Can not boot custom iMX6 board from SD Card

[hakanaydin]

We designed a custom imx6 board, based on the MCIMX6QP-SDB. All of the critical interfaces of the processor are intended to be identical to the kit.

We have a properly formatted and configured SD card. When we plug in this SD card to the kit and apply power, we start seeing the console output immediately and the board starts booting.

However, when we plug the same SD card in to our custom board, we see no activity. Here is a list of things that we did and some other details:

- Our board sinks approximately 300mA of current when turned on. All supply rails appear to be functioning correctly.

- Our board is designed to be booted by way of GPIO pins, so our BOOT_MODE[1:0] is '10'

- Other than that, the only 'high' boot mode config pins are, CFG1_6 and CFG2_4, the rest are all zeros.

- Just like the kit, our POR_B signal goes high a few ms after GEN_3V3 is generated.

- We confirmed that the boot mode config pins are stable before POR_B is asserted.

- As can be seen from the Boot settings, the board is configured to boot from SD3. Upon applying power, there is some initial activity on the SD3 CLK pin (at around 347 khz). The activity goes on for about 40ms. Then the CLK activity stops and we see no further progress.

- We tested the above on multiple assembled boards.

Any ideas why SD Card read may be stalling after the first 40ms of activity?

Thanks!

[hakanaydin]

I will be moving this to another thread since the original question is already answered

[hakanaydin]

Hello,

Thanks for the information, we managed to boot after running calibration. However we're now running into other problems.

After booting linux (and sometimes, *while* booting linux), at seemingly random times (after a few seconds, minutes, and in some cases, a couple hours), the system becomes completely unresponsive. There is no console output, ethernet connectivity is dead, etc. This appears to happen for no specific reason, it appears to be somewhat random. Nothing special is running on linux at the time of hang, it is just sitting there on the command line prompt.

When this happens, we checked the supply rails and all appear to be OK. Also, to rule out any DRAM related issues, we ran overnight tests with the stress tester on the DDR3 chips, and all appears to be OK. We also ran DDR tests in u-boot and that seems to be OK as well.

We're not sure how to go about finding the problem. What could be possible sources of hang and how can we go about zeroing in on the problem?

Thanks,

[igorpadykov · Accepted solution]

Hi HAKAN

for custom board image should be rebuilt with new ddr settings

obtained from ddr tester and changed in uboot/..board/freescale/board_name/*.cfg file

https://community.freescale.com/docs/DOC-105652 

Also recommended to check attached Porting Guide and

Chapter 6 Avoiding Board Bring-up Problems  i.MX6 System Development User’s Guide

http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf

Best regards
igor
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