How to use DDR3 with Cortex-A7 (STM32MP157C-DK2 - C++ project)?

FrancoB · ‎2021-01-11

Good morning,

I'm working on a C++ project to collect data from a peripheral sensor using the STM32MP157C-DK2.

The estimated amount of data is at least 100 MB, so I have to use the DDR3 to store these data and then trasmit them over Ethernet using at the moment ONLY Cortex-A7 (no M4).

The project is write in C++ language and NOT using CubeMX, so I'm asking how can I activate and use the DDR3.

I've read some tutorials/documents from various sources:

# https://www.st.com/en/microcontrollers-microprocessors/stm32mp157.html#documentation

# https://wiki.st.com/stm32mpu/wiki/How_to_exchange_large_data_buffers_with_the_coprocessor_-_principle#rpmsg_sdb_driver

# https://wiki.st.com/stm32mpu/wiki/How_to_exchange_large_data_buffers_with_the_coprocessor_-_example

and consequently I wrote the code (you will find it here attached with the dts in the card partition called "bootfs"), but I always receive the cout message "Mapping param failed.".

What I've to modify in the main code and, eventually, how/where can I add/modify the missing dts data to the MP1?

Olivier GALLIEN · ‎2021-01-19

Hi @FrancoB ,

Sorry, I'm a bit puzzled with description of your problem.

I understand you would like to achieve Ethernet transfer of data from a peripheral sensor on A7 Linux side right ?

M4 and A7 to M4 communication not involved right ?

But you refer to

# https://wiki.st.com/stm32mpu/wiki/How_to_exchange_large_data_buffers_with_the_coprocessor_-_principle#rpmsg_sdb_driver

# https://wiki.st.com/stm32mpu/wiki/How_to_exchange_large_data_buffers_with_the_coprocessor_-_example

Which demonstrate only buffer exchange between A7 and M4 ...

Can you please clarify ?

Thx

Olivier

Olivier GALLIEN
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FrancoB · ‎2021-01-19

Dear Olivier,
thank you for your useful tips.
I provide your informations at the people involved
Thank you very mach.

FrancoB · ‎2021-01-22

Your description is right, Oliver. The reason I've shared those links is because those are the principal tutorial references I've get to better understand how to send the data from a device to another (in this case M4 <-> A7).