PIC16C717_02 Datasheet, PDF (1/6 Pages) Microchip Technology – C Silicon/Data Sheet Errata

PIC16C717/770/771
PIC16C717/770/771 Rev. C Silicon/Data Sheet Errata
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
bcf
T1CON,NOT_T1SYNC
bcf
T1CON,TMR1ON
bsf
T1CON,NOT_T1SYNC
return
; entry point
; set for synchronous mode
; stop timer
; restore asynchronous mode
; return to calling routine
© 2002 Microchip Technology Inc.
DS80100C-page 1