PORTB.0 Insanity

[sayzer]

Sounds like an OSC issue to me.

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[paul borgmeier]

Still strange and still reaching here .... a long shot but it sounds like TRISB.0 could be getting changed somewhere during or after the Pause (by an erroneous interrupt?) – do you have an LCD hooked up where you can output the value of TRISB after your Pause that resets RB0 high?. The thought being you could monitor and see if it is getting changed. If you do not have an LCD or similar, you could put some lines like this in code AFTER the PAUSE for debugging purposes.

IF TRISB.0 = 1 THEN
	High PortB.7	' or whatever pin you have available
ELSE
	Low PortB.7
ENDIF
Pause 10000     ' measure PORTB.7 and see how TRISB.0 is set

Let us Know

Sounds like an OSC issue to me.

Sayzer ... OSC???? - I am interested in your theory – can you explain?

[sayzer]

....

Sayzer ... OSC???? - I am interested in your theory – can you explain?

When I worked with PICs with different internal OSC frequencies, like PIC18F8722, I had similar problems with latching PORTs.

I am not sure if Mark is using Internal OSC but what he is having sounds like it.

Mark, what is your OSC setting?

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[mokeymark]

I apologize for wasting your valuable time; I just combed through all of my code and found a stinking typo that resulted in PORTB.0 being set in another part of the program. That's why I could hold it low, but it would go high again as soon as I exited the interrupt service routine. Wow, I'm so ashamed! Thank you all; I have learned a valuable lesson. One important lesson is to get some sleep in stead of trying to work around the clock to finish the project!