pic18f6520/8520/6620/8620/6720/8720 data sheetpic18f8520 note 1:ccp2 is multiplexed with rc1 when...

2004 Microchip Technology Inc. DS39609B

PIC18F6520/8520/6620/8620/6720/8720Data Sheet

64/80-Pin High-Performance,256 Kbit to 1 Mbit Enhanced Flash

Microcontrollers with A/D

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DS39609B-page ii 2004 Microchip Technology Inc.

Information contained in this publication regarding deviceapplications and the like is intended through suggestion onlyand may be superseded by updates. It is your responsibility toensure that your application meets with your specifications.No representation or warranty is given and no liability isassumed by Microchip Technology Incorporated with respectto the accuracy or use of such information, or infringement ofpatents or other intellectual property rights arising from suchuse or otherwise. Use of Microchip’s products as criticalcomponents in life support systems is not authorized exceptwith express written approval by Microchip. No licenses areconveyed, implicitly or otherwise, under any intellectualproperty rights.

Trademarks

The Microchip name and logo, the Microchip logo, Accuron, dsPIC, KEELOQ, MPLAB, PIC, PICmicro, PICSTART, 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, SmartShunt and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A.

Application Maestro, dsPICDEM, dsPICDEM.net, dsPICworks, ECAN, ECONOMONITOR, FanSense, FlexROM, fuzzyLAB, In-Circuit Serial Programming, ICSP, ICEPIC, microPort, Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM, PICkit, PICDEM, PICDEM.net, PICtail, PowerCal, PowerInfo, PowerMate, PowerTool, rfLAB, rfPIC, Select Mode, SmartSensor, SmartTel 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.

© 2004, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved.

Printed on recycled paper.

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 ourproducts. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such actsallow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.

Microchip received ISO/TS-16949:2002 quality system certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona and Mountain View, California in October 2003. The Company’s quality system processes and procedures are for its PICmicro® 8-bit MCUs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified.


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2004 Microchip Technology Inc. DS39609B-page 1

PIC18F6520/8520/6620/8620/6720/8720

High-Performance RISC CPU:• C compiler optimized architecture/instruction set:

- Source code compatible with the PIC16 and PIC17 instruction sets

• Linear program memory addressing to 128 Kbytes• Linear data memory addressing to 3840 bytes • 1 Kbyte of data EEPROM• Up to 10 MIPs operation:

- DC – 40 MHz osc./clock input- 4 MHz – 10 MHz osc./clock input with PLL active

• 16-bit wide instructions, 8-bit wide data path• Priority levels for interrupts • 31-level, software accessible hardware stack• 8 x 8 Single Cycle Hardware Multiplier

External Memory Interface(PIC18F8X20 Devices Only):• Address capability of up to 2 Mbytes• 16-bit interface

Peripheral Features:• High current sink/source 25 mA/25 mA• Four external interrupt pins• Timer0 module: 8-bit/16-bit timer/counter • Timer1 module: 16-bit timer/counter • Timer2 module: 8-bit timer/counter • Timer3 module: 16-bit timer/counter • Timer4 module: 8-bit timer/counter • Secondary oscillator clock option – Timer1/Timer3• Five Capture/Compare/PWM (CCP) modules:

- Capture is 16-bit, max. resolution 6.25 ns (TCY/16)- Compare is 16-bit, max. resolution 100 ns (TCY)- PWM output: PWM resolution is 1 to 10-bit

• Master Synchronous Serial Port (MSSP) module with two modes of operation:- 3-wire SPI™ (supports all 4 SPI modes)- I2C™ Master and Slave mode

• Two Addressable USART modules:- Supports RS-485 and RS-232

• Parallel Slave Port (PSP) module

Analog Features:• 10-bit, up to 16-channel Analog-to-Digital

Converter (A/D): - Conversion available during Sleep

• Programmable 16-level Low-Voltage Detection (LVD) module:- Supports interrupt on Low-Voltage Detection

• Programmable Brown-out Reset (PBOR)• Dual analog comparators:

- Programmable input/output configuration

Special Microcontroller Features:• 100,000 erase/write cycle Enhanced Flash

program memory typical• 1,000,000 erase/write cycle Data EEPROM

memory typical• 1 second programming time• Flash/Data EEPROM Retention: > 40 years• Self-reprogrammable under software control• Power-on Reset (POR), Power-up Timer (PWRT)

and Oscillator Start-up Timer (OST)• Watchdog Timer (WDT) with its own On-Chip

RC Oscillator for reliable operation• Programmable code protection• Power saving Sleep mode• Selectable oscillator options including:

- 4X Phase Lock Loop (of primary oscillator)- Secondary Oscillator (32 kHz) clock input

• In-Circuit Serial Programming™ (ICSP™) via two pins

• MPLAB® In-Circuit Debug (ICD) via two pins

CMOS Technology:• Low-power, high-speed Flash technology• Fully static design• Wide operating voltage range (2.0V to 5.5V) • Industrial and Extended temperature ranges

Device

Program Memory Data Memory

I/O10-bit A/D (ch)

CCP (PWM)

MSSP

USARTTimers

8-bit/16-bitExt Bus

MaxFOSC(MHz)Bytes

# Single-Word Instructions

SRAM (bytes)

EEPROM (bytes)

SPI Master

I2C

PIC18F6520 32K 16384 2048 1024 52 12 5 Y Y 2 2/3 N 40

PIC18F6620 64K 32768 3840 1024 52 12 5 Y Y 2 2/3 N 25

PIC18F6720 128K 65536 3840 1024 52 12 5 Y Y 2 2/3 N 25

PIC18F8520 32K 16384 2048 1024 68 16 5 Y Y 2 2/3 Y 40

PIC18F8620 64K 32768 3840 1024 68 16 5 Y Y 2 2/3 Y 25

PIC18F8720 128K 65536 3840 1024 68 16 5 Y Y 2 2/3 Y 25

64/80-Pin High-Performance, 256 Kbit to 1 Mbit Enhanced Flash Microcontrollers with A/D



PIC18F6520/8520/6620/8620/6720/8720

DS39609B-page 2 2004 Microchip Technology Inc.

Pin Diagrams

PIC18F6620

1

2

3

4

56

7

8

9

1011

12

1314

38

37

3635

34

33

50 49

17 18 19 20 21 22 23 24 25 26

RE

2/C

S

RE

3

RE

4

RE

5

RE

6

RE

7/C

CP

2(1)

RD

0/P

SP

0

VD

D

VS

S

RD

1/P

SP

1

RD

2/P

SP

2

RD

3/P

SP

3

RD

4/P

SP

4

RD

5/P

SP

5

RD

6/P

SP

6

RD

7/P

SP

7

RE1/WRRE0/RD

RG0/CCP3RG1/TX2/CK2

RG2/RX2/DT2

RG3/CCP4

MCLR/VPPRG4/CCP5

VSS

VDD

RF7/SSRF6/AN11

RF4/AN9

RF3/AN8RF2/AN7/C1OUT

RB0/INT0RB1/INT1

RB2/INT2

RB3/INT3RB4/KBI0

RB5/KBI1/PGM

RB6/KBI2/PGC

VSS

OSC2/CLKO/RA6OSC1/CLKI

VDD

RB7/KBI3/PGD

RC4/SDI/SDA

RC3/SCK/SCLRC2/CCP1

RF

0/A

N5

RF

1/A

N6/

C2O

UT

AV

DD

AV

SS

RA

3/A

N3/

VR

EF+

RA

2/A

N2/

VR

EF-

RA

1/A

N1

RA

0/A

N0

VS

S

VD

D

RA

4/T

0CK

I

RA

5/A

N4/

LVD

IN

RC

1/T

1OS

I/CC

P2(

1)

RC

0/T

1OS

O/T

13C

KI

RC

7/R

X1/

DT

1

RC

6/T

X1/

CK

1

RC5/SDO

15

16

31

40

39

27 28 29 30 32

48

47

46

45

44

43

42

41

54 53 52 5158 57 56 5560 5964 63 62 61

PIC18F6720

RF5/AN10/CVREF

64-Pin TQFP

PIC18F6520

Note 1: CCP2 is multiplexed with RC1 when CCP2MX is set.




