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

Chou — Tue, 28 Jan 2025 10:36:17 GMT

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.

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.

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?

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?

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

Best regards,
Howard

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

Chavira — Tue, 28 Jan 2025 17:45:27 GMT

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

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

Best Regards!

Chavira

topic Re: [I.MX93] eMMC design : pull-up & pull-down resistor in i.MX Processors

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

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