stoyanoff
Full Member level 4
Greetings! I have to combine current loop and RS232 or RS485 and RS232. I have 2 free UART interfaces on a PIC uC and I have connected to them a current loop and RS485. I`m using 6N136 optocouplers for the current loop and SP485EEN for RS232. Now I have to add additional RS232. So it must share one of the UARTs. What`s bothers me is the input signal RX. I don`t think RX of MAX232 could be driven to high impedance state. So what can I do? I have seen devices with multiple interfaces on single UART - RS232,RS485 and so on... How do they achieve it?
Thanks!
Thanks!