Flash Memory: OCTOSPI feature with Quad SPI Flash

[KMew]

Hello,

I am using the STM32H7B3LIH6Q with a MX25U51245GMI00 flash memory. The flash is only capable of using Quad SPI, not Octo SPI. If I wanted to use it, do I just use the Dual-Quad SPI mode in CubeMX to utilize it? Or would it not work at all?

Also, is Data Strobe only a feature for Octo SPI?

 

Thank you in advance.

[KMew]

Just wanted to bump this thread. Can anyone provide any insight?

[ChahinezC · Accepted solution]

Hello @KMew​,

To verify the compatibility of the memory used please make sure to refer to the memory's datasheet.

In case it is manufactured to be only used in QuadSPI mode, unfortunately it is not compatible with the OCTOSPI interface on the STM32 MCU. It is mandatory to use the a memory that supports Octo or Dual-quad mode.

For the data strobe it is a feature of the OCTOSPI interface.

I hope this solves your problem, please mark my answer as Best by clicking on the "Select as Best" button, this can be very helpful for Community users to find this solution faster.

Kind regards,

Chahinez.

[LCE]

What, really?

You can't even use a simple quad SPI memory in standard read / write mode?

Memory-mapped or DMA not working, okay, bad, but simple quad read / write?

The OP didn't say how it's getting used, but anyway.

[ChahinezC]

Hello @Community member​,

The initial question was about using the OctoSPI mode with a memory which does not support the Octo mode, but using other modes (single/dual/quad....) with any memory is, as mentioned, should always be based on the memory's datasheet to verify first whether the memory supports the mode used or not.

In order to understand better the OCTOSPI interface and its modes, I recommend you checking the AN5050, and for the QSPI interface, I recommend you the AN4760, they will certainly help you get a better view.

I hope my answer has helped you.

Thank you.

Chahinez.

[KMew]

@ChahinezC​ Hello,

Thank you for your reply! I apologize if any of my replies are confusing since the terminology is still something I am getting used to.

As per @Community member​'s comment for clarification, my purpose for the Flash memory is for utilization of an LCD-TFT display using STM32's LTDC interface and generate a display using TouchGFX's application. This will include multiple images/fonts that could potentially add up to a Flash usage that exceeds the internal flash capabilities.

I have looked through the application notes, but I admit that my inexperience with them has me unsure of what to look for. We did run into a problem with sourcing our MCU and had to switch it to a different one (STM32H7B3IIT6). Its configuration is a little bit different too. This MCU explicitly states that one of the modes are "Quad SPI" mode, which is the same as the MX25U51245GMI00 flash memory.

 

So to return to my original question and expand upon it:

1) What parameters should I be looking for to determine if this is compatible?

2) Based on my use case of just storing fonts/images in the Flash, if the MCU has OctoSPI but then has an option in the configuration for QuadSPI, is that sufficient for compatibility?

[LCE]

@KMew​ 

How is that flash working in that application?

In memory-mapped mode?

If yes, there were some problems, at least with H723 & quad SPI RAM.

I don't know if these problems happen on your H7 with a quad SPI flash.

Anyway, before building your own PCB I recommend that you get a Nucleo and connect that flash and test it.

[KMew]

Hello LCE,

Thank you for your reply!

If my understanding of memory-mapped mode is correct (it basically gets perceived as internal memory), then yes, I will likely use it in memory-mapped mode.

I have the STM32H7B3I-EVAL board, which uses OctoSPI NOR Flash memory by Macronix. I am using the same family of NOR Flash, but QuadSPI instead of OctoSPI (due to part availability issues with the OctoSPI version).

So I do know how to use the NOR Flash over the SPI line and have reference designs I am using. Is there anything else I can check before using a Nucleo board and testing it? Like specific datasheet parameters to look up?

[LCE]

Check the datasheet and reference manual of the H7 concerning QSPI / memory-mapped access.

After my recent experience with the QSPI RAM I would never use something I haven't tested before putting it on a PCB.

Even when knowing that octal mode works, does it really work the same in quad mode ? (Okay, except for half speed...)