Dear, We are new design of board with STM32H7 and we need to put external SDRAM using Flexible memory controller (FMC). Could you say me routing rules or routing guidelines ? Thank you in advance

[FAlca.2]

We will use chips with lower data witdh than 32 bits, by this we put multiple chip form the data bus.

Could you help me?

[Imen.D]

Hello @Community member​,

First, let me first welcome you to the Community 🙂

I recommend you this article: How to set up the FMC peripheral to interface with the SDRAM IS42S16800F-6BLI from ISSI. This FAQ will help you on how to set up the FMC peripheral in the STM32H7B3I-DK TouchGFX Board Setup, to have the ability to have the frame buffers in the SDRAM.

Refer also to your product Datasheet to check the FMC characteristics suitable of STM32H7 product used (in FMC characteristics section).

Imen

[FAlca.2]

Thank you for your quiclky help,

I saw this application note, but I need routing rules ( by example with is more recommended routing chain of star rouitng, maching rules between lines,...)

Can you help me?

Bye

[Imen.D]

Hi @Community member​,

Sorry for the delayed reply on this post.

You can refer to this getting started AN5307 that may help you on the routing guidelines, in the 9.4.2 Flexible memory controller (FMC) interface section.

Imen

[FAlca.2]

Thank you for your answer, I have addional questions:

1. Could you say me what is the maximun number of devices SDRAM that they can connected to this interface? (1,2 or 4)
2. Could you say me constreins and matched of these signals to access to external SDRAM?
3. do you have a reference design?

Thank you in advance