development Tools
Microchip also offers a great collection of tools from
third-party vendors. These tools are carefully selected
to offer good value and unique functionality.
• Device Programmers and Gang Programmers
from companies, such as SoftLog and CCS
• Software Tools from companies, such as Gimpel
and Trace Systems
• Protocol Analyzers from companies, such as
Saleae and Total Phase
• Demonstration Boards from companies, such as
MikroElektronika, Digilent® and Olimex
• Embedded Ethernet Solutions from companies,
such as EZ Web Lynx, WIZnet and IPLogika®
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.
2002-2015 Microchip Technology Inc.
DS30009605G-page 229
PIC18F1220/1320
22.0
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, MCLR and RA4)........................................... -0.3V to (VDD + 0.3V)
Voltage on VDD with respect to VSS ......................................................................................................... -0.3V to +5.5V
Voltage on MCLR with respect to VSS (Note 2) ......................................................................................... 0V to +13.25V
Voltage on RA4 with respect to Vss ............................................................................................................... 0V to +8.5V
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 byall 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 pin, inducing currents greater than 80 mA, may cause latch-up.
Thus, a series resistor of 50-100 should be used when applying a “low” level to the MCLR/VPP 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.
DS30009605G-page 230
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 22-1:
PIC18F1220/1320 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
Voltage
5.0V
PIC18F1X20
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
40 MHz
Frequency
FIGURE 22-2:
PIC18LF1220/1320 VOLTAGE-FREQUENCY GRAPH (INDUSTRIAL)
6.0V
5.5V
Voltage
5.0V
PIC18LF1X20
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
40 MHz
4 MHz
Frequency
FMAX = (16.36 MHz/V) (VDDAPPMIN – 2.0V) + 4 MHz
Note: VDDAPPMIN is the minimum voltage of the PIC® device in the application.
2002-2015 Microchip Technology Inc.
DS30009605G-page 231
PIC18F1220/1320
FIGURE 22-3:
PIC18F1220/1320 VOLTAGE-FREQUENCY GRAPH (EXTENDED)
6.0V
5.5V
Voltage
5.0V
PIC18F1X20-E
4.5V
4.2V
4.0V
3.5V
3.0V
2.5V
2.0V
25 MHz
Frequency
DS30009605G-page 232
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.1
DC Characteristics: Supply Voltage
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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.
Symbol
VDD
D001
Characteristic
Min.
Typ.
Max.
Units
PIC18LF1220/1320
2.0
—
5.5
V
PIC18F1220/1320
4.2
—
5.5
V
Supply Voltage
D002
VDR
RAM Data Retention
Voltage(1)
1.5
—
—
V
D003
VPOR
VDD Start Voltage to ensure
internal Power-on Reset signal
—
—
0.7
V
D004
SVDD
VDD Rise Rate to ensure
internal Power-on Reset signal
0.05
—
—
VBOR
Brown-out Reset Voltage
D005D
Conditions
HS, XT, RC and LP Oscillator mode
See Section 4.1 “Power-on Reset (POR)”
for details.
V/ms See Section 4.1 “Power-on Reset (POR)”
for details.
PIC18LF1220/1320 Industrial Low Voltage (-10C to +85C)
D005F
BORV1:BORV0 = 11
N/A
N/A
N/A
V
BORV1:BORV0 = 10
2.50
2.72
2.94
V
Reserved
BORV1:BORV0 = 01
3.88
4.22
4.56
V
(Note 2)
BORV1:BORV0 = 00
4.18
4.54
4.90
V
(Note 2)
PIC18LF1220/1320 Industrial Low Voltage (-40C to -10C)
D005G
D005H
BORV1:BORV0 = 11
N/A
N/A
N/A
V
BORV1:BORV0 = 10
2.34
2.72
3.10
V
Reserved
BORV1:BORV0 = 01
3.63
4.22
4.81
V
(Note 2)
BORV1:BORV0 = 00
3.90
4.54
5.18
V
(Note 2)
PIC18F1220/1320 Industrial (-10C to +85C)
BORV1:BORV0 = 1x
N/A
N/A
N/A
V
Reserved
BORV1:BORV0 = 01
3.88
4.22
4.56
V
(Note 2)
BORV1:BORV0 = 00
4.18
4.54
4.90
V
(Note 2)
N/A
V
Reserved
PIC18F1220/1320 Industrial (-40C to -10C)
BORV1:BORV0 = 1x
D005J
N/A
N/A
BORV1:BORV0 = 01
N/A
N/A
N/A
V
Reserved
BORV1:BORV0 = 00
3.90
4.54
5.18
V
(Note 2)
PIC18F1220/1320 Extended (-10C to +85C)
D005K
BORV1:BORV0 = 1x
N/A
N/A
N/A
V
Reserved
BORV1:BORV0 = 01
3.88
4.22
4.56
V
(Note 3)
BORV1:BORV0 = 00
4.18
4.54
4.90
V
(Note 3)
PIC18F1220/1320 Extended (-40C to -10C, +85C to +125C)
BORV1:BORV0 = 1x
Legend:
Note 1:
2:
3:
N/A
N/A
N/A
V
Reserved
BORV1:BORV0 = 01
N/A
N/A
N/A
V
Reserved
BORV1:BORV0 = 00
3.90
4.54
5.18
V
(Note 3)
Shading of rows is to assist in readability of the table.
