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.
