Content originally posted in LPCWare by fjrg76 on Sat Nov 10 12:09:40 MST 2012
If it's full-duplex, then it becomes RS422 :D and it would all about your underlying hardware, e.g., you can use two RS485 chips to get the RS422 interface.
The point here is that RS485 uses three lines, Tx,Rx, and Dir. In the LPC1227 the Dir pin is multiplexed in the ~RTS pin for the UART0. Your uC must have something similar.