This is the limit to which VDD can be lowered in Sleep mode, or during a device Reset, without losing RAM data.
When BOR is on and BORV = 0x, the device will operate correctly at 40 MHz for any VDD at which the BOR allows
execution (low-voltage and industrial devices only).
When BOR is on and BORV = 0x, the device will operate correctly at 25 MHz for any VDD at which the BOR allows
execution (extended devices only).
2002-2015 Microchip Technology Inc.
DS30009605G-page 233
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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)
PIC18LF1220/1320
PIC18LF1220/1320
All devices
Extended devices
Supply Current (IDD)
PIC18LF1220/1320
All devices
Extended devices
2:
3:
4:
0.5
A
-40°C
0.1
0.5
A
+25°C
+85°C
VDD = 2.0V,
(Sleep mode)
0.2
1.9
A
0.1
0.5
A
-40°C
0.1
0.5
A
+ 25°C
0.3
1.9
A
+85°C
0.1
2.0
A
-40°C
0.1
2.0
A
+25°C
0.4
6.5
A
+85°C
11.2
50
A
+125°C
8
40
A
-40°C
9
40
A
+25°C
+85°C
VDD = 3.0V,
(Sleep mode)
VDD = 5.0V,
(Sleep mode)
(2,3)
PIC18LF1220/1320
Legend:
Note 1:
0.1
11
40
A
25
68
A
-40°C
25
68
A
+25°C
20
68
A
+85°C
55
80
A
-40°C
55
80
A
+25°C
50
80
A
+85°C
50
80
A
+125°C
VDD = 2.0V
VDD = 3.0V
FOSC = 31 kHz
(RC_RUN mode,
Internal oscillator source)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS30009605G-page 234
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
140
220
A
-40°C
145
220
A
+25°C
+85°C
Supply Current (IDD)(2,3)
PIC18LF1220/1320
PIC18LF1220/1320
-40°C
225
330
A
+25°C
235
330
A
+85°C
550
A
-40°C
A
+25°C
405
550
A
+85°C
Extended devices
410
650
A
+125°C
PIC18LF1220/1320
410
600
A
-40°C
425
600
A
+25°C
435
600
A
+85°C
650
900
A
-40°C
670
900
A
+25°C
680
900
A
+85°C
1.2
1.8
mA
-40°C
1.2
1.8
mA
+25°C
1.2
1.8
mA
+85°C
1.2
1.8
mA
+125°C
Extended devices
4:
A
550
All devices
3:
A
385
PIC18LF1220/1320
2:
220
330
390
All devices
Legend:
Note 1:
155
215
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHz
(RC_RUN mode,
Internal oscillator source)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 4 MHz
(RC_RUN mode,
Internal oscillator source)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2002-2015 Microchip Technology Inc.
DS30009605G-page 235
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
4.7
8
A
-40°C
5.0
8
A
+25°C
+85°C
Supply Current (IDD)(2,3)
PIC18LF1220/1320
PIC18LF1220/1320
-40°C
7.8
11
A
+25°C
8.7
15
A
+85°C
16
A
-40°C
A
+25°C
14
22
A
+85°C
Extended devices
25
75
A
+125°C
PIC18LF1220/1320
75
150
A
-40°C
85
150
A
+25°C
95
150
A
+85°C
110
180
A
-40°C
125
180
A
+25°C
135
180
A
+85°C
180
380
A
-40°C
195
380
A
+25°C
200
380
A
+85°C
350
435
A
+125°C
Extended devices
4:
A
16
All devices
3:
A
12
PIC18LF1220/1320
2:
11
11
14
All devices
Legend:
Note 1:
5.8
7.0
VDD = 2.0V
VDD = 3.0V
FOSC = 31 kHz
(RC_IDLE mode,
Internal oscillator source)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHz
(RC_IDLE mode,
Internal oscillator source)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS30009605G-page 236
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
140
275
A
-40°C
140
275
A
+25°C
+85°C
Supply Current (IDD)(2,3)
PIC18LF1220/1320
PIC18LF1220/1320
-40°C
220
375
A
+25°C
220
375
A
+85°C
800
A
-40°C
A
+25°C
380
800
A
+85°C
Extended devices
410
800
A
+125°C
PIC18LF1220/1320
150
250
A
-40°C
150
250
A
+25°C
160
250
A
+85°C
340
350
A
-40°C
300
350
A
+25°C
+85°C
Extended devices
4:
A
800
All devices
3:
A
390
PIC18LF1220/1320
2:
275
375
400
All devices
Legend:
Note 1:
150
220
280
350
A
0.72
1.0
mA
-40°C
0.63
1.0
mA
+25°C
0.58
1.0
mA
+85°C
0.53
1.0
mA
+125°C
VDD = 2.0V
VDD = 3.0V
FOSC = 4 MHz
(RC_IDLE mode,
Internal oscillator source)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 1 MHZ
(PRI_RUN mode,
EC oscillator)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2002-2015 Microchip Technology Inc.
