:)
Interrupt latency.
I have an app on a Mega32L, running at 4 MHz.
I'm trying to measure the widths of pulses that could be as short as 5uS.
The theory was to detect the first rising edge, and zero T1.
Then on the second rising edge, grab the count from T1, which is running at
CK/1
The problem I'm running into is that the generated ISR is showing a latency
of >7uS between the high edge of the pulse that generates INT0 and where my
code starts executing. Even taking the part to 8 MHZ doesn't look like it
will work, yet I know that at 4 MHz I can do this job in asm.
I understand what the compiler is doing, but the ISR it generates is way too
slow.
(see below)