AVR-Chat

At 08:40 AM 12/23/2004, Paul Maddox wrote:


>Dear all,
>
>   Daft question, I'm trying to setup a couple of IRQs (in assembly) and I'm
>getting some odd results, here's the first part of my setup ;-
>
>   LDI  Temp, Low(Ramend)
>   OUT  SPL, Temp    ; setup stack pointer
>
>   LDI  Temp, High(Ramend)
>   OUT  SPH, Temp
>
>   ; **** setup IRQs
>
>   LDI  Temp, 0b00001010
>   OUT  MCUCR,Temp    ; Setup MCUCR for falling edge interupts.
>
>   LDI  Temp, 0b11000000   ; enable ext. INT1 and INT0
>   OUT  GICR,Temp    ; by setting General Interupt Control Register
>
>I assume the stack and IRQ setup is ok?
>or is it shot to peices?

What's the chip??

What's your vector table look like?

I've seen some systems that only partially fill the vector table, but I 
really get squeamish at that.
I prefer a full table, with at least RETI's on the unused ints, and ideally 
a little code to turn them off in case they get accidentally turned on.. 
Put that in your template for a given processor, and then just populate the 
ones you want.  If you get pushed for space, then sacrifice the turnoffs 
for RETI's again.