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TMS320C6657: Keystone (C6657) DDR3 Qualification

David F
Intellectual 645 points
Part Number: TMS320C6657

Does a list of qualified DDR3 vendors/parts exist for Keystone DSPs?

The only reference to "qualified" product is suggested in SPRABI1B section 2.3:

"Devices from many manufacturers were available at the time this document was prepared. It is recommended that only high-quality DRAM parts that fully comply with the latest DDR3 JEDEC specification and are from well-known manufacturers be used. Incorrect DRAM part or manufacturer selection can cause performance problems that may not be resolvable within the available software or configuration limitations of the DSP."

The usual Micron MT41J128M16JT-125:K is in short supply for a production run.

ISSI IS43TR16128C-125KBL is a recommended cross. Is it qualified by TI?

  • 0
    TI__Guru 65405 points
    Hi David,

    I've forwarded your query to the hardware design experts. Their feedback should be posted here.

    BR
    Tsvetolin Shulev
  • 0 in reply to David F
    Intellectual 645 points

    Another bump...

  • 0
    TI__Mastermind 42545 points

    Hi David,

    As stated, the DDR3 interface for the C6657 is designed to meet the JEDEC specification for DDR3. Since this is a strict standard, we don't test the C6657 with various DDR3 memory parts. If the part is compliant with the JEDEC standard and the routing rules for the DDR3 interface are followed, the part should be compatible with the C6657. I don't have any experience with the ISSI part you referenced but if it is JEDEC compliant, you should be able to configure the C6657 to work with it.

    Regards, Bill

  • 0 in reply to Bill Taboada
    Intellectual 645 points
    Hi Bill,

    Your reply really only addresses the first part of the TI recommendation quoted above. My concern is that TI went out of its way to state the following:

    "It is recommended that only high-quality DRAM parts that fully comply with the latest DDR3 JEDEC specification and are from well-known manufacturers be used. Incorrect DRAM part or manufacturer selection can cause performance problems that may not be resolvable within the available software or configuration limitations of the DSP."

    This makes perfect sense given that DDR3 qualification is a real thing in the industry, and qualification for any particular hardware typically goes beyond simpy adhering to the DDR3 JEDEC standard.

    I guess the issue here is that TI documentation specifies:

    1. Parts that fully comply with the latest DDR3 JEDEC spec...

    AND

    2. Parts from a well-known manufacturer / not an "incorrect...manufacturer selection".

    Since "well-known manufacturers" and "incorrect...manufacturer selection" figure prominently in the TI documentation snippet, can you at least confirm how ISSI fits this description?

    Thanks.
  • 0 in reply to David F
    TI__Mastermind 46460 points

    David,

    The words in that document were chosen carefully.  Parts must be JEDEC compliant.  There have been instances in the past where customers used inexpensive SDRAMs from obscure manufacturers who then had performance issues because the parts were later found to not be JEDEC compliant.  It is not our place to qualify SDRAM vendors for our customers.  Our recommendation is that our customers only use parts from well known manufacturers and suppliers to avoid this type of issue.

    Tom