DS30009605G-page 237
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
415
600
A
-40°C
425
600
A
+25°C
+85°C
Supply Current (IDD)(2,3)
PIC18LF1220/1320
PIC18LF1220/1320
All devices
Extended devices
Extended devices
All devices
All devices
Legend:
Note 1:
2:
3:
4:
435
600
A
0.87
1.0
mA
-40°C
0.75
1.0
mA
+25°C
0.75
1.0
mA
+85°C
1.6
2.0
mA
-40°C
1.6
2.0
mA
+25°C
1.5
2.0
mA
+85°C
1.5
2.0
mA
+125°C
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
6.3
9.0
mA
+125°C
VDD = 4.2V
9.7
10.0
mA
+125°C
VDD = 5.0V
9.4
12
mA
-40°C
9.5
12
mA
+25°C
9.6
12
mA
+85°C
11.9
15
mA
-40°C
12.1
15
mA
+25°C
12.2
15
mA
+85°C
FOSC = 4 MHz
(PRI_RUN mode,
EC oscillator)
FOSC = 25 MHz
(PRI_RUN mode,
EC oscillator)
VDD = 4.2V
FOSC = 40 MHZ
(PRI_RUN mode,
EC oscillator)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS30009605G-page 238
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
35
50
A
-40°C
35
50
A
+25°C
+85°C
Supply Current (IDD)(2,3)
PIC18LF1220/1320
PIC18LF1220/1320
4:
A
-40°C
50
80
A
+25°C
60
100
A
+85°C
VDD = 3.0V
150
A
-40°C
150
A
+25°C
115
150
A
+85°C
Extended devices
125
300
A
+125°C
PIC18LF1220/1320
135
180
A
-40°C
140
180
A
+25°C
140
180
A
+85°C
215
280
A
-40°C
225
280
A
+25°C
230
280
A
+85°C
410
525
A
-40°C
420
525
A
+25°C
430
525
A
+85°C
Extended devices
450
800
A
+125°C
Extended devices
2.2
3.0
mA
+125°C
VDD = 4.2V
2.7
3.5
mA
+125°C
VDD = 5.0V
All devices
3:
A
110
PIC18LF1220/1320
2:
60
80
105
All devices
Legend:
Note 1:
35
55
VDD = 2.0V
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
FOSC = 25 MHz
(PRI_IDLE mode,
EC oscillator)
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2002-2015 Microchip Technology Inc.
DS30009605G-page 239
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
Supply Current (IDD)(2,3)
All devices
All devices
PIC18LF1220/1320
PIC18LF1220/1320
All devices
Legend:
Note 1:
2:
3:
4:
3.2
4.1
mA
-40°C
3.2
4.1
mA
+25°C
3.3
4.1
mA
+85°C
4.0
5.1
mA
-40°C
4.1
5.1
mA
+25°C
4.1
5.1
mA
+85°C
5.1
9
A
-10°C
5.8
9
A
+25°C
7.9
11
A
+70°C
7.9
12
A
-10°C
8.9
12
A
+25°C
10.5
14
A
+70°C
12.5
20
A
-10°C
16.3
20
A
+25°C
18.4
25
A
+70°C
VDD = 4.2 V
FOSC = 40 MHz
(PRI_IDLE mode,
EC oscillator)
VDD = 5.0V
VDD = 2.0V
VDD = 3.0V
FOSC = 32 kHz(4)
(SEC_RUN mode,
Timer1 as clock)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS30009605G-page 240
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
9.2
15
A
-10°C
9.6
15
A
+25°C
12.7
18
A
+70°C
22
30
A
-10°C
21
30
A
+25°C
20
35
A
+70°C
Supply Current (IDD)(2,3)
PIC18LF1220/1320
PIC18LF1220/1320
All devices
Legend:
Note 1:
2:
3:
4:
50
80
A
-10°C
45
80
A
+25°C
45
80
A
+70°C
VDD = 2.0V
VDD = 3.0V
FOSC = 32 kHz(4)
(SEC_IDLE mode,
Timer1 as clock)
VDD = 5.0V
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
2002-2015 Microchip Technology Inc.
