This example code will demonstrate how to use M2L31's LPUART and LPPDMA to receive data of variable length in Power-down mode, and then wake up the MCU. The MCU will process the data and then enter Power-down mode again, and so on. This reduces system power consumption.
You can download the sample code at https://www.nuvoton.com/resource-download.jsp?tp_GUID=EC012024061706154558