Note the following details of the code protection feature on Microchip devices:
•Microchip products meet the specification contained in their particular Microchip Data Sheet.
•Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
•There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip's Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
•Microchip is willing to work with the customer who is concerned about the integrity of their code.
•Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously impro ving the cod e protection features of our
products. Attempts to break microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical
components in life support systems is not authorized except
with express written approval by Microchip. No licenses are
conveyed, implicitly or otherwise, under any intellectual
property rights.
Trademarks
The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, K
EELOQ, MPLAB, PIC, PICmic ro, PI C START,
PRO MATE and PowerSmart are registered trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.
AmpLab, FilterLab, microID, MXDEV, MXLAB, PICMASTER,
SEEVAL and The Embedded Control Solutions Company are
registered trademarks of Microchip Technology Incorporated
in the U.S.A.
Application Maestro, dsPICDEM, dsPICDEM.net, ECAN,
ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, microPort,
Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM,
PICkit, PICDEM, PICDEM.net, PowerCal, PowerInfo,
PowerMate, PowerTool, rfLAB, rfPIC, Select Mode,
SmartSensor, SmartShunt, SmartT el and Total Endurance are
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.
Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip Technology Incorporated in the U.S.A.
All other trademarks mentioned herein are property of their
respective companies.
Microchip received QS-9000 quality system
certification for its worldwide headquarters,
design and wafer fabrication facilities in
Chandler and Tempe, Arizona in July 1999
and Mountain View, California in March 2002.
The Company’s quality system processes and
procedures are QS-9000 compliant for its
PICmicro
devices, Serial EEPROMs, microperipherals,
non-volatile memory and analog products. In
addition, Microchip’s quality system for the
design and manufacture of develop m ent
systems is ISO 9001 certified.
®
8-bit MCUs, KEELOQ
®
code hopping
DS39599C-page ii 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
28/40/44-Pin High-Performance, Enhance d Flash MCUs
17.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 155
23.0 Special Features of the CPU................................................................ ....................................................................................237
24.0 Instruction Set Summary.......................................................................................................................................................... 255
25.0 Development Support. .............................................................................................................................................................. 299
27.0 DC and AC Characteristics Graphs and Tables.......................................................................................................................343
Appendix D: Migration from Baseline to Enhanced Devices.............................................................................................................. 370
Appendix E: Migration from Mid-Range to Enhanced Devices ..........................................................................................................371
Appendix F: Migration from High-End to Enhanced Devices............................................................................................................. 371
Index ..................................................................................................................................................................................................373
Systems Information and Upgrade Hot Line...................................................................................................................................... 383
PIC18F2220/2320/4220/4320 Product Identification System ............................................................................................................385
DS39599C-page 4 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
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 c omm ents regarding t his publication, p lease c ontact the M arket ing Co mmunications Department via
E-mail at docerrors@mail.microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150.
We welcome your feedback.
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To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
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You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).
Errata
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
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To determine if an errata sheet exists for a particular device, please check with one of the following:
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When contacting a sales office or the literature center, please specify which device, revision of silicon and data sheet (include
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2003 Microchip Technology Inc.DS39599C-page 5
PIC18F2220/2320/4220/4320
NOTES:
DS39599C-page 6 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
1.0DEVICE OVERVIEW
This documen t conta i ns dev ic e spec if i c in for m at i on fo r
the following devices:
• PIC18F2220• PIC18F4220
• PIC18F2320• PIC18F4320
This family offers the advantages of all PIC18 microcontrollers – namely, high computational performance
at an economical price with the addition of highendurance Enhanced Flash program memory. On top
of these features, the PIC18F2220/2320/4220/4320
family introduces design enhancements that make
these microcontrollers a logical choice for many
high-performance, power sensitive applications.
1.1New Core Features
1.1.1nanoWatt TECHNOLOGY
All of the devices in the PIC18F2220/2320/4220/4320
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 c ore disable d, but the pe ripherals 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 th e user to inco rpor ate po wer sav ing id eas
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 1.8 and 2.2 µA, respectively.