DS30009605G-page 241
PIC18F1220/1320
22.2
DC Characteristics: Power-Down and Supply Current
PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (Industrial) (Continued)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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
Module Differential Currents (IWDT, IBOR, ILVD, IOSCB, IAD)
D022
(IWDT)
Watchdog Timer
1.5
4.0
A
-40°C
2.2
4.0
A
+25°C
3.1
5.0
A
+85°C
2.5
6.0
A
-40°C
3.3
6.0
A
+25°C
4.7
7.0
A
+85°C
3.7
10.0
A
-40°C
4.5
10.0
A
+25°C
6.1
13.0
A
+85°C
VDD = 2.0V
VDD = 3.0V
VDD = 5.0V
D022A
(IBOR)
Brown-out Reset
19
35.0
A
-40C to +85C
VDD = 3.0V
24
45.0
A
-40C to +85C
VDD = 5.0V
D022B
(ILVD)
Low-Voltage Detect
8.5
25.0
A
-40C to +85C
VDD = 2.0V
16
35.0
A
-40C to +85C
VDD = 3.0V
VDD = 5.0V
D025
(IOSCB)
Timer1 Oscillator
D026
(IAD)
A/D Converter
Legend:
Note 1:
2:
3:
4:
20
45.0
A
-40C to +85C
1.7
3.5
A
-40C
1.8
3.5
A
+25C
2.1
4.5
A
+85C
2.2
4.5
A
-40C
2.6
4.5
A
+25C
2.8
5.5
A
+85C
3.0
6.0
A
-40C
3.3
6.0
A
+25C
VDD = 2.0V
32 kHz on Timer1(4)
VDD = 3.0V
32 kHz on Timer1(4)
VDD = 5.0V
32 kHz on Timer1(4)
3.6
7.0
A
+85C
1.0
3.0
A
-40C to +85C
VDD = 2.0V
1.0
4.0
A
-40C to +85C
VDD = 3.0V
2.0
10.0
A
-40C to +85C
VDD = 5.0V
1.0
8.0
A
-40C to +125C
VDD = 5.0V
A/D on, not converting
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;
MCLR = VDD; WDT enabled/disabled as specified.
For RC oscillator configurations, current through REXT is not included. The current through the resistor can be estimated
by the formula Ir = VDD/2REXT (mA) with REXT in k.
Standard low-cost 32 kHz crystals have an operating temperature range of -10°C to +70°C. Extended temperature
crystals are available at a much higher cost.
DS30009605G-page 242
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.3
DC Characteristics: PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (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
with TTL buffer
VSS
0.15 VDD
V
VDD < 4.5V
—
0.8
V
4.5V VDD 5.5V
with Schmitt Trigger buffer
VSS
0.2 VDD
V
Input Low Voltage
I/O ports:
D030
D030A
D031
D032
MCLR
VSS
0.2 VDD
V
D032A
OSC1 (in XT, HS and LP modes)
and T1OSI
VSS
0.3 VDD
V
D033
OSC1 (in RC and EC mode)(1)
VSS
0.2 VDD
V
0.25 VDD + 0.8V
VDD
V
VDD < 4.5V
2.0
VDD
V
4.5V VDD 5.5V
0.8 VDD
VDD
V
VIH
Input High Voltage
I/O ports:
D040
with TTL buffer
D040A
D041
with Schmitt Trigger buffer
D042
MCLR, OSC1 (EC mode)
0.8 VDD
VDD
V
D042A
OSC1 (in XT, HS and LP modes)
and T1OSI
1.6 VDD
VDD
V
D043
OSC1 (RC mode)(1)
0.9 VDD
VDD
V
—
1
A
IIL
Input Leakage Current(2,3)
VSS VPIN VDD,
Pin at high-impedance
D060
I/O ports
D061
MCLR
—
5
A
VSS VPIN VDD
D063
OSC1
—
5
A
VSS VPIN VDD
50
400
A
VDD = 5V, VPIN = VSS
D070
Note 1:
2:
3:
4:
IPU
Weak Pull-up Current
IPURB
PORTB weak pull-up current
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.
Parameter is characterized but not tested.
2002-2015 Microchip Technology Inc.
DS30009605G-page 243
PIC18F1220/1320
22.3
DC Characteristics: PIC18F1220/1320 (Industrial)
PIC18LF1220/1320 (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.
VOL
Characteristic
Min.
Max.
Units
Conditions
Output Low Voltage
D080
I/O ports
—
0.6
V
IOL = 8.5 mA, VDD = 4.5V,
-40C to +85C
D083
OSC2/CLKO
(RC mode)
—
0.6
V
IOL = 1.6 mA, VDD = 4.5V,
-40C to +85C
VOH
Output High Voltage(3)
D090
I/O ports
VDD – 0.7
—
V
IOH = -3.0 mA, VDD = 4.5V,
-40C to +85C
D092
OSC2/CLKO
(RC mode)
VDD – 0.7
—
V
IOH = -1.3 mA, VDD = 4.5V,
-40C to +85C
—
8.5
V
RA4 pin
D150
VOD
Open-Drain High Voltage
Capacitive Loading Specs
on Output Pins
D100(4) COSC2
OSC2 pin
—
15
pF
In XT, HS and LP modes
when external clock is
used to drive OSC1
D101
CIO
All I/O pins and OSC2
(in RC mode)
—
50
pF
To meet the AC timing
specifications
D102
CB
SCL, SDA
—
400
pF
In I2C mode
Note 1:
2:
3:
4:
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.
Parameter is characterized but not tested.
