Is it bug or specification? Wake up from the low power mode by RTC overflow interrupt.

yasuhikokoumoto — Mon, 29 Sep 2014 12:58:16 GMT

Hi all,

I found a strange behavior which seems to be bug on FRDM-K20D50M board,
When Kinetis MCU wake up from the low power mode by RTC overflow interrupt, bit 28 of NVIC interrupt pending register (i.e. NVIC_ISPR0 and NVIC_ICPR0) will be set instead of bit 29. Although the interrupt enable (NVIC_ICER0) bit of the overflow interrupt is set, it will be ignored.
Therefore LLWU_ME should be assigned by the value of LLWU_RTCA_ME (i.e. 0x20) instead of LLWU_RTCS_ME (i.e. 0x80).

I think right way to set RTC overflow interrupt for wake up would be as following.
   enable_irq(LLWU_irq_no);
   enable_irq(RTCS_irq_no);
   LLWU_ME =LLWU_RTCS_ME;

However I actually set as following to work successfully.

enable_irq(LLWU_irq_no);
LLWU_ME =LLWU_RTCA_ME;

I would like to get comments from the Kinetis MCU (Kinetis K20 only?) designer.
For your information, even on FRDM-KL25Z, the situation was the same.

Best regards,

Yasuhiko Koumoto.

Re: Is it bug or specification? Wake up from the low power mode by RTC overflow interrupt.

yasuhikokoumoto — Wed, 01 Oct 2014 12:18:19 GMT

Hi all,

the following is my conclusion.

Both RTC overflow interrupt and RTC alarm interrupt use the common vector of RTC alarm.

RTC time seconds interrupt causes only by RTC_TSR change when RTC_IER[TSIE] is set.

Best regards,

Yasuhiko Koumoto.

topic Is it bug or specification? Wake up from the low power mode by RTC overflow interrupt. in Kinetis Microcontrollers

Is it bug or specification? Wake up from the low power mode by RTC overflow interrupt.

Re: Is it bug or specification? Wake up from the low power mode by RTC overflow interrupt.