Solved: I didn't realize that detailed setup info could be entered if you click on the USART_0 driver image in START, so that made setting up the pins to use and the particular USART/UART (uart3) straightforward.
However, the driver_example.c file only gives an example of how to set up a transmit example. There is nothing there about how to read data. I'll ask that in another thread.
I have URXD3 and URXD3 pins wired up in my hardware and these are UART3 pins (not USART). I see there is only a driver for the USART and not the UART. Am I not able to use ASF4 to control the UART? I can't at this point connect the USART as I already have PD28 and PD31 connected so can't change that meaning I'm stuck using UART4.
What steps would you suggest I take to get this to work. Am I able to use some ASF4 calls to setup the PIO and anything else, then use just low level register writes to configure the UART. There is so much documentation to read it's overwhelming, so any starting points would be helpful.
This is for a SAMS70 144 pin. Thanks,