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Clock drift in tickless idle mode

Question asked by Evgeny Erlihman on Aug 28, 2017
Latest reply on Aug 28, 2017 by Erich Styger

Hello,

 

From what i understand, please correct me if i am wrong, the lptmr was added to tickless idle  to minimize time drift during sleep. But from the following comment i can understand the some drift is still possible:

 

/* Stop the LPTMR and systick momentarily. The time the LPTMR and systick is stopped for
is accounted for as best it can be, but using the tickless mode will
inevitably result in some tiny drift of the time maintained by the
kernel with respect to calendar time. */

I have two questions:

 

1. What is the drift that i should expect in this case?

2. If i need to use LPTMR for other purposes, and will be using fsl_tickless_systick instead of fsl_tickless_lptmr. What is the drift that i should expect in this case?

 

Thanks,

Evgeny

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