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Explorer II
April 19, 2024
Solved

STM32 Muxed FMC reference schematic

  • April 19, 2024
  • 2 replies
  • 2259 views

Hi,

I'm working on a hardware design using the STM32F765VIH and I am trying to connect a MT28EW128ABA1HPC-0SIT NOR Flash and IS66WVH16M8DBLL-100B1LI PSRAM to the FMC in muxed mode. I'm struggling to understand how the muxed connection should be made and although I've searched a lot I cannot seem to find any reference schematics for this. 

 

Can anyone point me to reference material that could help me?

 

Thanks,

George

 

Edit: Corrected NOR Flash part number, was previously wrongly written as part IS29GL128-70DLEB

    This topic has been closed for replies.
    Best answer by mƎALLEm

    Hello,

    MT28EW128ABA1HPC: same thing -> No muxed Address-Data busses:

    SofLit_0-1713541562722.png

    Unfortunately (to my knowledge) there is no reference design provided by ST as all STM32 MCU boards are using memories having separated Address/Data lines: direct connections data-data, address-address (no shared busses / neither external latches).

    2 replies

    Super User
    April 19, 2024

    What exactly do you mean by "muxed mode" here?

    The PSRAM appears to be HyperBus interfaced; FMC does not support HyperBus. The 'F7 family does not have OCTOSPI interface which supports HyperBus, read AN5050.

    JW

    Technical Moderator
    April 19, 2024

    Hello,

    Not sure how do you plan to connect a HyperRAM to the FMC interface! The protocol is quiet different!

    SofLit_0-1713539200286.png

    Regarding the NOR Flash, FMC muxed mode needs either a memory having natively a shared Address-Data lines (which is not the case of IS29GL128-70) or you need to add external latches to hold the address during the read/write operations.

    gosalAuthor
    Explorer II
    April 19, 2024

    Sorry I had specified the wrong part number for the NOR Flash, I'm considering the MT28EW128ABA1HPC-0SIT but regardless of the actual partnumbers is there any reference design that shows how to interface the muxed FMC to standard parallel NOR Flash or PSRAM ?

    mƎALLEmAnswer
    Technical Moderator
    April 19, 2024

    Hello,

    MT28EW128ABA1HPC: same thing -> No muxed Address-Data busses:

    SofLit_0-1713541562722.png

    Unfortunately (to my knowledge) there is no reference design provided by ST as all STM32 MCU boards are using memories having separated Address/Data lines: direct connections data-data, address-address (no shared busses / neither external latches).