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STM32Uxx: OCTALSPI direction signal (is missing)

Senior III

I need level shifters, using QSPI signals with 1V2 logic (MCU can just be set for 1V8, so I need level shifters).

I have realized: bi-directional level shifters for 1V2 are pretty slow (and rare). Level shifters which have a DIR signal (to turn the direction) are way faster, e,g, SN74AXC2T45. Therefore, I want to use Level Shifter (LS) which have a DIR signal.

But how to get a DIR signal from MCU?

  • Can I pause the transmission after sending CMD, ADDR and ALT (before DUMMY), so that I can turn the direction of LS? I do not think so.
  • Can I get an indication signal from QSPI device when CMD, ADDR and ALT was sent?
    E.g. an INT (or flag) telling me the Preamble was sent, so that I can hurry to change the direction of LS? I do not think so.
  • Can I use DQS signal for this intention? I do not think so (DQS does not work in SDR mode)

Dear STM team:

Please, could you consider providing an (optional) OCTALSPI DIR signal, e.g. using DQS or any other GPIO pin?
I want to control external level shifters for the direction: when CMD, ADDR, ALT was sent, when it comes to clocking out the DUMMY: I want to turn an external level shifter, via a DIRection signal on another GPIO (for the following READ transaction).

  • Or make the MCU working for 1V2 VDD, so that OCTALSPI pins are 1V2 logic. Or provide the OCTALSPI pins on the VDDIO2 voltage domain..,

Thank you.


ST Employee

Hello @tjaekel ,


Thank you for your feedback and for your contribution in STCommunity.

I escalated your requests to involved team to take a closer look at these needs and feedbacks.


Thank you.


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