Datasheet PIC18F2420, PIC18F2520, PIC18F4420, PIC18F4520 Datasheet

PIC18F2420/2520/4420/4520

Data Sheet

28/40/44-Pin Enhanced Flash

Microcontrollers with 10-Bit A/D

and nanoWatt Technology

© 2008 Microchip Technology Inc. DS39631E

Note the following details of the code protection feature on Microchip devices:

• Microchip products meet the specification contained in their particular Microchip Data Sheet.

• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.

• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.

• Microchip is willing to work with the customer who is concerned about the integrity of their code.

• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”

Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Information contained in this publication regarding device
applications and the like is provided only for your convenience
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
MICROCHIP MAKES NO REPRESENTATIONS OR
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Trademarks

The Microchip name and logo, the Microchip logo, Accuron,
dsPIC, K

EELOQ, KEELOQ logo, MPLAB, PIC, PICmicro,

PICSTART, rfPIC, SmartShunt and UNI/O are registered
trademarks of Microchip Technology Incorporated in the
U.S.A. and other countries.

FilterLab, Linear Active Thermistor, MXDEV, MXLAB,
SEEVAL, SmartSensor and The Embedded Control Solutions
Company are registered trademarks of Microchip Technology
Incorporated in the U.S.A.

Analog-for-the-Digital Age, Application Maestro, CodeGuard,
dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,
ECONOMONITOR, FanSense, In-Circuit Serial
Programming, ICSP, ICEPIC, Mindi, MiWi, MPASM, MPLAB
Certified logo, MPLIB, MPLINK, mTouch, PICkit, PICDEM,
PICDEM.net, PICtail, PIC

32

logo, PowerCal, PowerInfo,
PowerMate, PowerTool, REAL ICE, rfLAB, Select Mode, Total
Endurance, WiperLock and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other
countries.

SQTP is a service mark of Microchip Technology Incorporated
in the U.S.A.

All other trademarks mentioned herein are property of their
respective companies.

© 2008, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserved.

Printed on recycled paper.

Microchip received ISO/TS-16949:2002 certification for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC
devices, Serial EEPROMs, microperipherals, nonvolatile memory and
analog products. In addition, Microchip’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.

®

MCUs and dsPIC® DSCs, KEELOQ

®

code hopping

DS39631E-page ii © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

28/40/44-Pin Enhanced Flash Microcontrollers with

10-Bit A/D and nanoWatt Technology

Power Management Features:

• Run: CPU on, Peripherals on

• Idle: CPU off, Peripherals on

• Sleep: CPU off, Peripherals off

• Ultra Low 50nA Input Leakage

• Run mode Currents Down to 11 μA Typical

• Idle mode Currents Down to 2.5 μA Typical

• Sleep mode Current Down to 100 nA Typical

• Timer1 Oscillator: 900 nA, 32 kHz, 2V

• Watchdog Timer: 1.4 μA, 2V Typical

• Two-Speed Oscillator Start-up

Flexible Oscillator Struc ture:

• Four Crystal modes, up to 40 MHz

• 4x Phase Lock Loop (PLL) – Available for Crystal
and Internal Oscillators

• Two External RC modes, up to 4 MHz

• Two External Clock modes, up to 40 MHz

• Internal Oscillator Block:

- Fast wake from Sleep and Idle, 1 μs typical

- 8 use-selectable frequencies, from 31 kHz to

8MHz

- Provides a complete range of clock speeds

from 31 kHz to 32 MHz when used with PLL

- User-tunable to compensate for frequency drift

• Secondary Oscillator using Timer1 @ 32 kHz

• Fail-Safe Clock Monitor:

- Allows for safe shutdown if peripheral clock stops

Peripheral Highlights:

• High-Current Sink/Source 25 mA/25 mA

• Three Programmable External Interrupts

• Four Input Change Interrupts

• Up to 2 Capture/Compare/PWM (CCP) modules,
one with Auto-Shutdown (28-pin devices)

• Enhanced Capture/Compare/PWM (ECCP)
module (40/44-pin devices only):

- One, two or four PWM outputs

- Selectable polarity

- Programmable dead time

- Auto-shutdown and auto-restart

-

Program Memory Data Memory

Device

PIC18F2420 16K 8192 768 256 25 10 2/0 Y Y 1 2 1/3

PIC18F2520 32K 16384 1536 256 25 10 2/0 Y Y 1 2 1/3

PIC18F4420 16K 8192 768 256 36 13 1/1 Y Y 1 2 1/3

PIC18F4520 32K 16384 1536 256 36 13 1/1 Y Y 1 2 1/3

Flash

(bytes)

# Single-Word

Instructions

SRAM
(bytes)

EEPROM

(bytes)

Peripheral Highlight s (Continued):

• Master Synchronous Serial Port (MSSP) module
Supporting 3-Wire SPI (all 4 modes) and I
Master and Slave modes

• Enhanced Addressable USART module:

- Supports RS-485, RS-232 and LIN/J2602

- RS-232 operation using internal oscillator

block (no external crystal required)

- Auto-wake-up on Start bit

- Auto-Baud Detect

• 10-Bit, up to 13-Channel Analog-to-Digital (A/D)
Converter module:

- Auto-acquisition capability

- Conversion available during Sleep

• Dual Analog Comparators with Input Multiplexing

• Programmable 16-Level High/Low-Voltage
Detection (HLVD) module:

- Supports interrupt on High/Low-Voltage Detection

Special Microcontroller Features:

• C Compiler Optimized Architecture:

- Optional extended instruction set designed to

optimize re-entrant code

• 100,000 Erase/Write Cycle Enhanced Flash
Program Memory Typical

• 1,000,000 Erase/Write Cycle Data EEPROM
Memory Typical

• Flash/Data EEPROM Retention: 100 Years Typical

• Self-Programmable under Software Control

• Priority Levels for Interrupts

• 8 x 8 Single-Cycle Hardware Multiplier

• Extended Watchdog Timer (WDT):

- Programmable period from 4 ms to 131s

• Single-Supply 5V In-Circuit Serial
Programming™ (ICSP™) via Two Pins

• In-Circuit Debug (ICD) via Two Pins

• Wide Operating Voltage Range: 2.0V to 5.5V

• Programmable Brown-out Reset (BOR) with
Software Enable Option

I/O

10-Bit

A/D (ch)

CCP/

ECCP

(PWM)

SPI

MSSP

Master

2

I

C™

EUSART

Comp.

2

C™

Timers

8/16-Bit

© 2008 Microchip Technology Inc. DS39631E-page 1

PIC18F2420/2520/4420/4520

PIC18F2520

10
11

2
3
4
5
6

1

8

7

9

12
13
14

15

16

17

18

19

20

23

24

25

26

27

28

22
21

MCLR/VPP/RE3

RA0/AN0
RA1/AN1

RA2/AN2/V

REF-/CVREF

RA3/AN3/VREF+

RA4/T0CKI/C1OUT

RA5/AN4/SS

/HLVDIN/C2OUT

V

SS

OSC1/CLKI/RA7

OSC2/CLKO/RA6

RC0/T1OSO/T13CKI

RC1/T1OSI/CCP2

(1)

RC2/CCP1

RC3/SCK/SCL

RB7/KBI3/PGD
RB6//KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2

(1)

RB2/INT2/AN8
RB1/INT1/AN10

RB0/INT0/FLT0/AN12
V

DD

VSS
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA

28-Pin SPDIP, SOIC

PIC18F2420

Note 1: RB3 is the alternate pin for CCP2 multiplexing.

