RTOS/TMS320C6657: C6657

Lingcon,

As far as I know, the largest standard DDR3 SDRAM is 8Gb.  Since the PHY only supports x8 and x16 SDRAMs, the largest DDR3 memory implementation supported on a 32-bit interface is 4GB.  Therefore, the C6657 can support no more than 4GB of DDR3 memory.  The C6678/4/2/1 devices from the same family support a 64-bit DDR3 interface.  Therefore, these support up to 8GB of DDR3 memory.

Tom

Meng,

I searched the C6657 Data Manual.  Technically, its statements about 8GB are not wrong but i can see how users of the document could misunderstand.  The architecture supports an addressable space of 8GB on the DDR3 interface.  However, with available DDR3 SDRAMs, the 32-bit interface cannot reach more than 4GB.  I will suggest that a footnote be added to make this more clear.

Tom

Shine,

It does not matter whether you have a single-rank or dual-rank SDRAM module - they are both 8Gb parts.  The most that you can achieve will be 4GB of memory with 4 of these SDRAM devices.

Monolithic (single-die) 8Gb devices are preferred for customer designs.  Even though we support dual-rank devices, customers encountered much more difficulty with the dual-rank leveling configuration.  Since all DDR3 SDRAM devices are mature, monolithic devices are low cost.

Tom