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Altera_Forum's avatar
Altera_Forum
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16 years ago

DDR2 DQSn Pin Question

Hi, All I am using Cyclone III and DDR2 as memory, I found there is no DQSn Pin in CycloneIII device. So how to connect DQSn pin in DDR2 memory device. Connect to Vtt=0.9V or GND, or somewhere...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
16 years ago

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Hi,

it depends.

In DDR2, the DQS signal may either be single ended or differential.

Take a look in your DDR2 device's datasheet about this.

If you are using a diferential DQS, then you need to set the DQS signal to the a differential SSTL I/O standard. The DQS_n signal will then be automatically assigned to the proper pin.

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But I can not find any DQSn pin in the Cyclone III device, is that means CIII device can not support differential DQS mode?

Thanks