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Altera_Forum
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17 years ago

DDR2 SDRAM: local_init_done not going high

I have built a DDR2 SDRAM v7.2 controlller, v7.2, using the Megawizard and a native interface. I have reviewed my schematic and pinout and it looks to be correct. The local_init_done is not going h...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
17 years ago

I remember that I had a similar issue with a SODIMM DDR2 design, I even used ModelSim to understand the initialisation steps and observable signals. But it turned out as very basic wiring fault that would have been detected by checking the design more thoroughly. Usual timing problems are rather causing data errors than calibration failure.

As you probably know, DDIO pins are accessible with SignalTap, so you can't easily debug DDR RAM operation.