Why Your STM32MP657 Can't Use SDR SDRAM (And How to Pick the Right DDR3)

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I just spent some time debugging a fundamental compatibility issue between an MPU and its RAM, and I wanted to share what I learned to save others the same headache.

I was looking at using the STM32MP657 (a powerful Cortex-A7 MPU) and almost made a critical error by assuming it could work with a common SDR SDRAM chip like the W9825G6KH-6.

Spoiler Alert: It can't. Here's why.

The STM32MP657 has a DDR3/LPDDR2/LPDDR3 memory controller. The W9825G6KH-6 is an SDR SDRAM. These are two completely different, incompatible memory technologies.

Think of it like trying to put diesel fuel in a gasoline engine. Both are fuels, but the underlying technology and "communication protocol" are entirely different.

[TDK]

Huh?

> STM32MP657

The STM32MP657 doesn't exist. Probably meant STM32N657?

> The STM32MP657 has a DDR3/LPDDR2/LPDDR3 memory controller. The W9825G6KH-6 is an SDR SDRAM. These are two completely different, incompatible memory technologies.

STM32N657 definitely support SDRAM. It can work with the W9825G6KH-6 in SDR mode.

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Sorry 

Yes im looking for STM32N657 

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I need  support for  developing a custom bord with maximum external ram and flash setup , bootloader and air application setup