PIC16LF870-I/SS - Microchip Technology

T IMER1 MODULE

The PIC® microcontrollers you have received all exhibit

anomalous behavior in their Timer1 modules, as

described in this document. They otherwise conform

functionally to the descriptions provided in their respective

Device Data Sheets and Reference Manuals, as

amended by any silicon release errata for particular

devices.

Users are e ncoura ged to rev iew the l atest D evice D at a

Sheets and errata available for additional information

concerning an individual device. These documents

may be obtained directly from the Microchip corporate

web site, at www.microchip.com.

These issues are expected to be resolved in future

silicon revisions of the designated parts.

Silicon issue 1 affects all silicon revisions of the

following devices:

• PIC12F609 • PIC12F615 • PIC12F629 • PIC12F675 • PIC14C000

• PIC12HV609 • PIC12HV615 • PIC12F635 • PIC12F683

• PIC16C62A • PIC16C745 • PIC16F616 • PIC16F716 • PIC16F876A

• PIC16C62B • PIC16C765 • PIC16HV616 • PIC16F737 • PIC16F877

• PIC16C63 • PIC16C773 • PIC16F627A • PIC16F747 • PIC16F877A

• PIC16C63A • PIC16C774 • PIC16F628A • PIC16F767 • PIC16F882

• PIC16C64A • PIC16C923 • PIC16F630 • PIC16F777 • PIC16F883

• PIC16C65A • PIC16C924 • PIC16F631 • PIC16F785 • PIC16F884

• PIC16C65B • PIC16C925 • PIC16F636 • PIC16HV785 • PIC16F886

• PIC16C66 • PIC16C926 • PIC16F639 • PIC16F818 • PIC16F887

• PIC16C67 • PIC16F72 • PIC16F648A • PIC16F819 • PIC16F913

• PIC16C72 • PIC16F73 • PIC16F676 • PIC16F870 • PIC16F914

• PIC16C72A • PIC16F74 • PIC16F677 • PIC16F871 • PIC16F916

• PIC16C73A • PIC16F76 • PIC16F684 • PIC16F872 • PIC16F917

• PIC16C73B • PIC16F77 • PIC16F685 • PIC16F873 • PIC16F946

• PIC16C74A • PIC16F87 • PIC16F687 • PIC16F873A

• PIC16C74B • PIC16F88 • PIC16F688 • PIC16F874

• PIC16C76 • PIC16F610 • PIC16F689 • PIC16F874A

• PIC16C77 • PIC16HV610 • PIC16F690 • PIC16F876

• PIC17C42A • PIC17C44 • PIC17C756 • PIC17C762

• PIC17C43 • PIC17C752 • PIC17C756A • PIC17C766

Timer1 Modu le Silic on Errata She e t

TIMER1 MODULE

• PIC18C242 • PIC18F2480 • PIC18F4685 • PIC18F25J10 • PIC18F84J11

• PIC18C252 • PIC18F2510 • PIC18F6490 • PIC18F44J10 • PIC18F84J90

• PIC18C442 • PIC18F2520 • PIC18F6520 • PIC18F45J10 • PIC18F85J10

• PIC18C452 • PIC18F2539 • PIC18F6525 • PIC18F63J11 • PIC18F85J11

• PIC18C601 • PIC18F2550 • PIC18F6527 • PIC18F63J90 • PIC18F85J15

• PIC18C658 • PIC18F2585 • PIC18F6585 • PIC18F64J11 • PIC18F85J50

• PIC18C801 • PIC18F2610 • PIC18F6620 • PIC18F64J90 • PIC18F85J90

• PIC18C858 • PIC18F2620 • PIC18F6621 • PIC18F65J10 • PIC18F86J10

• PIC18F242 • PIC18F2680 • PIC18F6622 • PIC18F65J11 • PIC18F86J11

• PIC18F248 • PIC18F4220 • PIC18F6627 • PIC18F65J15 • PIC18F86J15

• PIC18F252 • PIC18F4320 • PIC18F6680 • PIC18F65J50 • PIC18F86J16

• PIC18F258 • PIC18F4321 • PIC18F6720 • PIC18F65J90 • PIC18F86J50

• PIC18F442 • PIC18F4331 • PIC18F6722 • PIC18F66J10 • PIC18F86J55

• PIC18F452 • PIC18F4431 • PIC18F8490 • PIC18F66J11 • PIC18F86J60

• PIC18F458 • PIC18F4439 • PIC18F8520 • PIC18F66J15 • PIC18F86J65

• PIC18F1220 • PIC18F4455 • PIC18F8525 • PIC18F66J16 • PIC18F87J10

• PIC18F1230 • PIC18F4480 • PIC18F8527 • PIC18F66J50 • PIC18F87J11

• PIC18F1320 • PIC18F4510 • PIC18F8585 • PIC18F66J55 • PIC18F87J50

• PIC18F1330 • PIC18F4520 • PIC18F8620 • PIC18F66J60 • PIC18F87J60

