NRF52832 single wire uart

[szmodz]

Is it possible to use the NRF52832 UART in half-duplex single-wire mode, by assigning TXD and RXD to the same GPIO, setting the GPIO drive to disconnect '1' and using a pull-up resistor?

[Ole Bauck]

It is not possible.

It may work if you put a diode between TX and RX and use pullup resistor on the RX line. Do a search on the internet, there is a lot of information about this topic with other MCUs.

[szmodz]

Setting the output to disconnect '1' has basically the same effect as adding the diode. The diode is only needed with push-pull outputs, it's not needed in the case of open drain outputs. When the GPIO is set to open drain mode (or "disconnect '1'" as called in the NRF52832 manual), the pin will only actively drive the '0' state. '1' will be floating, and the high state will only be forced by the pull up resistor. When TX is idle, the output state is '1', or floating in case of open drain outputs.