12C671 - GP3 problem

[mackrackit]

If the _PWRTE_OFF idea does not work then I think you know the problem is in resetting as you mentioned if the chip has continuous power it works.

So you could add something to the GPIO.3 button to power the chip first, before the actual button is pressed. No magic but more circuits.

[financecatalyst]

I tried with 220nF at input & 100nF at output of 78L05. Changed the config a little to try this code on 12F635 which I happen to have quiet a lot. This way I can save few 12C671. The circuit remains the same.

_PWRTE_ON or OFF is not making any difference.

The problem is stuck on GP4 now. GP 0,1,2,3 are working fine.

[Archangel]

Hello F.C.
What voltage do you read on GP.3 when the switch is pressed? I ask because it is an input with schmitt Trigger input, perhaps the voltage is not low enough to switch it.

[financecatalyst]

Hello F.C.
What voltage do you read on GP.3 when the switch is pressed? I ask because it is the only input with schmitt Trigger input, perhaps the voltage is not low enough to switch it.

I read 0V when switch is pressed.

[Archangel]

I would look for anything (registers) that sets different on POR as opposed to a cold boot, I have not looked, does this chip have ANSELH ? I just gotta hunch it is some little analog something . . .

[financecatalyst]

Does this chip have ANSELH ?

No, I have checked the datasheet again for 12C671. Thanks

[malc-c]

It seems strange that you stated it works fine with one battery but not another. Is there any reason for using 12v, which will mean the regulator will need to drop 7v which would generate a fair amount of heat. I would make a simple supply for testing of 6v transformer, rectifier, and a couple of 2500uF electrolytic capacitors (or use one of those DC plug type power supplies, and do away with the rectifier ), Then use the 100 / 200 nf caps either side of the regulator. It's also worth mounting the regulator on a heatsink. This should give you a very stable, smooth 5V dc supply for testing.