Hi all
I am using yet another chip I've not worked with before. This time a
16C73
My problem is a little complicated. I am working on a program that
someone else wrote(basically sending data to a PC via RS-485). The
timing is kept using the RTC. What I am doing is using spare processing
time(between data sends, etc.) to do various functions(turn on/off
relays,etc).

I have a sequence in which some relays must turn on & off, with a three
second delay between each. In the simulator it simulates the time
correctly(ie. the bits change when the stopwatch has reached aprox. 3
sec.) but when I programmed the chip the sequence happens over a few
milliseconds. I dont know what could be the problem. Could it be I'm not
setting page bits correctly?(I never seem to get them right :) The code
is over 800 lines long!!! I don't get any warnings or anything about it
anyhow.
I thought it may be the RTC, but for the whole sequence to happen the
RTC has to "overflow."

Below is a snippet of the main code. It calls various other subroutines
for the RS485 but the processes that I have written are do_full,do_mt.
They are called every 256ms(in software simulator)

                 **********    RTC START    **********

rtc_start                                      ;1ms period
         load_tmr0
         bsf                 rtc_test         ;start external rtc pulse
         clrwdt
         bcf                 t0if                ;clear overflow flag
         call                do_coms       ;RS485 process
         incf                scan_time,1   ;256mS scan interval
         call                do_analog        ;sample RC0, RC1, RC2 and
RC3 (one per scan)
Reads some analog inputs(AFAIK)

         movf              scan_time,1      ;test for overflow on
scan_time
         btfss               z                      ;run full and mt on
zero condition
         goto               idle_state
         call                do_full
         call                do_mt

These are the processes the aren't working properly. The seqeunce is
called once every 256ms * 4  sequences = 1s. I dec a counter 3 times to
get 3 seconds and still return to the rest of the program(needed for
RS485 timing etc. I think)
eg. Set relay1, then dec the counter. If 0 then set relay2 and so on
I can post that part of the code (or attach the asm) too if it would
help any

         call                 do_batt

An unrelated process, used to collect battery level data(part of what
the chip send to the PC)

         btfss                relay2
         goto                $+3
         bcf                  relay2
         goto                $+2
         bsf                   relay2

This is a bit of code I put in afterward to try  "debug" the program. My
theory was that this is ran every 256ms.(It works okay in the simulator
also) And so the relay would switch four times a second..... but in
hardware it switches on when I turn on the power, and stays on( I
checked for pulses with an oscilliscope, but found none) until you turn
off the power

idle_state                      ;wait here for real time clock to expire

  bcf    rtc_test         ;switch off rtc monitor signal
  btfss  t0if
  goto   idle_state
  goto   rtc_start

I think this bit is self explanatory....... :? waits till the RTC has
overflowed and goes through the above cycle again( every 1ms AFAIK)

I can't think what could be the problem. The person I am doing this for
says the RS485 part works perfectly.......

If it would help to c the whole code I can send it.........

Thanks again
Christopher Tyler

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