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SD booting issue in DM385 Davinci Processor

Shanmugam Nachiappan
Prodigy 100 points


Hi,

We have three DM385 boards. In these, two boards are having SD booting issue.

We checked all the possibilities in hardware part, like continuity test between processor & SD card holder, Boot configuration and SD lines pull up values(10K).

Note: There is no issue in UART boot.

Initially board 2 was booting properly. After some days, we got the following error,

===================================================================

mmc0: host does not support reading read-only switch. assuming write-enable.
mmc0: new high speed SDHC card at address e624
mmcblk0: mmc0:e624 SU04G 3.69 GiB
mmcblk0: retrying using single block read
mmcblk0: error -110 sending status comand
mmcblk0: error -110 sending read/write command, response 0x0, card status 0x0
mmcblk0: error -110 transferring data, sector 0, nr 8, card status 0x0

===================================================================

It is also giving MMC fat load error, read and write error and hanging between some process.

These above mentioned errors are not stable, sometimes board will work normally. This normal working condition also not stable.

We have captured the SD lines waveforms and compared with working board. There was no similarity.

Recently we did board 3 bring up. Its not at all going to SD boot. This board also having SD booting issue.

Help us to resolve the issue.

Thanks in advance.

Regards,

Shanmugam Nachiappan

  • 0
    Guru 31670 points

    Shanmugam ,

    When this issue is happening are you able to boot up MLO always? Or are you seeing issues to boot MLO also consistently?

  • 0 in reply to Renjith Thomas
    Prodigy 100 points

    Hi Renjith,

    The boards current status as follows,

    Board-1: Firstly, We had done board-1 bring up. Till now there is no issue in this board, All the interfaces are working fine.

    Board-2: After Board bring up, it was having issue in uncompressing the Linux kernel. Driver team had found issue in PCIe block. So, we had masked the PCIe block, after there was no issue. After some time we had got mmc error. This issue was persists some couple of months. After we could able to get only MLO, immediately we will get mmc error. Presently we couldn't get MLO also. Its not at all going to MMC boot, we are getting CCCCC only. We verified different boot configurations, still the issue exists. We had replaced the SD connector also.

    Note: There is no issue in UART boot for Board-2.

    Board-3: After Board bring up, we couldn't get MLO also. Its not at all going to MMC boot, we are getting CCCCC only.

    Note: There is no issue in UART boot for Board-3.

    This is what present boards status.

    Thanks for your reply.

    Regards,

    Shanmugam Nachiappan

  • 0 in reply to Shanmugam Nachiappan
    Guru 31670 points

    Shanmugam,

    Since you are not able to load MLO also, its highly likely that it could be a hardware issue. Could you please share the portion of the schematics of the MMC/SD interface?

  • 0 in reply to Renjith Thomas
    Prodigy 100 points

    Hi Renjith,

    I have checked all the possibilities from hardware side, like continuity test between processor and sd card holder, pullup values and short test w.r.t. Ground. There was no issue.

    If the problem is in hardware, the Board-1 is working fine.

    The following figure shows MMC/SD Schematic portion, which you have asked.

    I have checked after removing the ESD protection IC also, still the issue is exists.

    Thanks for your reply.

    Regards,

    Shanmugam N

  • 0 in reply to Shanmugam Nachiappan
    Prodigy 100 points

    oops... its not uploading. Please find the below image.

  • 0 in reply to Shanmugam Nachiappan
    Guru 31670 points

    Shanmugam,

    Have you tried removing R108 and replacing it with 0Ohms? Also have you tried to observe if there is any difference in behavior after removing the ESD Protection device?

  • 0 in reply to Renjith Thomas
    Prodigy 100 points

    Hi Renjith,

    My responses,

    --> Have you tried removing R108 and replacing it with 0Ohms?

             Yes. I had tried. The same issue exists.

    --> Also have you tried to observe if there is any difference in behavior after removing the ESD Protection device?

              Nothing. There was no difference.

    And also, I have observed the following things.

    I had checked impedance of all the SD/MMC lines and compared with working board. There was some impedance mismatch. That is as follows.

    1. The following figure shows the impedance test between the SD/MMC lines.

    The above results shows, there is no similarity between the Board 1 & 2 & 3. Some Impedance values are not matched; there is some huge difference.

    2. The following table shows the impedance test between the SD/MMC Lines with respect to Ground.

     

    SOM Board

    Data3

    Data2

    Data1

    Data0

    Clk

    Cmd

    SOM - 1

    142K

    148K

    144K

    141K

    347K

    138K

    SOM - 2

    (MMC issue)

    100K

    104K

    108K

    110K

    329K

    112K

     These values are seems to be OK.


    Regards,

    Shanmugam Nachiappan

  • 0 in reply to Renjith Thomas
    Prodigy 100 points

    Hi Renjith,

    Controller Part Number is XDM385AAR2IF

    Regards,

    Shanmugam Nachiappan

  • 0 in reply to Shanmugam Nachiappan
    Guru 31670 points

    Hi Shanmugam,

    I checked with our hardware expert. He is saying that there is not much impact with the impedance values. Another thing I would like to know is that what is the voltage level of DVDD_SD pin?

  • 0 in reply to Renjith Thomas
    Guru 31670 points

    Shanmugham,

    Also can you try with 33 Ohms for R108?

  • 0 in reply to Renjith Thomas
    Prodigy 100 points

    Hi Renjith,

    The voltage level of DVDD_SD pin is 3.3V.


    Regards,

    Shanmugam Nachiappan

  • 0 in reply to Shanmugam Nachiappan
    Guru 31670 points

    Shanmugam,

    Our hardware expert will reply to this thread.

  • 0 in reply to Renjith Thomas
    Prodigy 20 points

    Shanmugam,

    The cards used in the board 1 and board 2,3 are same. i.e., whether they are from same manufacturer. Please format the card and try again

    Can you please check the sys_boot * pins are proper or not for SD MMC.

    Check all the powers are coming from Power Management IC or not again

    Can you please share the scope capture of the SD_CLK on working and non working board.

    Regards,

    Hariseran

  • 0 in reply to Renjith Thomas
    Prodigy 100 points

    Hi Renjith,

    I had replaced 22 Ohms and placed 33 Ohms. Still the issue is persists.

    Regards,

    Shanmugam Nachiappan

  • 0 in reply to Hariseran Kannan1
    Prodigy 100 points

    Hi Hariseran,

    We checked using different cards and then tried after format also. The Sys_boot pins are proper. The PMIC power up sequence and voltage level also proper.


    The following information is for your analyzing.

    Thanks for your reply.

     

    Regards,

    Shanmugam Nachiappan

     

  • 0 in reply to Shanmugam Nachiappan
    Prodigy 20 points

    Hi Shanmugam,

    There is a dip in the voltage on the command, clock and data lines intermittently. Because of this only, mmc boot is not happening. There are two cases:

    Case 1:

    MMC Power: there is some peripheral on the DVDD_3V3 line may draw more current. Whether the net name DVDD_3V3 is connected to DVVD_SD pin? Try removing each of the component one by one on the DVDD_3V3 line and do the mmc boot again.

    Case 2:

    There could be some problem in the assembly of the DM385 processor on the board. Some dry soldering issue on the ground pins of the processor. 

    On one board heat up the processor slightly using hot air blower or replace the DM385 on that board.

    On the other board remove each component one by one on the DVDD_3V3 line.

    Measure the resistance on the pull up of mmc lines.

    Regards,

    Hariseran