[time-nuts] A Simple PIC Divider
Joe McElvenney
ximac at btinternet.com
Sat Aug 5 17:16:09 UTC 2006
Hi,
While we are on the subject of PIC dividers, and if the lower
order outputs (other than 10kHz) are not required, the standard
divide-by-1000 part of a GPS-derived standard may easily be
implemented in an 8-pin 12F629/675 saving one chip and 20 pins.
My code, such as it is -
Setup the required ports
DIV:
Set RAn to '1'
Stuff here with 124 NOPs
Set RAn to '0'
Stuff here with 121 NOPs
Goto DIV
The result, a synchronous counter with a symmetrical 10kHz
square-wave on RAn from a 10MHz clock input. The 245 NOPs are
easily block pasted into a text editor thus saving the need to
calculate the numbers for timing loops. This is so basic that I
hate to mention it but someone might wish to save a bit of board
space.
Cheers - Joe
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