With harmony how to implement printf to uart?
I was facing a similar issue with a PIC32MX and my solution was to use the configuration as in the image below for the USART driver.



Then, I've enabled the 'Use Console System Service?', under 'Harmony Framework Configuration > System Services > Console', using the configurations listed in the image below.



Hopefully, these configurations may be applicable to your situation. Don't forget to configure the desired pins as U2TX and U2RX.