Scot Sakolish

clock frequency measurement

Discussion created by Scot Sakolish on Feb 6, 2012
Latest reply on Feb 8, 2012 by TomE

Hi,

I'm trying to find a way to measure the 80MHz instruction clock to determine if the crystal is drifting (as a kind of fail-safe).

 

I can add up the instruction cycles in an assembly loop and use the Periodic Interrupt Timer (PIT0) w/ microsecond resolution to determine the time it takes for those instruction cycles to run, but that seems kind of like measuring the clock with the clock.

 

Does anyone have any other ideas on how to accomplish this?

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