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Visitor II
January 15, 2024
Question

nucleu-h745zi-q rs485 without external module

  • January 15, 2024
  • 3 replies
  • 1083 views

Hello
//   nucleu-h745zi-q
I want to use hardware flow control rs485

Previously, i used an external module because there was only rs232 (f103).
** question ** . With this feature, can the module be removed and the microcontroller directly connected to A B receiver?

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    3 replies

    Super User
    January 15, 2024

    No.

    Super User
    January 15, 2024

    Hi,

    You need to connect a rs485 driver, thats all. And set a UART to 485-mode (thats capable to do this).

    Something like DS485M (from Ti) .

    look at mouser ... many :

    https://www.mouser.de/c/semiconductors/interface-ics/rs-485-interface-ic/?q=rs485&instock=y&sort=pricing

     

    January 15, 2024

    Thank you for your answer
    I used to run rs485 easily without hardware flow control
    I would like to know what difference will be made by adding this feature?

    Graduate II
    January 15, 2024

    The ST-LINK on the NUCLEO does not implement RS232 levels.

    RS485 differential pairs need a transceiver, and a control signal to enable the driver. Direction rather than "flow" control

    Perhaps RS422 where you have a separate pair for each of transmit and receive signals?