RS-232 TX and RX on one line...

Discussion in 'General Electronics Chat' started by dtvonly, Apr 25, 2014.

  1. dtvonly

    Thread Starter Member

    Dec 14, 2012
    Hi. I have a project where the limited "real-estate" on the target PCB has forced me to wire both TX and RX line together. This line from this target is to be connected to a microcontroller box which will transmit then receive data to and from the target. I am having trouble designing the circuit in the microcontroller box to both TX and RX to and from the target on one line. Any design suggestion/circuit would be greatly appreciated.
  2. vk6zgo

    Active Member

    Jul 21, 2012
    Convert it to RS485,which is better suited to use in that manner.
  3. dtvonly

    Thread Starter Member

    Dec 14, 2012
    ...or even I2C. But that is for the next revision. Any suggestions for the current revision?
  4. nsaspook

    AAC Fanatic!

    Aug 27, 2009
    If you have tx driver output enables on each side under software control you can make a ping-pong master slave polled protocol.

    Start with master tx enabled, slave tx disabled, each side programmed to ignore echoed own data.
    master sends data to slave then disables tx and listens for data
    slave processes sent data , enables it's tx to send (fixed or variable sized packets with a information header) to master then disables it's tx so it can listen again.
    master receives slave data and enables its tx so process can repeat.
    Last edited: Apr 25, 2014