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Graduate II
November 1, 2023
Question

Implementing 2 UART on same port

  • November 1, 2023
  • 2 replies
  • 4533 views

Hello,

I am trying to implement 2 separate UART channels on the single port. I have initialized the two UART channels and have connected the TXs and RXs of the two channels with each other. (Image attached)

When I run them separately, they work just fine. But when the TXs are connected they won't work. Is this the correct way to operate the two channels on same port?

Please assist.

-Regards

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    2 replies

    Graduate II
    November 1, 2023

    The point / purpose of this would be what?

    HDesa.1Author
    Graduate II
    November 1, 2023

    I have a single port which I can use to transfer the data. I want to transfer and communicate with both the core independently.

    Super User
    November 1, 2023

    If Tx pins are set to push-pull as is normal, you can't just simply connect them - they will "fight" with uncertain result, or even get damaged.

    JW

    HDesa.1Author
    Graduate II
    November 1, 2023

    So what is the solution for this. Should I initialize it to Open Drain. Will this affect the communication?

    Graduate II
    November 1, 2023

    You could use open drain with a pull-up, but you'd still need to manage / arbitrate usage so not to step on each other's communication. As the signal is Normally-High you could use an AND gate, or diodes, to mix a signal in Push-Pull mode.

    You could share one UART between cores, both have access to the registers. Arbitrate who has owner ship.