DS30009605G-page 244
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 22-1:
MEMORY PROGRAMMING REQUIREMENTS
Standard Operating Conditions (unless otherwise stated)
Operating temperature -40°C TA +85°C for industrial
DC CHARACTERISTICS
Param
Sym.
No.
Characteristic
Min.
Typ†
Max.
Units
Conditions
Internal Program Memory
Programming Specifications(1)
D110
VPP
Voltage on MCLR/VPP pin
9.00
—
13.25
V
D112
IPP
Current into MCLR/VPP pin
—
—
5
A
(Note 2)
D113
IDDP
Supply Current during
Programming
—
—
10
mA
E/W -40C to +85C
Data EEPROM Memory
D120
ED
Byte Endurance
100K
1M
—
D121
VDRW
VDD for Read/Write
VMIN
—
5.5
D122
TDEW
Erase/Write Cycle Time
—
4
—
D123
TRETD
Characteristic Retention
40
—
—
Year Provided no other
specifications are violated
D124
TREF
Number of Total Erase/Write
Cycles before Refresh(3)
1M
10M
—
E/W -40°C to +85°C
E/W -40C to +85C
V
Using EECON to read/write
VMIN = Minimum operating
voltage
ms
Program Flash Memory
D130
EP
Cell Endurance
10K
100K
—
D131
VPR
VDD for Read
VMIN
—
5.5
V
VMIN = Minimum operating
voltage
D132
VIE
VDD for Block Erase
4.5
—
5.5
V
Using ICSP port
D132A VIW
VDD for Externally Timed Erase
or Write
4.5
—
5.5
V
Using ICSP port
D132B VPEW
VDD for Self-Timed Write
VMIN
—
5.5
V
VMIN = Minimum operating
voltage
D133
TIE
ICSP™ Block Erase Cycle Time
—
4
—
ms
VDD > 4.5V
D133A TIW
ICSP Erase or Write Cycle Time
(externally timed)
1
—
—
ms
VDD > 4.5V
D133A TIW
Self-Timed Write Cycle Time
—
2
—
ms
40
—
—
D134
TRETD Characteristic Retention
Year Provided no other
specifications are violated
† 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: These specifications are for programming the on-chip program memory through the use of table write
instructions.
2: The pin may be kept in this range at times other than programming, but it is not recommended.
3: Refer to Section 7.8 “Using the Data EEPROM” for a more detailed discussion on data EEPROM
endurance.
2002-2015 Microchip Technology Inc.
DS30009605G-page 245
PIC18F1220/1320
FIGURE 22-4:
LOW-VOLTAGE DETECT CHARACTERISTICS
VDD
(LVDIF can be
cleared in software)
VLVD
(LVDIF set by hardware)
LVDIF
TABLE 22-2:
LOW-VOLTAGE DETECT CHARACTERISTICS
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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.
Symbol
Characteristic
LVD Voltage on VDD Transition High-to-Low
D420D
PIC18LF1220/1320
Legend:
†
Min.
Typ†
Max.
Units
Conditions
Industrial Low Voltage (-10°C to +85°C)
LVDL = 0000
N/A
N/A
N/A
V
Reserved
LVDL = 0001
N/A
N/A
N/A
V
Reserved
LVDL = 0010
2.08
2.26
2.44
V
LVDL = 0011
2.26
2.45
2.65
V
LVDL = 0100
2.35
2.55
2.76
V
LVDL = 0101
2.55
2.77
2.99
V
LVDL = 0110
2.64
2.87
3.10
V
LVDL = 0111
2.82
3.07
3.31
V
LVDL = 1000
3.09
3.36
3.63
V
LVDL = 1001
3.29
3.57
3.86
V
LVDL = 1010
3.38
3.67
3.96
V
LVDL = 1011
3.56
3.87
4.18
V
LVDL = 1100
3.75
4.07
4.40
V
LVDL = 1101
3.93
4.28
4.62
V
LVDL = 1110
4.23
4.60
4.96
V
Shading of rows is to assist in readability of the table.
Production tested at TAMB = 25°C. Specifications over temperature limits ensured by characterization.
DS30009605G-page 246
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 22-2:
LOW-VOLTAGE DETECT CHARACTERISTICS (CONTINUED)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(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.
D420F
Symbol
Characteristic
LVD Voltage on VDD Transition High-to-Low
PIC18LF1220/1320
LVDL = 0000
PIC18F1220/1320
PIC18F1220/1320
Legend:
†
PIC18F1220/1320
N/A
N/A
V
Reserved
Reserved
N/A
N/A
V
2.53
V
LVDL = 0011
2.16
2.45
2.75
V
LVDL = 0100
2.25
2.55
2.86
V
LVDL = 0101
2.43
2.77
3.10
V
LVDL = 0110
2.53
2.87
3.21
V
LVDL = 0111
2.70
3.07
3.43
V
LVDL = 1000
2.96
3.36
3.77
V
LVDL = 1001
3.14
3.57
4.00
V
LVDL = 1010
3.23
3.67
4.11
V
LVDL = 1011
3.41
3.87
4.34
V
LVDL = 1100
3.58
4.07
4.56
V
LVDL = 1101
3.76
4.28
4.79
V
LVDL = 1110
4.04
4.60
5.15
V
Industrial (-10°C to +85°C)
3.93
4.28
4.62
V
4.23
4.60
4.96
V
Industrial (-40°C to -10°C)
LVDL = 1101
3.76
4.28
4.79
V
LVDL = 1110
4.04
4.60
5.15
V
Extended (-10°C to +85°C)
LVDL = 1101
3.94
4.28
4.62
V
LVDL = 1110
4.23
4.60
4.96
V
LVD Voltage on VDD Transition High-to-Low
D420K
N/A
2.26
LVDL = 1101
Conditions
Industrial Low Voltage (-40°C to -10°C)
N/A
LVD Voltage on VDD Transition High-to-Low
D420J
Units
1.99
LVDL = 1110
PIC18F1220/1320
Max.
