Why is FMC-SDRAM no longer supported on STM32H533 compared to STM32F446?

[Mohamed Aymen]

Hello everyone,

I am migrating a design from STM32F446 (UFBGA-144) to STM32H533 (UFBGA-144) and noticed that FMC-SDRAM is no longer supported on the STM32H533.

On the STM32F446, the FMC supports SDRAM and provides signals such as SDCLK, SDCKE, and SDNE, allowing the use of external SDRAM devices. On the STM32H533, these SDRAM-related signals and the FMC SDRAM mode are completely absent, and only SRAM/PSRAM/NOR/NAND memories are supported. From the reference manual and datasheet, this appears to be a hardware design choice.

Could someone clarify the main reason for this architectural change between STM32F446 and STM32H533, and also for applications that previously relied on SDRAM performance, is OctoSPI PSRAM/HyperRAM considered the recommended alternative on STM32H5?

Thank you in advance for your clarification,

Best regards,

Aymen

[mƎALLEm]

Hello @Mohamed Aymen ;

STM32H563/H573 devices feature FMC-SDRAM ;)

https://www.st.com/resource/ja/datasheet/stm32h563ri.pdf

STM32H533 doesn't feature FMC-SDRAM interface and it was a choice.