KL Wakeup from LLS via UART Edge?

[CiaranMacA_hkc]

Hi All,

I have tested wakeup from VLPS via UART Rx Edge. Fine. Works well. I enabled the RXEDGIE and clear RXEDGEIF in the interrupt. Fine.

What about LLS? Will this work (using LLWU)?  (I know that LLS wakeup is possible via LLWU external pins. That's ok, the question is , on UART Rx?)

Thanks

Ciarán Mac Aonghusa

[kerryzhou · Accepted solution]

Hi Ciaran Mac Aonghusa,

      Just like Mark Butcher have said,  LLS can't use the LLWU wake up with UART Rx, because the wakeup sources for LLWU inputs don't have it.

You can find the wakeup source for LLWU inputs in the reference manual, chapter 3. Wakeup sources for LLWU inputs. if you need the UART Rx to wake up, just as Mark suggest, you can connect the RX pin to the LLWU input pin.

Wish it helps you!

If you still have question, please contact with me!

Have a great day,
Jingjing

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[mjbcswitzerland]

Hi

See Using Kinetis Low Power Stop Modes with unrestricted UART operation - a report

The UART edge interrupt is only possible from STOP based modes and not LLS.

If you need to wake from a LLS mode (much slower) you will need a LLWU input instead. You could do this by connecting the UART input together with a LLWU input (in parallel).

Regards

Mark

[CiaranMacA_hkc]

Thanks, Greatly appreciated.

Ciarán