LVDL = 0001
LVD Voltage on VDD Transition High-to-Low
D420H
Typ†
LVDL = 0010
LVD Voltage on VDD Transition High-to-Low
D420G
Min.
Extended (-40°C to -10°C, +85°C to +125°C)
LVDL = 1101
3.77
4.28
4.79
V
LVDL = 1110
4.05
4.60
5.15
V
Shading of rows is to assist in readability of the table.
Production tested at TAMB = 25°C. Specifications over temperature limits ensured by characterization.
2002-2015 Microchip Technology Inc.
DS30009605G-page 247
PIC18F1220/1320
22.4
22.4.1
AC (Timing) Characteristics
TIMING PARAMETER SYMBOLOGY
The timing parameter symbols have been created
following 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
DS30009605G-page 248
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
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
22.4.2
TIMING CONDITIONS
The temperature and voltages specified in Table 22-3
apply to all timing specifications unless otherwise
noted. Figure 22-5 specifies the load conditions for the
timing specifications.
TABLE 22-3:
TEMPERATURE AND VOLTAGE SPECIFICATIONS – AC
AC CHARACTERISTICS
FIGURE 22-5:
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 22.1 and
Section 22.3.
LF parts operate for industrial temperatures only.
LOAD CONDITIONS FOR DEVICE TIMING SPECIFICATIONS
Load Condition 2
Load Condition 1
VDD/2
RL
CL
Pin
VSS
CL
pin
RL = 464
VSS
2002-2015 Microchip Technology Inc.
CL = 50 pF
for all pins except OSC2/CLKO
DS30009605G-page 249
PIC18F1220/1320
22.4.3
TIMING DIAGRAMS AND SPECIFICATIONS
FIGURE 22-6:
EXTERNAL CLOCK TIMING (ALL MODES EXCEPT PLL)
Q4
Q1
Q2
Q3
Q4
Q1
OSC1
1
3
4
3
4
2
CLKO
TABLE 22-4:
Param.
No.
1A
EXTERNAL CLOCK TIMING REQUIREMENTS
Symbol
FOSC
Characteristic
Min.
Max.
Units
External CLKI Frequency(1)
DC
40
MHz
DC
25
MHz
EC, ECIO (Extended)
DC
4
MHz
RC oscillator
Oscillator Frequency(1)
1
TOSC
Conditions
EC, ECIO (LF and Industrial)
DC
1
MHz
XT oscillator
DC
25
MHz
HS oscillator
1
10
MHz
HS + PLL oscillator
DC
33
kHz
LP Oscillator mode
External CLKI Period(1)
25
—
ns
EC, ECIO (LF and Industrial)
40
—
ns
EC, ECIO (Extended)
Oscillator Period(1)
250
—
ns
RC oscillator
1000
—
ns
XT oscillator
25
100
—
1000
ns
ns
HS oscillator
HS + PLL oscillator
30
—
s
LP oscillator
2
TCY
Instruction Cycle Time(1)
100
—
ns
TCY = 4/FOSC
3
TosL,
TosH
External Clock in (OSC1)
High or Low Time
30
—
ns
XT oscillator
2.5
—
s
LP oscillator
10
—
ns
HS oscillator
TosR,
TosF
External Clock in (OSC1)
Rise or Fall Time
—
20
ns
XT oscillator
4
Note 1:
—
50
ns
LP oscillator
—
7.5
ns
HS oscillator
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.
DS30009605G-page 250
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 22-5:
Param
No.
PLL CLOCK TIMING SPECIFICATIONS, HS/HSPLL MODE (VDD = 4.2V TO 5.5V)
Sym.
Characteristic
Min.
Typ†
Max.
Units
Conditions
—
10
MHz
HS and HSPLL mode only
F10
FOSC Oscillator Frequency Range
4
F11
FSYS
On-Chip VCO System Frequency
16
—
40
MHz
HSPLL mode only
F12
TPLL
PLL Start-up Time (Lock Time)
—
—
2
ms
HSPLL mode only
CLK
CLKO Stability (Jitter)
-2
—
+2
%
HSPLL mode only
F13
† Data in “Typ” column is at 5V, 25C unless otherwise stated. These parameters are for design guidance
only and are not tested.
