Chain 2 TReX, but get RX working

I’m daisy chaining two TReX controllers together, and everything works as expected on the TX side. Also, individually, I can get back (RX) from each just fine. When trying to get back RX from each while chained (and I’m ensuring I’m not receiving from both at the same time) I see on the o-scope that the voltage drop for each bit is smaller when daisy chained together.

I see here: Control Program the following:

Now you can split the computer’s TX line, and wire it to the RX pins on both of your TReX controllers. You should also wire both controllers to the serial ground line. You should not wire both controller’s TX pins to the computer’s RX line, this will cause problems. You will probably need to leave one controller’s TX line connected to keep the configurator program happy, as it expects to get information back from the TReX. If you really need to get data back from both motor controllers you can do tricks with diodes and resistors (and time it so they’re never talking back at the same time) but in this case it would probably be much simpler to just get two USB to Serial adapters (you can do this anyway if it makes things simpler for you).

What would that circuit look like to get two chained RX lines to work?


Looks like the answer was on the website, here:


And this helps even further - no IC needed:

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