Cannot get comparator to work in PIC16F887

[Erik Nielsen]

Hi – I am new in programming PIC device and I have a project where I need to use one of the two Comparators in PIC16F887

I have read the datasheet several time but is still unsure about setting up the port – hope someone can come with an solution.

in my project I use tree 7 segment display so I use interrupt to make them work and its works fine.

I do not know for sure if this gives problem for my comparator!?

 

(I use Pascal as my sw)

 

– interrupt setup:

Procedure interrupt;
begin
    PORTB := 0;
    PORTD := ciffer[v] + blink_on;
    PORTB := zz; // turn on appropriate 7seg. display
    v := v + 1;
    zz := zz shr 1;
    if zz = 16 then zz := 128; // 4 // prepare mask for digit
    if v > 2 then v := 0; // 3 disp. // turn on 1st, turn off 2nd 7seg.
    TMR0 := 0;
    INTCON := $20;
end;

and my setup for the comparator:

ANSELH := 0;
// setup Port A :
TRISA :=%11011111; // input execp bit A5 – used for output for comparator
ANSEL :=%00001001; // bit A0 and A3 analog = input for comparator
CM1CON0 :=%11100000; // Comparator C1 enabled
SRCON :=%00000000; // no latch enabled
VRCON :=%00100000; // no v ref. enabled

this is the correct setting for comparator as best I know – but not sure because it not work.

here is the code where I retrieve the output 

If portA.5=1 then …

Can any help ? – do I need to do something for getting the the output

Best regards Erik Nielsen, Denmark.

 

[Erik Nielsen]

1. Just want to tell you that I get it to work now !

   – there was nothing wrong in my code but the PIC I used was damaged – when trying a

   new pic all works fine – thanks again

   Regrads Erik

 

[Ashutosh Bhatt]

for learning PIC you can follow tutorials on

EG Labs / micro controller / PIC

 

All the best

[Author]

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