Forums - Timer accuracy

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Timer accuracy
Join Date: 10 Jun 16
Posts: 9
Posted: Tue, 2016-06-21 01:47

I am developing a project based upon the CSRMesh1.3 and would likem to use the system clock as a real time clock.

I have configured a timer to generate a callback every 10ms and the first thing I do is to read the System Time using TimeGet32() which I then compare with the previous value.

I would expect that the difference between two 10ms interrupts would be a count of 10000 i.e. 10000uS in fact it is about 10090 which over a period of one second is 9000uS or 9ms - is this what would be expected?

I have tried setting the system in both DeepSleep and ShallowSleep with no noticable change.

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Dr. Nissim Zur
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Join Date: 6 Jun 16
Location: Skype: nissim.test CSR1010 External design house
Posts: 235
Posted: Tue, 2016-06-21 09:09

Serving time interrupt takes time, and can't be accurate since CSR1010 is a single thread.

All RF and back-task will be server before user interrupts.

But TimeGet32() TimeGet48() is HW free running without any software delays.

So over time all is OK.

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