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How to enter and exit low power mode

Posted by mige on January 26, 2018


we are developing a new product based on FreeRTOS that has to support a low power mode. Last year, we created a first prototype that seems to work.

Now, I read about the tickles idle mode (see https://www.freertos.org/low-power-tickless-rtos.html). Our Implementation does not use that mode.

If the provided power is under the normal limit, our implementation disables all peripherals and interrupts directly including the timer that would trigger the scheduler. Because of that, we had to enable the schedulers timer interrupt in portYIELDWITHINAPI in contrast to portYIELD, where that timer is still disabled. Only the RTC is enabled, to wake up the system after one minute.

We are using a Renesas YRDKRL78G13 evaluation board. If there is a port available for this processor/board that implements the low power mode, please let me know.

I would like to know your opinion about the implementation of the low power mode.


How to enter and exit low power mode

Posted by rtel on January 26, 2018

I think there is a tickless example for the RX100 (another Renesas proprietary core), but not the RL78.

In your application, does it matter if the system time is not maintained across sleeps? If so it is probably ok. The tickless mode is designed to correct the time after the system wakes.

How to enter and exit low power mode

Posted by mige on February 9, 2018

At the moment, our imlpementation is okay, if the decision depends on the system time. Maybe we should change it in the future depending on the needs.


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