i.MX ProcessorsのトピックRe: imx6ul emmc 8bit mode，boot fail

imx6ul emmc 8bit mode，boot fail

chunqiaohe — Tue, 06 Dec 2016 09:04:26 GMT

Hi all,

i have a project , the cpu is imx6ul. my hardware board 's boot device is EMMC. i use the plull_up/pull_down resistor to set EMMC 8bit mode (Boot_cfg2[7~5]=110) , then i build my u-boot, zImage and dtb. i use the mfgtool download firmware to my board. all are ok , there is on error happen . during the downloading , i measured the imx6ul's SDHC2 cmd,clk,d0-d7 all ok . the debug serial have normal log info.

but after the download, i power on my board ,but the system cann't boot up, the debug serial haven't any info.

finally , i try to change the hardware emmc setting to 1 bit mode ((Boot_cfg2[7~5]=000). then i power on my board, the system can boot up.,the debug serial have booting log . all the function is ok .

i don't know , why i use 8bit mode to down firmware is successful, i measured the D0-D7 data line are ok , but

i can't boot up with 8bit mode EMMC. how to change? is my u-boot issue?

thanks!

Re: imx6ul emmc 8bit mode，boot fail

igorpadykov — Tue, 06 Dec 2016 11:08:01 GMT

Hi chunqiao

in general one can try 4 bit mode. Then check with

oscilloscope all emmc lines, where it fails comparing with good

case. Also one can debug it with jtag using procedure described on

https://community.nxp.com/thread/301056#303710

Best regards
igor
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Re: imx6ul emmc 8bit mode，boot fail

chunqiaohe — Tue, 06 Dec 2016 11:33:35 GMT

Hi igorpadykov,

thanks for your quick replay. i already try to modify hardware boot_cfg to 4bit mode. but also the mfgtool download ok ,but cann't bootup.

in 8bit emmc mode. i measured all the emmc line, during downloading , the emmc_clk is 50MHz, D0-D7 have data wave .

when download finished, i power on my board, i test the emmc_clk is 20MHz, at the same time , only D0 line have data wave,D2-D7 lines are no data wave. so the system no bootup, the serial havn't any log information.

sorry , i design my board without JTAG PIN reserved.

how do i check my design? the firmware look like no problem , because i only change the hardware boot_cfg to 1bit, system can boot up , all function is ok. if the hardware's issue, i checked the boot_cfg pins setting are right.

thanks!

Re: imx6ul emmc 8bit mode，boot fail

igorpadykov — Wed, 07 Dec 2016 00:08:40 GMT

I do not think that it is possible to debug such issues without jtag.

Best regards
igor

Re: imx6ul emmc 8bit mode，boot fail

chunqiaohe — Wed, 07 Dec 2016 01:52:45 GMT

Hi igorpadykov,

would you please give some advice? without jtag, how to try to debug?

thanks!

Re: imx6ul emmc 8bit mode，boot fail

lemficb — Thu, 25 May 2017 05:55:54 GMT

Hi chunqiao,

I have the same issue with you. I can also boot up with 1 bit mode, but when I set 8 bit mode ,there is nothing on my debug serial. Can you tell me the method how to solve this problem ? This problem have troubled me for a long time.

I am looking forward to your reply.

Best regards

Link