Posted on April 11, 2006 at 11:30hello all,
i've problem triggering external interrupts and would like to confirm what've done wrong..
interrupt vectorvoid (* const _vectab[])() = {
NULL, /* 0xFFE0 pwmart*/
NULL, /* 0xFFE2 i2c*/
it_AVD, /* 0xFFE4 avd*/
it_sci, /* 0xFFE6 sci*/
it_timeB, /* 0xFFE8 timerb*/
it_timeA, /* 0xFFEA timera*/
it_spi, /* 0xFFEC spi*/
CAN_Interrupt, /* 0xFFEE can*/
it_ei3, /* 0xFFF0 pb4..7*/
it_ei2, /* 0xFFF2 pb0..3*/
it_ei1, /* 0xFFF4 pf0..2*/
it_ei0, /* 0xFFF6 pa0..3*/
it_clock, /* 0xFFF8 mcc*/
NULL, /* 0xFFFA tli*/
it_trap, /* 0xfffc trap*/
_stext, /* 0xfffe main*/
};
cpu initialization/*
pb0..3 = outputs
pb4..6 = digital inputs (encoder)
pb7 = output
*/
PBDR = 0x80;
PBDDR = 0x8f;
PBOR = 0x8f;
EICR = 0x40;
i'd like to use pb4 and pb5 for encoder input for both channels, and i need to have external interrupt 3 triggered on any edge of these inputs.
interrupt routine@interrupt void it_ei3(void)
{
encoder.extint++; // increase debug counter
if ((!(encoder.olda & BIT4)) && (PBDR & BIT4)) { // a rising edge
if (!(PBDR & DIN5)) encoder.counter++; // increase counter
else encoder.counter--; // decrease counter
}
encoder.olda = (PBDR); // store old state
}
In above, encoder is volatile structure, and even the counter value is not changed, also the debug counter does not count - which means that external interrupt is never triggered.
I just cannot figure out what's wrong with these settings. Please help!
