Forum Discussion

Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
15 years ago

DM Pins on DDR2

Hello,

I am trying to save some pins in interfacing to DDR2. I am thinking about grounding the DM pins on the memory module and not connecting the DM outputs from the DDR2 IP. In my implementation, I always write the full width of the bus, so the DDR2 IP should always be driving DM low. Is this a safe assumption? Are the DM pins used for anything other than write width? Is there something critical I am overlooking with this implementation?

Thank you for you help.

2 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    If you stick to whole-word writes you can safely forget about the DM pins and ground them at the DDR2 device(s). We have been doing that on all our projects sofar (for both SDR and DDR2 designs).

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Thank you josyb. I will go with that then since it will save on pin count and routing.