topic Re: In reading SD card, CMD18 returns communication error in i.MX Processors

In reading SD card, CMD18 returns communication error

heill2england — Tue, 17 Dec 2019 07:49:08 GMT

Hi community,

I am trying to customize U-boot for my custom i.MX 6SoloX board, with using a Yocto-Linux(4.14.98).

I have a i.MX 6SoloX SABRE board, I will porting the U-boot after confirming on the board.

The boot process loads the environment data from SDHC4.

At the data loading, CMD17(Read one SD card block) returns OK, but CMD18(Read multiple SD card block) returns error code.

The error code is ECOMM, it is "Communication error on send".

I checked source code, and dumped logs, I found that "Data End Bit Error" and " Data CRC Error " occurred at reading the register of Interrupt Status (uSDHC4_INT_STATUS) in CMD18.

Do you have any idea of that cause?

How should I debug?

Thank you.

Re: In reading SD card, CMD18 returns communication error

igorpadykov — Wed, 18 Dec 2019 00:38:35 GMT

Hi Takashi

issue may be related to sd signal integrity issues, one can try solutions described on

eMMC 8GB to 4GB - crash on linux (yocto) boot

Best regards
igor
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Re: In reading SD card, CMD18 returns communication error

heill2england — Thu, 19 Dec 2019 10:03:44 GMT

Hi igor

Thank you for your information.

I tried low speed uSD card, and configured SD Speed by BOOT_CFG1-SW on my board .

it works well.