Interfacing GPIO pins between a uC and RS-485 tranceiver
Just tie the direction control pins together and drive them directly. I use 3073 with 3.3V GPIO and a TTL UART and it works great. If you are going a long distance - RS-485 on a twisted pair is good for a thousand meters or more - put a termination resistor at the far end. 220 Ohms is good (opinions vary on termination).