AM5729: What is the maximum DDR3 memory?

Hi Kannan,

I am not sure where to look for the reference to "8Gb" - I did not see that in section 15.3.1 of the TRM but may have missed it. Also, did you mean to write 2GB and 8GB? Just making this distinction as the lower "b" and upper "B" can imply "bit" / "byte" respectively.

Table 3-1 of the datasheet shows a maximum of 2GB for EMIF1 and maximum of 2GB for EMIF2 (total of 4GB if using both EMIF1 and EMIF2). Please consider 2GB to be the maximum supported memory when using a single EMIF and 4GB to be the maximum supported memory when using both EMIF1 and EMIF2 on AM5729. However, please also review the note in the datasheet regarding SDRAM space. Any physical DDR memory greater than 2GB is only accessible by the MPU via LPAE.

In the Unified L3 memory map, there is maximum of 2GB of SDRAM space which is available to all L3 initiators including MPU (MPU, GPU, DSP, IVA, DMA, etc). Typically this space is interleaved across both EMIFs to optimize memory performance. If a system populates > 2GB of physical memory, that additional addressable space can be accessed only by the MPU via the Arm V7 Large Physical Address Extensions (LPAE).

Thanks,
Kevin

Kannan Sockalingam said:

Hi team, my customer had a question on DDR3 for AM5729.

Is the customer interested in running Linux or RTOS?

RTOS/AM5728: ARM LPAE and/or 4GB mapped memory support has some ideas about how to configure LPAE in TI-RTOS to access physical DDR memory greater than 2GB.