RAK11720 (Ambiq Apollo 3) Power Management APIs don't work with UART

[Giovannicampo]

Hello devs, I am trying to reduce power consumption in my application developed in Zephyr OS and RAK11720. The application makes use of several peripherals and radios such as UART, I2C, Lora and BLE. That clearly makes the power optimization more challenging than usual. Using system power management enabled on Zephyr, the application, in an idle state where no peripherals are on, really shows low consumption. The issue rises once we activate UART; then, consumption increases of more than 100 μA. I tried to disable UART at runtime using zephyr PM APIs for device handling like pm_device_action_run() or UART APIs but nothing worked. Has anyone had dealt with it before?

const struct device *uart_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_console));
int ret = pm_device_action_run(uart_dev, PM_DEVICE_ACTION_SUSPEND);

[AlessandroLuo]

Hi @Giovannicampo, sorry for late reply, we have switched to use our own uart_ambiq driver which is fully PM functional instead of previous pl011, please check ambiq-stable branch for the latest codes. Thank you.