Pull Up resistor for SDIO interface on i.MX 6SoloX

[andy_kim]

Hello,

I've been checking i.MX 6SoloX Reference schematic and had a query about SDIO interface.

All of SDIO interface have pull up resistor only on SDx_DATA0 and SDx_CMD line.

I don't understand why pull up resistors applied only for two lines except the rest of SDx_DATA lines.

Shouldn't they all SDIO Data lines have pull up resistors?

Thanks,

Andy

[IvanRuiz]

Hello,

At the booting process normally those pins are required to detect the change of the voltage (NVCC_SD4) switching from 1V8 to 3V1, so please keep them as they are in the design.

Hope it helps!

BR,

Ivan.

[andy_kim]

Dear Ivan,

Thanks for your prompt reply.

Then, All of SD1 to SD4 port should be pull up for SDx_DATA0 and SDx_CMD to VCC_SD4? right?

Thanks,

Andy

[IvanRuiz · Accepted solution]

Hello,

You are welcome! Answering your question, the ones used in the design are the minimum required but it does not cause any harm implementing the other pull-ups. 

BR,

Ivan.

[andy_kim]

Dear Ivan,

Thanks for your confirmation.

Andy