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

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

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

Jump to solution
3,175 Views
Chou
Contributor II

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 

Tags (2)
0 Kudos
Reply
1 Solution
3,154 Views
Chavira
NXP TechSupport
NXP TechSupport

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

 

View solution in original post

0 Kudos
Reply
1 Reply
3,155 Views
Chavira
NXP TechSupport
NXP TechSupport

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

 

0 Kudos
Reply
%3CLINGO-SUB%20id%3D%22lingo-sub-2035036%22%20slang%3D%22en-US%22%20mode%3D%22CREATE%22%3E%5BI.MX93%5D%20eMMC%20design%20%3A%20pull-up%20%26amp%3B%20pull-down%20resistor%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-2035036%22%20slang%3D%22en-US%22%20mode%3D%22CREATE%22%3E%3CP%3EDear%20NXP%20Community%2C%3C%2FP%3E%3CP%3EI%20am%20currently%20working%20on%20the%20eMMC%20PCBA%20design%20for%20the%20I.MX93%20and%20noticed%20some%20differences%20between%20the%20NXP%20EVK%20design%20and%20our%20initial%20design.%20I%20would%20like%20to%20seek%20clarification%20on%20this%20matter.%3C%2FP%3E%3CP%3EBased%20on%20the%20eMMC%20design%20guidelines%20I%20reviewed%2C%20it%20appears%20that%20pull-up%20resistors%20are%20generally%20required%20for%20CMD%20and%20DAT0-DAT7%2C%20and%20a%20pull-down%20resistor%20is%20needed%20for%20DS.%3C%2FP%3E%3CP%3E%3CSPAN%20class%3D%22lia-inline-image-display-wrapper%20lia-image-align-inline%22%20image-alt%3D%22Chou_0-1738060316587.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cspan%20class%3D%22lia-inline-image-display-wrapper%22%20image-alt%3D%22Chou_0-1738060316587.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cimg%20src%3D%22https%3A%2F%2Fcommunity.nxp.com%2Ft5%2Fimage%2Fserverpage%2Fimage-id%2F321635i37B220CD770C3723%2Fimage-size%2Fmedium%3Fv%3Dv2%26amp%3Bpx%3D400%22%20role%3D%22button%22%20title%3D%22Chou_0-1738060316587.png%22%20alt%3D%22Chou_0-1738060316587.png%22%20%2F%3E%3C%2Fspan%3E%3C%2FSPAN%3E%3CBR%20%2F%3EHowever%2C%20upon%20referencing%20your%20design%20in%20the%20%3CSTRONG%3ESPF-94611_B1.pdf%3C%2FSTRONG%3E%2C%20I%20noticed%20that%20these%20additional%20external%20resistors%20are%20not%20present%20in%20the%20eMMC%20circuitry.%3C%2FP%3E%3CP%3E%3CSPAN%20class%3D%22lia-inline-image-display-wrapper%20lia-image-align-inline%22%20image-alt%3D%22Chou_1-1738060352184.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cspan%20class%3D%22lia-inline-image-display-wrapper%22%20image-alt%3D%22Chou_1-1738060352184.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cimg%20src%3D%22https%3A%2F%2Fcommunity.nxp.com%2Ft5%2Fimage%2Fserverpage%2Fimage-id%2F321636i3ADF39E6E2BBAF86%2Fimage-size%2Fmedium%3Fv%3Dv2%26amp%3Bpx%3D400%22%20role%3D%22button%22%20title%3D%22Chou_1-1738060352184.png%22%20alt%3D%22Chou_1-1738060352184.png%22%20%2F%3E%3C%2Fspan%3E%3C%2FSPAN%3E%3C%2FP%3E%3CP%3ECould%20you%20kindly%20confirm%20if%20the%20absence%20of%20these%20external%20resistors%20is%20due%20to%20the%20presence%20of%20%3CSTRONG%3Einternal%20pull-up%20or%20pull-down%20resistors%3C%2FSTRONG%3E%20for%20DAT0-DAT7%20and%20CMD%20within%20the%20I.MX93%3F%3C%2FP%3E%3CP%3E%3CSPAN%20class%3D%22lia-inline-image-display-wrapper%20lia-image-align-inline%22%20image-alt%3D%22Chou_2-1738060378021.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cspan%20class%3D%22lia-inline-image-display-wrapper%22%20image-alt%3D%22Chou_2-1738060378021.