I have recently switched my comparator on my PIC16f628 over from using an external reference voltage to the internal one.

THe problem is the state of the comparator doesnt change anymore.


Here is some pseudocode of a test program:

CMCON = %00000100 'set up internal comparator
VRCON = %10100010 'set up voltage reference module
TRISA = %11111100 'set all porta as input
TRISB = %11110000 'set portb


start:
High PORTA.6

While CMCON.0 = 1
Low PORTA.6
Wend

Goto start


I have checked the value of my reference voltage and it falls between the high and low values.

Its just meant to switch the light on and off as the comparator changes, but the light remains on.

Can someone help.

Thanks

__________________
The first rule of mstechca club is do not talk about mstechca club.
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The CMCON setting you currently use doesn't connect the reference output to a comparator input...

you might want to take a look at the comparator IO operating modes in the datasheet again

 

Yeah cheers Im an idiot and I know it ops: ops: ops:

__________________
The first rule of mstechca club is do not talk about mstechca club.
http://www.electro-tech-online.com/s...induser&u=1245