[time-nuts] 5 MHZ PIC PPS Divider?

John Ackermann N8UR jra at febo.com
Sat Apr 12 10:34:34 EDT 2008


Thanks, Dave.  I was under the impression from discussion long ago (and
my memory may be wrong) that the change wasn't as trivial as it seemed.
 But if no other solution surfaces, I'll give this a try.

By the way, I don't need 50% duty cycle, but I am trying to minimize
jitter sources.  See my reply to Bruce below for more on what I'm trying
to accomplish.

Thanks!

John
----
David Forbes said the following on 04/11/2008 04:12 PM:
> At 3:23 PM -0400 4/11/08, John Ackermann N8UR wrote:
>> Has anyone come up with a 5 MHz input version of TVB's PIC divider?  I
>> could use one...
>>
>> Thanks,
>>
>> John
>>
> 
> John,
> 
> I haven't done that, but it looks easy to do. Change the second stage 
> to divide by 5 instead of 10. You will get 50 KHz instead of 100 KHz, 
> but so what.
> 
> This takes two changes in the constants for Digit1's tests:
> 
> first...
> 
> Loop1           BTFSC   STATUS, Zero
>                    INCF    Digit1
>                  MOVLW   BASE10      <-- change BASE10 to 0x5
>                  SUBWF   Digit1, W
>                  BTFSC   STATUS, Zero
>                    CLRF    Digit1
> 
> 
> later...
> 
>                  MOVLW   HALF10   <-- change HALF10 to 0x2
>                  SUBWF   Digit1, W
>                  RRF     OutByte, 1
> 




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