1.1.2MULTIPLE OSCILLATOR OPTIONS
AND FEATURES
All of the devices in the PIC18F2220/2320/4220/4320
family offer nine different oscillator options, allowing
users a wide ran ge of choice s in develo ping applic ation
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 a 31 kHz
INTRC clock and an 8 MHz clock with 6 program
selectable divider ratios (4 MHz to 125 kHz) for a
total of 8 clock frequencies.
Besides its ava ilability as a cloc k source, the intern al
oscillator block pro vid es a s t ab le re fere nce source that
gives the family additional features for robust
operation:
• Fail-Safe Clock Monitor: This option constantly
monitors the main clock source against a reference
signal provided by the internal oscillator. If a clock
failure occurs, the controller is switched to the
internal oscillator block, allowing for continued
low-speed operation or a safe application shutdown.
• Two-Speed Start-up: This option allows the internal
oscillator to serve as the clock source from Power-on
Reset, or wake-up from Sleep mode, until the primary
clock source is available. 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.
1.2Other 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.
• Addressable USART: This serial communication
module is capable of standard RS-232 operation
using the internal oscillator block, removing the
need for an external crystal (and its accompanying
power requirement) in applications that talk to the
outside world.
• 10-bit A/D Converter: This module incorporates
programmable acquisition time, allowing for a channel to be sel ected and a convers ion 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 ra nge from 4 ms to over 2 mi nutes, that is
stable across operating voltage and temperature.
2003 Microchip Technology Inc.DS39599C-page 7
PIC18F2220/2320/4220/4320
1.3Details on Individual Family
Members
Devices in the PIC18F 2220/2320/42 20/4320 famil y are
available in 28-pin (PIC18F2X20) and 40/44-pin
(PIC18F4X20) packages. Block diagrams for the two
groups are shown in Figure 1-1 and Figure 1-2.
The devices are differentiated from each other in five
ways:
1.Flash program memory (4 Kbytes for
PIC18FX220 devices, 8 Kbytes for PIC18FX320)
2.A/D channels (10 for PIC18F2X20 devices, 13 for
PIC18F4X20 devices)
3.I/O ports (3 bidirectional ports and 1 input only
port on PIC18F2X20 devices, 5 bidirectional
ports on PIC18F4X20 devices)
4.CCP and Enhanced CCP implementation
(PIC18F2X20 devices have 2 standard CCP
modules, PIC18F4X20 devices have one
standard CCP module and one ECCP module)
5.Parallel Slave Port (present only on
PIC18F4X20 devices)
All other features fo r device s in this family are identi cal.
These are summarized in Table 1-1.
The pinouts for all devices are listed in Table 1-2 and
Table 1-3.
TABLE 1-1:DEVICE FEATURES
FeaturesPIC18F2220PIC18F2320PIC18F4220PIC18F4320
Operating FrequencyDC – 40 MHzDC – 40 MHzDC – 40 MHzDC – 40 MHz
Program Memory (Bytes)4096819240968192
Program Memory (Instruction s)2048409620 484096
Data Memory (Bytes)512512512512
Data EEPROM Memory (Bytes)256256256256
Interrupt Sources19192020
I/O PortsPorts A, B, C (E)Ports A, B, C (E)Ports A, B, C, D, E Ports A, B, C, D, E
Timers4444
Capture/Compare/PWM Modules2211
Enhanced Capture/
Note 1: Optional multiplexing of CCP2 input/output with RB3 is enabled by selection of the CCPMX2 configuration bit.
2: RE3 is available only when the MCLR
3: OSC1, OSC2, CLKI and CLKO are only ava ilable in select o scillator modes and when th ese pins are not being use d as digital I/O.
Refer to Section 2.0 “Oscillator Configurations” for additional information.
Note 1: Optional multiplexing of CCP2 input/output with RB3 is enabled by selection of the CCP2MX configuration bit.
2: RE3 is available only when the MCLR
3: OSC1, OSC2, CLKI and CL KO are only av ailable in se lect oscillator modes and when th ese pins a re not being us ed as digital I /O.
Refer to Section 2.0 “Oscillator Configurations” for additional information.
Timer1Timer2
(16-bit)(8-bit)
Master
CCP2
Synchronous
Serial Por t
Resets are disabled.
