Getting Stuck in loop

[sayzer]

Looking at the first post,

I think this could be the issue here.

X var PORTA.5
Y var PORTF.6


REPEAT
UNTIL x = 0  ' X = 1 ;  wait until it is 0.

High y       ' Here, X = 0.

while x = 0 : wend  ' Here, X = 0, wait until it is 1.

REPEAT
UNTIL x = 0  ' X = 1 ;  wait until it is 0. 
        Pauseus 1
		Location1=PortJ

while x = 0 : wend  ' Here, X = 0, wait until it is 1.


REPEAT
UNTIL x = 0         ' X = 1 ;  wait until it is 0. 
        pauseus 1
		CharLow=PortJ

while x = 0 : wend  ' Here, X = 0, wait until it is 1.

REPEAT
UNTIL x = 0
        pauseus 1
		CharHigh=PortJ
		
while x = 0 : wend  ' Here, X = 0, wait until it is 1.

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[Frozen001]

sayzer:

I'll give it a try and see if that helps...

[Frozen001]

sayzer:

I'll give it a try and see if that helps...

I made the change and it made no difference at all.

[sayzer]

If these changes made no difference, then you have an issue with your inputs.

_______________-

[Frozen001]

If these changes made no difference, then you have an issue with your inputs.

_______________-

I don't know... the signals on the ports are TTL level, so it is pretty definite if it is a high or low on the port.

I have been digging around the code, and actually looked at the Assemble that PBP creates. After you work through all the macros and stuff some of the commands are LONG. A while loop command can be well over 20 instructions depending on the logical operator used. This sort of explains why the my code does not work when I use while:wend combinations. 20 instructions on the 18F8722 at 20MHz takes like 4uS to excicute... seeing how the signal I am looking for is only there 1 uS I can see how it will miss it...

[rmteo]

As you have correctly surmised, trying to detect a 1uS pulse by polling a port pin is not going to be reliable.

Use an external (or pin change) interrupt instead and you will not miss any of these short pulses.