External Flash memory(octal SPI) supply shortage issues for TouchGFX applications like STM32U5G9J-DK2

[NAmam.2]

Hi,

We are currently facing serious supply shortage issues with the MX66LM1G45GXDI00 flash memory.

As a potential solution, I am considering modifying the design to use an external Quad-SPI flash memory instead of the current Octo-SPI flash.

My understanding is that this change may require us to develop or modify the following:

• Quad-SPI flash drivers for the STM32U5G9
• Flash initialization and memory-mapped access configuration
• Programming/firmware download utilities
• Production programming support
• Bootloader and/or application changes, if required
• TouchGFX/external-memory configuration, if applicable

Could you please let us know whether suitable Quad-SPI flash drivers, BSP components, or programming utilities are already available that we could leverage, particularly for the STM32U5G9?

I would also appreciate your comments on the key challenges and any guidelines or recommendations you may have for this development effort. In particular, I would like to understand the potential impact on memory-mapped operation, performance, TouchGFX, production programming, and software development effort.

Our goal is to identify a reliable Quad-SPI flash alternative that can address the current supply constraints while minimizing the impact to the existing design and software.

Thank you for your guidance.

[NAmam.2]

I found some useful application notes, AN5050 and AN4760.

I also found some code examples for QSPI read/write operations. I’m going to work with these examples to better understand the challenges of using Quad-SPI Flash in place of Octal-SPI Flash.

Please let me know if anyone has any comments, suggestions, or recommendations on this topic.

[KDJEM.1]

Hello ​@NAmam.2 ;

 

To better understand the main differences between using Quad-SPI flash memory and Octal-SPI flash, I recommend you to look at  AN5050 “Table 7. STM32CubeMX - Configuration of OCTOSPI signals and mode” and “III. Quad-SPI PSRAM in Regular-command protocol example” sections 

Also, I think the BSP example can help you. This example shows how to use the different functionalities of components available on the board like as HSPI and TOUCHSCREEN.

 

Thank you.

Kaouthar

[NAmam.2]

Hi Kaouthar,

Thanks for your reply.

As you may know, this task required changes to the controller-side QSPI driver that accesses the Flash memory containing the graphic assets using Memory-Mapped Mode. The second major challenge was developing an External Loader to transfer the graphic assets to the external Flash during programming.

The first part—changing the HSPI configuration from Octal SPI to Quad SPI (QSPI)—was relatively straightforward.

For the second part, External Loader development, I referred to the documentation and resources shared by KDJEM.1 on the STMicroelectronics Community:

• How to Implement and Use Your Own External Flash Loader: An Example Using STM32U5A9J-DK 

• STMicroelectronics – External Memory Loaders on GitHub 

Using these resources, I was able to customize an existing STM32U5 external memory loader application to meet our specific requirements.

Finally, we successfully completed the task, including the controller-side QSPI driver changes and the External Loader development, with the help of the documentation and reference implementations mentioned above.

[KDJEM.1]

Hello ​@NAmam.2 ;

 

Thank you for updated post and shared the solution.

Thank you for your contribution in STCommunity.

 

Kaouthar