DDR3 reference clock input on TMS320C6678EVM board

Philly

Hi,

On C6678EVM board， the recommended reference clock input for DDR3 is 66.667MHz。can I apply any other frequency ? What's the constraint of the reference frequency for DDR3, since it can work at 800MHz，1333MHz，etc.

best regards!

Philly

over 11 years ago

0 Madhu Balasubramanian over 11 years ago

TI__Expert 4400 points

As per the DSP specs, the DDR3 reference clock can be between 40MHz and 312.5MHz.

0 Philly over 11 years ago in reply to Madhu Balasubramanian

Intellectual 310 points

hello Madhu,

You mean,Unlike the reference clock of SRIO must be 156.25,250 or 312.5MHz, any frequency between 40 to 312.5MHz can be an input for DDRCLK in C6678?But how should I configure the PLL register if there is a specific PLL for DDR module inside C6678?Where is the user's guide?

Thank you very much!

Philly.

0 Madhu Balasubramanian over 11 years ago in reply to Philly

TI__Expert 4400 points

Hi Philly,

The recommended DDR3 reference clock frequency is 66.67MHz but the range is what I provided before. Please post in the C6678 forum for help on the device's user guide and help with what's recommended for that device.

0 Philly over 11 years ago in reply to Madhu Balasubramanian

Intellectual 310 points

Hi Madhu,

Thanks a lot. I was just confused of those reference clock. since I focus on the difference between them , the problem doesn't exist for now.

thank you!

Philly.

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DDR3 reference clock input on TMS320C6678EVM board