i.MX Processors中的主题 Is IMX8M Plus using WDQS?

Is IMX8M Plus using WDQS?

haryanl — Thu, 30 May 2024 02:08:38 GMT

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?

Thanks,

Re: Is IMX8M Plus using WDQS?

pengyong_zhang — Thu, 30 May 2024 06:26:59 GMT

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:

Re: Is IMX8M Plus using WDQS?

haryanl — Thu, 30 May 2024 07:09:17 GMT

Hi @pengyong_zhang ,

Thank for your reply.

in the RPA file, is it confirmed here?
By default it is set to enabled

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?

pengyong_zhang — Thu, 30 May 2024 07:42:40 GMT

Hi, @haryanl

Yes! You are right!

B.R