PIC18F6520/8520/6620/8620/6720/8720

Pin Diagrams (Continued)

PIC18F8620

345678910111213141516

4847464544434241

4039

64 63 62 61

21 22 23 24 25 26 27 28 29 30 31 32

RE

2/C

S/A

D10

(3)

RE

3/A

D11

RE

4/A

D12

RE

5/A

D13

RE

6/A

D14

RE

7/C

CP

2/A

D15

(2)

RD

0/P

SP

0/A

D0(

3)

VD

D

VS

S

RD

1/P

SP

1/A

D1(

3)

RD

2/P

SP

2/A

D2(

3)

RD

3/P

SP

3/A

D3(

3)

RD

4/P

SP

4/A

D4(

3)

RD

5/P

SP

5/A

D5(

3)

RD

6/P

SP

6/A

D6(

3)

RD

7/P

SP

7/A

D7(

3)

RE1/WR/AD9(3)

RE0/RD/AD8(3)

RG0/CCP3RG1/TX2/CK2RG2/RX2/DT2

RG3/CCP4MCLR/VPPRG4/CCP5

VSSVDD

RF7/SSRF6/AN11

RF5/AN10/CVREFRF4/AN9RF3/AN8

RF2/AN7/C1OUT

RB0/INT0RB1/INT1RB2/INT2RB3/INT3/CCP2(1)

RB4/KBI0RB5/KBI1/PGMRB6/KBI2/PGCVSSOSC2/CLKO/RA6OSC1/CLKIVDDRB7/KBI3/PGD

RC4/SDI/SDARC3/SCK/SCLRC2/CCP1

RF

0/A

N5

RF

1/A

N6/

C2O

UT

AV

DD

AV

SS

RA

3/A

N3/

VR

EF+

RA

2/A

N2/

VR

EF-

RA

1/A

N1

RA

0/A

N0

VS

S

VD

D

RA

4/T

0CK

IR

A5/

AN

4/LV

DIN

RC

1/T

1OS

I/CC

P2(

1)

RC

7/R

X1/

DT

1

RC

6/T

X1/

CK

1

RC5/SDOR

J0/A

LE

RJ1

/OE

RH

1/A

17R

H0/

A16

12

RH2/A18RH3/A19

1718

RH7/AN15RH6/AN14

RH

5/A

N13

RH

4/A

N12

RJ5

/CE

RJ4

/BA

0

37

RJ7/UB

RJ6/LB

5049

RJ2/WRL

RJ3/WRH

1920

33 34 35 36 38

5857565554535251

6059

68 67 66 6572 71 70 6974 7378 77 76 757980

80-Pin TQFP

PIC18F8720R

C0/

T1O

SO

/T13

CK

I

PIC18F8520

Note 1: CCP2 is multiplexed with RC1 when CCP2MX is set.2: CCP2 is multiplexed by default with RE7 when the device is configured in Microcontroller mode.3: PSP is available only in Microcontroller mode.



PIC18F6520/8520/6620/8620/6720/8720


Table of Contents

1.0 Device Overview .......................................................................................................................................................................... 72.0 Oscillator Configurations ............................................................................................................................................................ 213.0 Reset .......................................................................................................................................................................................... 294.0 Memory Organization ................................................................................................................................................................. 395.0 Flash Program Memory.............................................................................................................................................................. 616.0 External Memory Interface ......................................................................................................................................................... 717.0 Data EEPROM Memory ............................................................................................................................................................. 798.0 8 X 8 Hardware Multiplier ........................................................................................................................................................... 859.0 Interrupts .................................................................................................................................................................................... 8710.0 I/O Ports ................................................................................................................................................................................... 10311.0 Timer0 Module ......................................................................................................................................................................... 13112.0 Timer1 Module ......................................................................................................................................................................... 13513.0 Timer2 Module ......................................................................................................................................................................... 14114.0 Timer3 Module ......................................................................................................................................................................... 14315.0 Timer4 Module ......................................................................................................................................................................... 14716.0 Capture/Compare/PWM (CCP) Modules ................................................................................................................................. 14917.0 Master Synchronous Serial Port (MSSP) Module .................................................................................................................... 15718.0 Addressable Universal Synchronous Asynchronous Receiver Transmitter (USART).............................................................. 19719.0 10-Bit Analog-to-Digital Converter (A/D) Module ..................................................................................................................... 21320.0 Comparator Module.................................................................................................................................................................. 22321.0 Comparator Voltage Reference Module................................................................................................................................... 22922.0 Low-Voltage Detect .................................................................................................................................................................. 23323.0 Special Features of the CPU.................................................................................................................................................... 23924.0 Instruction Set Summary .......................................................................................................................................................... 25925.0 Development Support............................................................................................................................................................... 30126.0 Electrical Characteristics .......................................................................................................................................................... 30727.0 DC and AC Characteristics Graphs and Tables....................................................................................................................... 34328.0 Packaging Information.............................................................................................................................................................. 357Appendix A: Revision History............................................................................................................................................................. 361Appendix B: Device Differences......................................................................................................................................................... 361Appendix C: Conversion Considerations ........................................................................................................................................... 362Appendix D: Migration from Mid-Range to Enhanced Devices .......................................................................................................... 362Appendix E: Migration from High-End to Enhanced Devices............................................................................................................. 363Index .................................................................................................................................................................................................. 365On-Line Support................................................................................................................................................................................. 375Systems Information and Upgrade Hot Line ...................................................................................................................................... 375Reader Response .............................................................................................................................................................................. 376PIC18F6520/8520/6620/8620/6720/8720 Product Identification System .......................................................................................... 377




PIC18F6520/8520/6620/8620/6720/8720

TO OUR VALUED CUSTOMERS

It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchipproducts. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined andenhanced as new volumes and updates are introduced.

If you have any questions or comments regarding this publication, please contact the Marketing Communications Department viaE-mail at [email protected] or fax the Reader Response Form in the back of this data sheet to (480) 792-4150.We welcome your feedback.

Most Current Data SheetTo obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:

http://www.microchip.com

You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).

ErrataAn errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for currentdevices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revisionof silicon and revision of document to which it applies.

To determine if an errata sheet exists for a particular device, please check with one of the following:

• Microchip’s Worldwide Web site; http://www.microchip.com• Your local Microchip sales office (see last page)• The Microchip Corporate Literature Center; U.S. FAX: (480) 792-7277

When contacting a sales office or the literature center, please specify which device, revision of silicon and data sheet (include liter-ature number) you are using.

Customer Notification SystemRegister on our Web site at www.microchip.com/cn to receive the most current information on all of our products.



PIC18F6520/8520/6620/8620/6720/8720


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PIC18F6520/8520/6620/8620/6720/8720

1.0 DEVICE OVERVIEW

This document contains device specific information forthe following devices:

This family offers the same advantages of all PIC18microcontrollers – namely, high computationalperformance at an economical price – with the addition ofhigh endurance Enhanced Flash program memory. ThePIC18FXX20 family also provides an enhanced range ofprogram memory options and versatile analog featuresthat make it ideal for complex, high-performanceapplications.

1.1 Key Features

1.1.1 EXPANDED MEMORY

The PIC18FXX20 family introduces the widest range ofon-chip, Enhanced Flash program memory availableon PICmicro® microcontrollers – up to 128 Kbyte (or65,536 words), the largest ever offered by Microchip.For users with more modest code requirements, thefamily also includes members with 32 Kbyte or64 Kbyte.

Other memory features are:

• Data RAM and Data EEPROM: The PIC18FXX20 family also provides plenty of room for application data. Depending on the device, either 2048 or 3840 bytes of data RAM are available. All devices have 1024 bytes of data EEPROM for long-term retention of nonvolatile data.

• 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.

1.1.2 EXTERNAL MEMORY INTERFACE

In the event that 128 Kbytes of program memory isinadequate for an application, the PIC18F8X20members of the family also implement an ExternalMemory Interface. This allows the controller’s internalprogram counter to address a memory space of up to2 Mbytes, permitting a level of data access that few8-bit devices can claim.

With the addition of new operating modes, the ExternalMemory Interface offers many new options, including:

• Operating the microcontroller entirely from externalmemory

• Using combinations of on-chip and externalmemory, up to the 2-Mbyte limit

• Using external Flash memory for reprogrammableapplication code, or large data tables

• Using external RAM devices for storing largeamounts of variable data

1.1.3 EASY MIGRATION

Regardless of the memory size, all devices share thesame rich set of peripherals, allowing for a smoothmigration path as applications grow and evolve.

The consistent pinout scheme used throughout theentire family also aids in migrating to the next largerdevice. This is true when moving between the 64-pinmembers, between the 80-pin members, or evenjumping from 64-pin to 80-pin devices.

1.1.4 OTHER SPECIAL FEATURES

• Communications: The PIC18FXX20 family incorporates a range of serial communications peripherals, including 2 independent USARTs and a Master SSP module, capable of both SPI and I2C (Master and Slave) modes of operation. For PIC18F8X20 devices, one of the general purpose I/O ports can be reconfigured as an 8-bit Parallel Slave Port for direct processor-to-processor communications.