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cimg%20src%3D%22https%3A%2F%2Fcommunity.nxp.com%2Ft5%2Fimage%2Fserverpage%2Fimage-id%2F321637i178132288BD569AB%2Fimage-size%2Fmedium%3Fv%3Dv2%26amp%3Bpx%3D400%22%20role%3D%22button%22%20title%3D%22Chou_2-1738060378021.png%22%20alt%3D%22Chou_2-1738060378021.png%22%20%2F%3E%3C%2Fspan%3E%3C%2FSPAN%3E%3C%2FP%3E%3CP%3EIf%20this%20understanding%20is%20correct%2C%20could%20you%20also%20advise%20whether%20configuring%20the%20internal%20pull-up%20or%20pull-down%20settings%20appropriately%20in%20the%20software%20will%20be%20sufficient%20to%20meet%20the%20design%20requirements%3F%3C%2FP%3E%3CP%3E%3CSPAN%20class%3D%22lia-inline-image-display-wrapper%20lia-image-align-inline%22%20image-alt%3D%22Chou_3-1738060397029.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cspan%20class%3D%22lia-inline-image-display-wrapper%22%20image-alt%3D%22Chou_3-1738060397029.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cimg%20src%3D%22https%3A%2F%2Fcommunity.nxp.com%2Ft5%2Fimage%2Fserverpage%2Fimage-id%2F321638i3B5336DED05B992B%2Fimage-size%2Fmedium%3Fv%3Dv2%26amp%3Bpx%3D400%22%20role%3D%22button%22%20title%3D%22Chou_3-1738060397029.png%22%20alt%3D%22Chou_3-1738060397029.png%22%20%2F%3E%3C%2Fspan%3E%3C%2FSPAN%3E%3C%2FP%3E%3CP%3EThank%20you%20for%20your%20support%2C%20and%20I%20look%20forward%20to%20your%20guidance!%3C%2FP%3E%3CP%3EBest%20regards%2C%3CBR%20%2F%3EHoward%26nbsp%3B%3C%2FP%3E%3C%2FLINGO-BODY%3E%3CLINGO-SUB%20id%3D%22lingo-sub-2035235%22%20slang%3D%22en-US%22%20mode%3D%22CREATE%22%3ERe%3A%20%5BI.MX93%5D%20eMMC%20design%20%3A%20pull-up%20%26amp%3B%20pull-down%20resistor%3C%2FLINGO-SUB%3E%3CLINGO-BODY%20id%3D%22lingo-body-2035235%22%20slang%3D%22en-US%22%20mode%3D%22CREATE%22%3E%3CP%3EHi%20%3CA%20href%3D%22https%3A%2F%2Fcommunity.nxp.com%2Ft5%2Fuser%2Fviewprofilepage%2Fuser-id%2F244612%22%20target%3D%22_blank%22%3E%40Chou%3C%2FA%3E!%3CBR%20%2F%3EThank%20you%20for%20contacting%20NXP%20Support!%3C%2FP%3E%0A%3CBR%20%2F%3E%0A%3CP%3Ein%20iMX93-EVK%20board%20we%20configure%20the%20internal%20pull%20up%20resistors%20in%20those%20pins%2C.%20but%20I%20recommend%20to%20put%20external%20pull-up%20resistors%20to%20guarantee%20the%20logical%20state.%3C%2FP%3E%0A%3CBR%20%2F%3E%0A%3CP%3EThis%20is%20a%20reference%20schematic%3C%2FP%3E%0A%3CBR%20%2F%3E%0A%3CP%3E%3CSPAN%20class%3D%22lia-inline-image-display-wrapper%20lia-image-align-inline%22%20image-alt%3D%22Chavira_0-1738086072091.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cspan%20class%3D%22lia-inline-image-display-wrapper%22%20image-alt%3D%22Chavira_0-1738086072091.png%22%20style%3D%22width%3A%20400px%3B%22%3E%3Cimg%20src%3D%22https%3A%2F%2Fcommunity.nxp.com%2Ft5%2Fimage%2Fserverpage%2Fimage-id%2F321691i2C7FDF5B4C834783%2Fimage-size%2Fmedium%3Fv%3Dv2%26amp%3Bpx%3D400%22%20role%3D%22button%22%20title%3D%22Chavira_0-1738086072091.png%22%20alt%3D%22Chavira_0-1738086072091.png%22%20%2F%3E%3C%2Fspan%3E%3C%2FSPAN%3E%3C%2FP%3E%0A%3CBR%20%2F%3E%0A%3CP%3EThe%20pull-up%20resistors%20are%20configured%20in%20%3CA%20href%3D%22https%3A%2F%2Fgithub.com%2Fnxp-imx%2Flinux-imx%2Fblob%2Flf-6.1.y%2Farch%2Farm64%2Fboot%2Fdts%2Ffreescale%2Fimx93-11x11-evk.dts%22%20target%3D%22_self%22%20rel%3D%22nofollow%20noopener%20noreferrer%22%3Eu-boot%20device%20tree%3C%2FA%3E%20and%20maintain%20the%20configuration%20on%20%3CA%20href%3D%22https%3A%2F%2Fgithub.com%2Fnxp-imx%2Flinux-imx%2Fblob%2Flf-6.6.y%2Farch%2Farm64%2Fboot%2Fdts%2Ffreescale%2Fimx93-11x11-evk.dts%22%20target%3D%22_self%22%20rel%3D%22nofollow%20noopener%20noreferrer%22%3ELinux%20device%20tree%3C%2FA%3E%3C%2FP%3E%0A%3CBR%20%2F%3E%0A%3CP%3EBest%20Regards!%3C%2FP%3E%0A%3CP%3EChavira%3C%2FP%3E%0A%3CBR%20%2F%3E%3C%2FLINGO-BODY%3E