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ngrigoriadis
Senior
September 7, 2023
Question

Riverdi (display) connection with external PHY

  • September 7, 2023
  • 8 replies
  • 2498 views

Hello. I have a RIVERDI display with the STM32H757XIH6 (2MB Flash, 1MB RAM) microcontroller. I am trying to develop for this display a program  in order to connect it with an external PHY. In my research for external PHY I have found the LAN8720. Although, many topics here saying that this PHY drivers cant connect with the CubeMX and also I have read that in a lot of cases it is not working with this microcontroller. I am a bit confused and I want a feedback about this: 1) Is this LAN8720 a good solution to connect to my display and work with some protocols in order to receive messages like MQTT? If yes, is there any compatible library for this interface with this microcontroller?

2) If the LAN8720, isn't a good solution for my project, could you please provide to me some compatible and working external PHY's for developing this task, in order to buy them and start developing?

Thank you in advance!

This topic has been closed for replies.

8 replies

Issamos
Issamos
Super User
September 7, 2023

Hello @ngrigoriadis 

I suggest you to use the LAN8742 for your application with the stm32h7. This component is supported by stm32cubeh7.

Best regards.

II

    ngrigoriadisAuthor
    Senior
    September 7, 2023

    Thank you for your reply. I did a research on that PHY (LAN8742) and unfortunately I couldn't find a board (complete product) to buy only for PCB build.

    mƎALLEm
    mƎALLEm
    ST Technical Moderator
    September 7, 2023

    Hello,

    The LAN8742A PHY is already used on ST boards, STM32H757-EVAL board or NUCLEO-H755ZI as an examples.

    To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
    Bob S
    Bob S
    Super User
    September 8, 2023

    How do you intend to connect the display board to an external LAN8742?  Does the Riverdi have some kind of expansion connector that intended for this purpose?  Sending 50MHz clock and data over jumper wires will not be easy.

    You could always buy the NUCLEO board, unsolder the CPU (or hard-wire the RESET pin low) and wire the on-board PHY to our display board (keeping in mind the caveat about 50MHz and jumper wires above).

    ngrigoriadisAuthor
    Senior
    September 8, 2023

    Hello and thank you for your reply. Yes the riverdi display that I have supports expansion connector but I can only use RMII and not MII. As far as the 50MHz clock speed that needs to syncronize the system, it must be through an external crystal or from internal source if the microcontroller support it? This is the riverdi screen that I have:https://riverdi.com/product/7-inch-lcd-display-capacitive-touch-panel-optical-bonding-uxtouch-stm32h7-rvt70hssnwc00-b. What do you think about that? Should I need to apply an external crystal for this purpose or not? I would appreciate if you give me a feedback. Thank you in advance!

    Piranha
    Piranha
    Principal III
    September 8, 2023

    Maybe one should first look around...

    https://riverdi.com/product/stm32h7-poe-add-on

    Bob S
    Bob S
    Super User
    September 13, 2023

    See also new thread https://community.st.com/t5/stm32-mcus-products/riverdi-diplay-with-stm32h7-and-external-phy/td-p/590262

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