LPTMR is not working in LLS mode unless we configure it as Wake up source

[Bulusu]

Hi,

I have been trying to implement a low power timer(LPTMR) with LPO as clock source. Interrupt should be triggered every 250ms. The timer seems to work fine in normal mode, but when MCU goes to sleep interrupt is not triggered at all. (power mode is set to LLS). I configured LLWU (PTC1) pin as wakeup source, unless i configure LPTMR as Wakeup source it does not work. LPTMR should run in all power modes.

Can you help on this.

- Kiran Bulusu

[PabloAvalos]

Hi, @Bulusu 

Due to holidays the replies were delayed. Hoping you are excellent and having happy holidays too.

I would like to ask for you, which mcu or development board you are using for?
Here you will find a thread from our community that can be helpful regarding your issue:
https://community.nxp.com/t5/Kinetis-Microcontrollers/Can-MKL03Z32CAF4-processor-be-woken-from-LLWU-...

In addition, this application note about the power management for Kinetis MCU's might be helpful:

https://www.nxp.com/docs/en/application-note/AN4503.pdf

Hoping the links are useful for you, please let me know if you have more questions or if you need anything else.

Best Regards.

Pablo Avalos.

[Bulusu]

Hi,

Thanks for your response.

We are using the K32L2B31 mcu.

The LPTMR when configured on LPO should work in LLS mode and give configured interrupt.

But we are observing that when we configure it as an wakeup source , only then the LPTMR is working in LLS, otherwise its not.

Please guide how we can do that

[PabloAvalos]

Hi @Bulusu 

I really appreciate your patience. Due holidays the replies were delayed.

Regarding your concern on how can you do that? What are you referring to? You are trying to have LPTMR working in Low-Leakage Stop without LPTMR being configured as the wakeup source of the mcu?

If it is possible, may you share with me the code snippet that you have? And the function that you are trying to achieve?

Please let me know more details so I can help you with, also, let me know if you have more questions.

Best Regards.
Pablo Avalos.