IMX6UL processor SD lines related query

ramesh6663 — Fri, 05 May 2017 05:44:26 GMT

Hi,

Imx6UL NXP EVK board design - In SD1 CMD and DATA0 lines only have external pull-up.

1. Why CMD and Data0 lines has pulled-up any specific reasons related to processor ?

2. Why other Data lines doesn't have Pull-ups?

3. By processor default it has Internal pull-up, so we didn't use external pull-ups?

Thanks & Regards,

Rameshkumar

Re: IMX6UL processor SD lines related query

weidong_sun — Fri, 05 May 2017 14:46:10 GMT

Hello ramesh,

CPU PADs of SD1 list is from datasheet:

Recommended design from MMC protocol:

1. Why CMD and Data0 lines has pulled-up any specific reasons related to processor ?

According to SD protocol, all signal lines should have external pull-up resistors.

2. Why other Data lines doesn't have Pull-ups?

During initialization, only CMD and DATA0 line work, other data lines(DATA1--DATA3) are not used. After initialization, SD interface can be configured as 4-line mode, and there exists internal pull-up resistor on every SD pad, software can sets driving capability for these pads via configuring different pull-up resistors.

3. By processor default it has Internal pull-up, so we didn't use external pull-ups?

Yes, right.

But According to above list shown, if you don't configure pads in software, SD1 pads have no pull-up resistors! so you had better refer to EVK to design your schematic.

Have a great day,
wediong sun

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Re: IMX6UL processor SD lines related query

ramesh6663 — Tue, 23 May 2017 07:24:04 GMT

Thanks for your Great help.

topic IMX6UL processor SD lines related query in i.MX Processors

IMX6UL processor SD lines related query

Re: IMX6UL processor SD lines related query

Re: IMX6UL processor SD lines related query