© 2002 Microchip Technology Inc.

DS80100C-page 1

PIC16C717/770/771

The PIC16C717/770/771 parts you have received con-

form

functionally

to

the

Device

Data

Sheet

(DS41120B), except for the anomalies described

below.

All problems listed here will be addressed in future revi-

sions of the PIC16C717/770/771 silicon.

1.

Module: A/D Converter

Exception to Table 15-12, Parameter A04.

PIC16C770/771 (12-bit A/D): No missing codes to

11-bits of resolution, up to 4 non-consecutive

missing codes may occur when used to 12-bits of

resolution.

Work around

None.

2.

Module: Timer1

When Timer1 is configured to operate as an asyn-

chronous counter, care must be taken that there is

no incoming pulse while the module is being

turned off. If an incoming pulse arrives while

Timer1 is being turned off (i.e., TMR1ON transi-

tions from 1 to 0), the value of registers TMR1L

and TMR1H will be unpredictable.

Work around

This solution involves changing Timer1 from Asyn-

chronous to Synchronous mode before turning off

Timer1. No additional resources are required for

this solution.

Timer1 synchronization will start, effectively stop-

ping Timer1, one Q period after the Synchronous

mode is enabled, or one Q period later than would

have been realized by simply clearing the

TMR1ON bit. One additional count, in excess of

the counts accrued during this extra Q period, may

be accumulated before the TMR1ON bit is eventu-

ally cleared in the next instruction. The occurrence

of this additional count is dependent on the phase

relationship between OSC1, or the internal system

clock, and T1CKI.

CODE EXAMPLE :

**************************************************************************************

;

Call this routine to stop Timer1 asynchronous counting

;

;

Timer1 is stopped after the timer is changed to synchronous mode

;

The captured timer value resides in TMR1H and TMR1L at the completion of this

;

routine.

TMR1Capture

; entry point

bcf

T1CON,NOT_T1SYNC

; set for synchronous mode

bcf

T1CON,TMR1ON

; stop timer

bsf

T1CON,NOT_T1SYNC

; restore asynchronous mode

return

; return to calling routine

PIC16C717/770/771 Rev. C Silicon/Data Sheet Errata