• PIC18F2220 • PIC18F4539 • PIC18F8621 • PIC18F66J65 • PIC18F96J60

• PIC18F2320 • PIC18F4550 • PIC18F8622 • PIC18F67J10 • PIC18F96J65

• PIC18F2321 • PIC18F4580 • PIC18F8627 • PIC18F67J11 • PIC18F97J60

• PIC18F2331 • PIC18F4585 • PIC18F8680 • PIC18F67J50

• PIC18F2431 • PIC18F4610 • PIC18F8720 • PIC18F67J60

• PIC18F2439 • PIC18F4620 • PIC18F8722 • PIC18F83J11

• PIC18F2455 • PIC18F4680 • PIC18F24J10 • PIC18F83J90

TIMER1 MODULE

1. Module: Timer1 (Asynchronous Counter)

When writing to the TMR1H register, under

specific conditions, it is possible that the TMR1L

external oscil lator vi a the T1O SO and T1 OSI pins .

When Timer1 is started, the circuitry looks for a

falling edge before a rising edge c an increment th e

counter. Writin g to the TMR1H reg ister is sim ilar to

starting Timer1; therefore, the former logic stated

applies any time the TMR1H register is written. If

the TMR1H register is not completely written to

during th e high pulse of t he external clock, then the

TMR1L regis ter w ill miss a cou nt du e to the ci rcu it

operation stated previously. The high pulse of a

32.768 kHz exte rnal clock cryst al yields a 15.25 μs

window for the write to TMR1H to occur. The

amount of instruc tions that can b e exec uted withi n

this window is frequency dependent, as shown in

Table 1 below.

TABLE 1: FREQUENCY DEPENDENT INSTRUCTION EXECUTION AMOUNTS

Work around

Operating Conditions: FOSC ≥ 4 MHz, no wake-ups

from Sleep, Timer1 interrupt enabled, global

interrupts enabled.

The code excerpts in Example 1, Example 2 and

Example 3 show how the TMR1H register can be

updated while the external clock (32.768 kHz) is

still on its high pulse.

The importance of the code examples is that the

bold instructions are executed within the first

15.25 μs high pulse on the ex tern al clo ck after the

Timer1 overflow occurred. This will allow the

TMR1L register to increment correctly.

FOSC TCY (μs) TCY within 15.25 μs

1MHz 4 3.81

2MHz 2 7.63

4 MHz 1 15.25

8 MHz 0.5 30.5

16 MHz 0.25 61

20 MHz 0.2 76.25

40 MHz (PIC18) 0.1 152.5

TIMER1 MODULE

EXAMPLE 1: PIC12/PIC 14/ PIC16 I NTERRUPT SER VI CE ROU TINE

EXAMPLE 2: PIC18 HIGH PRIORITY INTERRUP T SERVICE ROUTINE

EXAMPLE 3: PIC18 LOW PRIORITY INTERRUPT SERVICE ROUTINE

Note: These instructions are required based on the function of the ISR. If the only code in the ISR is to reload

Timer1, then they are not required, but may be required if additional code is added.

ISR @ 0x004 ; (3-4Tcy), fixed interrupt latency

MOVWF w_temp ; (1Tcy), save off current W register contents

MOVF STATUS,w ; (1Tcy), move status register into W register

MOVWF status_temp ; (1Tcy), save off contents of STATUS register

BANKSEL PIR ; (2Tcy), choose correct SFR bank

BTFSS PIR,TMRIF ; (2Tcy), did a Timer1 overflow occur?

GOTO EXIT ; No

RELOAD

BSF TMR1H,7 ; (1Tcy) Yes, reload for a 1 second overflow

EXIT

MOVF status_temp,w ; retrieve copy of STATUS register

MOVWF STATUS ; restore pre-isr STATUS register contents

SWAPF w_temp,f

SWAPF w_temp,w ; restore pre-isr W register contents

RETFIE Total = 11-12 TCY (if Timer1 ov erfl ow occurred)

ISR @ 0x0008 ; (3-4Tcy), fixed interrupt latency

BRA HIGHINT ; (2Tcy), go to high priority interrupt routine

HIGHINT

BTFSC PIR,TMRIF ; (1Tcy), did a Timer1 overflow occur?

