Expanding SRAM on STM32H723VGH6

[sirin]

Hi everyone,

I'm a beginner, and this might be a basic question for many of you, but I appreciate your help nonetheless.

I'm working on a project using the STM32H723VGH6 (due to size and design constraints, I can't use the ZG series) and I want to expand the RAM by connecting an IS62WV51216 SRAM. However, I noticed that in CubeMX, the FMC configuration only has a "Muxed PSRAM" option and no SRAM option (the ZG series has an SRAM option in CubeMX).

Even with the PSRAM option, I found that PSRAM typically has both address lines (Ax) and data lines (Dx), but CubeMX only shows pinout for data lines, not address lines.

I have a couple of questions:

1. Is it possible to support SRAM or PSRAM with address lines? If so, how should I connect the GPIOs?
2. If it's not possible, is there a suitable PSRAM model that fits this data-line-only configuration?
3. When using the HAL library for development, are there any code differences between regular SRAM/PSRAM and this configuration?

Thanks a lot for your help!

[BarryWhit]

 > If it's not possible, is there a suitable PSRAM model that fits this data-line-only configuration?

I don't have experience with this, but perhaps Cypress/Infineon PSRAM with "Hyperbus" interface is what you want?

Totally Random Example: Infineon-S27KL0642 64Mbit HYPERRAM™ self-refresh DRAM (PSRAM)  

Some (all?) of those chips are DDR, I'm not sure if that's standard for PSRAM or not.

Another option is to look at the eval boards ST provides, and see if one of them includes a SRAM/PSRAM which suits your requirements. Once you have an example part number, it's easier to find alternatives (for example, with different capacity).

[mƎALLEm · Accepted solution]

Hello,

STM32H723VG is a TFBGA100 package contrarily to ZG (LQFP144 package ) some FMC signals are not available on that package like FMC_A0 to to FMC_A15 address lines. So you need to use "muxed" config in that package i.e. using FMC_AD0 to FMC_AD15: they are multiplexed Address and Data lines which are selected by FMC_ALE (Address Latch Enable).

See datasheet:

But here you need either a memory supporting the mux mode or you need to add an external Latch to hold the address while handling the data.

But as I can see from IS62WV51216 datasheet, it does not support the mux mode so you need to add an external latch (managed by FMC_ALE).

Otherwise, you can use an external hyperRam over OSPI interface in memory mapped mode.

Hope I answered your question.

[LCE]

I use the H733 / H735 with Infineon HyperRam S70KL1281 / S70KL1282 via OCTOSPI in memory-mapped mode.

Works perfectly here at 100 MHz with data rates > 50 MByte/s.

The H723 should be able to do the same.

[sirin]

Thanks, I’ll check those HyperRAM later.:thumbs_up:

[sirin]

Thank you, I will check it out.

[sirin]

Thank you for your patient response. Your explanation solved my problem perfectly.:smiling_face_with_heart_eyes: