Millisecond Timer Inaccuracy

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jclasquin
Pre-kindergarten
Pre-kindergarten
Posts: 1
Joined: Wed Aug 07, 2019 3:01 am

Millisecond Timer Inaccuracy

Post by jclasquin » Wed Aug 07, 2019 3:40 am

Hello,

Has anyone else tried running the "GPIO" sample (BareMetal) project? The LED blink intervals are supposed to be 125, 250 and 500 milliseconds but they are not.

When I run the unmodified sample code and connect an oscilloscope I see that each interval is actually about 50% longer, i.e. 250 ms is actually 375 ms, 500 is actually 750 ms, etc.

I've seen the note in the Gpt_LaunchTimerMs function saying the accuracy ultimately depends on the clock source, but 50% is a big error.

Thanks,
Joel

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