1877743_en-US

Is IMX8M Plus using WDQS?

Hi all,

I am confirming whether the IMX8M Plus has the WDQS function enabled?
I checked the RPA excel file, but I don't understand clearly.
Can you confirm this for me?
1. If it is enabled then, use Mode 1 or Mode 2 as shown below (From DDR datasheet)
2. In the RPA file, where can Enable/Disable be confirmed?

haryanl_0-1717034852012.png

Thanks,

i.MX 8 Family | i.MX 8QuadMax (8QM) | 8QuadPlus

i.MX 8M | i.MX 8M Mini | i.MX 8M Nano

Linux

Re: Is IMX8M Plus using WDQS?

Hi, @haryanl

Yes! You are right!

B.R

Re: Is IMX8M Plus using WDQS?

Hi @pengyong_zhang ,

Thank for your reply.

in the RPA file, is it confirmed here?
By default it is set to enabled
haryanl_0-1717051794890.png

Because WDQS_Extension is used, is it correct that I understand that corresponds to DDR Mode 2: WDQS_on / WDQS_off definition based control?

Thanks,

Re: Is IMX8M Plus using WDQS?

Hi, @haryanl

on i.MX8MP, we enable the WDQSEXTENSION feature of the DDR PHY whose description is as follows:

When set, DQS_T and DQS_C will be driven differentially to 0 and 1, respectively,
before and after a write burst, except during a memory read transaction.

From that I understand that DQS should be driven low at all times except a memory read transaction.

Here is measured the behavior of the system on 8MP EVK when WDQSEXTENSION is enabled and disabled:

pengyong_zhang_0-1717050378634.jpeg