BSF TMR1H,7 ; (1Tcy) Yes, reload for a 1 second overflow

RETFIE FAST Total = 7-8 TCY (if Timer1 overflow occurred)

ISR @ 0x0018 ; (3-4Tcy), fixed interrupt latency

MOVFF STATUS,STATUS_TEMP ; (2Tcy), save STATUS register

MOVFF WREG,WREG_TEMP ; (2Tcy), save working register, refer to note 1

MOVFF BSR,BSR_TEMP ; (2Tcy), save BSR register, refer to note 1

BTFSS PIR,TMRIF ; (2Tcy), did a Timer1 overflow occur?

BRA EXIT ; No

RELOAD

BSF TMR1H,7 ; (1Tcy) Yes, reload for a 1 second overflow

EXIT

MOVFF BSR_TEMP,BSR ;restore BSR register, refer to note 1

MOVFF WREG_TEMP,WREG ;restore working register, refer to note 1

MOVFF STATUS_TEMP,STATUS ;restore STATUS register

RETFIE

Total = 12-13 TCY (if Timer1 overflow occurred)

TIMER1 MODULE

REVISION HISTORY

Revision A Document (4/2005):

Original version of this document. Silicon issue 1

(Timer1 – Asynchronous Counter).

Revision B Document (9/2005):

Updated the list of affected devices.

Revi s ion C Document (1/2007):

Updated the list of affected devices.

TIMER1 MODULE

NOTES:

Information contained in this publication regarding device

applications a nd t he like is pro vid ed only f or yo ur conve nience

and may be su persed ed by upda t es . I t is y our respo n s ibility to

ensure that your application meets with your specifications.

MICROCHIP MAKES NO REPRESENTATIONS OR

WARRANTIES OF ANY KIND WHETHER EXPRESS OR

IMPLIED, WRITTEN OR ORAL, STATUTORY OR

OTHERWISE, RELATED TO THE INFORMATION,

INCLUDING BUT NOT LIMITED TO ITS CONDITION,

QUALITY, PERFORMANCE, MERCHANTABILITY OR

FITNESS FOR PURPOSE. Microchip disclaims all liability

arising from this information and its use. Use of Microchip

devices in life support and/or safety applications is entirely at

the buyer’s risk, and the buyer agrees to defend, indemnify and

hold harmless Microchip from any and all damages, claims,

suits, or expenses resulting from such use. No licenses are

conveyed, implicitly or otherwise, under any Microchip

intellectual property rights.

Trademarks

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

dsPIC, KEELOQ, KEELOQ logo, microID, MPLAB, PI C,

PICmic ro, PI C START, PRO MATE, PowerSm art , rfPIC, and

SmartShunt are registered trademark s of Microchip

Technology Incorporated in the U.S.A. and other countries.

AmpLab, FilterLab, Linear Active Thermistor, Migratable

Memory, MXDEV, MXLAB, PS logo, 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, ECAN,

ECONOMONITOR, FanSense, FlexROM, fuzzyLAB,

In-Circuit Serial Programming, ICSP, ICEPIC, Mindi, MiWi,

MPASM, MPLAB Certified logo, MPLIB, MPLINK, PICkit,

PICDEM, PICDEM.net, PICLAB, PICtail, PowerCal,

PowerInf o, PowerMate, Pow e rTool, RE AL ICE , rfLAB,

rfPICDEM, Select Mode, Smart Serial, SmartTel, Total

Endurance, UNI/O, 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.

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 it s 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 c onstantly evolving. We a t Microchip are committed to continuously improving t he c ode protect ion f eatures of our

products. Attempts to break Microchip’ s code protection f eature may be a violati on of t he Digit al Millennium Copyright Act. If such act s

allow 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 certification for its worldwide

headquarters, design and wafer fabrication facilities in Chandler and

T empe, Arizona, Gresham, Oregon and Mountain View, California. The

Company’s quality system processes and procedures are for its PIC®

MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial

EEPROMs, microperipherals, nonvolatile memory and analog

products. In addition, Microchip’s quality system for the design and

manufacture of development systems is ISO 9001:2000 certified.