10 11

2
3

6

1

18

19

20

21

22

12 13 14

15

8

7

16

17

232425262728

9

PIC18F2420

RC0/T1OSO/T13CKI

5

4

RB7/KBI3/PGD

RB6/KBI2/PGC

RB5/KBI1/PGM

RB4KBI0/AN11

RB3/AN9/CCP2

(1)

RB2/INT2/AN8
RB1/INT1/AN10
RB0/INT0/FLT0/AN12
V

DD

VSS
RC7/RX/DT

RC6/TX/CK

RC5/SDO

RC4/SDI/SDA

MCLR

/VPP/RE3

RA0/AN0

RA1/AN1

RA2/AN2/VREF-/CVREF

RA3/AN3/VREF+

RA4/T0CKI/C1OUT

RA5/AN4/SS

/HLVDIN/C2OUT

V

SS

OSC1/CLKI/RA7

OSC2/CLKO/RA6

RC1/T1OSI/CCP2

(1)

RC2/CCP1

RC3/SCK/SCL

PIC18F2520

28-Pin QFN

RB7/KBI3/PGD
RB6/KBI2/PGC
RB5/KBI1/PGM
RB4/KBI0/AN11
RB3/AN9/CCP2

(1)

RB2/INT2/AN8
RB1/INT1/AN10

RB0/INT0/FLT0/AN12
V

DD

VSS
RD7/PSP7/P1D
RD6/PSP6/P1C

RD5/PSP5/P1B
RD4/PSP4
RC7/RX/DT
RC6/TX/CK
RC5/SDO
RC4/SDI/SDA
RD3/PSP3
RD2/PSP2

MCLR/VPP/RE3

RA0/AN0
RA1/AN1

RA2/AN2/V

REF-/CVREF

RA3/AN3/VREF+

RA4/T0CKI/C1OUT

RA5/AN4/SS

/HLVDIN/C2OUT

RE0/RD

/AN5

RE1/WR

/AN6

RE2/CS

/AN7

V

DD

VSS

OSC1/CLKI/RA7

OSC2/CLKO/RA6

RC0/T1OSO/T13CKI

RC1/T1OSI/CCP2

(1)

RC2/CCP1/P1A

RC3/SCK/SCL

RD0/PSP0
RD1/PSP1

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20

40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21

PIC18F4520

40-Pin PDIP

PIC18F4420

Pin Diagrams

DS39631E-page 2 © 2008 Microchip Technology Inc.

Pin Diagrams (Cont.’d)

Note 1: RB3 is the alternate pin for CCP2 multiplexing.

10
11

2
3
4
5
6

1

1819202122

121314

15

38

8

7

4443424140

39

16

17

29

30

31

32

33

23

24

25

26

27

28

363435

9

PIC18F4420

37

RA3/AN3/V

REF+

RA2/AN2/V

REF-/CVREF

RA1/AN1

RA0/AN0

MCLR

/VPP/RE3

RB3/AN9/CCP2

(1)

RB7/KBI3/PGD

RB6/KBI2/PGC

RB5/KBI1/PGM

RB4/KBI0/AN11

NC

RC6/TX/CK

RC5/SDO

RC4/SDI/SDA

RD3/PSP3

RD2/PSP2

RD1/PSP1

RD0/PSP0

RC3/SCK/SCL

RC2/CCP1/P1A

RC1/T1OSI/CCP2

(1)

RC0/T1OSO/T13CKI

OSC2/CLKO/RA6
OSC1/CLKI/RA7
V

SS

VSS
VDD
VDD
RE2/CS/AN7
RE1/WR

/AN6

RE0/RD

/AN5

RA5/AN4/SS

/HLVDIN/C2OUT

RA4/T0CKI/C1OUT

RC7/RX/DT

RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D

V

SS

VDD
VDD

RB0/INT0/FLT0/AN12

RB1/INT1/AN10

RB2/INT2/AN8

44-pin QFN

PIC18F4520

10
11

2
3
4
5
6

1

1819202122

121314

15

38

8

7

4443424140

39

16

17

29

30

31

32

33

23

24

25

26

27

28

363435

9

PIC18F4420

37

RA3/AN3/VREF+

RA2/AN2/V

REF-/CVREF

RA1/AN1

RA0/AN0

MCLR

/VPP/RE3

NC

RB7/KBI3/PGD

RB6/KBI2/PGC

RB5/KBI1/PGM

RB4/KBI0/AN11

NC

RC6/TX/CK

RC5/SDO

RC4/SDI/SDA

RD3/PSP3

RD2/PSP2

RD1/PSP1

RD0/PSP0

RC3/SCK/SCL

RC2/CCP1/P1A

RC1/T1OSI/CCP2

(1)

NC

NC
RC0/T1OSO/T13CKI
OSC2/CLKO/RA6
OSC1/CLKI/RA7
V

SS

VDD
RE2/CS/AN7
RE1/WR

/AN6

RE0/RD

/AN5

RA5/AN4/SS

/HLVDIN/C2OUT

RA4/T0CKI/C1OUT

RC7/RX/DT

RD4/PSP4
RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D

V

SS

VDD

RB0/INT0/FLT0/AN12

RB1/INT1/AN10

RB2/INT2/AN8

RB3/AN9/CCP2

(1)

44-pin TQFP

PIC18F4520

PIC18F2420/2520/4420/4520

© 2008 Microchip Technology Inc. DS39631E-page 3

PIC18F2420/2520/4420/4520

Table of Contents

1.0 Device Overview .......................................................................................................................................................................... 7

2.0 Oscillator Configurations ............................................................................................................................................................ 23

3.0 Power-Managed Modes ............................................................................................................................................................. 33

4.0 Reset .......................................................................................................................................................................................... 41

5.0 Memory Organization ................................................................................................................................................................. 53

6.0 Flash Program Memory.............................................................................................................................................................. 73

7.0 Data EEPROM Memory ............................................................................................................................................................. 83

8.0 8 x 8 Hardware Multiplier............................................................................................................................................................ 89

9.0 Interrupts .................................................................................................................................................................................... 91

10.0 I/O Ports ................................................................................................................................................................................... 105

11.0 Timer0 Module ......................................................................................................................................................................... 123

12.0 Timer1 Module ......................................................................................................................................................................... 127

13.0 Timer2 Module ......................................................................................................................................................................... 133

14.0 Timer3 Module ......................................................................................................................................................................... 135

15.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 139

16.0 Enhanced Capture/Compare/PWM (ECCP) Module ................................................................................................................ 147

17.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 161

18.0 Enhanced Universal Synchronous Asynchronous Receiver Transmitter (EUSART) ............................................................... 201

19.0 10-Bit Analog-to-Digital Converter (A/D) Module ..................................................................................................................... 223

20.0 Comparator Module.................................................................................................................................................................. 233

21.0 Comparator Voltage Reference Module ................................................................................................................................... 239

22.0 High/Low-Voltage Detect (HLVD) ............................................................................................................................................. 243

23.0 Special Features of the CPU.................................................................................................................................................... 249

24.0 Instruction Set Summary .......................................................................................................................................................... 267

25.0 Development Support............................................................................................................................................................... 317

26.0 Electrical Characteristics .......................................................................................................................................................... 321

27.0 DC and AC Characteristics Graphs and Tables ....................................................................................................................... 361

28.0 Packaging Information.............................................................................................................................................................. 383

Appendix A: Revision History............................................................................................................................................................. 395

Appendix B: Device Differences......................................................................................................................................................... 395

Appendix C: Migration from Mid-Range to Enhanced Devices .......................................................................................................... 396

Appendix D: Migration from High-End to Enhanced Devices............................................................................................................. 396

Index .................................................................................................................................................................................................. 397

The Microchip Web Site..................................................................................................................................................................... 407

Customer Change Notification Service .............................................................................................................................................. 407

Customer Support .............................................................................................................................................................................. 407

Reader Response .............................................................................................................................................................................. 408

PIC18F2420/2520/4420/4520 Product Identification System ............................................................................................................ 409

DS39631E-page 4 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

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
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The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).

