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Altera_Forum's avatar
Altera_Forum
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16 years ago

SOPC HP DDR2 Controller Clock Rate

I've installed a HP DDR2 Controller in the SOPC Builder. I'm curious what clock rate I can run this at. My memory can run at 400MHz CL = 3, 533MHz at CL = 4 and 667MHz at CL = 5. I'm running the c...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

Hi guys,

I'm a bit curious about this frequency stuff for DDR2...

If you say your memory can run at 400MHz, doesn't it actually will be clocked with 200MHz, because the 'feeled' data rate of 400MHz results from transmitted/received data are on both edges of your 200MHz ram clock???

If now, you can tune up your Stratix up to fMAX=333MHz, wouldn't this lead to driving your memory in "667MHz" mode and you have to take care that you put the CAS Latency to CL=5 etc. for proper operation???

Just some thoughts, because I'm starting to work with DDR2 on Cyclone-III on my own...

Regards,

det