why the code working with PIC16f84a and not in PIC16f877a ? MIKROC & isis proteus

[mot1639]

hi all

i am trying to switch LED in PIC16f877a when i press push button..
it work with PIC16f84a and not in PIC16f877a ...
where is the problem
i build the circuit in isis proteus .... it work for PIC16f84a and not with PIC16f877a ...

void main() {
  ADCON1=1;
TRISA=0xff;
TRISB=0;
PORTB=0;

while(1){
if (RA2_bit==0){
PORTB=0xFF;
delay_ms(1000);
}
}
}

where is the Problem

regards for all and thanks in advance...

 

[luben111]

Re: why the code working with PIC16f84a and not in PIC16f877a ? MIKROC & isis proteus

as far as I can remember 16F877A has analog comparator on this pin and you need to disable it first

 

[Tahmid]

Re: why the code working with PIC16f84a and not in PIC16f877a ? MIKROC & isis proteus

16F877A has an analogue comparator and an ADC. You need to disable them.

Change your code to:

void main() {
ADCON1=7; //This disables ADC
CMCON = 7; //This disables analogue comparator
TRISA=0xff;
TRISB=0;
PORTB=0;

while(1){
if (RA2_bit==0){
PORTB=0xFF;
delay_ms(1000);
}
}
}

Hope this helps.
Tahmid.

 

[mot1639]

Re: why the code working with PIC16f84a and not in PIC16f877a ? MIKROC & isis proteus

thanks for your support , it works now

regards