Forum Discussion
Altera_Forum
Honored Contributor
Honored ContributorLarge fast counters (MaxII)
I'm trying to create a large fast long variable delay. My obvious approach is a 17-bit counter that loads when the trigger arrives and counts down to zero when it stops. Unfortunately even with a -3 ...
Altera_ForumHonored Contributor
Honored Contributor --- Quote Start --- Try chaining small counters together. --- Quote End --- To get to 17-bit equivalent with 8-bit counters, I'd need 512 of them, so this isn't viable. === I've realised that carry lookahead won't work in the same way as on a 74163 because the logic is ram lookup and therefore any input change could cause a glitch defeating the lookaheads purpose of a longer setting time. My current thought is to divide the 250MHz clock by 4 (synced at 250MHz to the trigger input) and use this 62.5MHz clock to do 15-bits of the delay plus about three-bits of 250MHz delay. Is it possible to connect an internally generated signal to a global clock line? If so how?
