Instant Interrupts - Revisited

[Ioannis]

I think next one Darrel has to answer, but if anyone knows...

How fast will the DT-INTS 14 interrupts (with PBP service) respond to a PORTB Interrupt on change?

Or better put, how many cycles will it take?

I am testing a Wiegand-26 reader the has 48uSec pulses every 2ms and at 4MHz the 16F628 chip does not feel it at all.

Another reader the has 0,38ms pulse is OK with the 16F628. The PIC is running rather slow at 4MHz.

I'd prefer a way to calculate the time it takes to respond on an Interrupt.

My service test routine is something like this:

CardReader:
   if d0=0 then
        array[index]=0
        index=index+1
    endif
   
    if d1=0 then
        array[index]=1
        index=index+1
    endif
@ INT_RETURN

Ioannis


P.S. After some testings I found that the pulse must stay at more that 150uSec for the PIC to grab it. Thats it at 4MHz.