topic Re: PWM like signal during LLS in Kinetis Microcontrollers

PWM like signal during LLS

dusek_martin — Sun, 03 Nov 2019 20:09:52 GMT

Hi,

I would like to generate square wave on some pin during sleep mode (e.g. LLS). Duty is not important, the frequency can be 1 kHz - 10 kHz.

Are there any options for MKL27? E.g. LPO, LPTMR, LPUART... ?

Re: PWM like signal during LLS

nxf56274 — Mon, 04 Nov 2019 06:09:35 GMT

Hi,

In VLPW , You can use LPTMR to generate pwm. In the interrupt of lptmr, you toggle the IO‘s level. But in LLS, you can't generate the PWM. Because the pins will be latched.
Have a great day,
TIC

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Re: PWM like signal during LLS

dusek_martin — Mon, 04 Nov 2019 12:21:28 GMT

This is not ideal as I will have to wake the MCU quite frequently.

I found out that it is possible to output LPO clock using SIM->SOPT1 = SIM_SOPT1_OSC32KSEL(3) | SIM_SOPT1_OSC32KOUT(1);

LPO runs even in LLS mode, so I have 1 kHz square wave everytime.