AnsweredAssumed Answered

Custom i.MX283 board, odd behaviour when booting SD card under battery power

Question asked by Jan Nyman on Sep 29, 2015
Latest reply on Sep 29, 2015 by Jan Nyman

Dear all,

 

I am bringing up a custom board with a i.MX283 part. I am working with the fsl-community-bsp Yocto with Kernel 2.6.35.3-r45.

My board is intended to boot from a (micro) SD card.  It seems that booting fails with most (but not all) SD cards, if the board is under battery power only. If I connect a wall USB charger to the USB port, the board can boot from all SD cards. Here is the output from Debug UART:

 

(When Battery connected the following immediately appears:)

HTLFLCMHTLLCL0x8050100b

HTLLCL0x8050100b

(Then a 20 seconds interval)

0x80502008

          HTLFLCMHTLLCL0x8050100b

(Again, 20 second interval)

0x80502008

          HTLFLCMHTLLCL0x8050100b

 

We now connect the board to a USB charger, then after some delay to board boots:

 

0x80502008

          HTLFLCMHTLLCLLC

 

 

U-Boot 2014.10+fslc+g5fd0b60 (Sep 29 2015 - 13:57:17)

(etc...)

The board appears to boot reliably every time when powered with a USB charger. Also, if there is no battery connected, the board boots immediately after applying power, with all the SD cards I have tested. I happen to have one SD card from which the board boots immediately after applying power, but this seems to be a coincidence. If I transfer the same contents on a different SD card, it wont boot until charger is connected.

 

I have an I2C EEPROM chip on the board, and I have loaded it with the patch "mx28_polarity_issue_ssp1.sb" and I have set up my board to boot from EEPROM. I have blown the ENABLE_SSP_12MA_DRIVE fuse. However, I am still experiencing the above problems.

 

Do you have any tips how to solve this problem? I expect the board to boot immediately when battery is connected.

 

BR,

Jan

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