Is there a way to increase RAM on STM32mp157C ?

ABous.1 · ‎2021-03-01

Hello,

We want to transfer a project from STM32F7 to STM32MP157C ( cortex M4 side). To do that we need an external RAM (arround 20 Mbytes).

Is there a way to map an external RAM on cortex M4 side with cubeMX ?

Best regards,

Arnaud

PatrickF · ‎2021-03-08

Hi,

You could assign FMC to M4 and use it to connect an external SRAM (not SDRAM nor DDR), but due to async domain crossing and no cache on M4 side, performance would be quite poor for code storage (read: not usable). Might be suitable to store data, e.g. using DMA.

Note: for SW point of view, Cortex-M4 does not have direct access to Linux DDR (Although, performance from M4 would be poor as well as with many potential hurdle and performance impact for Linux), but maybe your project could be split differently to make more use of Linux for memory intensive tasks.

Btw, did you know this big source of information : https://wiki.st.com/stm32mpu/wiki/Main_Page ?

Regards.

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PatrickF · ‎2021-03-08

Hi,

You could assign FMC to M4 and use it to connect an external SRAM (not SDRAM nor DDR), but due to async domain crossing and no cache on M4 side, performance would be quite poor for code storage (read: not usable). Might be suitable to store data, e.g. using DMA.

Note: for SW point of view, Cortex-M4 does not have direct access to Linux DDR (Although, performance from M4 would be poor as well as with many potential hurdle and performance impact for Linux), but maybe your project could be split differently to make more use of Linux for memory intensive tasks.

Btw, did you know this big source of information : https://wiki.st.com/stm32mpu/wiki/Main_Page ?

Regards.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

ABous.1 · ‎2021-03-09

Hi,

thanks for these details.

We tired to assign FMC to M4 in cubeMX but it seem to be not possible with our MP1 firmware version V1.2.0.

Should we assign FMC manualy in DTS side for A7 and in our code for M4 ?

Regards,

Arnaud

PatrickF · ‎2021-03-09

I encourage you to use latest CubeMx (with CubeMP1 V1.3.0), even to build a dummy project, then check and reuse part of the generated DT and CubeMP1 FW.

Regards.

In order to give better visibility on the answered topics, please click on 'Accept as Solution' on the reply which solved your issue or answered your question.

ABous.1 · ‎2021-03-09

We have download the latest CubeMx version (6.2.0) and the latest CubeMP1 version (1.3.0) and every things work properly.

Thanks for support.

Regards,

Arnaud