Timer3
(16-bit)
Addressable
USART
10-bit A/D
Converter
Data EEPROM
(256 Bytes)
DS39599C-page 10 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
T ABLE 1-2:PIC18F2220/2320 PINOUT I/O DESCRIPTIONS
Pin Name
Pin Number
PDIP SOIC
Pin
Type
Buffer
Type
Description
/VPP/RE3
MCLR
MCLR
VPP
RE3
OSC1/CLKI/RA7
OSC1
CLKI
RA7
OSC2/CLKO/RA6
OSC2
CLKO
RA6
RA0/AN0
RA0
AN0
RA1/AN1
RA1
AN1
RA2/AN2/V
RA2
AN2
VREFCV
RA3/AN3/V
RA3
AN3
V
RA4/T0CKI/C1OUT
RA4
T0CKI
C1OUT
RA5/AN4/SS
RA5
AN4
SS
LVDIN
C2OUT
RA6See the OSC2/CLKO/RA6 pin.
RA7See the OSC1/CLKI/RA7 pin.
Note 1: Default assignment for CCP2 when CCP2MX (CONFIG3H<0>) is set.
REF-/CVREF
REF
REF+
REF+
/LVDIN/C2O UT
ST = Schmitt Trigger input with CMOS levels I= Input
O= Output P= Power
OD = Open-drain (no diode to V
2: Alternate assignment for CCP2 when CCP2MX is cleared.
11
99
1010
22
33
44
55
66
77
I
ST
P
I
ST
I
ST
I
CMOS
I/O
TTL
O
O
I/O
I/OITTL
I/OITTL
I/O
O
I/O
I/O
O
I/O
O
I
I
I
I
I
I
I
I
DD)
—
—
TTL
Analog
Analog
TTL
Analog
Analog
Analog
TTL
Analog
Analog
ST/OD
ST
—
TTL
Analog
TTL
Analog
—
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.
External clock source input. Always associated with pin
function OSC1. (See related OSC1/CLKI, OSC2/CLKO pins.)
General purpose I/O pin.
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO which has 1/4 the
frequency of OSC1 and denotes the instruction cycle rate.
General purpose I/O pin.
PORTA is a bidirectional I/O port.
Digital I/O.
Analog input 0.
Digital I/O.
Analog input 1.
Digital I/O.
Analog input 2.
A/D Reference Voltage (Low) input.
Comparator Reference Voltage output.
Digital I/O.
Analog input 3.
A/D Reference Voltage (High) input.
Digital I/O. Open-drain when configured as output.
Timer0 external clock input.
Comparator 1 output.
Digital I/O.
Analog input 4.
SPI Slave Select input.
Low-Voltage Detect input.
Comparator 2 output.
Note 1: Default assignment for CCP2 wh en CCP2MX (CONFIG3H<0>) is set.
REF-/CVREF
RA2
AN2
V
REF-
CV
REF
REF+
RA3
AN3
V
REF+
RA4
T0CKI
C1OUT
RA5
AN4
SS
LVDIN
C2OUT
ST = Schmitt Trigger input with CMOS levels I= Input
O= Output P= Power
OD = Open-drain (no diode to V
2: Alternate assignment for CCP2 when CCP2MX is cleared.
11818
133032
143133
21919
32020
42121
52222
62323
72424
I
P
I
I
I
CMOS
I/O
O
O
I/O
I/OITTL
Analog
I/OITTL
Analog
I/O
Analog
I
Analog
I
Analog
O
I/O
I
Analog
I
Analog
I/O
ST/OD
I
O
I/O
Analog
I
I
Analog
I
O
DD)
Master Clear (input) or programming voltage (input).
ST
ST
ST
TTL
—
—
TTL
TTL
TTL
ST
—
TTL
TTL
—
Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage inpu t.
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.
External cl ock source input. Always associated with
pin function OSC1. (See related OSC1/CLKI,
OSC2/CLKO pins.)
General purpose I/O pin.
Oscillator crystal or clock output.
Oscillator crystal output. Connects to crystal or resonator
in Crystal Oscillator mode.
