STM32L4R9 OCTOSPI / HyperRAM support and errata clarification

[prathamvora090]

Hi everyone,

I’m currently trying to bring up an external RAM (HyperRAM over the HyperBus protocol) on the STM32L4R9I-EVAL board. While going through the documentation, I’m finding that information related to OCTOSPI and HyperBus on this family is quite scattered, and it’s been difficult to form a clear picture.

From ST forums and discussions, I’ve come across mentions of a silicon/errata limitation on the STM32L4R9 family that affects HyperBus support on OCTOSPI. Some posts even suggest that PSRAM/HyperRAM is not reliably supported despite the presence of the IP, which has left me a bit confused about the actual capabilities and intended use.

My goal is to use the external HyperRAM in memory-mapped mode (for example, as a framebuffer). In parallel, the board also has an external NOR flash connected over OCTOSPI (non-HyperBus), for which ST provides example projects. However, in those examples the flash is configured on OCTOSPI2, while the schematics show it connected to OCTOSPI1, which adds to the confusion.

I’d really appreciate hearing from anyone who has worked on something similar.

Links :
https://community.st.com/t5/stm32-mcus-embedded-software/stm32l4q5agix-hyperbus-psram-issues/td-p/642884#:~:text=Could%20you%20please%20check%20the,Kaouthar

https://community.st.com/t5/stm32-mcus-products/stm32l4r9i-eval-octospi-problem-with-8bit-access/td-p/407831#:~:text=event%20is%20masked%22.-,Thus%2C%20the%20octospi%20interface%20cannot%20be%20used%20as%20direct%20ram,0%20Kudos

https://community.st.com/t5/stm32-mcus-products/stm32l4rxxx-octospi-with-psram/td-p/130684#:~:text=Dear%20All%2C,that%20have%20Hyperbus%20differential%20clock.&text=on%20page%2026%2C%20it%20is,What%20I%20am%20missing?&text=Labels:,STM32L4%20series

https://www.st.com.cn/content/ccc/resource/training/technical/product_training/group0/38/14/f0/84/28/e0/4b/40/STM32L4Plus_Introduction_Delta_STM32L4_Series/files/STM32L4Plus_Introduction_Delta_STM32L4_Series.pdf/_jcr_content/translations/en.STM32L4Plus_Introduction_Delta_STM32L4_Series.pdf

https://www.st.com/resource/en/errata_sheet/es0393-stm32l4rxxx-and-stm32l4sxxx-device-errata-stmicroelectronics.pdf

[KDJEM.1 · Accepted solution]

Hello @prathamvora090 and welcome to the community;

According the erratasheet and STM32L4Plus-Peripheral-OctoSPI interface (OCTOSPI) all the PSRAM memories are not supported in the STM32L4R9 products including the HyperRAM memories, We support only HyperFlash memories.

So we recommend you to use a parallel memory using FSMC or if possible to switch to the STM32L4P5/Q5 products in which the OCTOSPI support PSRAM memories including HyperRAM.

I reported the examples issue internally.

Internal ticket number: 224275 (This is an internal tracking number and is not accessible or usable by customers).

Thank you.

Kaouthar

[prathamvora090]

Hi @KDJEM.1 , thank you for the update this helps in making a right decision. we are just curious how it is that there is support for hyperbus flash but not ram or psram and can you please provide the link to this information any pdf link will help. there is a much more crucial thing i want to bring to your attention I have a eval board and with macronix flash memory the examples and template projects for this are missing and what exists does not work . 

[KDJEM.1]

Hello @prathamvora090 ,

-> we are just curious how it is that there is support for hyperbus flash but not ram or psram and can you please provide the link to this information any pdf link will help.

You can find this information in:

The erratasheet : STM32L4Rxxx and STM32L4Sxxx device errata - Errata sheet

The product training: STM32L4Plus-Peripheral-OctoSPI interface (OCTOSPI)

Thank you.

Kaouthar