MKL26Z256 LPTMR0_CNR value after wake up from VLLS1

[testertester]

We use LLWU to wake up the MCU. There are different sources to wake up: CMP, gpio and LPTMR. When we wake up by CMP or gpio, we have to get a value from LPTMR0_CNR to find sleep time. But it is always 0. Is there any recomendations to get LPTMR0_CNR after VLLS1?

[testertester · Accepted solution]

The problem was in SIM_SCGC5. We didn't enable LPTMR bit before reading CNR.

[Alice_Yang]

Hello Tester,

About the register of "LPTMR_CNR" :

- The CNR is reset when the LPTMR is disabled or if the counter register overflows. If

CSR[TFC] is cleared, then the CNR is also reset whenever CSR[TCF] is set.

- And On each read of the CNR, software must first write to the CNR with any value.

About the detail description , please refer to KL26P121M48SF4RM.pdf -> 33.4.5 LPTMR counter .

If you have mentioned this , it still have question , could you please show your code clearly ?

Hope it helps

Have a great day,
Alice

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