AMERICAS

Corporate Office

2355 West Chandler Blvd.

Chandler, AZ 85224-6199

Tel: 480-792-7200

Fax: 480-792-7277

Technical Support:

http://support.microchip.com

Web Address:

www.microchip.com

Atlanta

Duluth, GA

Tel: 678-957-9614

Fax: 678-957-1455

Boston

Westborough, MA

Tel: 774-760-0087

Fax: 774-760-0088

Chicago

Itasc a , IL

Tel: 630-285-0071

Fax: 630-285-0075

Dallas

Addison, TX

Tel: 972-818-7423

Fax: 972-818-2924

Detroit

Farmington Hills, MI

Tel: 248-538-2250

Fax: 248-538-2260

Kokomo

Kokomo, IN

Tel: 765-864-8360

Fax: 765-864-8387

Los A n ge les

Mission Viejo, CA

Tel: 949-462-9523

Fax: 949-462-9608

Santa Clara

Santa Clara, CA

Tel: 408-961-6444

Fax: 408-961-6445

Toronto

Mississauga, Ontario,

Canada

Tel: 905-673-0699

Fax: 905-673-6509

ASIA/PACIFIC

Asia Pacific Office

Suites 3707-14, 37th Floor

Tower 6, The Gateway

Habour City, Kowloon

Hong Kong

Tel: 852-2401-1200

Fax: 852-2401-3431

Australia - Sydney

Tel: 61-2-9868-6733

Fax: 61-2-9868-6755

China - Beijing

Tel: 86-10-8528-2100

Fax: 86-10-8528-2104

China - Chengdu

Tel: 86-28-8665-5511

Fax: 86-28-8665-7889

China - Fuzhou

Tel: 86-591-8750-3506

Fax: 86-591-8750-3521

China - Hong Kong SAR

Tel: 852-2401-1200

Fax: 852-2401-3431

China - Qingdao

Tel: 86-532-8502-7355

Fax: 86-532-8502-7205

China - Shanghai

Tel: 86-21-5407-5533

Fax: 86-21-5407-5066

China - Shenyang

Tel: 86-24-2334-2829

Fax: 86-24-2334-2393

China - Shenzhen

Tel: 86-755-8203-2660

Fax: 86-755-8203-1760

China - Shunde

Tel: 86-757-2839-5507

Fax: 86-757-2839-5571

China - Wuhan

Tel: 86-27-5980-5300

Fax: 86-27-5980-5118

China - Xian

Tel: 86-29-8833-7250

Fax: 86-29-8833-7256

ASIA/PACIFIC

India - Bangalore

Tel: 91-80-4182-8400

Fax: 91-80-4182-8422

India - New Delhi

Tel: 91-11-4160-8631

Fax: 91-11-4160-8632

India - Pune

Tel: 91-20-2566-1512

Fax: 91-20-2566-1513

Japan - Yokohama

Tel: 81-45-471- 6166

Fax: 81-45-471-6122

Korea - Gumi

Tel: 82-54-473-4301

Fax: 82-54-473-4302

Korea - Seoul

Tel: 82-2-554-7200

Fax: 82-2-558-5932 or

82-2-558-5934

Malaysia - Penang

Tel: 60-4-646-8870

Fax: 60-4-646-5086

Philippines - Manila

Tel: 63-2-634-9065

Fax: 63-2-634-9069

Singapore

Tel: 65-6334-8870

Fax: 65-6334-8850

Taiwan - Hsin Chu

Tel: 886-3-572-9526

Fax: 886-3-572-6459

Taiwan - Kaohsiung

Tel: 886-7-536-4818

Fax: 886-7-536-4803

Taiwan - Taipei

Tel: 886-2-2500-6610

Fax: 886-2-2508-0102

Thail a nd - Bangkok

Tel: 66-2-694-1351

Fax: 66-2-694-1350

EUROPE

Austria - Wels

Tel: 43-7242-2244-39

Fax: 43-7242-2244-393

Denmark - Copenhage n

Tel: 45-4450-2828

Fax: 45-4485-2829

France - Paris

Tel: 33-1-69-53-63-20

Fax: 33-1-69-30-90-79

Germany - Munich

Tel: 49-89-627-144-0

Fax: 49-89-627-14 4-44

Italy - Milan

Tel: 39-0331-742611

Fax: 39-0331-466781

Netherlands - Drunen

Tel: 31-416-690399

Fax: 31-416-690340

Sp ain - Ma drid

Tel: 34-91-708-08-90

Fax: 34-91-708-08 -91

UK - Wokingham

Tel: 44-118-921-5869

Fax: 44-118-921- 5820

WORLDWIDE SALES AND SERVICE

12/08/06