Errata

An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current
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To determine if an errata sheet exists for a particular device, please check with one of the following:

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When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are

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© 2008 Microchip Technology Inc. DS39631E-page 5

PIC18F2420/2520/4420/4520

NOTES:

DS39631E-page 6 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

1.0 DEVICE OVERVIEW

This document contains device-specific information for
the following devices:

• PIC18F2420 • PIC18LF2420

• PIC18F2520 • PIC18LF2520

• PIC18F4420 • PIC18LF4420

• PIC18F4520 • PIC18LF4520

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 PIC18F2420/2520/4420/
4520 family introduces design enhancements that
make these microcontrollers a logical choice for many
high-performance, power sensitive applications.

1.1 New Core Features

1.1.1 nanoWatt TECHNOLOGY

All of the devices in the PIC18F2420/2520/4420/4520
family incorporate a range of features that can signifi­cantly reduce power consumption during operation.
Key items include:

• Alternate Run Modes: By clocking the controller

from the Timer1 source or the internal oscillator
block, power consumption during code execution
can be reduced by as much as 90%.

• Multiple Idle Modes: The controller can also run

with its CPU core disabled but the peripherals still
active. In these states, power consumption can be
reduced even further, to as little as 4% of normal
operation requirements.

• On-the-Fly Mode Switching: The power-

managed modes are invoked by user code during
operation, allowing the user to incorporate
power-saving ideas into their application’s
software design.

• Low Consumption in Key Modules: The

power requirements for both Timer1 and the
Watchdog Timer are minimized. See

Section 26.0 “Electrical Characteristics”

for values.

1.1.2 MULTIPLE OSCILLATOR OPTIONS AND FEATURES

All of the devices in the PIC18F2420/2520/4420/4520
family offer ten different oscillator options, allowing
users a wide range of choices in developing application
hardware. These include:

• Four Crystal modes, using crystals or ceramic

resonators

• Two External Clock modes, offering the option of

using two pins (oscillator input and a divide-by-4
clock output) or one pin (oscillator input, with the
second pin reassigned as general I/O)

• Two External RC Oscillator modes with the same

pin options as the External Clock modes

• An internal oscillator block which provides an

8 MHz clock and an INTRC source
(approximately 31 kHz), as well as a range of
6 user-selectable clock frequencies, between
125 kHz to 4 MHz, for a total of 8 clock
frequencies. This option frees the two oscillator
pins for use as additional general purpose I/O.

• A Phase Lock Loop (PLL) frequency multiplier,

available to both the High-Speed Crystal and Inter­nal Oscillator modes, which allows clock speeds of
up to 40 MHz. Used with the internal oscillator, the
PLL gives users a complete selection of clock
speeds, from 31 kHz to 32 MHz – all without using
an external crystal or clock circuit.

Besides its availability as a clock source, the internal
oscillator block provides a stable reference source that
gives the family additional features for robust
operation:

• Fail-Safe Clock Monitor: This option constantly

monitors the main clock source against a refer­ence signal provided by the internal oscillator. If a
clock failure occurs, the controller is switched to
the internal oscillator block, allowing for continued
low-speed operation or a safe application
shutdown.

• T wo-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.

© 2008 Microchip Technology Inc. DS39631E-page 7

PIC18F2420/2520/4420/4520

1.2 Other Special Features

• Memory Endurance: The Enhanced Flash cells

for both program memory and data EEPROM are
rated to last for many thousands of erase/write
cycles – up to 100,000 for program memory and
1,000,000 for EEPROM. Data retention without
refresh is conservatively estimated to be greater
than 40 years.

• Self-Programmability: These devices can write

to their own program memory spaces under
internal software control. By using a bootloader
routine located in the protected Boot Block at the
top of program memory, it becomes possible to
create an application that can update itself in the
field.

• Extended Instruction Set: The PIC18F2420/

2520/4420/4520 family introduces an optional
extension to the PIC18 instruction set, which adds
8 new instructions and an Indexed Addressing
mode. This extension, enabled as a device con­figuration option, has been specifically designed
to optimize re-entrant application code originally
developed in high-level languages, such as C.

• Enhanced CCP Module: In PWM mode, this

module provides 1, 2 or 4 modulated outputs for
controlling half-bridge and full-bridge drivers.
Other features include auto-shutdown, for dis­abling PWM outputs on interrupt, or other select
conditions, and auto-restart to reactivate outputs
once the condition has cleared.

• Enhanced Addressable USART: This serial

communication module is capable of standard
RS-232 operation and provides support for the LIN
bus protocol. Other enhancements include
automatic baud rate detection and a 16-bit Baud
Rate Generator for improved resolution. When the
microcontroller is using the internal oscillator
block, the EUSART provides stable operation for
applications that talk to the outside world without
using an external crystal (or its accompanying
power requirement).

• 10-Bit A/D Converter: This module incorporates

programmable acquisition time, allowing for a
channel to be selected and a conversion to be
initiated without waiting for a sampling period and
thus, reducing code overhead.

• Extended Watchdog Timer (WDT): This

enhanced version incorporates a 16-bit prescaler,
allowing an extended time-out range that is stable
across operating voltage and temperature. See

Section 26.0 “Electrical Characteristics” for

time-out periods.

1.3 Details on Individual Family Members

Devices in the PIC18F2420/2520/4420/4520 family are
available in 28-pin and 40/44-pin packages. Block
diagrams for the two groups are shown in Figure 1-1
and Figure 1-2.

The devices are differentiated from each other in five
ways:

1. Flash program memory (16 Kbytes for

PIC18F2420/4420 devices and 32 Kbytes for
PIC18F2520/4520 devices).

2. A/D channels (10 for 28-pin devices, 13 for

40/44-pin devices).

3. I/O ports (3 bidirectional ports on 28-pin devices,

5 bidirectional ports on 40/44-pin devices).

4. CCP and Enhanced CCP implementation

(28-pin devices have 2 standard CCP
modules, 40/44-pin devices have one standard
CCP module and one ECCP module).

5. Parallel Slave Port (present only on 40/44-pin

devices).

All other features for devices in this family are identical.
These are summarized in Table 1-1.

The pinouts for all devices are listed in Table 1-2 and
Table 1-3.

Like all Microchip PIC18 devices, members of the
PIC18F2420/2520/4420/4520 family are available as
both standard and low-voltage devices. Standard
devices with Enhanced Flash memory, designated with

an “F” in the part number (such as PIC18F2420),

accommodate an operating V
Low-voltage parts, designated by “LF” (such as

PIC18LF2420), function over an extended VDD range

of 2.0V to 5.5V.

DD range of 4.2V to 5.5V.

