RA2 as input

[patroclus]

Hello again
I got a new problem when using RA2 as input.
Once my program gets to a point where it must get data in RA2 pin, it stops working.

btfss porta, SLatch
goto $-1

SLatch is 0x02
It does not go out there, so I suppose RA2 is read always low ??
Even when RA2 pin gets a pulse clock, it does not go out...

Does it have anything to do with CMCON or VRCON registers??

thank you!

 

[Nigel Goodwin]

Hello again
I got a new problem when using RA2 as input.
Once my program gets to a point where it must get data in RA2 pin, it stops working.

btfss porta, SLatch
goto $-1

SLatch is 0x02
It does not go out there, so I suppose RA2 is read always low ??
Even when RA2 pin gets a pulse clock, it does not go out...

Does it have anything to do with CMCON or VRCON registers??

thank you!

You don't mention what processor you're using?, but assuming it's the 16F628?, then RA2 can be set as a voltage reference OUTPUT, or as a comparator input, as well as normal I/O - have you set the CMCON and VRCON registers correctly?.

 

[patroclus]

I did not set any of them. I thought VRCON was clear for default. Would it be enough setting CMCON to b'00000111' ??

Thank you!

 

[Nigel Goodwin]

I did not set any of them. I thought VRCON was clear for default. Would it be enough setting CMCON to b'00000111' ??

That's why it doesn't work then, by default the comparators are ON, you don't normally need to alter VRCON (I never have!), but you need to set CMCON to turn the comparators OFF - see my tutorials that all do that!.