topic Re: Wakeup Reset in Kinetis Microcontrollers

Wakeup Reset

pietrodicastri — Thu, 05 Feb 2015 13:45:12 GMT

Good morning

I wander if there is a sense in expecting the SRS0_PIN active without SRS0_WAKEUP also active.

It seems if a wake up from the pin exists, also a wake up is there.

So if I am interested in wakeup from pin I can just check the SRS0_PIN and skip the SRS0_WAKEUP.

Fix me

Thank You

Re: Wakeup Reset

Hui_Ma — Fri, 06 Feb 2015 02:17:23 GMT

Hi,

The Kinetis RCM_SRS0 register [WAKEUP] bit indicate the a reset has been caused by an enabled LLWU module wakeup source while the chip was in a low leakage mode.

When the chip enter into low leakage mode, it need to use LLWU wakeup the chip.

The external pin need to be the LLWU module related wakeup source.

Related info could be found at related Kinetis product reference manual: chapter 3 Wakeup sources for LLWU inputs.

Wish it helps.

Have a great day,
best regards,

Ma Hui

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Re: Wakeup Reset

pietrodicastri — Fri, 06 Feb 2015 07:27:51 GMT

Good morning Hui_Ma

Yes it is clear the general meaning. I would like to have a confirmation that

there is no way to get SRS0_PIN active without the SRS0_WAKEUP.

It would be like saying: there is a wake up from the pin, but no wakeup.

If this situation happens something is wrong.

Just a comment on my thinking

Thank You

Pietro

Re: Wakeup Reset

yasuhikokoumoto — Sat, 07 Feb 2015 19:51:45 GMT

Hi Pietro,

according to my experiment, the external reset assertion did not set RCM_SRS0[WAKEUP] but only set RCM_SRS0[PIN].

If I activated the external reset in during LLS or LLVSx modes, both RCM_SRS0[WAKEUP] and RCM_SRC0[PIN] was set.

I think you need not to check RCM_SRS0[WAKEUP] but only check RCM_SRS0[PIN], unless you would not perform the wakeup sequences.

Best regards,

Yasuhiko Koumoto.

Re: Wakeup Reset

pietrodicastri — Sun, 08 Feb 2015 16:32:18 GMT

Hei Yasuhiko

Thank You. This answer is very precious.

Pietro