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Visitor II
August 20, 2025
Question

Low Power on Zephyr RTOS

  • August 20, 2025
  • 1 reply
  • 387 views

Hello,
I'm working with a RAK3172 based on STM32WLE5CC chip.
I'm using Zephyr RTOS and trying to use the power management features.
I've an uart communication, when CONFIG_PM=n, everything works well. When setting CONFIG_PM=y, I don't receive any data.
I've configured, the lsi, hsi, pll and rcc in my dts file.
I've tried a bunch of configuration, but impossible to get power management to work alongside uart.
I just have the following code:

 
int main(void)
{
 while (1) {
 gpio_pin_toggle_dt(&gpio_led0);
 printk("Hello, World from main!\n");
 k_msleep(1000);
 }

	return 0;
}

Thanks for the help

    This topic has been closed for replies.

    1 reply

    ST Employee
    August 20, 2025

    Hi @rbouteiller

    Before entering low-power modes, check that all UART transfers are fully completed.

    You can add a check in your code, such as:

    while (HAL_UART_GetState(&huart1) != HAL_UART_STATE_READY) { }