After a long hiatus from PICs, I picked up a project recently that I am
using a 12C509(A) for the first time.  The project is simple - when powered
on check a jumper - if jumper high send 4 characters through a bit bang
serial port (9600,8,n,1), if jumper low send 2 characters through the bit
bang serial port (9600,8,n,1).  Then wait for the first returned character
and verify if it is what was expected.

 

All that works.  As a visual indicator, I have a LED that flashes several
times on power up, flashes once when sending data, and if the returned data
is good it flashes several more times and the 12C509 goes to sleep.  If the
returned character is not valid, it turns on for a short period of time and
goes out, and again the PIC goes to sleep.  The problem I am having is that
the flashing occurs at two different rates.  The fast rate is 50ms per
on/off cycle and the slow rate happens so in often I have not been able to
clock it, but it is about 1s per on/off cycle.  I am running an external
4.00 MHz oscillator.

 

Here is the code for the loop

general_delay_out

                                mov       delay_cntr,0ffh

:loop_1                 nop

                                mov       delay_inner, 0a0h

:loop_2                 djnz       delay_inner, :loop_2

                                djnz       delay_cntr, :loop_1

                                ret

 

Thanks,

 

David

 

David V. Fansler

s/v Annabelle

dfansler@dv-fansler.com

www.dv-fansler.com

 

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