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EDMA3 TRANSFER RATES

Tuli
Prodigy 180 points

 

On the card EVM6678L, we used EDMA3 to copy 16KBytes data block from DDR3 to L2.

We have received various transfer rates for different TC's (2.5-4 Gbytes/sec)  on the same EDMA (From L2 to DDR3 we received the same rate for all TC's). These results were received for EDMA#1 and  EDMA#2.

 What transfer rates should I expect?

Thanks

Naftali

 

  • 0
    TI__Guru* 84110 points

    naftali belz,

    For an 8-Byte-wide DDR3 interface running at 300MHz DDRCLK you have a maximum data transfer rate of 600M transfers per second or 4800M Bytes per second. 4GBps or 83% utilization is pretty good, although I have not seen or tried any benchmarks to say what the best sustainable transfer rate is.

    Try EDMA#0, since it is closest to the MSMC controller and is intended for DDR3 transfers. And try some transfers with EDMA0 between DDR3 and the MSMC Shared L2. This relationship will be clearer in a future release of the datasheet that will show the interconnect architecture within the C6678 device. For now, try it and see how it works.

    Let us know what transfer rates you get there.

    For best results, use more than one Transfer Controller and start more than one 16KByte transfer running at the same time. This should minimize the effect of EDMA delays that might be introduced into the transfer time.

    Regards,
    RandyP