Hi,
I agree, generally. BUT the "few uS" quickly add up... The servo code, including the PID, is supposed to run at 1220Hz and currently takes up to 400uS from "input to output". Let's say we're stepping at 50kHz and each interrupt takes 20uS. This means that during the 400uS it takes the servo code to execute there will be 20 interrupts, each taking 18uS for a total of another 360uS - the servo code now takes 760uS from "input to output".

However, the numbers will be the same no matter "where" the servo code is run - it's just a matter of finding which works the best. One benefit of moving it to the main routine is that it makes it at least possible for me to have the ISRs in "real" ASM which will help bring the latency down further. Don't know how I'll handle the USART though.... I love DT-Ints.... :-/

Thanks!
/Henrik.