DS39631E-page 8 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

TABLE 1-1: DEVICE FEATURES

Features PIC18F2420 PIC18F2520 PIC18F4420 PIC18F4520

Operating Frequency DC – 40 MHz DC – 40 MHz DC – 40 MHz DC – 40 MHz

Program Memory (Bytes) 16384 32768 16384 32768

Program Memory
(Instructions)

Data Memory (Bytes) 768 1536 768 1536

Data EEPROM Memory (Bytes) 256 256 256 256

Interrupt Sources 19 19 20 20

I/O Ports Ports A, B, C, (E) Ports A, B, C, (E) Ports A, B, C, D, E Ports A, B, C, D, E

Timers 4 4 4 4

Capture/Compare/PWM Modules 2 2 1 1

Enhanced
Capture/Compare/PWM Modules

Serial Communications MSSP,

Parallel Communications (PSP) No No Yes Yes

10-Bit Analog-to-Digital Module 10 Input Channels 10 Input Channels 13 Input Channels 13 Input Channels

Resets (and Delays) POR, BOR,

Underflow (PWRT, OST),

Programmable
High/Low-Voltage Detect

Programmable Brown-out Reset Yes Yes Yes Yes

Instruction Set 75 Instructions;

Packages 28-Pin SPDIP

8192 16384 8192 16384

0011

Enhanced USART

RESET Instruction,

Stack Full, Stack

MCLR

(optional), WDT

Ye s Ye s Ye s Ye s

83 with Extended

Instruction Set Enabled

28-Pin SOIC

28-Pin QFN

MSSP,

Enhanced USART

POR, BOR,

RESET Instruction,

Stack Full, Stack

Underflow (PWRT, OST),

MCLR (optional), WDT

75 Instructions;

83 with Extended

Instruction Set Enabled

28-Pin SPDIP

28-Pin SOIC

28-Pin QFN

MSSP,

Enhanced USART

POR, BOR,

RESET Instruction,

Stack Full, Stack

Underflow (PWRT, OST),

MCLR (optional), WDT

75 Instructions;

83 with Extended

Instruction Set Enabled

40-Pin PDIP

44-Pin QFN

44-Pin TQFP

MSSP,

Enhanced USART

POR, BOR,

RESET Instruction,

Stack Full, Stack

Underflow (PWRT, OST),

MCLR (optional), WDT

75 Instructions;

83 with Extended

Instruction Set Enabled

40-Pin PDIP

44-Pin QFN

44-Pin TQFP

© 2008 Microchip Technology Inc. DS39631E-page 9

PIC18F2420/2520/4420/4520

Instruction

Decode and

Control

PORTA

PORTB

PORTC

RA4/T0CKI/C1OUT
RA5/AN4/SS

/HLVDIN/C2OUT

RB0/INT0/FLT0/AN12

RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2

(1)

RC2/CCP1
RC3/SCK/SCL
RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT

RA3/AN3/VREF+

RA2/AN2/VREF-/CVREF

RA1/AN1

RA0/AN0

RB1/INT1/AN10

Data Latch

Data Memory

( 3.9 Kbytes )

Address Latch

Data Address<12>

12

Access

BSR

FSR0
FSR1
FSR2

inc/dec

logic

Address

4

12

4

PCH PCL

PCLATH

8

31-Level Stack

Program Counter

PRODLPRODH

8 x 8 Multiply

8

BITOP

8

8

ALU<8>

Address Latch

Program Memory

(16/32 Kbytes)

Data Latch

20

8

8

Table Pointer<21>

inc/dec logic

21

8

Data Bus<8>

Table Latch

8

IR

12

3

ROM Latch

RB2/INT2/AN8
RB3/AN9/CCP2

(1)

PCLATU

PCU

OSC2/CLKO

(3)

/RA6

Note 1: CCP2 is multiplexed with RC1 when Configuration bit, CCP2MX, is set, or RB3 when CCP2MX is not set.

2: RE3 is only available when MCLR

functionality is disabled.

3: OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.

Refer to Section 2.0 “Oscillator Configurations” for additional information.

RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD

EUSARTComparator

MSSP

10-Bit

ADC

Timer2Timer1 Timer3Timer0

CCP2

HLVD

CCP1

BOR

Data

EEPROM

W

Instruction Bus <16>

STKPTR

Bank

8

State Machine
Control Signals

Decode

8

8

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

OSC1

(3)

OSC2

(3)

VDD,

Brown-out

Reset

Internal

Oscillator

Fail-Safe

Clock Monitor

Precision

Reference

Band Gap

V

SS

MCLR

(2)

Block

INTRC

Oscillator

8 MHz

Oscillator

Single-Supply

Programming

In-Circuit

Debugger

T1OSO

OSC1/CLKI

(3)

/RA7

T1OSI

PORTE

MCLR/VPP/RE3

(2)

FIGURE 1-1: PIC18F2420/2520 ( 28-PIN) BLOCK DI AGRAM

DS39631E-page 10 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

Instruction

Decode and

Control

Data Latch

Data Memory

( 3.9 Kbytes )

Address Latch

Data Address<12>

12

Access

BSR

FSR0
FSR1
FSR2

inc/dec

logic

Address

4

12

4

PCH PCL

PCLATH

8

31-Level Stack

Program Counter

PRODLPRODH

8 x 8 Multiply

8

BITOP

8

8

ALU<8>

Address Latch

Program Memory

(16/32 Kbytes)

Data Latch

20

8

8

Table Pointer<21>

inc/dec logic

21

8

Data Bus<8>

Table Latch

8

IR

12

3

ROM Latch

PORTD

RD0/PSP0

PCLATU

PCU

PORTE

MCLR/VPP/RE3

(2)

RE2/CS/AN7

RE0/RD/AN5
RE1/WR/AN6

Note 1: CCP2 is multiplexed with RC1 when Configuration bit, CCP2MX, is set, or RB3 when CCP2MX is not set.

2: RE3 is only available when MCLR

functionality is disabled.

3: OSC1/CLKI and OSC2/CLKO are only available in select oscillator modes and when these pins are not being used as digital I/O.

Refer to Section 2.0 “Osc illa to r Config ura tions ” for additional information.

:RD4/PSP4

EUSARTComparator

MSSP

10-Bit

ADC

Timer2Timer1 Timer3Timer0

CCP2

HLVD

ECCP1

BOR

Data

EEPROM

W

Instruction Bus <16>

STKPTR

Bank

8

State Machine
Control Signals

Decode

8

8

Power-up

Timer

Oscillator

Start-up Timer

Power-on

Reset

Watchdog

Timer

OSC1

(3)

OSC2

(3)

VDD,

Brown-out

Reset

Internal

Oscillator

Fail-Safe

Clock Monitor

Precision

Reference

Band Gap

V

SS

MCLR

(2)

Block

INTRC

Oscillator

8 MHz

Oscillator

Single-Supply

Programming

In-Circuit

Debugger

T1OSI

T1OSO

RD5/PSP5/P1B
RD6/PSP6/P1C
RD7/PSP7/P1D

PORTA

PORTB

PORTC

RA4/T0CKI/C1OUT
RA5/AN4/SS

/HLVDIN/C2OUT

RB0/INT0/FLT0/AN12

RC0/T1OSO/T13CKI
RC1/T1OSI/CCP2

(1)

RC2/CCP1/P1A
RC3/SCK/SCL

RC4/SDI/SDA
RC5/SDO
RC6/TX/CK
RC7/RX/DT

RA3/AN3/VREF+

RA2/AN2/VREF-/CVREF

RA1/AN1

RA0/AN0

RB1/INT1/AN10
RB2/INT2/AN8
RB3/AN9/CCP2

(1)

OSC2/CLKO

(3)

/RA6

RB4/KBI0/AN11
RB5/KBI1/PGM
RB6/KBI2/PGC
RB7/KBI3/PGD

OSC1/CLKI

(3)

/RA7

FIGURE 1-2: PIC18F4420/452 0 ( 40/44 -P IN ) B LOCK DI AGR AM

© 2008 Microchip Technology Inc. DS39631E-page 11

PIC18F2420/2520/4420/4520

TABLE 1-2: PIC18F2420/2520 PINOUT I/O DESCRIPTIONS

Pin Number

Pin Name

MCLR

/VPP/RE3

MCLR

VPP
RE3

OSC1/CLKI/RA7

OSC1

CLKI

RA7

OSC2/CLKO/RA6

OSC2

CLKO

RA6

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

SPDIP ,

SOIC

126

96

10 7

QFN

Pin

Type

I

P

I

I

I

I/O

O

O

I/O

Buffer

Type

ST

ST

ST

CMOS

TTL

—

—

TTL

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.
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.

