[M480] UART Wake Up and Compensation

[chhsieh3]

• Application: This sample code uses the UART to wake up the M480 from power down mode and perform frequency compensation.
• BSP Version: M480 Series BSP CMSIS V3.04.000
• Hardware: NuMaker-PFM-M487 Ver 3.0

In this example code, the M480 will enter the power down mode. When the received UART data reaches the threshold, it will wake up the M480. Since the UART clock source needs to
be set to LXT in power down mode, UART baud rate compensation is used to achieve a more accurate frequency. Set the register WKRFRTEN (UART_WKCTL[2]) to enable the UART
wake-up function.

After entering the power down mode, when the data received in the RX FIFO reaches the threshold setting RFITL (UART_FIFO[7:4]), the receive data flag RFRTWKF (UART_WKSTS[2]) is set.

You can download the sample code at https://www.nuvoton.com/resource-downlo ... 0313102638