In RC mode, OSC2 pin outputs CLKO which has 1/4 the
frequency of OSC1 and denotes the instruction cycle rate.
General purpose I/O pin.
PORTA is a bidirectional I/O port.
Digital I/O.
Analog input 0.
Digital I/O.
Analog input 1.
Digital I/O.
Analog input 2.
A/D reference voltage (Low) input.
Comparator reference voltage output.
Digital I/O.
Analog input 3.
A/D reference voltage (High) input.
Digital I/O. Open-drain when configured as output.
Timer0 external clock input.
Comparator 1 output.
Digital I/O.
Analog input 4.
SPI slave select input.
Low-Voltage Detect input.
Comparator 2 output.
DS39599C-page 14 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
T ABLE 1-3:PIC18F4220/4320 PINOUT I/O DESCRIPTIONS (CONTINUED)
ST = Schmitt Trigger input with CMOS levels I= Input
O= Output P= Power
OD = Open-drain (no diode to V
Note 1: Default assignment for CCP2 when CCP2MX (CONFIG3H<0>) is set.
2: Alternate assignment for CCP2 when CCP2MX is cleared.
Pin Number
PDIP TQFP QFN
193838
203939
214040
224141
2722
2833
2944
3055
Pin
Buffer
Type
I/O
I/OSTTTL
I/O
I/OSTTTL
I/O
I/OSTTTL
I/O
I/OSTTTL
I/O
I/OSTTTL
I/O
I/O
O
I/O
I/O
O
I/O
I/O
O
DD)
Type
PORTD is a bidirectional I/O port or a Parallel Slave Port
(PSP) for interfacing to a microprocessor port. These pins
have TTL input buffers when PSP module is enabled.
Digital I/O.
Parallel Slave Port data.
Digital I/O.
Parallel Slave Port data.
Digital I/O.
Parallel Slave Port data.
Digital I/O.
Parallel Slave Port data.
Digital I/O.
Parallel Slave Port data.
ST
TTL
—
ST
TTL
—
ST
TTL
—
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
Digital I/O.
Parallel Slave Port data.
Enhanced CCP1 output.
ST = Schmitt Trigger input with CMOS levels I= Input
O= Output P= Power
OD = Open-drain (no diode to V
Note 1: Default assignment for CCP2 wh en CCP2MX (CONFIG3H<0>) is set.
2: Alternate assignment for CCP2 when CCP2MX is cleared.
Pin Number
PDIP TQFP QFN
82525
92626
102727
6, 29 6, 30, 31P—Ground reference for logic and I/O pins.
31
28, 29
Pin
Buffer
Type
DD)
Type
PORTE is a bidirectional I/O port.
I/O
I/O
I/O
ST
I
Analog
I
TTL
ST
I
Analog
I
TTL
ST
I
Analog
I
TTL
P—Positive supply for logic and I/O pins.
Digital I/O.
Analog input 5.
Read control for Parallel Slave Port
(see also WR
Digital I/O.
Analog input 6.
Write control for Parallel Slave Port
(see CS
Digital I/O.
Analog input 7.
Chip select control for Parallel Slave Port
(see related RD
and RD pins).
/VPP/RE3 pin.
Description
and CS pins).
and WR).
DS39599C-page 18 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
2.0OSCILLATOR
CONFIGURATIONS
2.1Oscillator Types
The PIC18F2X20 and PIC18F4X20 devices can be
operated in ten dif ferent osci llator modes . The user can
program the configuration bits, FOSC3:FOSC0, in
Configuration Register 1H to select one of these ten
modes:
1.LPLow-Power Crystal
2.XTCrystal/Resonator
3.HSHigh-Speed Crystal/Resonator
4.HSPLLHigh-Speed Crystal/Resonator
with PLL enabled
5.RCExternal Resistor/Cap ac ito r with
OSC/4 output on RA6
F
6.RCIOExternal Resistor/Capacito r with
I/O on RA6
7.INTIO1Internal Oscillator with F
output on RA6 and I/O on RA7
8.INTIO2Internal O scil lat or with I/O on RA6
and RA7
9.ECExternal Clock with F
10. ECIOExternal Clock with I/O on RA6
2.2Crystal 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 fre-
quency out of the crystal manufacturers
specifications.