DS39631E-page 12 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

TABLE 1-2: PIC18F2420/2520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Number

Pin Name

RA0/AN0

RA0
AN0

RA1/AN1

RA1
AN1

RA2/AN2/V

RA2
AN2
V
CV

RA3/AN3/V

RA3
AN3
V

RA4/T0CKI/C1OUT

RA4
T0CKI
C1OUT

RA5/AN4/SS
C2OUT

RA5
AN4
SS
HLVDIN
C2OUT

RA6 See the OSC2/CLKO/RA6 pin.

RA7 See the OSC1/CLKI/RA7 pin.

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

REF-/CVREF

REF-

REF

REF+

REF+

/HLVDIN/

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

SPDIP ,

SOIC

227

328

41

52

63

74

QFN

Pin

Buffer

Type

Type

I/OITTL

Analog

I/OITTL

Analog

I/O

TTL

I

Analog

I

Analog

O

Analog

I/O

TTL

I

Analog

I

Analog

I/O

I

O

I/O

TTL

I

Analog

I

TTL

I

Analog

O

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.

ST
ST

—

—

Digital I/O.
Timer0 external clock input.
Comparator 1 output.

Digital I/O.
Analog input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.

Description

© 2008 Microchip Technology Inc. DS39631E-page 13

PIC18F2420/2520/4420/4520

TABLE 1-2: PIC18F2420/2520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Number

Pin Name

RB0/INT0/FLT0/AN12

RB0
INT0
FLT0
AN12

RB1/INT1/AN10

RB1
INT1
AN10

RB2/INT2/AN8

RB2
INT2
AN8

RB3/AN9/CCP2

RB3
AN9

(1)

CCP2

RB4/KBI0/AN11

RB4
KBI0
AN11

RB5/KBI1/PGM

RB5
KBI1
PGM

RB6/KBI2/PGC

RB6
KBI2
PGC

RB7/KBI3/PGD

RB7
KBI3
PGD

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

SPDIP ,

SOIC

21 18

22 19

23 20

24 21

25 22

26 23

27 24

28 25

QFN

Pin

Type

I/O

I
I
I

I/O

I
I

I/O

I
I

I/O

I

I/O

I/O

I
I

I/O

I

I/O

I/O

I

I/O

I/O

I

I/O

Buffer

Type

TTL

ST
ST

Analog

TTL

ST

Analog

TTL

ST

Analog

TTL

Analog

ST

TTL
TTL

Analog

TTL
TTL

ST

TTL
TTL

ST

TTL
TTL

ST

Description

PORTB is a bidirectional I/O port. PORTB can be software
programmed for internal weak pull-ups on all inputs.

Digital I/O.
External interrupt 0.
PWM Fault input for CCP1.
Analog input 12.

Digital I/O.
External interrupt 1.
Analog input 10.

Digital I/O.
External interrupt 2.
Analog input 8.

Digital I/O.
Analog input 9.
Capture 2 input/Compare 2 output/PWM2 output.

Digital I/O.
Interrupt-on-change pin.
Analog input 11.

Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP™ Programming enable pin.

Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming clock pin.

Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming data pin.

DS39631E-page 14 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

TABLE 1-2: PIC18F2420/2520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Number

Pin Name

RC0/T1OSO/T13CKI

RC0
T1OSO
T13CKI

RC1/T1OSI/CCP2

RC1
T1OSI

(2)

CCP2

RC2/CCP1

RC2
CCP1

RC3/SCK/SCL

RC3
SCK
SCL

RC4/SDI/SDA

RC4
SDI
SDA

RC5/SDO

RC5
SDO

RC6/TX/CK

RC6
TX
CK

RC7/RX/DT

RC7
RX
DT

RE3 — — — — See MCLR

VSS 8, 19 5, 16 P — Ground reference for logic and I/O pins.

VDD 20 17 P — Positive supply for logic and I/O pins.

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

SPDIP ,

SOIC

11 8

12 9

13 10

14 11

15 12

16 13

17 14

18 15

QFN

Pin

Buffer

Type

Type

I/O

O

I

I/O

I

Analog

I/O

I/O
I/OSTST

I/O
I/O
I/O

I/O

I

I/O

I/OOST

I/O

O

I/O

I/O

I

I/O

PORTC is a bidirectional I/O port.

ST

—

ST

ST

ST

ST
ST
ST

ST
ST
ST

—

ST

—

ST

ST
ST
ST

Digital I/O.
Timer1 oscillator output.
Timer1/Timer3 external clock input.

Digital I/O.
Timer1 oscillator input.
Capture 2 input/Compare 2 output/PWM2 output.

Digital I/O.
Capture 1 input/Compare 1 output/PWM1 output.

Digital I/O.
Synchronous serial clock input/output for SPI mode.
Synchronous serial clock input/output for I

Digital I/O.
SPI data in.
I2C data I/O.

Digital I/O.
SPI data out.

Digital I/O.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).

Digital I/O.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).

/VPP/RE3 pin.

Description

2

C™ mode.

© 2008 Microchip Technology Inc. DS39631E-page 15

PIC18F2420/2520/4420/4520

TABLE 1-3: PIC18F4420/4520 PINOUT I/O DESCRIPTIONS

Pin Name

/VPP/RE3

MCLR

MCLR

VPP
RE3

OSC1/CLKI/RA7

OSC1

CLKI

RA7

OSC2/CLKO/RA6

OSC2

CLKO

RA6

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

Pin Number

PDIP QFN TQFP

11818

13 32 30

14 33 31

Pin

Type

I

P

I

I

I

I/O

O

O

I/O

Buffer

Type

ST

ST

ST

CMOS

TTL

—

—

TTL

Description

Master Clear (input) or programming voltage (input).

Master Clear (Reset) input. This pin is an active-low
Reset to the device.
Programming voltage input.
Digital input.

Oscillator crystal or external clock input.

Oscillator crystal input or external clock source input.
ST buffer when configured in RC mode;
analog otherwise.
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.

DS39631E-page 16 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

TABLE 1-3: PIC18F4420/4520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

RA0/AN0

RA0
AN0

RA1/AN1

RA1
AN1

RA2/AN2/V

RA3/AN3/V

RA4/T0CKI/C1OUT

RA5/AN4/SS
C2OUT

RA6 See the OSC2/CLKO/RA6 pin.

RA7 See the OSC1/CLKI/RA7 pin.

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

REF-/CVREF

RA2
AN2
VREF-

REF

CV

REF+

RA3
AN3

REF+

V

RA4
T0CKI
C1OUT

/HLVDIN/

RA5
AN4
SS
HLVDIN
C2OUT

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

Pin Number

PDIP QFN TQFP

21919

32020

42121

52222

62323

72424

Pin

Buffer

Type

Type

I/OITTL

Analog

I/OITTL

Analog

I/O

TTL

I

Analog

I

Analog

O

Analog

I/O

TTL

I

Analog

I

Analog

I/O

I

O

I/O

TTL

I

Analog

I

TTL

I

Analog

O

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.

ST
ST

—

—

Digital I/O.
Timer0 external clock input.
Comparator 1 output.

Digital I/O.
Analog input 4.
SPI slave select input.
High/Low-Voltage Detect input.
Comparator 2 output.

