topic Re: IMX6Q EMMC Write Protection PROBLEM in i.MX Processors

IMX6Q EMMC Write Protection PROBLEM

wangwangwang — Thu, 29 Dec 2016 12:32:34 GMT

Dear community.

We have a problem about the EMMC Write Protection for specific segments。

We coded the program according to the JESD84-B45（emmc 4.5）.This process is shown in the following diagram.But we found that the return value of the CMD31(SEND_WR_PROTECT_TYPE) was always not correct, and after executing this code，we could still write this block, so we thought the block was unlocked. And we found that the register was set correctly（US_PERM_WP_DIS and US_PWR_WP_EN）, and the CMD28(SET_WR_PROT) was transferred correctly whose response was also OK.

So would you know the reason why we were failed？Or can you offer us some suggests or some code examples?

Thanks very much!.

Best.

wangwang.wang

Re: IMX6Q EMMC Write Protection PROBLEM

igorpadykov — Thu, 29 Dec 2016 23:24:21 GMT

Hi wangwang

cmd31 marked as "reserved" in Table 67-5. Commands for MMC/SD/SDIO Cards

i.MX6DQ Reference Manual

http://cache.freescale.com/files/32bit/doc/ref_manual/IMX6DQRM.pdf

In general one can try to narrow down if this is caused by emmc or i.mx by

testing emmc on another processor or trying brand new card.

Best regards
igor
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Re: IMX6Q EMMC Write Protection PROBLEM

wangwangwang — Fri, 30 Dec 2016 01:19:20 GMT

But the function of CMD31 is to verify whether Write Protection is successful.Even if we didn't use CMD31, we could still write this block.

Re: IMX6Q EMMC Write Protection PROBLEM

igorpadykov — Fri, 30 Dec 2016 07:48:45 GMT

you can try to narrow down if this is caused by emmc or i.mx by

testing emmc on another processor or trying brand new card.