OSC/4
OSC/4 output
FIGURE 2-1:CRYSTAL/CERAMIC
RESONATOR OPERATION
(XT, LP, HS OR HSPLL
CONFIGURATION)
(1)
C1
(1)
C2
Note 1:See Table 2-1 and Table 2-2 for initial values
2:A series resistor (R
3:R
OSC1
To
Internal
XTAL
(2)
RS
OSC2
of C1 and C2.
strip cut crystals.
F varies with the oscillator mode chosen.
(3)
RF
PIC18FXXXX
S) may be required for AT
Logic
Sleep
T ABLE 2-1:CAPACITOR SELECTION FOR
CERAMIC RESONATORS
Typical Capacitor Values Used:
ModeFreqOSC1OSC2
XT455 kHz
2.0 MHz
4.0 MHz
HS8.0 MHz
16.0 MHz
Capacitor values are for design guidance only.
These capacitors were tested with the resonators
listed below for basic start-up and operation. Thesevalues are not optimized.
Different cap acitor values may be required to prod uce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
DD and temperature range for the application.
V
See the notes on page 20 for additional information.
Resonators Used:
455 kHz4.0 MHz
2.0 MHz8.0 MHz
16.0 MHz
56 pF
47 pF
33 pF
27 pF
22 pF
56 pF
47 pF
33 pF
27 pF
22 pF
2003 Microchip Technology Inc.DS39599C-page 19
PIC18F2220/2320/4220/4320
TABLE 2-2:CAPACITOR SELECTION FOR
CRYSTAL OSCILLATOR
Osc T y pe
Crystal
Freq
LP32 kHz33 pF33 pF
200 kHz15 pF15 pF
XT1 MHz33 pF33 pF
4 MHz27 pF27 pF
HS4 MHz27 pF27 pF
8 MHz22 pF22 pF
20 MHz15 pF15 pF
Capacitor values are for design guidance only.
These capacitors were tested with the crystals listed
below for basic start-up and op erat ion . These values
are not optimized.
Different capa citor values may be required to produc e
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected
DD and temperature range for the application.
V
See the notes following this table for additional
information.
32 kHz4 MHz
200 kHz8 MHz
1 MHz20 MHz
Note 1: Higher capacitance increases the stability
of the oscillator, but also increases the
start-up time.
2: When operating below 3V V
using certain ceramic resonators at any
voltage, it may be necessary to use the
HS mode or switch to a crystal oscillator.
3: Since each resonator/crystal has its own
characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate values of external
components.
S may be required to avoid overdriving
4: R
crystals with low driv e lev e l spe ci fic ati on.
5: Always verify oscillator performance over
DD and temperature range that is
the V
expected for the application.
T ypical Cap acitor V alues
Tested:
C1C2
Crystals Used:
DD, or when
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)
Clock from
Ext. System
Open
OSC1
OSC2
PIC18FXXXX
(HS Mode)
2.3HSPLL
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 make s use of the HS mode osc illator
for frequencies up t o 10 MHz. A PLL then multipl ies 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:PLL BLOCK DIAGRAM
HS Osc Enable
PLL Enable
(from Configuration Register 1H)
OSC2
OSC1
HS Mode
Crystal
Osc
IN
F
FOUT
÷4
Phase
Comparator
Loop
Filter
VCO
SYSCLK
MUX
DS39599C-page 20 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
2.4External Clock Input
The EC and ECIO Oscillator mode s require an externa l
clock source to be conn ected to the OSC1 pi n. 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 f or t e st pu r pos es or t o sy nc hr o n iz e ot he r
logic. Figure 2-4 shows the pin connections for the EC
Oscillator mode.
FIGURE 2-4:EXTERNAL CLOCK INPUT
OPERATION
(EC CONFIGURATION)
Clock from
Ext. System
OSC/4
F
The ECIO Oscillator mode func ti ons li ke t he EC m od e,
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
Clock from
Ext. System
RA6
OSC1/CLKI
PIC18FXXXX
OSC2/CLKO
OPERATION
(ECIO CONFIGURATION)
OSC1/CLKI
PIC18FXXXX
I/O (OSC2)
2.5RC 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 (R
ues and the operating temperature. In addition to this,
the oscillator frequency will vary from uni t 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 C
EXT 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 f or t e st pu r pos es or t o sy nc hr o n iz e ot he r
logic.