• CCP Modules: All devices in the family incorporate five Capture/Compare/PWM modules to maximize flexibility in control applications. Up to four different time bases may be used to perform several different operations at once.

• Analog Features: All devices in the family feature 10-bit A/D converters, with up to 16 input channels, as well as the ability to perform conversions during Sleep mode. Also included are dual analog comparators with programmable input and output configuration, a programmable Low-Voltage Detect module and a programmable Brown-out Reset module.

• Self-programmability: These devices can write to their own program memory spaces under inter-nal 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.

• PIC18F6520 • PIC18F8520

• PIC18F6620 • PIC18F8620

• PIC18F6720 • PIC18F8720



PIC18F6520/8520/6620/8620/6720/8720


1.2 Details on Individual Family Members

The PIC18FXX20 devices are available in 64-pin and80-pin packages. They are differentiated from eachother in five ways:

1. Flash program memory (32 Kbytes forPIC18FX520 devices, 64 Kbytes forPIC18FX620 devices and 128 Kbytes forPIC18FX720 devices)

2. Data RAM (2048 bytes for PIC18FX520devices, 3840 bytes for PIC18FX620 andPIC18FX720 devices)

3. A/D channels (12 for PIC18F6X20 devices, 16 for PIC18F8X20)

4. I/O pins (52 on PIC18F6X20 devices, 68 onPIC18F8X20)

5. External program memory interface (presentonly on PIC18F8X20 devices)

All other features for devices in the PIC18FXX20 familyare identical. These are summarized in Table 1-1.

Block diagrams of the PIC18F6X20 and PIC18F8X20devices are provided in Figure 1-1 and Figure 1-2,respectively. The pinouts for these device families arelisted in Table 1-2.

TABLE 1-1: PIC18FXX20 DEVICE FEATURES

Features PIC18F6520 PIC18F6620 PIC18F6720 PIC18F8520 PIC18F8620 PIC18F8720

Operating Frequency DC – 40 MHz DC – 25 MHz DC – 25 MHz DC – 40 MHz DC – 25 MHz DC – 25 MHz

Program Memory (Bytes)

32K 64K 128K 32K 64K 128K

Program Memory (Instructions)

16384 32768 65536 16384 32768 65536

Data Memory (Bytes)

2048 3840 3840 2048 3840 3840

Data EEPROM Memory (Bytes)

1024 1024 1024 1024 1024 1024

External MemoryInterface

No No No Yes Yes Yes

Interrupt Sources 17 17 17 18 18 18

I/O Ports Ports A, B, C, D, E, F, G

Ports A, B, C, D, E, F, G

Ports A, B, C, D, E, F, G

Ports A, B, C, D, E, F, G, H, J



Timers 5 5 5 5 5 5

Capture/Compare/PWM Modules

5 5 5 5 5 5

Serial Communications MSSP, Addressable USART (2)

MSSP, Addressable USART (2)





Parallel Communications PSP PSP PSP PSP PSP PSP

10-bit Analog-to-Digital Module

12 input channels

12 input channels

12 input channels

16 input channels

16 input channels

16 input channels

Resets (and Delays) POR, BOR, RESET

Instruction, Stack Full,

Stack Underflow (PWRT, OST)

POR, BOR, RESET



POR, BOR, RESET



POR, BOR, RESET



POR, BOR, RESET



POR, BOR, RESET



Programmable Low-Voltage Detect

Yes Yes Yes Yes Yes Yes

Programmable Brown-out Reset

Yes Yes Yes Yes Yes Yes

Instruction Set 77 Instructions 77 Instructions 77 Instructions 77 Instructions 77 Instructions 77 Instructions

Package 64-pin TQFP 64-pin TQFP 64-pin TQFP 80-pin TQFP 80-pin TQFP 80-pin TQFP




PIC18F6520/8520/6620/8620/6720/8720

FIGURE 1-1: PIC18F6X20 BLOCK DIAGRAM

Power-upTimer

OscillatorStart-up Timer

Power-onReset

WatchdogTimer

InstructionDecode &

Control

OSC1/CLKIOSC2/CLKO

MCLR/VPP VDD, VSS

PORTA

PORTB

PORTC

RA4/T0CKIRA5/AN4/LVDIN

RB0/INT0

RC0/T1OSO/T13CKIRC1/T1OSI/CCP2RC2/CCP1RC3/SCK/SCLRC4/SDI/SDARC5/SDORC6/TX1/CK1RC7/RX1/DT1

Brown-outReset

USART1

Comparator

Synchronous

BOR

Serial Port

RA3/AN3/VREF+RA2/AN2/VREF-RA1/AN1RA0/AN0

TimingGeneration

RB1/INT1

Data Latch

Data RAM

Address Latch

Address

12

Bank0, FBSR FSR0FSR1FSR2

inc/declogicDecode

4 12 4

PCH PCL

PCLATH

8

31 Level Stack

Program Counter

PRODLPRODH

8 x 8 Multiply

WREG

8

BITOP88

ALU

8

Address Latch

Program Memory

Data Latch

21

21

16

8

8

8

Table Pointer

inc/dec logic

218

Data Bus

Table Latch

8

IR

12

3

ROM Latch

PORTD

RD7/PSP7:RD0/PSP0

RB2/INT2RB3/INT3

PCLATU

PCU

Precision

ReferenceBand Gap

PORTE

PORTF

PORTGRG0/CCP3RG1/TX2/CK2RG2/RX2/DT2RG3/CCP4RG4/CCP5

RF7/SS

RE6RE7/CCP2

RE5RE4RE3RE2/CS

RE0/RDRE1/WR

LVD

RA6

Timer0 Timer1 Timer2 Timer3 Timer4

CCP1 CCP2 CCP3 CCP4 CCP5

USART2

10-bit A/D

RF6/AN11RF5/AN10/CVREFRF4/AN9RF3/AN8RF2/AN7/C1OUT


RB4/KBI0RB5/KBI1/PGMRB6/KBI2/PGCRB7/KBI3/PGD

DataEEPROM



PIC18F6520/8520/6620/8620/6720/8720


FIGURE 1-2: PIC18F8X20 BLOCK DIAGRAM

Power-upTimer

OscillatorStart-up Timer

Power-onReset

WatchdogTimer

InstructionDecode &

Control

OSC1/CLKIOSC2/CLKO

MCLR/VPP VDD, VSS

PORTA

PORTB

PORTC

RA4/T0CKIRA5/AN4/LVDIN

RC0/T1OSO/T13CKIRC1/T1OSI/CCP2RC2/CCP1RC3/SCK/SCLRC4/SDI/SDARC5/SDORC6/TX1/CK1RC7/RX1/DT1

Brown-outReset

USART1

Comparator

Synchronous

BOR

Serial Port

RA3/AN3/VREF+RA2/AN2/VREF-RA1/AN1RA0/AN0

TimingGeneration

10-bit A/D

Data Latch

Data RAM

Address Latch

Address

12

Bank0, FBSR FSR0FSR1FSR2

inc/declogicDecode

4 12 4

PCH PCL

PCLATH

8

31 Level Stack

Program Counter

PRODLPRODH

8 x 8 Multiply

WREG

8

BITOP88

ALU

8

Address Latch

Program Memory

Data Latch

21

21

16

8

8

8

Table Pointer

inc/dec logic

218

Data Bus

Table Latch

8

IR

12

3

ROM Latch

PORTD

RD7/PSP7/AD7:

PCLATU

PCU

Precision

ReferenceBand Gap

PORTE

PORTF

PORTGRG0/CCP3RG1/TX2/CK2RG2/RX2/DT2RG3/CCP4RG4/CCP5

RF7/SS

RE6/AD14RE7/CCP2/AD15

RE5/AD13RE4/AD12RE3/AD11RE2/CS/AD10

RE0/RD/AD8RE1/WR/AD9

LVD

PORTH

PORTJRJ0/ALERJ1/OERJ2/WRLRJ3/WRH

RA6

Timer0 Timer1 Timer2 Timer3 Timer4

CCP1 CCP2 CCP3 CCP4 CCP5

USART2

Sys

tem

Bus

Inte

rfac

e

AD15:AD0, A19:A16(1)

Note 1: External memory interface pins are physically multiplexed with PORTD (AD7:AD0), PORTE (AD15:AD8) and PORTH (A19:A16).

