How to change DDR DQ Drive Strength?

kwmst · ‎03-19-2023

Hello,

I'm designing a board with a configuration of Alder Lake P(7305E) + DDR4 (Onboard).
SI Result is no problem, and RMT Result is ALL Pass.
However, when I measured the waveform of the DDR I/F, the DQ slew rate during Write operation became Fail. It was 12V/ns against the spec 9V/ns (Max).
I need to weaken the Drive Strength to meet the JEDEC spec, but I don't know how.

Questions
1. Is it possible to check the Drive Strength (CPU Ron) from the MRC log?
2. Is there a way to manually change the Drive Strength?
3. Will Intel support me if I need to modify the MRC source code?
4. Is there documentation about MRC? I want to check the settings and training item and algorithm.

Thanks.

CarlosAM_INTEL · ‎03-20-2023

Hello, @kwmst:

Thank you for contacting Intel Embedded Community.

We sent an email to the address associated with this account with information that may help you.

Best regards,

@CarlosAM_INTEL.