FIGURE 2-6:RC OSCILLATOR MODE
VDD
REXT
CEXT
VSS
F
OSC/4
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
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).
EXT) and capacitor (CEXT) val-
OSC1
Internal
Clock
PIC18FXXXX
OSC2/CLKO
EXT > 20 pF
C
FIGURE 2-7:RCIO OSCILLATOR MODE
VDD
REXT
OSC1
CEXT
VSS
RA6
Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ
2003 Microchip Technology Inc.DS39599C-page 21
I/O (OSC2)
C
EXT > 20 pF
Internal
Clock
PIC18FXXXX
PIC18F2220/2320/4220/4320
2.6Internal Oscillator Block
The PIC18F2X20/4X20 devices include an internal
oscillator block wh ich generat es two dif ferent cl ock 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-Spe ed Start-up
These features are discussed in greater detail in
Section 23.0 “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 (page 26).
2.6.1INTIO MODES
Using the internal oscillator as the clock source can
eliminate the need for up to two external oscillator pin s
which can then be used for digital I/O. Two distinct
configurations are available:
• In INTIO1 mode, the OSC2 pin outputs F
while OSC1 functions as RA 7 fo r dig it a l in put a nd
output.
• In INTIO2 mode, OSC1 functions as RA7 and
OSC2 functions as RA6, both for digital input and
output.
OSC/4,
2.6.2INTRC OUTPUT FREQUENCY
The internal oscillator block is calibrated at the factory
to produce an INTOSC output frequency of 8.0 MHz.
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 ±1% as temperature and
DD change across their full specified operating
V
ranges.
2.6.3OSCTUNE REGISTER
The internal oscillator’s output has been calibrated at
the factory but c an be adjusted in the user's ap plication.
This is done by writing to the OSCTUNE register
(Register 2-1). The tuning sensitivity is constant
throughout the tuning range.
When the OSCTUNE regis ter is mo di fied , the IN T O SC
and INTRC frequencies will begin shifting to the new
frequency. The INTRC clock will reach the new frequency within 8clock cycles (approximately
8*32µs = 256 µs). The INTOSC clock will stabilize
within 1 ms. Code execution conti nues du ring th is shift.
There is no indicati on that th e shift ha s occurre d. 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.
DS39599C-page 22 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
REGISTER 2-1:OSCTUNE: OSCILLATOR TUNING REGISTER
U-0 U-0R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
——TUN5TUN4TUN3TUN2TUN1TUN0
bit 7bit 0
bit 7-6Unimplemented: Read as ‘0’
bit 5-0TUN<5:0>: Frequency Tuning bits
011111 = Maximum frequency (+12.5%, approximately)
• •
• •
000001
000000 = Center frequency. Oscillator module is running at the calibrated frequency.
111111
• •
• •
100000 = Minimum frequency (-12.5%, approximately)
Legend:
R = Readable bitW = Writable bitU = Unimplemented bit, read as ‘0’
-n = Value at POR‘1’ = Bit is set‘0’ = Bit is clearedx = Bit is unknown
2003 Microchip Technology Inc.DS39599C-page 23
PIC18F2220/2320/4220/4320
2.7Clock Sources and Oscillator
Switching
Like previous PIC18 devices, the PIC18F2X20 and
PIC18F4X20 devices include a feature that allows the
system clock source to be switched from the main
oscillator to an alternate low-frequency clock source.
PIC18F2X20/4X20 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 E xternal Crystal
and Resonator modes, the External RC modes, the
External Clock modes and the internal oscillator block.
The particular mod e is defined on POR by the content s
of Configuration Register 1H. The details of these
modes are covered earlier in this chapter.
The s econdary oscillat ors 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.
PIC18F2X20/4X20 devices offer only the Timer1
oscillator as a seco ndary oscilla tor . This oscil lator , in all
power managed modes, is often the time base for
functions such as a real-time clock.