RB0/INT0RB1/INT1RB2/INT2RB3/INT3/CCP2RB4/KBI0RB5/KBI1/PGMRB6/KBI2/PGCRB7/KBI3/PGD

RH7/AN15:RH4/AN12

RH3/AD19:RH0/AD16

RJ4/BA0RJ5/CERJ6/LBRJ7/UB

RF6/AN11RF5/AN10/CVREFRF4/AN9RF3/AN8RF2/AN7/C1OUT


DataEEPROM

RD0/PSP0/AD0




PIC18F6520/8520/6620/8620/6720/8720

TABLE 1-2: PIC18FXX20 PINOUT I/O DESCRIPTIONS

Pin NamePin Number Pin

TypeBufferType

DescriptionPIC18F6X20 PIC18F8X20

MCLR/VPP

MCLR

VPP

7 9

I

P

ST

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

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

OSC1/CLKIOSC1

CLKI

39 49I

I

CMOS/ST

CMOS

Oscillator crystal or external clock input.Oscillator crystal input or external clock source input. ST buffer when configured in RC mode; otherwise CMOS.External clock source input. Always associated with pin function OSC1 (see OSC1/CLKI, OSC2/CLKO pins).

OSC2/CLKO/RA6OSC2

CLKO

RA6

40 50O

O

I/O

—

—

TTL

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.

Legend: TTL = TTL compatible input CMOS = CMOS compatible input or output ST = Schmitt Trigger input with CMOS levels Analog = Analog input I = Input O = Output P = Power OD = Open-Drain (no P diode to VDD)

Note 1: Alternate assignment for CCP2 when CCP2MX is not selected (all operating modes except Microcontroller).

2: Default assignment when CCP2MX is set.3: External memory interface functions are only available on PIC18F8X20 devices.4: CCP2 is multiplexed with this pin by default when configured in Microcontroller mode. Otherwise, it is

multiplexed with either RB3 or RC1.

5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices.6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for

proper operation of the part in user or ICSP modes. See parameter D001A for details.



PIC18F6520/8520/6620/8620/6720/8720


PORTA is a bidirectional I/O port.

RA0/AN0RA0AN0

24 30I/OI

TTLAnalog

Digital I/O.Analog input 0.

RA1/AN1RA1AN1

23 29I/OI

TTLAnalog


RA2/AN2/VREF-RA2AN2VREF-

22 28I/OII

TTLAnalogAnalog

Digital I/O.Analog input 2.A/D reference voltage (Low) input.

RA3/AN3/VREF+RA3AN3VREF+

21 27I/OII

TTLAnalogAnalog

Digital I/O.Analog input 3.A/D reference voltage (High) input.

RA4/T0CKIRA4

T0CKI

28 34I/O

I

ST/OD

ST

Digital I/O – Open-drain when configured as output.Timer0 external clock input.

RA5/AN4/LVDINRA5AN4LVDIN

27 33I/OII

TTLAnalogAnalog

Digital I/O.Analog input 4.Low-Voltage Detect input.

RA6 See the OSC2/CLKO/RA6 pin.

TABLE 1-2: PIC18FXX20 PINOUT I/O DESCRIPTIONS (CONTINUED)


TypeBufferType











PIC18F6520/8520/6620/8620/6720/8720

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

RB0/INT0RB0INT0

48 58I/OI

TTLST

Digital I/O.External interrupt 0.

RB1/INT1RB1INT1

47 57I/OI

TTLST


RB2/INT2RB2INT2

46 56I/OI

TTLST


RB3/INT3/CCP2RB3INT3CCP2(1)

45 55I/OI/OI/O

TTLSTST

Digital I/O.External interrupt 3.Capture2 input, Compare2 output, PWM2 output.

RB4/KBI0RB4KBI0

44 54I/OI

TTLST

Digital I/O.Interrupt-on-change pin.

RB5/KBI1/PGMRB5KBI1PGM

43 53I/OI

I/O

TTLSTST

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

RB6/KBI2/PGCRB6KBI2PGC

42 52I/OI

I/O

TTLSTST

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

RB7/KBI3/PGDRB7KBI3PGD

37 47I/OI/O

TTLST

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



TypeBufferType





multiplexed with either RB3 or RC1.5: PORTH and PORTJ are only available on PIC18F8X20 (80-pin) devices.6: AVDD must be connected to a positive supply and AVSS must be connected to a ground reference for




PIC18F6520/8520/6620/8620/6720/8720


PORTC is a bidirectional I/O port.

RC0/T1OSO/T13CKIRC0T1OSOT13CKI

30 36I/OOI

ST—ST

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

RC1/T1OSI/CCP2RC1T1OSICCP2(2)

29 35I/OI

I/O

STCMOS

ST

Digital I/O.Timer1 oscillator input.Capture2 input/Compare2 output/PWM2 output.

RC2/CCP1RC2CCP1

33 43I/OI/O

STST

Digital I/O.Capture1 input/Compare1 output/PWM1 output.

RC3/SCK/SCLRC3SCK

SCL

34 44I/OI/O

I/O

STST

ST

Digital I/O.Synchronous serial clock input/output for SPI mode.Synchronous serial clock input/output for I2C mode.

RC4/SDI/SDARC4SDISDA

35 45I/OI

I/O

STSTST

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

RC5/SDORC5SDO

36 46I/OO

ST—

Digital I/O.SPI data out.

RC6/TX1/CK1RC6TX1CK1

31 37I/OO

I/O

ST—ST

Digital I/O.USART 1 asynchronous transmit.USART 1 synchronous clock (see RX1/DT1).

RC7/RX1/DT1RC7RX1DT1

32 38I/OI

I/O

STSTST

Digital I/O.USART 1 asynchronous receive.USART 1 synchronous data (see TX1/CK1).



TypeBufferType










PIC18F6520/8520/6620/8620/6720/8720

PORTD is a bidirectional I/O port. These pins have TTL input buffers when external memory is enabled.

RD0/PSP0/AD0RD0PSP0AD0(3)

58 72I/OI/OI/O

STTTLTTL

Digital I/O.Parallel Slave Port data.External memory address/data 0.


55 69I/OI/OI/O

STTTLTTL



54 68I/OI/OI/O

STTTLTTL



53 67I/OI/OI/O

STTTLTTL



52 66I/OI/OI/O

STTTLTTL



51 65I/OI/OI/O

STTTLTTL



50 64I/OI/OI/O

STTTLTTL



49 63I/OI/OI/O

STTTLTTL




TypeBufferType









PIC18F6520/8520/6620/8620/6720/8720


PORTE is a bidirectional I/O port.

RE0/RD/AD8RE0RD

AD8(3)

2 4I/OI

I/O

STTTL

TTL

Digital I/O.Read control for Parallel Slave Port (see WR and CS pins).External memory address/data 8.

RE1/WR/AD9RE1WR

AD9(3)

1 3I/OI

I/O

STTTL

TTL

Digital I/O.Write control for Parallel Slave Port (see CS and RD pins).External memory address/data 9.

RE2/CS/AD10RE2CS

AD10(3)

64 78I/OI

I/O

STTTL

TTL

Digital I/O.Chip select control for Parallel Slave Port (see RD and WR).External memory address/data 10.

RE3/AD11RE3AD11(3)

63 77I/OI/O

STTTL

Digital I/O.External memory address/data 11.

RE4/AD12RE4AD12

62 76I/OI/O

STTTL


RE5/AD13RE5AD13(3)

61 75I/OI/O

STTTL


RE6/AD14RE6AD14(3)

60 74I/OI/O

STTTL


RE7/CCP2/AD15RE7CCP2(1,4)

AD15(3)

59 73I/OI/O

I/O

STST

TTL

Digital I/O.Capture2 input/Compare2 output/PWM2 output.External memory address/data 15.



TypeBufferType











PIC18F6520/8520/6620/8620/6720/8720

PORTF is a bidirectional I/O port.

RF0/AN5RF0AN5

18 24I/OI

STAnalog


RF1/AN6/C2OUTRF1AN6C2OUT

17 23I/OIO

STAnalog

ST

Digital I/O.Analog input 6.Comparator 2 output.

RF2/AN7/C1OUTRF2AN7C1OUT

16 18I/OIO

STAnalog

ST

Digital I/O.Analog input 7.Comparator 1 output.

RF3/AN8RF1AN8

15 17I/OI

STAnalog


RF4/AN9RF1AN9

14 16I/OI

STAnalog


RF5/AN10/CVREFRF1AN10CVREF

13 15I/OIO

STAnalogAnalog

Digital I/O.Analog input 10.Comparator VREF output.

RF6/AN11RF6AN11

12 14I/OI

STAnalog


RF7/SSRF7SS

11 13I/OI

STTTL

Digital I/O.SPI slave select input.



