Octospi multiplexed hyperbus on STM32L4R9 with STMCubeMX

[Jschpmn]

Hi

According to the datasheets, the STM32L4R9 LQFP100 devices should be able to support a multiplex hyperbus ram/flash device. (for example the cypress S71KSS12SCO)

But in STM32CubeMX, I'm unable to select the multiplexed hyperbus mode. I notice that I can with other devices like the STM32H7

Is this a problem with STM32CubeMX or am I not understanding the constraints and multiplexed hyperbus isn't supported on these devices after all?

thanks

[Imen.D]

Hello @Jschpmn​ and welcome to the Community 🙂

The multiplexed mode is not supported for STM32L4R/Sxxx series.

You can check the "Table 124. OCTOSPIM implementation on STM32L4+ Series", in the STM32L4+ Reference Manual (RM0432) described that the multiplexed mode is not supported for STM32L4R/Sxxx.

 

Note that the OCTOSPI-PSRAM memories (including HyperRAMs) are not supported in the STM32L4R/Sxxx products.

For more details, please have a look at the STM32L4Rxxx / STM32L4Sxxx errata sheet.

So, It's recommended to use Parallel PSRAM memories with FMC or to switch, if possible, to a STM32L4P5/Q5xx product which supports OCTOSPI PSRAM memories. 

Please mark my answer as best by clicking on the "Select as Best" button if it fully answered your question. This will help other users find this answer more quickly.

Imen

[Jschpmn]

Hi Imen

Thanks for your answer. Shame about the multiplexing thing. I'm working on a device which needs to drive a MIPI DSI display, and also needs lots of RAM/FLASH which doesn't have to be that fast. The combined hyperbus device was ideal, as I'm quite space constrained as well. (Aren't we always!)

Are you sure about the lack of support for hyperram on the STM32L4R9? The schematics for the STM32L4Rx-EVAL board clearly have an ISSI IS66WVH8M8BLL-100BLI

hyperbus psram device. If that can work I'll probably go with that and a slow non memory mapped flash on standard spi,

thanks

[Imen.D]

Hi @Jschpmn​ ,

Regarding the DSI, you can use SPI or LTDC RGB222. For more detail, please refer to the AN4861 Application note LCD-TFT display controller (LTDC) on STM32 MCUs.

Imen

[Jschpmn]

Thanks

But what about the hyperram? I do need the MIPI-DSI-PHY. I assume that hyperram is supported in the stm32l4r9 because of the dev board, and some threads I've seen, but you've got me worried now!

jim

[Imen.D · Accepted solution]

In fact, the PSRAM HyperRAM is available in the STM32L4R9-Eval, but due to the OCTOSPI limitations with PSRAMs, there is no longuer support OCTOSPI PSRAMs as described in the erratasheet.

Imen

[Jschpmn]

thanks