How to configure 2 external PSRAM of 64MByte with STM32H7S7

[Zeya]

Hi, we are in the initial stage of our project and planning to use STM32H7S7I8T6, we need to have a 128MByte of external RAM as per our requirements but only 64MByte of PSRAM is available in market currently, is it possible to add two 64MByte of PSRAM to the MCU (If any please provide the guidance/design note) or any other options ?

 

[KDJEM.1]

Hello ​@Zeya and welcome to the community;

 

According to RM0477, from the FMC point of view, the external memory is divided into fixed-size banks of 256 Mbytes each :

• Bank 1 is used to address up to 4 NOR flash memory or PSRAM devices.

This bank is split into 4 NOR/PSRAM subbanks with 4 dedicated Chip Selects, as follows:

– Bank 1 - NOR/PSRAM 1

– Bank 1 - NOR/PSRAM 2

– Bank 1 - NOR/PSRAM 3

– Bank 1 - NOR/PSRAM 4

• Bank 2 and Bank 4 are not used by the FMC.

• Bank 3 is used to address NAND flash memory devices.The MPU memory attribute for this space must be reconfigured by software to Device.

• Bank 5 and 6 are used to address SDRAM devices (1 device per bank)can support two external SDRAM devices, because the FMC provides two SDRAM banks,. So, Bank 5 and 6 are used to address SDRAM devices (1 device per bank).

For Hardware recommendation, I advise you to look at  Getting started with STM32H7Rx/7Sx MCUs hardware development - Application note precisely section 10.4.2 Flexible memory controller (FMC) interface.

 

Thank you.

Kaouthar

[mƎALLEm]

Changed the title ton contain “PSRAM” instead of “SDRAM” as the question is related to PSRAM.