AVR-Chat

At 05:58 PM 3/1/2005, John Samperi wrote:

>At 09:50 AM 2/03/2005, you wrote:
>
> >Hmm.. I only have three of the 128Ls in hand.
> >This is a 3V app.
>
>Can you raise the voltage (5v?) for testing purposes.
>Maybe a border case chip??? (scary thought)
>
>I think I better go and do some work....but this is so
>interesting...I know, I must be leading a boring life :-)

Got it, at least the first half.
Genuine HomerCode(tm)

The vector table needs to be JMPs, not Rjmps, as the JMPs are 4 bytes, and 
Rjmp is two.
Which means that the int that's been driving me nuts is really T0OV.

That's good because I need T00V, but bad because T0 is running impossibly fast.
With the three bits set for prescale select, I've seen TCNT0 jump from A4 
to 7F in ONE instruction.
Resetting the prescaler isn't helping, and it seems that any prescaler 
value results in the same thing, wether I do it in code, or clicking the 
bits in the ice.
When this is happening, it's virtually guaranteed that the T0OV flag will 
be set when I exit the ISR.