• State TI Thinks Resolved
  • Locked Locked
  • Replies 2 replies
  • Answers 1 answer
  • Subscribers 98 subscribers
  • Views 339 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

TMS320DM8168: Query regarding SD card issue

Vijetha HN
Intellectual 715 points

Part Number: TMS320DM8168

Hi,

We are using TMS320DM8168CCYGA2 in our design since past 8+ years. The boards are already under production since many years.

In one board we are facing an issue w.r.t SD card write. The write is failing with echo commands.

If we execute command : mount -o remount,rw /media/mmcblk0p1 /media/mmcblk0p1, then the write works fine. But with all other boards, this command is not required.
On every reboot, we need to execute this command with this particular board. If we dont execute this command, then write does not work.

What might have gone bad?

Here is the picture of schematics w,r,t SD card.

We are not using SD card for boot purpose. It is just a storage.

We replaced the connector, series resistors and pull up resistors. Still issue persists.

The WP pin at processor is not connected. Do you think the WP pin of processor is stuck at Low under BGA due to some sort of short?

Attached the boot logs of working and non working board for reference.

Fullscreen dmesg_NON WORKING BOARD.txt Download 
root@pdlu:~# dmesg | grep -i mmc
mmc0: new high speed SDHC card at address aaaa
mmcblk0: mmc0:aaaa SS08G 7.40 GiB (ro)
 mmcblk0: p1 p2
VFS: Can't find a valid FAT filesystem on dev mmcblk0.
yaffs: dev is 187695104 name is "mmcblk0" ro
yaffs: yaffs: Attempting MTD mount of 179.0,"mmcblk0"
yaffs: dev is 187695104 name is "mmcblk0" ro
yaffs: yaffs: Attempting MTD mount of 179.0,"mmcblk0"
EXT3-fs (mmcblk0p2): mounted filesystem with writeback data mode
Fullscreen dmesg_WORKING BOARD.txt Download 
root@pdlu:~# dmesg | grep -i mmc
mmc0: new high speed SDHC card at address aaaa
mmcblk0: mmc0:aaaa SS08G 7.40 GiB
 mmcblk0: p1
VFS: Can't find a valid FAT filesystem on dev mmcblk0.
yaffs: dev is 187695104 name is "mmcblk0" rw
yaffs: yaffs: Attempting MTD mount of 179.0,"mmcblk0"
yaffs: dev is 187695104 name is "mmcblk0" rw
yaffs: yaffs: Attempting MTD mount of 179.0,"mmcblk0"

Regards,
Vijetha HN

  • 0
    TI__Guru**** 191886 points

    Hi,

    Vijetha HN said:

    We are using TMS320DM8168CCYGA2 in our design since past 8+ years. The boards are already under production since many years.

    In one board we are facing an issue w.r.t SD card write. The write is failing with echo commands.

    Based on your description, this is not a new design. Is that correct? You have one board that has an issue while others based on the same design are all working correctly. Is that a correct understanding? I will suggest you do a ABA swap test to confirm if this is a MCU problem or a board level problem. This is what I will suggest you diagnose the problem. We no longer provide direct support for this device on the E2E forum as noted on this device's product page. 

    The A-B-A Swap Method is a simple cross check test, which can confirm the observed issue is not systemic.

    • A-B-A Swap Method
      (1) Remove the suspected component (A) from the original failing board.
      (2) Replace the suspected component (A) with a known good component (B) and check if the original board now works properly.
      (3) Mount the suspected component (A) to a known good board and see if the same faliure occurs on the good board.

    Step 3 is important because it helps us to exclude any possibility that the issue is caused by a systemic issue or the interaction of multiple slightly bad components on a good board.

  • 0 in reply to Charles Tsai
    Intellectual 715 points

    This is not a new design and it is working design. Lot of boards manufactured and tested and delivered successfully without any issues. So obviously this issue in one board is board specifoic Hardware issue.

    Yesterday, we identified one thing. We tried reading SDIO register values for WPP (polarity of SD write protect)  and WP (value of Write protect) in 2 boards (one working and one non working). In working board WP value is 1 (which means Not Write protected) and in non working board value is 0 (which means Write protectd). If you see the schematics image, the SD card connector does not support WP. So WP pin of Processor is not connected anywhere and it is hanging.

    So we suspect WP pin of processor might be shorted to GND inside the BGA. We will initiate X-ray inspection to confirm.

    But if WP is not connected and if it is connected to GND, do you think it will ctreate issues in writing?