Description

© 2008 Microchip Technology Inc. DS39631E-page 17

PIC18F2420/2520/4420/4520

TABLE 1-3: PIC18F4420/4520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

RB0/INT0/FLT0/AN12

RB0
INT0
FLT0
AN12

RB1/INT1/AN10

RB1
INT1
AN10

RB2/INT2/AN8

RB2
INT2
AN8

RB3/AN9/CCP2

RB3
AN9

(1)

CCP2

RB4/KBI0/AN11

RB4
KBI0
AN11

RB5/KBI1/PGM

RB5
KBI1
PGM

RB6/KBI2/PGC

RB6
KBI2
PGC

RB7/KBI3/PGD

RB7
KBI3
PGD

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

Pin Number

PDIP QFN TQFP

33 9 8

34 10 9

35 11 10

36 12 11

37 14 14

38 15 15

39 16 16

40 17 17

Pin

Type

I/O

I
I
I

I/O

I
I

I/O

I
I

I/O

I

I/O

I/O

I
I

I/O

I

I/O

I/O

I

I/O

I/O

I

I/O

Buffer

Type

TTL

ST
ST

Analog

TTL

ST

Analog

TTL

ST

Analog

TTL

Analog

ST

TTL
TTL

Analog

TTL
TTL

ST

TTL
TTL

ST

TTL
TTL

ST

Description

PORTB is a bidirectional I/O port. PORTB can be
software programmed for internal weak pull-ups on all
inputs.

Digital I/O.
External interrupt 0.
PWM Fault input for Enhanced CCP1.
Analog input 12.

Digital I/O.
External interrupt 1.
Analog input 10.

Digital I/O.
External interrupt 2.
Analog input 8.

Digital I/O.
Analog input 9.
Capture 2 input/Compare 2 output/PWM2 output.

Digital I/O.
Interrupt-on-change pin.
Analog input 11.

Digital I/O.
Interrupt-on-change pin.
Low-Voltage ICSP™ Programming enable pin.

Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming
clock pin.

Digital I/O.
Interrupt-on-change pin.
In-Circuit Debugger and ICSP programming
data pin.

DS39631E-page 18 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

TABLE 1-3: PIC18F4420/4520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

RC0/T1OSO/T13CKI

RC0
T1OSO
T13CKI

RC1/T1OSI/CCP2

RC1
T1OSI

(2)

CCP2

RC2/CCP1/P1A

RC2
CCP1
P1A

RC3/SCK/SCL

RC3
SCK

SCL

RC4/SDI/SDA

RC4
SDI
SDA

RC5/SDO

RC5
SDO

RC6/TX/CK

RC6
TX
CK

RC7/RX/DT

RC7
RX
DT

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

Pin Number

PDIP QFN TQFP

15 34 32

16 35 35

17 36 36

18 37 37

23 42 42

24 43 43

25 44 44

26 1 1

Pin

Type

I/O

O

I

I/O

I

I/O

I/O
I/O

O

I/O
I/O

I/O

I/O

I

I/O

I/O

O

I/O

O

I/O

I/O

I

I/O

Buffer

Type

ST

—

ST

ST

CMOS

ST

ST
ST

—

ST
ST

ST

ST
ST
ST

ST

—

ST

—

ST

ST
ST
ST

Description

PORTC is a bidirectional I/O port.

Digital I/O.
Timer1 oscillator output.
Timer1/Timer3 external clock input.

Digital I/O.
Timer1 oscillator input.
Capture 2 input/Compare 2 output/PWM2 output.

Digital I/O.
Capture 1 input/Compare 1 output/PWM1 output.
Enhanced CCP1 output.

Digital I/O.
Synchronous serial clock input/output for
SPI mode.
Synchronous serial clock input/output for I

Digital I/O.
SPI data in.

2

C data I/O.

I

Digital I/O.
SPI data out.

Digital I/O.
EUSART asynchronous transmit.
EUSART synchronous clock (see related RX/DT).

Digital I/O.
EUSART asynchronous receive.
EUSART synchronous data (see related TX/CK).

2

C™ mode.

© 2008 Microchip Technology Inc. DS39631E-page 19

PIC18F2420/2520/4420/4520

TABLE 1-3: PIC18F4420/4520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

RD0/PSP0

RD0
PSP0

RD1/PSP1

RD1
PSP1

RD2/PSP2

RD2
PSP2

RD3/PSP3

RD3
PSP3

RD4/PSP4

RD4
PSP4

RD5/PSP5/P1B

RD5
PSP5
P1B

RD6/PSP6/P1C

RD6
PSP6
P1C

RD7/PSP7/P1D

RD7
PSP7
P1D

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

Pin Number

PDIP QFN TQFP

19 38 38

20 39 39

21 40 40

22 41 41

27 2 2

28 3 3

29 4 4

30 5 5

Pin

Buffer

Type

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

TTL

O

I/O
I/O

TTL

O

I/O
I/O

TTL

O

Description

PORTD is a bidirectional I/O port or a Parallel Slave
Port (PSP) for interfacing to a microprocessor port.
These pins have TTL input buffers when 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

—

ST

—

ST

—

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.

DS39631E-page 20 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

TABLE 1-3: PIC18F4420/4520 PINOUT I/O DESCRIPTIONS (CONTINUED)

Pin Name

RE0/RD

RE1/WR/AN6

RE2/CS/AN7

RE3 — — — — — See MCLR

VSS 12, 31 6, 30, 316, 29 P — Ground reference for logic and I/O pins.

/AN5
RE0
RD

AN5

RE1
WR

AN6

RE2
CS

AN7

Pin Number

PDIP QFN TQFP

82525

92626

10 27 27

Pin

Type

I/O

I

I

I/O

I

I

I/O

I

I

Buffer

Type

ST

TTL

Analog

ST

TTL

Analog

ST

TTL

Analog

Description

PORTE is a bidirectional I/O port.

Digital I/O.
Read control for Parallel Slave Port
(see also WR
Analog input 5.

Digital I/O.
Write control for Parallel Slave Port
(see CS
Analog input 6.

Digital I/O.
Chip Select control for Parallel Slave Port
(see related RD
Analog input 7.

and CS pins).

and RD pins).

and WR).

/VPP/RE3 pin.

V

DD 11, 32 7, 8,

28, 29

NC — 13 12, 13,

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output

ST = Schmitt Trigger input with CMOS levels I = Input
O = Output P = Power

Note 1: Default assignment for CCP2 when Configuration bit, CCP2MX, is set.

2: Alternate assignment for CCP2 when Configuration bit, CCP2MX, is cleared.

7, 28 P — Positive supply for logic and I/O pins.

— — No Connect.

33, 34

© 2008 Microchip Technology Inc. DS39631E-page 21

PIC18F2420/2520/4420/4520

NOTES:

DS39631E-page 22 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

Note 1: See Table 2-1 and Table 2-2 for initial values of

C1 and C2.

2: A series resistor (R

S) may be required for AT

strip cut crystals.

3: R

F varies with the oscillator mode chosen.

C1

(1)

C2

(1)

XTAL

OSC2

OSC1

RF

(3)

Sleep

To

Logic

PIC18FXXXX

RS

(2)

Internal

2.0 OSCILLATOR CONFIGURATIONS

FIGURE 2-1: CRYSTAL/CERAMIC

RESONATOR OPERATION
(XT, LP , HS O R HSP LL

2.1 Oscillator Types

PIC18F2420/2520/4420/4520 devices can be operated
in ten different oscillator modes. The user can program
the Configuration bits, FOSC<3:0>, in Configuration
Register 1H to select one of these ten modes:

1. LP Low-Power Crystal

2. XT Crystal/Resonator

3. HS High-Speed Crystal/Resonator

4. HSPLL High-Speed Crystal/Resonator

with PLL Enabled

5. RC External Resistor/Capacitor with

F

OSC/4 Output on RA6

6. RCIO External Resistor/Capacitor with I/O

on RA6

7. INTIO1 Internal Oscillator with F

on RA6 and I/O on RA7

8. INTIO2 Internal Oscillator with I/O on RA6

and RA7

9. EC External Clock with F

10. ECIO External Clock with I/O on RA6

2.2 Crystal Oscillator/Ceramic Resonators

In XT, LP, HS or HSPLL Oscillator modes, a crystal or
ceramic resonator is connected to the OSC1 and
OSC2 pins to establish oscillation. Figure 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 manufacturer’s
specifications.

