Hi there, I'm using an Arduino m0 mini board. I need my board to sleep until it receives a message from a GSM module through UART. Im using the Serial1 interface. I checked out all the registers configured in SERCOM.cpp and according to the datasheet I think it should be able to wake up only by enabling the "start of frame detection" with SERCOM_USART_CTRLB_SFDE.
The problem is it doesn't wake up nor trigger the receive complete (RXC) interrupt. I tried enabling the receive start (RXS) interrupt and in this case it DOES wake up. (I had to clear the RXS flag in the interrupt handler, other wise it kept triggering continuously).
So the question is: why does RXS wake up the processor and RXC doesn't? I can't figure it out and I didn't find anything in the forums.
I need an answer because I don't want to make all those modifications to the core files (Uart.cpp and SERCOM.cpp).
I'm using the LowPower library to make the processor sleep.
SCB->SCR |= SCB_SCR_SLEEPDEEP_Msk;
__DSB();
__WFI();
Thanks!