Carbide Motion Board TX pin + USB

So I just noticed that the Carbide Motion Board has TX and RX pins meaning a serial port. If I’m sending commands via the USB interface do those commands get mirrored to these pins? If so it will greatly simplify my BLDC spindle controller. I can just grab the M3 gcode commands from the serial pins and get the RPMs directly.

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You can’t use both USB and the tx/rx lines directly. As far as I know, it’s all just highs and lows on the lines. Your mc that is trying to read the same rx signal will be, at the same time, connecting the RX to its state.
I’m not saying you can’t somehow split the signal, but it will not be as trivial as connecting to those pins.
The PWM signal won’t work for what you’re doing?

The controller I am using allows you to say, “Go 14342 RPM” and it will go 14342 RPM (not that I need that level of precision). The PWM output is noisy so I have to limit the RPMs to 500 RPM increments. Anything lower than that and the RPM will jump around.

Also I have to use a PWM look up table to figure out what RPM it should be running. That look up table might need to be different for other people.

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Gotcha…In my mind, you’d use something to get the signal directly from USB and then pass it along to the Carbide 3D board.