use one GPIO to do Duplex communication

[zsong.2]

hi ,

I have to STM32 chip, how to use one GPIO to do Duplex communication bettween this two STM32 ?

thanks

[S.Ma]

No details will yield fuzzy answers.

There is a protocol for 1 wire interface, like the ones to communicate with smart batteries, which could be worth exploring.

Otherwise, open drain usart on tx pin with external pull up and sw swap rx tx to get bidirectional. You will need to implement protocol and collisions.

[Piranha]

A push-pull with an internal pull-up and a series 1k resistor for safety performs much better. And with a SWAP configuration bit the same half-duplex communication can be done on Rx pin.