I'm trying to understand why I am seeing RX interrupts when tying RX to TX of my SAMR34 but not when I connect it to the transmitting device. The transmitting device notes the following restrictions:
Serial hardware flow controls (RTS/CTS and DTR/DSR) are not used and will be ignored. In addition, the receiver must not use software flow control (XON/XOFF)
I do see data from the transmitter when I poll. Does interrupt driven UART require support from the transmitter? Should I switch to DMA to resolve this issue? Here is my setup