Most often, a 32.768 kHz watch crystal is connected
between the RC0/T1OSO/ T1CKI and RC1 /T1OSI pins.
Like the LP mode oscillator circuit, loading capacitors
are also connected from each pin to ground.
The Timer1 oscillator is discussed in greater detail in
Section 12.2 “Timer1 Oscillator”.
In addition to being a p rimary clock source, the internaloscillator block is available as a power managed
mode clock source. The INTRC source is a lso us ed as
the clock source for several special features, such as
the WDT and Fail-Safe Clock Monitor.
The clock sources for the PIC18F2X20/4X20 devices
are shown in Figure 2-8. See Section 12.0 “Timer1
Module” for further details of th e Timer1 os cillator . See
Section 23.1 “Configuration Bits” for Configuration
register details.
2.7.1OSCILLATOR CONTROL REGISTER
The OSCCON register (Register 2-2) controls several
aspects of the system clock’s operation, both in full
power 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 ava ilable c lock sou rces
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 opera tion.
The SCS bits are cleared on all forms of Reset.
The Internal Oscill ator Select bit s, IRCF2:IRCF0, select
the frequency output of the interna l oscill ator block th at
is used to dr ive t he sys tem clo ck. Th e choi ces are t he
INTRC source, the INTOSC source (8 MHz) or one of
the six frequencies derived from the INTOSC
postscaler (125kHz to 4 MHz). If the internal oscillator
block is supplying the system clock, changing the
states of thes e bits w ill ha ve an immedi ate cha nge on
the internal oscillator’s output.
The OSTS, IOFS and T1RUN bits ind icate wh ich cl oc k
source is currently providing the system clock. The
OSTS indicates that the Oscillator Start-up Timer has
timed out and the prima ry clock is providin g the system
clock in pri mary clock mode s. The IOFS b it indicates
when the internal oscillator block has stabilized and is
providing the system clock in RC Clock modes. The
T1RUN bit (T1CON<6>) indicates when the Timer1
oscillator is providing the system clock in secondary
clock modes. If none of th ese bit s are set, th e INTRC is
providing the system clock, or the internal oscillator
block has just started and is not yet stable.
The IDLEN bit controls the selective shutdown of the
controller’s CPU in power managed mo des. The use of
these bits is discussed in more detail in Section 3.0
“Power Managed Modes”.
Note 1: The Timer1 oscillator must be enabled to
select the secondary clock source. The
Timer1 osc illator is enabled by s etting the
T1OSCEN bit in th e T imer1 C ontrol re gister (T1CON<3>). If the Timer1 oscillator
is not enabled, then any atte mpt to set the
SCS0 bit will be ignored.
2: It is recommended that the Timer1
oscillator be operating and stable before
executing the SLEEP instr u ct ion or a very
long delay may occur while the Timer1
oscillator starts.
DS39599C-page 24 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
FIGURE 2-8:PIC18F2X20/4X20 CLOCK DIAGRAM
OSC2
OSC1
T1OSO
T1OSI
Primary Oscillator
Sleep
Secondary Oscillator
T1OSCEN
Enable
Oscillator
OSCCON<6:4>
Internal
Oscillator
Block
INTRC
Source
8 MHz
(INTOSC)
PIC18F2X20/4X20
4 x PLL
OSCCON<6:4>
8 MHz
111
4 MHz
110
2 MHz
101
1 MHz
31 kHz
100
011
010
001
000
Postscaler
500 kHz
250 kHz
125 kHz
CONFIG1H<3:0>
HSPLL
LP, XT, HS, RC, EC
Clock Source Option
for Other Modules
Internal Oscillator
MUX
T1OSC
Clock
Control
MUX
OSCCON<1:0>
Peripherals
CPU
IDLEN
WDT, FSCM
2003 Microchip Technology Inc.DS39599C-page 25
PIC18F2220/2320/4220/4320
REGISTER 2-2:OSCCON REGISTER
R/W-0R/W-0R/W-0R/W-0R
IDLENIRCF2IRCF1IRCF0OSTSIOFSSCS1SCS0
bit 7bit 0
bit 7IDLEN: Idle Enable bit
1 = Idle mode enabled; CPU core is not clocked in power managed modes
0 = Run mode enabled; CPU core is clocked in power managed modes
bit 6-4IRCF2:IRCF0: Internal Oscillator Frequency Select bits
bit 3OSTS: Oscillator Start-up Time-out Status bit
1 = Oscillator start-up time-out timer has expired; primary oscillator is running
0 = Oscillator start-up time-out timer is running; primary oscillator is not ready
bit 2IOFS: INTOSC Frequency Stable bit
1 = INTOSC frequency is stable
0 = INTOSC frequency is not stable
Note 1: Depends on state of IESO bit in Configuration Register 1H.
