AVR-Chat

> So I have this Mega32 running at 4 MHz (yes, 4 MHz, I checked the fuses)
>
> I'm trying to measure two pulse widths, on INT0 and INT1 using T1 with
> a divisor of 1.
> The pulses have a minimum period of 5uS, nominal period of 14uS, and
> max of 23uS.
> I can't adjust those values.
>
> I enable INT0 for a rising edge int.
> When the int happens, I zero T1, and exit the ISR.
> When the int happens again, I read T1 and store it.
>
> Then I disable INT0, enable INT1, and do the same thing for the pulse
> on that input.
>
>
> My problem is that the system seems to be running much slower than I
> would expect.
> The interrupt latency is measuring out more than 5uS!
>
> I don't have any other ints enabled, other than a very simple T0 ISR
> (see previous post)
>
> There's no point where I have ints disabled, at least not in the code
> that I wrote.
>
> Do I really have to run the machine faster than this?
> I wouldn't expect to have to in Asm..
>
>
>
>
> --
>
> "The very powerful and the very stupid have one thing in common. Instead
> of
> altering their views to fit the facts, they alter the facts to fit their
> views... which can be very uncomfortable if you happen to be one of the
> facts that needs altering." Doctor Who, Face of Evil
>

Well, interrupts are disabled inside ISRs!

Jim Wagner