RAM for STMP157

[muffss]

Hi,

I am building my STMP157 board using the reference of "STMP15X-SOM" of Olimex. In that the RAM used is K4B4G1646D-BYK0, but I am unable to find the part number in online store. Can you please help me in finding the different RAM which can be used instead of it.

If I am changing the RAM what are the changes needed to be done in the U-boot file to run the processor.

[PatrickF]

Hi @muffss 

any DDR3L of same voltage/density/width (here 1.35V, 4Gbit with 16-bit bus) would work, probably without any changes in SW.

If needed to change DDR initialization values, you should regenerate some files using CubeMx, then recompile TF-A.

https://wiki.st.com/stm32mpu/wiki/DDRCTRL_and_DDRPHYC_device_tree_configuration

https://wiki.st.com/stm32mpu/wiki/Cross-compile_with_OpenSTLinux_SDK

Regards,

[muffss]

Hi Patrick,

Thank you for your assistance. I would like to clarify a few points regarding the use of different DDR generations in my current design.

As mentioned earlier, I am working on a board based on the STM32MP157AAA processor, and the reference design uses the 5th generation DDR RAM, "K4B4G1646D-BYK0." However, I am unable to source this specific part. Instead, I have found the "K4B4G1646E-BYK0," which is a 6th generation DDR RAM.

Could you kindly advise on the necessary changes, both in hardware and software, that would be required to ensure compatibility with the 6th generation DDR, or if any other considerations should be taken into account when making this substitution?

I appreciate your guidance on this matter.

[muffss]

Hi,

can you please help me ???

[muffss]

Hi,

can you please help me ??

[PatrickF]

Hi @muffss 

DDR3/DDR3L are standardized by JEDEC, there is no concept of 'generation' in it.

'generation' is probably only meaning product technology enhancements on supplier manufacturing side (to reduce cost or reach higher performances or lower consumption). Higher performance memory will work at lower frequencies (we use 533MHz as maximum for STM32MP1 DDR3/DDR3L).

DDR3/DDR3L is configured by CubeMX. 'standard' settings are intended for maximum compatibility and should work without specific issues (could be tailored in case of issues).

Absolutely no HW changes are needed (except if difference in mechanical size of the memory and ballout).

Most important for DDR is to follow the routing guidelines (see also AN5168, AN5122 and AN5031).

regards.