TypeBufferType









PIC18F6520/8520/6620/8620/6720/8720


PORTG is a bidirectional I/O port.

RG0/CCP3RG0CCP3

3 5I/OI/O

STST


RG1/TX2/CK2RG1TX2CK2

4 6I/OO

I/O

ST—ST

Digital I/O.USART 2 asynchronous transmit.USART 2 synchronous clock (see RX2/DT2).

RG2/RX2/DT2RG2RX2DT2

5 7I/OI

I/O

STSTST

Digital I/O.USART 2 asynchronous receive.USART 2 synchronous data (see TX2/CK2).

RG3/CCP4RG3CCP4

6 8I/OI/O

STST


RG4/CCP5RG4CCP5

8 10I/OI/O

STST




TypeBufferType










PIC18F6520/8520/6620/8620/6720/8720

PORTH is a bidirectional I/O port(5).

RH0/A16RH0A16

— 79I/OO

STTTL

Digital I/O.External memory address 16.

RH1/A17RH1A17

— 80I/OO

STTTL


RH2/A18RH2A18

— 1I/OO

STTTL


RH3/A19RH3A19

— 2I/OO

STTTL


RH4/AN12RH4AN12

— 22I/OI

STAnalog


RH5/AN13RH5AN13

— 21I/OI

STAnalog


RH6/AN14RH6AN14

— 20I/OI

STAnalog


RH7/AN15RH7AN15

— 19I/OI

STAnalog




TypeBufferType









PIC18F6520/8520/6620/8620/6720/8720


PORTJ is a bidirectional I/O port(5).

RJ0/ALERJ0ALE

— 62I/OO

STTTL

Digital I/O.External memory address latch enable.

RJ1/OERJ1OE

— 61I/OO

STTTL

Digital I/O.External memory output enable.

RJ2/WRLRJ2WRL

— 60I/OO

STTTL

Digital I/O.External memory write low control.

RJ3/WRHRJ3WRH

— 59I/OO

STTTL

Digital I/O.External memory write high control.

RJ4/BA0RJ4BA0

— 39I/OO

STTTL

Digital I/O.External memory Byte Address 0 control.

RJ5/CERJ5CE

— 40I/OO

STTTL

Digital I/O.External memory chip enable control.

RJ6/LBRJ6LB

— 41I/OO

STTTL

Digital I/O.External memory low byte select.

RJ7/UBRJ7UB

— 42I/OO

STTTL

Digital I/O.External memory high byte select.

VSS 9, 25, 41, 56

11, 31, 51, 70

P — Ground reference for logic and I/O pins.

VDD 10, 26, 38, 57

12, 32, 48, 71

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

AVSS(6) 20 26 P — Ground reference for analog modules.

AVDD(6) 19 25 P — Positive supply for analog modules.



TypeBufferType











PIC18F6520/8520/6620/8620/6720/8720

2.0 OSCILLATOR CONFIGURATIONS

2.1 Oscillator Types

The PIC18FXX20 devices can be operated in eightdifferent oscillator modes. The user can program threeconfiguration bits (FOSC2, FOSC1 and FOSC0) toselect one of these eight modes:

1. LP Low-Power Crystal2. XT Crystal/Resonator3. HS High-Speed Crystal/Resonator

4. HS+PLL High-Speed Crystal/Resonator with PLL enabled

5. RC External Resistor/Capacitor6. RCIO External Resistor/Capacitor with

I/O pin enabled7. EC External Clock8. ECIO External Clock with I/O pin

enabled

2.2 Crystal Oscillator/Ceramic Resonators

In XT, LP, HS or HS+PLL Oscillator modes, a crystal orceramic resonator is connected to the OSC1 andOSC2 pins to establish oscillation. Figure 2-1 showsthe pin connections.

The PIC18FXX20 oscillator design requires the use ofa parallel cut crystal.

FIGURE 2-1: CRYSTAL/CERAMIC RESONATOR OPERATION (HS, XT OR LP CONFIGURATION)

TABLE 2-1: CAPACITOR SELECTION FOR CERAMIC RESONATORS

Note: Use of a series cut crystal may give a fre-quency out of the crystal manufacturer’sspecifications.

Note 1: See Table 2-1 and Table 2-2 for recommendedvalues of C1 and C2.

2: A series resistor (RS) may be required for ATstrip cut crystals.

3: RF varies with the oscillator mode chosen.

C1(1)

C2(1)

XTAL

OSC2

OSC1

RF(3)

Sleep

To

Logic

PIC18FXX20RS(2)

Internal

Ranges Tested:

Mode Freq C1 C2

XT 455 kHz2.0 MHz4.0 MHz

68-100 pF15-68 pF15-68 pF

68-100 pF15-68 pF15-68 pF

HS 8.0 MHz16.0 MHz

10-68 pF10-22 pF

10-68 pF10-22 pF

These values are for design guidance only. See notes following this table.

Resonators Used:

2.0 MHz Murata Erie CSA2.00MG ± 0.5%4.0 MHz Murata Erie CSA4.00MG ± 0.5%8.0 MHz Murata Erie CSA8.00MT ± 0.5%

16.0 MHz Murata Erie CSA16.00MX ± 0.5%All resonators used did not have built-in capacitors.

Note 1: Higher capacitance increases the stabilityof the oscillator, but also increases thestart-up time.

2: When operating below 3V VDD, or whenusing certain ceramic resonators at anyvoltage, it may be necessary to use highgain HS mode, try a lower frequencyresonator, or switch to a crystal oscillator.

3: Since each resonator/crystal has its owncharacteristics, the user should consultthe resonator/crystal manufacturer forappropriate values of externalcomponents, or verify oscillatorperformance.



PIC18F6520/8520/6620/8620/6720/8720


TABLE 2-2: CAPACITOR SELECTION FOR CRYSTAL OSCILLATOR

An external clock source may also be connected to theOSC1 pin in the HS, XT and LP modes, as shown inFigure 2-2.

FIGURE 2-2: EXTERNAL CLOCK INPUT OPERATION (HS, XT OR LP OSC CONFIGURATION)

2.3 RC Oscillator

For timing insensitive applications, the “RC” and“RCIO” device options offer additional cost savings.The RC oscillator frequency is a function of the supplyvoltage, the resistor (REXT) and capacitor (CEXT) val-ues and the operating temperature. In addition to this,the oscillator frequency will vary from unit to unit, dueto normal process parameter variation. Furthermore,the difference in lead frame capacitance between pack-age types will also affect the oscillation frequency,especially for low CEXT values. The user also needs totake into account variation due to tolerance of externalR and C components used. Figure 2-3 shows how theR/C combination is connected.

In the RC Oscillator mode, the oscillator frequencydivided by 4 is available on the OSC2 pin. This signalmay be used for test purposes or to synchronize otherlogic.

FIGURE 2-3: RC OSCILLATOR MODE

The RCIO Oscillator mode functions like the RC mode,except that the OSC2 pin becomes an additionalgeneral purpose I/O pin. The I/O pin becomes bit 6 ofPORTA (RA6).

Ranges Tested:

Mode Freq C1 C2

LP 32 kHz15-22 pF 15-22 pF

200 kHz

XT 1 MHz15-22 pF 15-22 pF

4 MHz

HS 4 MHz

15-22 pF 15-22 pF8 MHz

20 MHz

Capacitor values are for design guidance only.

These capacitors were tested with the above crystalfrequencies for basic start-up and operation. Thesevalues are not optimized.

Different capacitor values may be required to produceacceptable oscillator operation. The user should testthe performance of the oscillator over the expectedVDD and temperature range for the application.

See the notes following this table for additionalinformation.

Note 1: Higher capacitance increases the stabilityof the oscillator, but also increases thestart-up time.

2: When operating below 3V VDD, or whenusing certain ceramic resonators at anyvoltage, it may be necessary to use theHS mode or switch to a crystal oscillator.

3: Since each resonator/crystal has itsown characteristics, the user shouldconsult the resonator/crystal manufac-turer for appropriate values of externalcomponents, or verify oscillatorperformance.

4: RS may be required to avoid overdrivingcrystals with low drive level specification.

5: Always verify oscillator performance overthe VDD and temperature range that isexpected for the application.

OSC1

OSC2Open

Clock fromExt. System PIC18FXX20

OSC2/CLKO

CEXT

REXT

PIC18FXX20

OSC1

FOSC/4

InternalClock

VDD

VSS

Recommended values: 3 kΩ ≤ REXT ≤ 100 kΩ

CEXT > 20 pF




PIC18F6520/8520/6620/8620/6720/8720

2.4 External Clock Input

The EC and ECIO Oscillator modes require an externalclock source to be connected to the OSC1 pin. Thefeedback device between OSC1 and OSC2 is turnedoff in these modes to save current. There is a maximum1.5 µs start-up required after a Power-on Reset, orwake-up from Sleep mode.

