Joined: 08 Aug 2016
|Posted: Mon Oct 24, 2016 8:27 Post subject: Automatic RTS control for RS-232 to RS-485 converters
|I got my prototype RS-485 circuit working. Now, I've connected it to my PC through RS-232 as I want to make the PC as the master. However, when I connect to the circuit using Hyperterminal, the RTS line, connected to RE and DE, always goes high. The PC can send data to the circuit but not receive, since the RTS never goes low. Changing the handshaking from none to hardware didn't help.
I later made mods to the circuit, so that, on the PIC side, the pin that drives the SN75176's RE and DE high when transmitting data will also drive the SN75176's RE and DE on the PC side low to enable receiving. This in effect turns the line from two to three. It's wrong, but I'm just doing it to see how it'll really work if the RTS pin is working properly.
How do I go on making the RTS pin working correctly? I know I can just create an app using Visual Studio to connect to the line and have RTS toggled manually, but doing so is too troublesome and I'd rather have a hardware solution if possible.[/img]