Xiao SAMD21 2nd UART?

I am trying to interface an xBee Zigbee module to the Xiao SAMd21 module using a uart interface. I am using the A6/TX and A7/RX pins but this does not seem to work. Is this uart not available because it is used by the USB interface? Is there another UART interface available?
I see the data signal from my xBee module which goes to A7 on the Xiao module. I have serial.available() in my code which is never triggered…



Hi, richas
On SAMD32, you can see through the pin definition diagram that other than A6/TX and A7/RX as UART pins, others seem not to support, USB cannot use serial ports, I wrote a program to simply test A6/TX and A7/RX is no problem, and will not be occupied by USB. Perhaps the problem is that SAMD21 is not compatible with Zigbee use, and this problem needs to be explored in depth

void setup() {
    while (!Serial);
void loop() {