Dear Sir/Madam
I used sample project uart_pac10040 loopback. It works with not define ENABLE_LOOPBACK_TEST. However, if define ENABLE_LOOPBACK_TEST, and wire the pin RX_PIN_NUMBER 8 with TX_PIN_NUMBER 6 on the board, it fails and stays at show_error(void). Note: if I don't use a wire to connect P0.8 and P0.9, it shows the same.
Thanks