I’m having trouble with UART6 after setup. Unable to RX data on this port. The following is the procedure used to setup the port. Use device tree editor to assign UART6 to pins 30 to 33. Rx is pin 30 and Tx is pin 31. Save config and reboot board. After boot up issue the following commands to assign to dialout group and add permissions. Code: udooer@udooneo:~$ ls -l /dev/ttymxc5 crw------- 1 root root 207, 21 Dec 31 1969 /dev/ttymxc5 udooer@udooneo:~$ sudo chgrp dialout /dev/ttymxc5 udooer@udooneo:~$ ls -l /dev/ttymxc5 crw------- 1 root dialout 207, 21 Dec 31 1969 /dev/ttymxc5 udooer@udooneo:~$ sudo chmod g+rw /dev/ttymxc5 udooer@udooneo:~$ ls -l /dev/ttymxc5 crw-rw---- 1 root dialout 207, 21 Dec 31 1969 /dev/ttymxc5 Then test the port. Program the M4 with the Multiserial example program from the Arduino IDE change ports to Serial.begin(115200); and Serial0.begin(9600); Open Serial Monitor in IDE. Open another Terminal window and run minicom -s to setup access to UART6 Parameters set to Port = /dev/ttymxc5 Comm Parameters = 9600 8N1 Hardware Flow Control = No Cross connect the TX and RX of M4 pins 0,1 to UART6 pins 30,31 With this setup entering text into the Minicom window will appear in the IDE Serial Monitor window. SUCCESS Enter text to send in the IDE Serial Monitor window hit SEND the text should appear in the Minicom window. FAIL Hope there is something that I have left out that has caused this to not work. Proved that the IDE Serial Monitor section works by connecting it to an Arduino Due. I can send text back and forth between the M4 and the Arduino Due using IDE Serial Monitor on each. So back to RX problem with UART6. Sorry this message is so long but it might help someone point out the error I have made with UART6 setup.