Could anyone help me out. I have included my C code. I want to create two signals on the my PIC DEMO PLUS 2 board RA0 and RA1. I am getting an interrupt on RA0 but nothing on RA1. RB0 is my interrupt PIN. I have set all my registers according to the datasheet. but getting confused.

#include <io16f877.h>

#pragma vector = 0x1
__interrupt void externISR()
{
if(INTF) //loop controllling software design of interrupts on PIC
{
RA0 = 0; // ensuring RA0 set low
RA1 = 0;

TMR1H = 0xF6; // Pre - load timer with this value = 63035
TMR1L = 0x3B; // We want an overflow after 2500 ticks (interval of 20ms)
// As (2^16 -1)-2500 = 63035
TMR2 = 0x0;
TMR2IF = 0x0;

TMR1IF = 0; // no interrupt flag
INTF = 0; //related with INTCON register in void main, set to 0 here to clear interrupt.
}
else if(TMR1IF)
{
RA0 = 1; // RA0 set high when interrupt occurs
}
else if(TMR2IF)
{
RA1 = 1;
}

}

void main()
{
TRISA = 0x0; //Set as an output on PortA
TRISB = 0x1; //Set as an input on PortB
RA0 = 0; // RA0 always set low
RA1 = 0;

INTEDG = 0x1; // Set to trigger off the rising clock edge.
INTCON = 0x90; //this is our control and status of our interrupts.
T1CON = 0x3d; // sets the prescaler value of clock 1:8, oscillator enabled,internal clock selected
TMR1IE = 1;
TMR1IF = 0; // set at zero, flags are seen when = 1

T2CON = 0x7F;
TMR2IE = 1;
TMR2IF = 0;
PEIE = 1;
PR2 = 0xFF;

while(1);
}

 

Hi,

There are control registers (TMR1ON, TMR2ON) that enable and disable the timers on 16f877. I did not see where they are explicitly being set.

I would also personaly reset the relevant timers once the interrupt has occured (does tmr2 get reset if tmr1 has caused an interrupt?).

How is the INTF being triggered?

 

yeah , i am the beginner . can u help me . post the link to the C compiler for PIC . thanks

__________________
Rock Mental

 

Did you try googling? Also take a look at gnupic.