In the EC Oscillator mode, the oscillator frequencydivided by 4 is available on the OSC2 pin. This signalmay be used for test purposes or to synchronize otherlogic. Figure 2-4 shows the pin connections for the ECOscillator mode.

FIGURE 2-4: EXTERNAL CLOCK INPUT OPERATION (EC CONFIGURATION)

The ECIO Oscillator mode functions like the EC mode,except that the OSC2 pin becomes an additional gen-eral purpose I/O pin. The I/O pin becomes bit 6 ofPORTA (RA6). Figure 2-5 shows the pin connectionsfor the ECIO Oscillator mode.

FIGURE 2-5: EXTERNAL CLOCK INPUT OPERATION (ECIO CONFIGURATION)

2.5 HS/PLL

A Phase Locked Loop circuit (PLL) is provided as aprogrammable option for users that want to multiply thefrequency of the incoming crystal oscillator signal by 4.For an input clock frequency of 10 MHz, the internalclock frequency will be multiplied to 40 MHz. This isuseful for customers who are concerned with EMI dueto high-frequency crystals.

The PLL is one of the modes of the FOSC config-uration bits. The oscillator mode is specified duringdevice programming.

The PLL can only be enabled when the oscillator con-figuration bits are programmed for HS mode. If they areprogrammed for any other mode, the PLL is notenabled and the system clock will come directly fromOSC1. Also, PLL operation cannot be changed “on-the-fly”. To enable or disable it, the controller musteither cycle through a Power-on Reset, or switch theclock source from the main oscillator to the Timer1oscillator and back again. See Section 2.6 “OscillatorSwitching Feature” for details on oscillator switching.

A PLL lock timer is used to ensure that the PLL haslocked before device execution starts. The PLL locktimer has a time-out that is called TPLL.

FIGURE 2-6: PLL BLOCK DIAGRAM

OSC1

OSC2FOSC/4


OSC1

I/O (OSC2)RA6


MU

X

VCOLoopFilter

Divide by 4

CrystalOsc

OSC2

OSC1

PLL Enable

FINFOUT

SYSCLK

PhaseComparator

(from Configuration HS Oscbit Register)



PIC18F6520/8520/6620/8620/6720/8720


2.6 Oscillator Switching Feature

The PIC18FXX20 devices include a feature that allowsthe system clock source to be switched from the mainoscillator to an alternate low-frequency clock source.For the PIC18FXX20 devices, this alternate clocksource is the Timer1 oscillator. If a low-frequencycrystal (32 kHz, for example) has been attached to theTimer1 oscillator pins and the Timer1 oscillator hasbeen enabled, the device can switch to a low-power

execution mode. Figure 2-7 shows a block diagram ofthe system clock sources. The clock switching featureis enabled by programming the Oscillator SwitchingEnable (OSCSEN) bit in Configuration Register 1H to a‘0’. Clock switching is disabled in an erased device.See Section 12.0 “Timer1 Module” for further detailsof the Timer1 oscillator. See Section 23.0 “SpecialFeatures of the CPU” for Configuration registerdetails.

FIGURE 2-7: DEVICE CLOCK SOURCES

PIC18FXX20

TOSC

4 x PLL

TT1P

TSCLK

ClockSource

MU

X

TOSC/4

Timer1 Oscillator

T1OSCENEnableOscillator

T1OSO

T1OSI

Clock Source Option for other Modules

OSC1

OSC2

Sleep

Main Oscillator




PIC18F6520/8520/6620/8620/6720/8720

2.6.1 SYSTEM CLOCK SWITCH BIT

The system clock source switching is performed undersoftware control. The system clock switch bit, SCS(OSCCON), controls the clock switching. When theSCS bit is ‘0’, the system clock source comes from themain oscillator that is selected by the FOSC configura-tion bits in Configuration Register 1H. When the SCSbit is set, the system clock source will come from theTimer1 oscillator. The SCS bit is cleared on all forms ofReset.

REGISTER 2-1: OSCCON REGISTER

Note: The Timer1 oscillator must be enabledand operating to switch the system clocksource. The Timer1 oscillator is enabledby setting the T1OSCEN bit in the Timer1Control register (T1CON). If the Timer1oscillator is not enabled, then any write tothe SCS bit will be ignored (SCS bit forcedcleared) and the main oscillator willcontinue to be the system clock source.

U-0 U-0 U-0 U-0 U-0 U-0 U-0 R/W-1

— — — — — — — SCSbit 7 bit 0

bit 7-1 Unimplemented: Read as ‘0’

bit 0 SCS: System Clock Switch bitWhen OSCSEN Configuration bit = 0 and T1OSCEN bit is set:1 = Switch to Timer1 oscillator/clock pin 0 = Use primary oscillator/clock input pin

When OSCSEN and T1OSCEN are in other states:Bit is forced clear.

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



PIC18F6520/8520/6620/8620/6720/8720


2.6.2 OSCILLATOR TRANSITIONS

PIC18FXX20 devices contain circuitry to prevent“glitches” when switching between oscillator sources.Essentially, the circuitry waits for eight rising edges ofthe clock source that the processor is switching to. Thisensures that the new clock source is stable and that itspulse width will not be less than the shortest pulsewidth of the two clock sources.

A timing diagram indicating the transition from the mainoscillator to the Timer1 oscillator is shown in Figure 2-8.The Timer1 oscillator is assumed to be running all thetime. After the SCS bit is set, the processor is frozen atthe next occurring Q1 cycle. After eight synchronizationcycles are counted from the Timer1 oscillator, operationresumes. No additional delays are required after thesynchronization cycles.

FIGURE 2-8: TIMING DIAGRAM FOR TRANSITION FROM OSC1 TO TIMER1 OSCILLATOR

The sequence of events that takes place when switch-ing from the Timer1 oscillator to the main oscillator willdepend on the mode of the main oscillator. In additionto eight clock cycles of the main oscillator, additionaldelays may take place.

If the main oscillator is configured for an externalcrystal (HS, XT, LP), then the transition will take placeafter an oscillator start-up time (TOST) has occurred. Atiming diagram, indicating the transition from theTimer1 oscillator to the main oscillator for HS, XT andLP modes, is shown in Figure 2-9.

FIGURE 2-9: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS, XT, LP)

Q3Q2Q1Q4Q3Q2

OSC1

Internal

SCS(OSCCON)Program PC + 2PC

Note 1: Delay on internal system clock is eight oscillator cycles for synchronization.

Q1

T1OSI

Q4 Q1

PC + 4

Q1

TSCS

Clock

Counter

System

Q2 Q3 Q4 Q1

TDLY

TT1P

TOSC

21 3 4 5 6 7 8

Q3Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2

OSC1

Internal

SCS(OSCCON)

ProgramPC PC + 2

Note 1: TOST = 1024 TOSC (drawing not to scale).

T1OSI

System Clock

OSC2

TOST

Q1

PC + 6

TT1P

TOSC

TSCS

1 2 3 4 5 6 7 8

Counter




PIC18F6520/8520/6620/8620/6720/8720

If the main oscillator is configured for HS-PLL mode, anoscillator start-up time (TOST), plus an additional PLLtime-out (TPLL), will occur. The PLL time-out is typically2 ms and allows the PLL to lock to the main oscillator

frequency. A timing diagram, indicating the transitionfrom the Timer1 oscillator to the main oscillator forHS-PLL mode, is shown in Figure 2-10.

FIGURE 2-10: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (HS WITH PLL)

If the main oscillator is configured in the RC, RCIO, ECor ECIO modes, there is no oscillator start-up time-out.Operation will resume after eight cycles of the mainoscillator have been counted. A timing diagram,

indicating the transition from the Timer1 oscillator to themain oscillator for RC, RCIO, EC and ECIO modes, isshown in Figure 2-11.

FIGURE 2-11: TIMING FOR TRANSITION BETWEEN TIMER1 AND OSC1 (RC, EC)

Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2

OSC1

Internal System

SCS(OSCCON)

Program Counter PC PC + 2

Note 1:TOST = 1024 TOSC (drawing not to scale).

