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TMS320C6678 EVM DDR3 Configuration

KeckSoon Lim
Prodigy 160 points

Hi,

I am wondering if it is possible to use software to control the frequency/speed of the DDR3 that came with the eval kit. If yes, how can I do it? I am trying to make it run at a slower frequency/speed, that is to read/write slower without adding software delays for testing purposes. Any helps would be greatly appreciated. 

  • 0
    Expert 1240 points

    Hi KeckSoon Lim,
    Yes we can control the frequency/speed of DDR3 device by software. Can you tell us which processor and EVM you are using?
    In C66x Keystone devices (for example), we have 3 PLL modules. Main PLL, DDR3 PLL and PA PLL. By setting the multiplier and divider values for PLL 2 (DDR3 PLL), we can achieve the required DDR3 frequency. 

    Regards

    Sud

  • 0 in reply to Sudarshan R
    Prodigy 160 points

    Hi Sud,

    thanks for the reply. I am currently using TMS320C6678L. Processor is C6678. Do you happen to have an example on how can we set the multiplier and divider values for DDR3 PLL?

  • 0 in reply to KeckSoon Lim
    Expert 1240 points

    Hi KeckSoon Lim,

    You need to write your own code/APIs for PLL  Initialization. The EVM runs at default system clock = 1GHz. How ever this can also be changed by setting the multiplier and divider values for Main PLL (PLL 1). I believe there are no example code which performs PLL Init alone. But you can find the init code in the GEL file for the EVM. Try duplicating what all the GEL file does for PLL  init, make a separate API for the all the three PLL modules where in you can provide the mult and div values as there arguments. In this way, you can control the out frequency of Main, DDR3 and PA (Packet Accelerator) PLL.

    Regards

    Sud