OSC/4 Output

OSC/4 Output

T ABLE 2-1: CAPACITOR SELECTION FOR

Typical Capacitor Values Used:

Mode Freq OSC1 OSC2

XT 3.58 MHz

4.19 MHz

Capacitor values are for design guidance only.

Different capacitor values may be required to produce
acceptable oscillator operation. The user should test
the performance of the oscillator over the expected

DD and temperature range for the application.

V

See the notes following Table 2-2 for additional
information.

Note: When using resonators with frequencies

above 3.5 MHz, the use of HS mode,
rather than XT mode, is recommended.
HS mode may be used at any V
which the controller is rated. If HS is
selected, it is possible that the gain of the
oscillator will overdrive the resonator.
Therefore, a series resistor should be
placed between the OSC2 pin and the
resonator. As a good starting point, the
recommended value of R

CONFIGURATION)

CERAMIC RESONATORS

15 pF

15 pF
4 MHz
4 MHz

30 pF

50 pF

S is 330Ω.

15 pF
15 pF
30 pF
50 pF

DD for

© 2008 Microchip Technology Inc. DS39631E-page 23

PIC18F2420/2520/4420/4520

OSC1

OSC2

Open

Clock from
Ext. System

PIC18FXXXX

(HS Mode)

OSC1/CLKI

OSC2/CLKO

F

OSC/4

Clock from
Ext. System

PIC18FXXXX

OSC1/CLKI

I/O (OSC2)

RA6

Clock from
Ext. System

PIC18FXXXX

TABLE 2-2: CAPACITOR SELECTION FOR

CRYSTAL OSCILLATOR

Osc T y pe

Crystal

Freq

LP 32 kHz 30 pF 30 pF

XT 1 MHz

4 MHz

HS 4 MHz

10 MHz
20 MHz
25 MHz
25 MHz

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

DD and temperature range for the application.

V

See the notes following this table for additional
information.

32 kHz 4 MHz

25 MHz 10 MHz

1 MHz 20 MHz

T ypical Cap acitor V alues

Tested:

C1 C2

15 pF
15 pF

15 pF
15 pF
15 pF

0 pF

15 pF

Crystals Used:

15 pF
15 pF

15 pF
15 pF
15 pF

5 pF

15 pF

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)

2.3 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 2-3 shows the pin connections for the EC
Oscillator mode.

FIGURE 2-3: EXTERNAL CLO CK

INPUT OPERATION
(EC CONFIGURATION)

Note 1: Higher capacitance increases the stability

of the oscillator but also increases the
start-up time.

2: When operating below 3V V

DD, or when

using certain ceramic resonators at any
voltage, it may be necessary to use the
HS mode or switch to a crystal oscillator.

3: Since each resonator/crystal has its own

characteristics, the user should consult
the resonator/crystal manufacturer for
appropriate values of external
components.

4: Rs may be required to avoid overdriving

crystals with low drive level specification.

5: Always verify oscillator performance over

DD and temperature range that is

the V
expected for the application.

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 2-4 shows the pin connections
for the ECIO Oscillator mode.

FIGURE 2-4: EXTERNAL CLO CK

INPUT OPERATION
(ECIO CONFIG URAT ION)

DS39631E-page 24 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

OSC2/CLKO

CEXT

REXT

PIC18FXXXX

OSC1

F

OSC/4

Internal

Clock

VDD

VSS

Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ

C

EXT > 20 pF

CEXT

REXT

PIC18FXXXX

OSC1

Internal

Clock

VDD

VSS

Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ

C

EXT > 20 pF

I/O (OSC2)

RA6

MUX

VCO

Loop
Filter

Crystal

Osc

OSC2

OSC1

PLL Enable

F

IN

FOUT

SYSCLK

Phase

Comparator

HS Oscillator Enable

÷4

(from Configuration Register 1H)

HS Mode

2.4 RC Oscillator

For timing insensitive applications, the “RC” and
“RCIO” device options offer additional cost savings.
The actual oscillator frequency is a function of several
factors:

• supply voltage

• values of the external resistor (R
capacitor (C

EXT)

• operating temperature

Given the same device, operating voltage and tempera­ture and component values, there will also be unit-to-unit
frequency variations. These are due to factors such as:

• normal manufacturing variation

• difference in lead frame capacitance between
package types (especially for low C

• variations within the tolerance of limits of REXT

EXT

and C

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 2-5 shows how the R/C combination is
connected.

FIGURE 2-5: RC OSCIL LAT OR MODE

EXT) and

EXT values)

2.5 PLL Frequency Multiplier

A Phase Locked Loop (PLL) circuit is provided as an
option for users who wish to use a lower frequency
oscillator circuit or to clock the device up to its highest
rated frequency from a crystal oscillator. This may be
useful for customers who are concerned with EMI due
to high-frequency crystals or users who require higher
clock speeds from an internal oscillator.

2.5.1 HSPLL OSCILLATOR MODE

The HSPLL mode makes use of the HS Oscillator
mode for frequencies up to 10 MHz. A PLL then multi­plies the oscillator output frequency by 4 to produce an
internal clock frequency up to 40 MHz. The PLLEN bit
is not available in this oscillator mode.

The PLL is only available to the crystal oscillator when
the FOSC<3:0> Configuration bits are programmed for
HSPLL mode (= 0110).

FIGURE 2-7: PLL BLOCK DIAGRAM (HS

MODE)

The RCIO Oscillator mode (Figure 2-6) functions like
the RC mode, except that the OSC2 pin becomes an
additional general purpose I/O pin. The I/O pin
becomes bit 6 of PORTA (RA6).

FIGURE 2-6: RCIO OSCILLATOR MODE

© 2008 Microchip Technology Inc. DS39631E-page 25

2.5.2 PLL AND INTOSC

The PLL is also available to the internal oscillator block
in selected oscillator modes. In this configuration, the
PLL is enabled in software and generates a clock out­put of up to 32 MHz. The operation of INTOSC with the

PLL is described in Section 2.6.4 “PLL in INTOSC

Modes”.

PIC18F2420/2520/4420/4520

2.6 Internal Oscillator Block

The PIC18F2420/2520/4420/4520 devices include an
internal oscillator block which generates two different
clock signals; either can be used as the micro­controller’s clock source. This may eliminate the need
for external oscillator circuits on the OSC1 and/or
OSC2 pins.

The main output (INTOSC) is an 8 MHz clock source
which can be used to directly drive the device clock. It
also drives a postscaler which can provide a range of
clock frequencies from 31 kHz to 4 MHz. The INTOSC
output is enabled when a clock frequency from 125 kHz
to 8 MHz is selected.

The other clock source is the internal RC oscillator
(INTRC), which provides a nominal 31 kHz output.
INTRC is enabled if it is selected as the device clock
source; it is also enabled automatically when any of the
following are enabled:

• Power-up Timer

• Fail-Safe Clock Monitor

• Watchdog Timer

• Two-Speed 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 30).

2.6.1 INTIO MODES

Using the internal oscillator as the clock source elimi­nates the need for up to two external oscillator pins,
which can then be used for digital I/O. Two distinct
configurations are available:

• In INTIO1 mode, the OSC2 pin outputs F
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.

2.6.2 INTOSC OUTPUT FREQUENCY

The internal oscillator block is calibrated at the factory
to produce an INTOSC output frequency of 8.0 MHz.

The INTRC oscillator operates independently of the
INTOSC source. Any changes in INTOSC across
voltage and temperature are not necessarily reflected
by changes in INTRC and vice versa.

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).

OSC/4,

When the OSCTUNE register is modified, the INTOSC
frequency will begin shifting to the new frequency. The
INTRC clock will reach the new frequency within
8 clock cycles (approximately 8 * 32 μs=256μs). The
INTOSC clock will stabilize within 1 ms. Code execu­tion continues during this shift. There is no indication
that the shift has occurred.