T1OSI

Clock

TOST

Q3

PC + 4

TPLL

TOSC

TT1P

TSCS

Q4

OSC2

PLL ClockInput 1 2 3 4 5 6 7 8

Q3 Q4 Q1 Q1 Q2 Q3 Q4 Q1 Q2 Q3

OSC1

Internal System

SCS(OSCCON)

ProgramPC PC + 2

Note 1:RC Oscillator mode assumed.

PC + 4

T1OSI

Clock

OSC2

Q4TT1P

TOSC

TSCS

1 2 3 4 5 6 7 8

Counter



PIC18F6520/8520/6620/8620/6720/8720


2.7 Effects of Sleep Mode on the On-Chip Oscillator

When the device executes a SLEEP instruction, the on-chip clocks and oscillator are turned off and the deviceis held at the beginning of an instruction cycle (Q1state). With the oscillator off, the OSC1 and OSC2signals will stop oscillating. Since all the transistorswitching currents have been removed, Sleep modeachieves the lowest current consumption of the device(only leakage currents). Enabling any on-chip featurethat will operate during Sleep will increase the currentconsumed during Sleep. The user can wake fromSleep through external Reset, Watchdog Timer Resetor through an interrupt.

2.8 Power-up Delays

Power up delays are controlled by two timers so that noexternal Reset circuitry is required for mostapplications. The delays ensure that the device is keptin Reset until the device power supply and clock arestable. For additional information on Reset operation,see Section 3.0 “Reset”.

The first timer is the Power-up Timer (PWRT), whichoptionally provides a fixed delay of 72 ms (nominal) onpower-up only (POR and BOR). The second timer isthe Oscillator Start-up Timer (OST), intended to keepthe chip in Reset until the crystal oscillator is stable.

With the PLL enabled (HS/PLL Oscillator mode), thetime-out sequence following a Power-on Reset is differ-ent from other oscillator modes. The time-out sequenceis as follows: First, the PWRT time-out is invoked aftera POR time delay has expired. Then, the OscillatorStart-up Timer (OST) is invoked. However, this is stillnot a sufficient amount of time to allow the PLL to lockat high frequencies. The PWRT timer is used to providean additional fixed 2 ms (nominal) time-out to allow thePLL ample time to lock to the incoming clock frequency.

TABLE 2-3: OSC1 AND OSC2 PIN STATES IN SLEEP MODE

OSC Mode OSC1 Pin OSC2 Pin

RC Floating, external resistor should pull high At logic low

RCIO Floating, external resistor should pull high Configured as PORTA, bit 6

ECIO Floating Configured as PORTA, bit 6

EC Floating At logic low

LP, XT and HS Feedback inverter disabled at quiescent voltage level

Feedback inverter disabled at quiescent voltage level

Note: See Table 3-1 in Section 3.0 “Reset” for time-outs due to Sleep and MCLR Reset.




PIC18F6520/8520/6620/8620/6720/8720

3.0 RESET

The PIC18FXX20 devices differentiate betweenvarious kinds of Reset:

a) Power-on Reset (POR)

b) MCLR Reset during normal operationc) MCLR Reset during Sleep d) Watchdog Timer (WDT) Reset (during normal

operation)e) Programmable Brown-out Reset (PBOR)

f) RESET Instructiong) Stack Full Reseth) Stack Underflow Reset

Most registers are unaffected by a Reset. Their statusis unknown on POR and unchanged by all otherResets. The other registers are forced to a “Resetstate” on Power-on Reset, MCLR, WDT Reset, Brown-out Reset, MCLR Reset during Sleep and by theRESET instruction.

Most registers are not affected by a WDT wake-up,since this is viewed as the resumption of normaloperation. Status bits from the RCON register, RI, TO,PD, POR and BOR, are set or cleared differently indifferent Reset situations, as indicated in Table 3-2.These bits are used in software to determine the natureof the Reset. See Table 3-3 for a full description of theReset states of all registers.

A simplified block diagram of the On-Chip Reset Circuitis shown in Figure 3-1.

The Enhanced MCU devices have a MCLR noise filterin the MCLR Reset path. The filter will detect andignore small pulses. The MCLR pin is not driven low byany internal Resets, including the WDT.

FIGURE 3-1: SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT

S

R Q

External Reset

MCLR

VDD

OSC1

WDTModule

VDD RiseDetect

OST/PWRT

On-chipRC OSC(1)

WDTTime-out

Power-on Reset

OST

10-bit Ripple Counter

PWRT

Chip_Reset

10-bit Ripple Counter

Reset

Enable OST(2)

Enable PWRT

Sleep

Note 1: This is a separate oscillator from the RC oscillator of the CLKI pin.

2: See Table 3-1 for time-out situations.

Brown-outReset

BOREN

RESET Instruction

StackPointer

Stack Full/Underflow Reset



PIC18F6520/8520/6620/8620/6720/8720


3.1 Power-on Reset (POR)

A Power-on Reset pulse is generated on-chip whenVDD rise is detected. To take advantage of the PORcircuitry, tie the MCLR pin through a 1 kΩ to 10 kΩresistor to VDD. This will eliminate external RCcomponents usually needed to create a Power-onReset delay. A minimum rise rate for VDD is specified(parameter D004). For a slow rise time, see Figure 3-2.

When the device starts normal operation (i.e., exits theReset condition), device operating parameters (volt-age, frequency, temperature, etc.) must be met toensure operation. If these conditions are not met, thedevice must be held in Reset until the operatingconditions are met.

FIGURE 3-2: EXTERNAL POWER-ON RESET CIRCUIT (FOR SLOW VDD POWER-UP)

3.2 Power-up Timer (PWRT)

The Power-up Timer provides a fixed nominal time-out(parameter #33) only on power-up from the POR. ThePower-up Timer operates on an internal RC oscillator.The chip is kept in Reset as long as the PWRT is active.The PWRT’s time delay allows VDD to rise to an accept-able level. A configuration bit is provided to enable/disable the PWRT.

The power-up time delay will vary from chip-to-chip dueto VDD, temperature and process variation. See DCparameter #33 for details.

3.3 Oscillator Start-up Timer (OST)

The Oscillator Start-up Timer (OST) provides 1024oscillator cycles (from OSC1 input) delay after thePWRT delay is over (parameter #32). This ensures thatthe crystal oscillator or resonator has started andstabilized.

The OST time-out is invoked only for XT, LP and HSmodes and only on Power-on Reset, or wake-up fromSleep.

3.4 PLL Lock Time-out

With the PLL enabled, the time-out sequence followinga Power-on Reset is different from other oscillatormodes. A portion of the Power-up Timer is used toprovide a fixed time-out that is sufficient for the PLL tolock to the main oscillator frequency. This PLL locktime-out (TPLL) is typically 2 ms and follows theoscillator start-up time-out.

3.5 Brown-out Reset (BOR)

A configuration bit, BOREN, can disable (if clear/programmed), or enable (if set) the Brown-out Resetcircuitry. If VDD falls below parameter D005 for greaterthan parameter #35, the brown-out situation will resetthe chip. A Reset may not occur if VDD falls belowparameter D005 for less than parameter #35. The chipwill remain in Brown-out Reset until VDD rises aboveBVDD. If the Power-up Timer is enabled, it will beinvoked after VDD rises above BVDD; it then will keepthe chip in Reset for an additional time delay (parame-ter #33). If VDD drops below BVDD while the Power-upTimer is running, the chip will go back into a Brown-outReset and the Power-up Timer will be initialized. OnceVDD rises above BVDD, the Power-up Timer willexecute the additional time delay.

3.6 Time-out Sequence

On power-up, the time-out sequence is as follows:First, PWRT time-out is invoked after the POR timedelay has expired. Then, OST is activated. The totaltime-out will vary based on oscillator configuration andthe status of the PWRT. For example, in RC mode withthe PWRT disabled, there will be no time-out at all.Figures 3-3 through 3-7 depict time-out sequences onpower-up.

Since the time-outs occur from the POR pulse, thetime-outs will expire if MCLR is kept low long enough.Bringing MCLR high will begin execution immediately(Figure 3-5). This is useful for testing purposes, or tosynchronize more than one PIC18FXX20 deviceoperating in parallel.

Table 3-2 shows the Reset conditions for some SpecialFunction Registers, while Table 3-3 shows the Resetconditions for all of the registers.

Note 1: External Power-on Reset circuit is requiredonly if the VDD power-up slope is too slow.The diode D helps discharge the capacitorquickly when VDD powers down.

2: R < 40 kΩ is recommended to make sure thatthe voltage drop across R does not violatethe device’s electrical specification.

3: R1 = 1 kΩ to 10 kΩ will limit any current flow-ing into MCLR from external capacitor C, inthe event of MCLR/VPP pin breakdown due toElectrostatic Discharge (ESD) or ElectricalOverstress (EOS).

