KL03Z: Trouble Keeping Processor in VLPR Mode

[sarastout-grand]

Hello,

I am trying to run my KL03Z processor in VLPR mode instead of RUN mode. I have set my core clock to 4MHz and the bus clock to 1MHz. I have both TPM timers running off an external clock which remains enabled, one of the timers generates an interrupt every now and then. I have set the PMPROT_AVLP bit for VLPR and the PMCTRL_RUNM bits to VLPR mode. I believe this is all I have to do to get into VLPR mode.

When I step through my code using the debugger, I can clearly see that the I'm in the VLPR mode since the current is as I expect it to be. However, when I run the code (i.e. no longer stepping through), the current jumps up to the RUN value.

Something is causing it to exit VLPR mode without my changing the RUNM bit. I understood that KL03 devices would not exit VLPR from an interrupt. Is that true? Is the only way to exit from VLPR with the KL03 is to change the RUNM bit to 00?

Am I missing something?

Thanks,

Sara

[Hui_Ma · Accepted solution]

Hi Sara,

The interrupt doesn't transfer the VLPR mode to RUN mode.

Please check below conditions will switch between RUN with VLRP:

Please check if there with code to change the SMC_PMCTRL[RUNM] bits value.

Or there with a reset happens.

BTW:

You could refer MCUXpresso SDK for FRDM-KL03Z SDK package, which provided [power_mode_switch] demo.

I also do a test, there doesn't happen you mentioned issue during debug.

The MCUXpresso SDK for FRDM-KL03Z could be downloaded from here.

Have a great day,
Ma Hui

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[sarastout-grand]

Hi Hui,

Thanks, you have confirmed what I understood about exit from VLPR. I have also been able to confirm that I am still in VLPR mode by looking at the PMSTAT register. I had assumed that I wasn't in VLPR  because of the current draw, it is not as I expected to see for VLPR. I have already asked another question about that.

Thanks,

Sara