2: SCS0 may not be set while T1OSCEN (T1CON<3>) is clear.
(1)
(2)
(1)
R-0R/W-0R/W-0
Legend:
R = Readable bitW = Writable bitU = Unimplemented bit, read as ‘0’
- n = Value at POR‘1’ = Bit is set‘0’ = Bit is clearedx = Bit is unknown
DS39599C-page 26 2003 Microchip Technology Inc.
PIC18F2220/2320/4220/4320
2.7.2OSCIL LAT OR TRANSITIONS
The PIC18F2X20/4X20 de vices contain ci rcuitry to prevent clocking “glitches” when switching between clock
sources. A short p aus e in the sy stem c lock o ccurs during the clock switch. The length of this pause is
between 8 and 9 clock pe riods of the n ew clock sourc e.
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”.
2.8Effects 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 o scillat or) will sto p oscillat ing.
In secondary clock modes (SEC_RUN and
SEC_IDLE), the Timer1 oscillator is op erat ing an d p roviding the s ystem clo ck. The T ime r1 osci llator m ay als o
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 23.2 “Watchdog
Timer (WDT)” through Section 23.4 “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 out put is disabled if the sy stem clock
is provided directly from the INTRC output.
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 co nsumed duri ng Sleep.
The INTRC is required to support WDT operation. The
Timer1 oscillator may be operating to support a realtime clock. Ot her features may be operating that do n ot
require a system clock source (i.e., SSP slave, PSP,
INTn pins, A/D conversions and others).
2.9Power-up Delays
Power-up delays are c ontrolled by two ti mers so that no
external Reset circuitry is required for most applications. The delays ensure that the device is kept in
Reset until the device powe r supply i s stable under normal circumstan ces and the pri mary clock is ope rating
and stable. For additional information on power-up
delays, see Section 4.1 “Power-on Reset (POR)”
through Section 4.5 “Brown-out Reset (BOR)”.
The first timer is the Power-up Timer (PWRT) which
provides a fixed delay on power-up (parameter 33,
Table 26-10), if enabled, in Configuration Register 2L.
The second timer is the Oscillator Start-up Timer
(OST), intended to keep the chip in Rese t 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 Res et for an add iti onal 2ms, following
the HS mode OST delay, so the PLL can lock to the
incoming clock frequ enc y.
There is a delay of 5 to 10 µs, following POR, while the
controller becomes ready to execute instructions. This
delay runs concurrently with any other delays. This
may be the only del ay that occurs when any o f the EC ,
RC or INTIO modes are used as the primary clock
source.
TABLE 2-3:OSC1 AND OSC2 PIN STATES IN SLEEP MODE
OSC ModeOSC1 PinOSC2 Pin
RC, INTIO1Floating, external resistor
should pull high
RCIO, INTIO2Floating, external resistor
should pull high
ECIOFloating, pulled by external clockConfigured as PORTA, bit 6
ECFloating, pulled by external clockAt logic low (clock/4 output)
LP, XT, and HSFeedback inverter disabled at
quiescent voltage level
Note:See Table 4-1 in Section 4.0 “Reset” for time-outs due to Sleep and MCLR
2003 Microchip Technology Inc.DS39599C-page 27
At logic low (clock/4 output)
Configured as PORTA, bit 6
Feedback inverter disabled at
quiescent voltage level
Reset.
PIC18F2220/2320/4220/4320
NOTES:
DS39599C-page 28 2003 Microchip Technology Inc.
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