TABLE 22-6:
INTERNAL RC ACCURACY: PIC18F1220/1320 (INDUSTRIAL)
PIC18LF1220/1320 (INDUSTRIAL)
PIC18LF1220/1320
(Industrial)
Standard Operating Conditions (unless otherwise stated)
Operating temperature
-40°C TA +85°C for industrial
PIC18F1220/1320
(Industrial)
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(1)
PIC18LF1220/1320
PIC18F1220/
1320PIC18F1220/1320
-2
+/-1
2
%
+25°C
VDD = 2.7-3.3V
-5
—
5
%
-10°C to +85°C VDD = 2.7-3.3V
-10
—
10
%
-40°C to +85°C VDD = 2.7-3.3V
-2
+/-1
2
%
-5
—
5
%
-10°C to +85°C VDD = 4.5-5.5V
-10
—
10
%
-40°C to +85°C VDD = 4.5-5.5V
+25°C
VDD = 4.5-5.5V
INTRC Accuracy @ Freq = 31 kHz(2)
PIC18LF1220/1320
26.562
—
35.938
kHz
-40°C to +85°C VDD = 2.7-3.3V
PIC18F1220/
1320PIC18F1220/1320
26.562
—
35.938
kHz
-40°C to +85°C VDD = 4.5-5.5V
Legend:
Shading of rows is to assist in readability of the table.
Note 1:
Frequency calibrated at 25°C. OSCTUNE register can be used to compensate for temperature and VDD drift.
2:
INTRC frequency after calibration.
3:
Change of INTRC frequency as VDD changes.
2002-2015 Microchip Technology Inc.
DS30009605G-page 251
PIC18F1220/1320
FIGURE 22-7:
CLKO AND I/O TIMING
Q1
Q4
Q2
Q3
OSC1
11
10
CLKO
13
14
12
18
19
16
I/O pin
(Input)
15
17
I/O pin
(Output)
New Value
Old Value
20, 21
Note:
Refer to Figure 22-5 for load conditions.
TABLE 22-7:
CLKO AND I/O TIMING REQUIREMENTS
Param.
Symbol
No.
10
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
—
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)
CLKO Rise Time
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
PIC18F1X20
Input Invalid (I/O in hold time) PIC18LF1X20
19
TioV2osH Port Input Valid to OSC1
(I/O in setup time)
20
TioR
Port Output Rise Time
20A
21
TioF
Port Output Fall Time
21A
Note 1:
0.25 TCY + 25
—
—
ns
(Note 1)
0
—
—
ns
(Note 1)
—
50
150
ns
100
—
—
ns
200
—
—
ns
0
—
—
ns
PIC18F1X20
—
10
25
ns
PIC18LF1X20
—
—
60
ns
PIC18F1X20
—
10
25
ns
PIC18LF1X20
—
—
60
ns
Measurements are taken in RC mode, where CLKO output is 4 x TOSC.
DS30009605G-page 252
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
FIGURE 22-8:
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
Note:
Refer to Figure 22-5 for load conditions.
FIGURE 22-9:
BROWN-OUT RESET TIMING
BVDD
VDD
35
VBGAP = 1.2V
VIRVST
Enable Internal
Reference Voltage
Internal Reference
Voltage Stable
2002-2015 Microchip Technology Inc.
36
DS30009605G-page 253
PIC18F1220/1320
TABLE 22-8:
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER, POWER-UP TIMER
AND BROWN-OUT RESET REQUIREMENTS
Param.
Symbol
No.
Characteristic
Min.
Typ.
Max.
Units
2
—
—
s
30
TmcL
MCLR Pulse Width (low)
31
TWDT
Watchdog Timer Time-out Period
(No postscaler)
3.48
4.00
4.71
ms
32
TOST
Oscillation Start-up Timer Period
1024 TOSC
—
1024 TOSC
—
33
TPWRT
Power-up Timer Period
—
65.5
132
ms
34
TIOZ
I/O High-Impedance from MCLR
Low or Watchdog Timer Reset
—
2
—
s
35
TBOR
Brown-out Reset Pulse Width
36
TIVRST
Time for Internal Reference
Voltage to become stable
37
TLVD
Low-Voltage Detect Pulse Width
FIGURE 22-10:
200
—
—
s
—
20
50
s
200
—
—
s
Conditions
TOSC = OSC1 period
VDD BVDD (see D005)
VDD VLVD
TIMER0 AND TIMER1 EXTERNAL CLOCK TIMINGS
T0CKI
41
40
42
T1OSO/T13CKI
46
45
47
48
TMR0 or
TMR1
Note:
Refer to Figure 22-5 for load conditions.
DS30009605G-page 254
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 22-9:
TIMER0 AND TIMER1 EXTERNAL CLOCK REQUIREMENTS
Param
Symbol
No.
Characteristic
40
Tt0H
T0CKI High Pulse Width
41
Tt0L
T0CKI Low Pulse Width
42
Tt0P
T0CKI Period
Min.
