Hi, I am trying to use Arduino UNO to control a stepper motor via RS485, but I am not sure about the wiring between the UNO and the MAX485 ttl to RS485 conversion board. Wiring the TX and RX pins of the UNO to the DI and RO pins of the MAX485 board is sure, but there seems a number of ways of connecting the DE and RE pins of the MAX485 board to the UNO pins. I am not sure which to choose. Since the pulse and the direction need to be defined, it seems another two pins, e.g., 2 and 3, of the UNO should be connected with the MAX485 board. Thus, I have the following wiring. However, the RE pin of the MAX485 is the Receiver Enable pin for receiving data. So, the below wiring seems incorrect.
Anyone has relevant experience? Thanks a lot.