Working clock example using 32K watch crystal

[Archangel]

INCLUDE "DT_INTS-18.pbp" ; Base Interrupt System
INCLUDE "ReEnterPBP-18.pbp" ; Include if using PBP interrupts"

[timc]

The earlier versions I wrote had NO asm but lost almost a minute an hour. To make up for that one could re-tune using TMR1H and TMR1L with a larger value. Problem is every change made to the program would mean spending a few days retuning and it would never be as precise.

So yea I would love to be able to do this without asm in PBP AND be as accurate!

Down the road I intend to join this interrupt sample with a SNTP internet program so I can have a near perfect millisecond low power $60 clock.

Regards
Tim C

[Bruce]

   ' Int handler doesn't mess with any PBP system variables - or lower 15-bits
   ' of TMR1 accumulated time. Uses only 4 instructions to set TMR1H high bit,
   ' increment seconds, clear the interrupt flag bit, save & restore WREG, STATUS,
   ' BSR and return from int handler.
 
@myint                  ; create myint label
   TMR1H.7=1            ' Set TMR1 high bit for 1 second overflows
   seconds = seconds+1  ' Increment seconds
   PIR1.0=0             ' Clear TMR1 int flag
   @ retfie  FAST       ; Return with 'auto restore' of WREG, STATUS and BSR

Should do it.