TIDA-00862: TIDA-00862

I have RS422 Full duplex RX+,RX-, TX+, TX-  output coming from device and another device requires RS485 (2 wire) DATA+ and DATA- in order to communicate this i need a reference design kindly suggest any reference design

For full duplex to half duplex conversion, you can refer to this diagram.

The TMUX6121 (Hi-RON mux)

• Will support +/-16.5V VDD and VSS
• The signal on S/D pin will still be rail to rail between VDD and VSS
• The digital control pins support 2V logic.

Hi Hao,

Thank you for your reponse . I have a doubt regarding \RE  and DE pins to be used while transmitting and receiving from RS422 4 wire to 4S485 2 wire. The During Full duplex AB,Y,Z pins the termination resistors needed to be used?

For full-duplex, \RE=L, DE=H. For half-duplex, you can control \RE and DE with the same logic.

What's the data rate and cable length? Is there termination at the receiver side of RS422? If it doesn't affect the signal that much, you can put termination at A/B pins to only cover the half-duplex case.

The data rate is 50Mbps and Cable length is 10meter and here simulataneously and we can connect A to RX+ and B to RX- and Y and Z to TX+ and TX- for RS422 full duplex and  R and D pins to be connected to the RS485 Half duplex pins to the RS485A and RS485B comming from the source is this correct. Do i need to isolation between rs485 output and RS422 output in this schematic

The connection looks right to me. I'm not sure what you meant by 'isolating' RS-485 and RS-422 output. If you referred to the logic side (R/D), you could do it with optocoupler.

BTW, if you need to terminate both TX and RX of RS-422, you may have to add another switch for one of them.

But how to terminate the RS422TX+ and RS422 RX+ and RS422TX- and RS422RX- pins .Kindly can you show me how to terminate and use those signals for RS422 Full duplex configuration