PAUSEUS does not working properly (wrong timing)

[HenrikOlsson]

Hi,
Are you sure you don't have the timebase setting on the scope set in the uncal mode, ie. not an even 1-2-5 whatever per division? Try something simple like

TRISB = 0
Again:
   PortB.2 = 1
   Pause 500
   PortB.2 = 0
   Pause 500
Goto Again

That should give you a 1Hz toggle which would be easy enough to eyeball with a simple a LED. Then change to PAUSE 5 and check again with scope. I'm pretty sure it has nothing to do with the PAUSEUS statement in your code but rather something like the oscillator isn't running at the correct frequency or you're not measuring it correctly. But of course, I could be wrong.

/Henrik.

[LinkMTech]

After you find your real timing problem, don't forget to consider the Pulsout statement execution time.

I measured 47us delay between these signals running at 4MHz:

AGAIN:
    PULSOUT PORTC.3, 1
    PULSOUT PORTC.3, 1
GOTO AGAIN

This showed 147us between the end of one to beginning of the next pulse:

AGAIN:
    PULSOUT PORTC.3, 1
    PAUSEUS 100
    PULSOUT PORTC.3, 1
    PAUSE 100
GOTO AGAIN

[CuriousOne]

Scope xefinetly not the case, and the pause statement is working properly. the problem is with pauseus statement and only on small durations. say, pauseus 1200 and above, give almost perfect result. it is very interesting fact that, pauseus 1, gives 200 us delay between pulsout statements on 16 f628a @ 4 mhz, and only 48 us delay on 12 f683!

[AvionicsMaster1]

The define OSC 4 needs to be DEFINE OSC 4 though I think the default is 4Meg it might require a correct DEFINE statement to make it work.

With the 12f683 internal oscillator you need both the DEFINE OSC and the OSCCON to make it work properly. Not sure with the 16F628 if you need a PCON statement in addition to the DEFINE OSC.