The OSCTUNE register also implements the INTSRC
and PLLEN bits, which control certain features of the
internal oscillator block. The INTSRC bit allows users
to select which internal oscillator provides the clock
source when the 31 kHz frequency option is selected.

This is covered in greater detail in Section 2.7.1
“Oscillator Control Register”.

The PLLEN bit controls the operation of the frequency
multiplier, PLL, in internal oscillator modes.

2.6.4 PLL IN INTOSC MODES

The 4x frequency multiplier can be used with the inter­nal oscillator block to produce faster device clock
speeds than are normally possible with an internal
oscillator. When enabled, the PLL produces a clock
speed of up to 32 MHz.

Unlike HSPLL mode, the PLL is controlled through
software. The control bit, PLLEN (OSCTUNE<6>), is
used to enable or disable its operation.

The PLL is available when the device is configured to
use the internal oscillator block as its primary clock
source (FOSC<3:0> = 1001 or 1000). Additionally, the
PLL will only function when the selected output fre­quency is either 4 MHz or 8 MHz (OSCCON<6:4> = 111
or 110). If both of these conditions are not met, the PLL
is disabled.

The PLLEN control bit is only functional in those inter­nal oscillator modes where the PLL is available. In all
other modes, it is forced to ‘0’ and is effectively
unavailable.

2.6.5 INTOSC FREQUENCY DRIFT

The factory calibrates the internal oscillator block
output (INTOSC) for 8 MHz. However, this frequency
may drift as V
affect the controller operation in a variety of ways. It is
possible to adjust the INTOSC frequency by modifying
the value in the OSCTUNE register. This has no effect
on the INTRC clock source frequency.

Tuning the INTOSC source requires knowing when to
make the adjustment, in which direction it should be
made, and in some cases, how large a change is
needed. Three compensation techniques are discussed

in Section 2.6.5.1 “Compensating with the

EUSART”, Section 2.6.5.2 “Compensating with the
Timers” and Section 2.6.5.3 “Compe nsa tin g w it h th e
CCP Module in Capture Mode”, but other techniques

may be used.

DD or temperature changes, which can

DS39631E-page 26 © 2008 Microchip Technology Inc.

PIC18F2420/2520/4420/4520

REGISTER 2-1: OSCTUNE: OSCILLATOR TUNING REGISTER

R/W-0 R/W-0

INTSRC PLLEN

bit 7 bit 0

Legend:

R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’

-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown

bit 7 INTSRC: Internal Oscillator Low-Frequency Source Select bit

1 = 31.25 kHz device clock derived from 8 MHz INTOSC source (divide-by-256 enabled)
0 = 31 kHz device clock derived directly from INTRC internal oscillator

bit 6 PLLEN: Frequency Multiplier PLL for INTOSC Enable bit

1 = PLL enabled for INTOSC (4 MHz and 8 MHz only)
0 = PLL disabled

bit 5 Unimplemented: Read as ‘0’
bit 4-0 TUN<4:0>: Frequency Tuning bits

011111 = Maximum frequency

• •

• •

000001
000000 = Center frequency. Oscillator module is running at the calibrated frequency.
111111

• •

• •
100000 = Minimum frequency

(1)

(1)

U-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0

— TUN4 TUN3 TUN2 TUN1 TUN0

(1)

Note 1: Available only in certain oscillator configurations; otherwise, this bit is unavailable and reads as ‘0’. See

Section 2.6.4 “PLL in INTOSC Modes” for details.

2.6.5.1 Compensating with the EUSART

An adjustment may be required when the EUSART
begins to generate framing errors or receives data with
errors while in Asynchronous mode. Framing errors
indicate that the device clock frequency is too high. To
adjust for this, decrement the value in OSCTUNE to
reduce the clock frequency. On the other hand, errors
in data may suggest that the clock speed is too low. To
compensate, increment OSCTUNE to increase the
clock frequency.

2.6.5.2 Compensating with the Timers

This technique compares device clock speed to some
reference clock. Two timers may be used; one timer is
clocked by the peripheral clock, while the other is
clocked by a fixed reference source, such as the
Timer1 oscillator.

Both timers are cleared, but the timer clocked by the
reference generates interrupts. When an interrupt
occurs, the internally clocked timer is read and both
timers are cleared. If the internally clocked timer value
is greater than expected, then the internal oscillator
block is running too fast. To adjust for this, decrement
the OSCTUNE register.

2.6.5.3 Compensating with the CCP Module
in Capture Mode

A CCP module can use free-running Timer1 (or
Timer3), clocked by the internal oscillator block and an
external event with a known period (i.e., AC power fre­quency). The time of the first event is captured in the
CCPRxH:CCPRxL registers and is recorded for use
later. When the second event causes a capture, the
time of the first event is subtracted from the time of the
second event. Since the period of the external event is
known, the time difference between events can be
calculated.

If the measured time is much greater than the calcu­lated time, the internal oscillator block is running too
fast; to compensate, decrement the OSCTUNE register.
If the measured time is much less than the calculated
time, the internal oscillator block is running too slow; to
compensate, increment the OSCTUNE register.

© 2008 Microchip Technology Inc. DS39631E-page 27

PIC18F2420/2520/4420/4520

4 x PLL

FOSC<3:0>

Secondary Oscillator

T1OSCEN
Enable
Oscillator

T1OSO

T1OSI

Clock Source Option
for Other Modules

OSC1

OSC2

Sleep

HSPLL, INTOSC/PLL

LP, XT, HS, RC, EC

T1OSC

CPU

Peripherals

IDLEN

Postscaler

MUX

MUX

8 MHz

4 MHz

2 MHz

1 MHz

500 kHz

125 kHz

250 kHz

OSCCON<6:4>

111

110

101

100

011

010

001

000

31 kHz

INTRC

Source

Internal

Oscillator

Block

WDT, PWRT, FSCM

8 MHz

Internal Oscillator

(INTOSC)

OSCCON<6:4>

Clock

Control

OSCCON<1:0>

Source

8 MHz

31 kHz (INTRC)

OSCTUNE<6>

0

1

OSCTUNE<7>

and Two-Speed Start-up

Primary Oscillator

PIC18F2420/2520/4420/4520

2.7 Clock Sources and Oscillator Switching

Like previous PIC18 devices, the PIC18F2420/2520/
4420/4520 family includes a feature that allows the
device clock source to be switched from the main oscil­lator to an alternate low-frequency clock source.
PIC18F2420/2520/4420/4520 devices offer two alternate
clock sources. When an alternate clock source is enabled,
the various power-managed operating modes are
available.

Essentially, there are three clock sources for these
devices:

• Primary oscillators

• Secondary oscillators

• Internal oscillator block

The primary oscillators include the External Crystal

and Resonator modes, the External RC modes, the
External Clock modes and the internal oscillator block.
The particular mode is defined by the FOSC<3:0> Con­figuration bits. The details of these modes are covered
earlier in this chapter.

The s econdary 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.

PIC18F2420/2520/4420/4520 devices offer 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 (RTC).

Most often, a 32.768 kHz watch crystal is connected
between the RC0/T1OSO/T13CKI and RC1/T1OSI
pins. Like the LP Oscillator mode circuit, loading
capacitors are also connected from each pin to ground.

The Timer1 oscillator is discussed in greater detail in

Section 12.3 “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 PIC18F2420/2520/4420/4520

devices are shown in Figure 2-8. See Section 23.0
“Special Features of the CPU” for Configuration

register details.

FIGURE 2-8: PIC18F2420/252 0/ 442 0/ 452 0 CL OCK D IA GRA M

DS39631E-page 28 © 2008 Microchip Technology Inc.