C

R1RD

VDD

MCLR

PIC18FXX20




PIC18F6520/8520/6620/8620/6720/8720

TABLE 3-1: TIME-OUT IN VARIOUS SITUATIONS

REGISTER 3-1: RCON REGISTER BITS AND POSITIONS

TABLE 3-2: STATUS BITS, THEIR SIGNIFICANCE AND THE INITIALIZATION CONDITION FOR RCON REGISTER

OscillatorConfiguration

Power-up(2)

Brown-out Wake-up from

Sleep orOscillator SwitchPWRTE = 0 PWRTE = 1

HS with PLL enabled(1) 72 ms + 1024 TOSC + 2ms

1024 TOSC + 2 ms

72 ms(2) + 1024 TOSC + 2 ms

1024 TOSC + 2 ms

HS, XT, LP 72 ms + 1024 TOSC 1024 TOSC 72 ms(2) + 1024 TOSC 1024 TOSC

EC 72 ms 1.5 µs 72 ms(2) 1.5 µs(3)

External RC 72 ms — 72 ms(2) —

Note 1: 2 ms is the nominal time required for the 4xPLL to lock.2: 72 ms is the nominal power-up timer delay, if implemented.3: 1.5 µs is the recovery time from Sleep. There is no recovery time from oscillator switch.

R/W-0 U-0 U-0 R/W-1 R/W-1 R/W-1 R/W-1 R/W-1

IPEN — — RI TO PD POR BOR

bit 7 bit 0

Note 1: Refer to Section 4.14 “RCON Register” for bit definitions.

ConditionProgram Counter

RCONRegister

RI TO PD POR BOR STKFUL STKUNF

Power-on Reset 0000h 0--1 1100 1 1 1 0 0 u u

MCLR Reset during normal operation

0000h 0--u uuuu u u u u u u u

Software Reset during normal operation

0000h 0--0 uuuu 0 u u u u u u

Stack Full Reset during normal operation

0000h 0--u uu11 u u u u u u 1

Stack Underflow Reset during normal operation

0000h 0--u uu11 u u u u u 1 u

MCLR Reset during Sleep 0000h 0--u 10uu u 1 0 u u u u

WDT Reset 0000h 0--u 01uu 1 0 1 u u u u

WDT Wake-up PC + 2 u--u 00uu u 0 0 u u u u

Brown-out Reset 0000h 0--1 11u0 1 1 1 1 0 u u

Interrupt wake-up from Sleep PC + 2(1) u--u 00uu u 1 0 u u u u

Legend: u = unchanged, x = unknown, – = unimplemented bit, read as ‘0’Note 1: When the wake-up is due to an interrupt and the GIEH or GIEL bits are set, the PC is loaded with the

interrupt vector (0x000008h or 0x000018h).



PIC18F6520/8520/6620/8620/6720/8720


TABLE 3-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS

Register Applicable DevicesPower-on Reset,Brown-out Reset

MCLR ResetsWDT Reset

RESET InstructionStack Resets

Wake-up via WDT or Interrupt

TOSU PIC18F6X20 PIC18F8X20 ---0 0000 ---0 0000 ---0 uuuu(3)

TOSH PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu(3)

TOSL PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu(3)

STKPTR PIC18F6X20 PIC18F8X20 00-0 0000 uu-0 0000 uu-u uuuu(3)

PCLATU PIC18F6X20 PIC18F8X20 ---0 0000 ---0 0000 ---u uuuuPCLATH PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuuPCL PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 PC + 2(2)

TBLPTRU PIC18F6X20 PIC18F8X20 --00 0000 --00 0000 --uu uuuuTBLPTRH PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuuTBLPTRL PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu

TABLAT PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuuPRODH PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuPRODL PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuu

INTCON PIC18F6X20 PIC18F8X20 0000 000x 0000 000u uuuu uuuu(1)

INTCON2 PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuu(1)

INTCON3 PIC18F6X20 PIC18F8X20 1100 0000 1100 0000 uuuu uuuu(1)

INDF0 PIC18F6X20 PIC18F8X20 N/A N/A N/APOSTINC0 PIC18F6X20 PIC18F8X20 N/A N/A N/APOSTDEC0 PIC18F6X20 PIC18F8X20 N/A N/A N/A

PREINC0 PIC18F6X20 PIC18F8X20 N/A N/A N/APLUSW0 PIC18F6X20 PIC18F8X20 N/A N/A N/AFSR0H PIC18F6X20 PIC18F8X20 ---- xxxx ---- uuuu ---- uuuu

FSR0L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuWREG PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuINDF1 PIC18F6X20 PIC18F8X20 N/A N/A N/A

POSTINC1 PIC18F6X20 PIC18F8X20 N/A N/A N/APOSTDEC1 PIC18F6X20 PIC18F8X20 N/A N/A N/APREINC1 PIC18F6X20 PIC18F8X20 N/A N/A N/A

PLUSW1 PIC18F6X20 PIC18F8X20 N/A N/A N/ALegend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.

Shaded cells indicate conditions do not apply for the designated device.Note 1: One or more bits in the INTCONx or PIRx registers will be affected (to cause wake-up).

2: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the PC is loaded with the interrupt vector (0008h or 0018h).

3: When the wake-up is due to an interrupt and the GIEL or GIEH bit is set, the TOSU, TOSH and TOSL are updated with the current value of the PC. The STKPTR is modified to point to the next location in the hardware stack.

4: See Table 3-2 for Reset value for specific condition.5: Bit 6 of PORTA, LATA and TRISA are enabled in ECIO and RCIO Oscillator modes only. In all other

oscillator modes, they are disabled and read ‘0’. 6: Bit 6 of PORTA, LATA and TRISA are not available on all devices. When unimplemented, they are read ‘0’.




PIC18F6520/8520/6620/8620/6720/8720

FSR1H PIC18F6X20 PIC18F8X20 ---- xxxx ---- uuuu ---- uuuuFSR1L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuBSR PIC18F6X20 PIC18F8X20 ---- 0000 ---- 0000 ---- uuuu

INDF2 PIC18F6X20 PIC18F8X20 N/A N/A N/APOSTINC2 PIC18F6X20 PIC18F8X20 N/A N/A N/APOSTDEC2 PIC18F6X20 PIC18F8X20 N/A N/A N/A

PREINC2 PIC18F6X20 PIC18F8X20 N/A N/A N/APLUSW2 PIC18F6X20 PIC18F8X20 N/A N/A N/AFSR2H PIC18F6X20 PIC18F8X20 ---- xxxx ---- uuuu ---- uuuu

FSR2L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuSTATUS PIC18F6X20 PIC18F8X20 ---x xxxx ---u uuuu ---u uuuuTMR0H PIC18F6X20 PIC18F8X20 0000 0000 uuuu uuuu uuuu uuuu

TMR0L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuT0CON PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 uuuu uuuuOSCCON PIC18F6X20 PIC18F8X20 ---- ---0 ---- ---0 ---- ---u

LVDCON PIC18F6X20 PIC18F8X20 --00 0101 --00 0101 --uu uuuuWDTCON PIC18F6X20 PIC18F8X20 ---- ---0 ---- ---0 ---- ---uRCON(4) PIC18F6X20 PIC18F8X20 0--q 11qq 0--q qquu u--u qquu

TMR1H PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuTMR1L PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuT1CON PIC18F6X20 PIC18F8X20 0-00 0000 u-uu uuuu u-uu uuuu

TMR2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuuPR2 PIC18F6X20 PIC18F8X20 1111 1111 1111 1111 1111 1111T2CON PIC18F6X20 PIC18F8X20 -000 0000 -000 0000 -uuu uuuu

SSPBUF PIC18F6X20 PIC18F8X20 xxxx xxxx uuuu uuuu uuuu uuuuSSPADD PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuuSSPSTAT PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu

SSPCON1 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuuSSPCON2 PIC18F6X20 PIC18F8X20 0000 0000 0000 0000 uuuu uuuu

TABLE 3-3: INITIALIZATION CONDITIONS FOR ALL REGISTERS (CONTINUED)

Register Applicable DevicesPower-on Reset,Brown-out Reset

MCLR ResetsWDT Reset

RESET InstructionStack Resets

Wake-up via WDT or Interrupt

Legend: u = unchanged, x = unknown, - = unimplemented bit, read as ‘0’, q = value depends on condition.Shaded cells indicate conditions do not apply for the designated device.

pic18f6520/8520/6620/8620/6720/8720 data sheetpic18f8520 note 1:ccp2 is multiplexed with rc1 when...

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