[I.MX93] eMMC design : pull-up & pull-down resistor

[Chou]

Dear NXP Community,

I am currently working on the eMMC PCBA design for the I.MX93 and noticed some differences between the NXP EVK design and our initial design. I would like to seek clarification on this matter.

Based on the eMMC design guidelines I reviewed, it appears that pull-up resistors are generally required for CMD and DAT0-DAT7, and a pull-down resistor is needed for DS.

Chou_0-1738060316587.png
However, upon referencing your design in the SPF-94611_B1.pdf, I noticed that these additional external resistors are not present in the eMMC circuitry.

Chou_1-1738060352184.png

Could you kindly confirm if the absence of these external resistors is due to the presence of internal pull-up or pull-down resistors for DAT0-DAT7 and CMD within the I.MX93?

Chou_2-1738060378021.png

If this understanding is correct, could you also advise whether configuring the internal pull-up or pull-down settings appropriately in the software will be sufficient to meet the design requirements?

Chou_3-1738060397029.png

Thank you for your support, and I look forward to your guidance!

Best regards,
Howard 

[Chavira · Accepted solution]

Hi @Chou!
Thank you for contacting NXP Support!

in iMX93-EVK board we configure the internal pull up resistors in those pins,. but I recommend to put external pull-up resistors to guarantee the logical state.

This is a reference schematic

Chavira_0-1738086072091.png

The pull-up resistors are configured in u-boot device tree and maintain the configuration on Linux device tree

Best Regards!

Chavira