No prescaler
0.5 TCY + 20
—
ns
With prescaler
No prescaler
10
—
ns
0.5 TCY + 20
—
ns
With prescaler
45
Tt1H
10
—
ns
TCY + 10
—
ns
Greater of:
20 ns or TCY + 40
N
—
ns
No prescaler
With prescaler
T13CKI High Time Synchronous, no prescaler
0.5 TCY + 20
—
ns
Synchronous, PIC18F1X20
with prescaler PIC18LF1X20
10
—
ns
25
—
ns
Asynchronous PIC18F1X20
30
—
ns
PIC18LF1X20
46
Tt1L
50
—
ns
0.5 TCY + 5
—
ns
Synchronous, PIC18F1X20
with prescaler PIC18LF1X20
10
—
ns
25
—
ns
Asynchronous PIC18F1X20
30
—
ns
50
—
ns
Greater of:
20 ns or TCY + 40
N
—
ns
T13CKI Low Time Synchronous, no prescaler
PIC18LF1X20
47
Tt1P
T13CKI Input
Period
Synchronous
Ft1
T13CKI Oscillator Input Frequency Range
Asynchronous
48
Tcke2tmrI Delay from External T13CKI Clock Edge to
Timer Increment
FIGURE 22-11:
Max. Units
60
—
ns
DC
50
kHz
2 TOSC
7 TOSC
—
Conditions
N = prescale
value
(1, 2, 4,..., 256)
N = prescale
value
(1, 2, 4, 8)
CAPTURE/COMPARE/PWM TIMINGS (ALL CCP MODULES)
CCPx
(Capture Mode)
50
51
52
CCPx
(Compare or PWM Mode)
53
Note:
54
Refer to Figure 22-5 for load conditions.
2002-2015 Microchip Technology Inc.
DS30009605G-page 255
PIC18F1220/1320
TABLE 22-10: CAPTURE/COMPARE/PWM REQUIREMENTS (ALL CCP MODULES)
Param.
Symbol
No.
50
TccL
Characteristic
Min.
Max.
Units
CCPx Input Low No prescaler
Time
With prescaler PIC18F1X20
0.5 TCY + 20
—
ns
10
—
ns
20
—
ns
PIC18LF1X20
51
TccH
CCPx Input High No prescaler
Time
With prescaler PIC18F1X20
0.5 TCY + 20
—
ns
10
—
ns
PIC18LF1X20
20
—
ns
3 TCY + 40
N
—
ns
PIC18F1X20
—
25
ns
PIC18LF1X20
—
45
ns
PIC18F1X20
—
25
ns
—
45
ns
52
TccP
CCPx Input Period
53
TccR
CCPx Output Fall Time
54
TccF
CCPx Output Fall Time
PIC18LF1X20
FIGURE 22-12:
Conditions
N = prescale
value (1, 4 or 16)
EUSART SYNCHRONOUS TRANSMISSION (MASTER/SLAVE) TIMING
RB1/AN5/TX/
CK/INT1 pin
121
121
RB4/AN6/RX/
DT/KBI0 pin
120
Note:
122
Refer to Figure 22-5 for load conditions.
TABLE 22-11: EUSART SYNCHRONOUS TRANSMISSION REQUIREMENTS
Param.
Symbol
No.
120
121
122
Characteristic
TckH2dtV SYNC XMIT (MASTER & SLAVE)
Clock High to Data Out Valid
Tckrf
Tdtrf
Min.
Max.
Units
PIC18F1X20
—
40
ns
PIC18LF1X20
—
100
ns
Clock Out Rise Time and Fall Time
(Master mode)
PIC18F1X20
—
20
ns
PIC18LF1X20
—
50
ns
Data Out Rise Time and Fall Time
PIC18F1X20
—
20
ns
PIC18LF1X20
—
50
ns
FIGURE 22-13:
RB1/AN5/TX/
CK/INT1 pin
Conditions
EUSART SYNCHRONOUS RECEIVE (MASTER/SLAVE) TIMING
125
RB4/AN6/RX/
DT/KBI0 pin
126
Note:
Refer to Figure 22-5 for load conditions.
DS30009605G-page 256
2002-2015 Microchip Technology Inc.
PIC18F1220/1320
TABLE 22-12: EUSART SYNCHRONOUS RECEIVE REQUIREMENTS
Param.
No.
Symbol
Characteristic
Min.
Max.
Units
125
TdtV2ckl
SYNC RCV (MASTER & SLAVE)
Data Hold before CK (DT hold time)
10
—
ns
126
TckL2dtl
Data Hold after CK (DT hold time)
15
—
ns
Conditions
TABLE 22-13: A/D CONVERTER CHARACTERISTICS: PIC18F1220/1320 (INDUSTRIAL)
PIC18LF1220/1320 (INDUSTRIAL)
Param
Symbol
No.
Characteristic
Min.
Typ.
Max.
Units
Conditions
VREF 3.0V
A01
NR
Resolution
—
—
10
A03
EIL
Integral Linearity Error
—
—
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