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Inconsistency in the SD interface of DaVinci(DM8168) Processor

Nanjunda M
Expert 2485 points


Hi,

We are using TMS320DM8168CCYGA2 in our design. We have the micro SD interface to the processor for booting and file transfer functions.
Now we are finding inconsistency in the working of SD interface.

We are getting the IO error while booting the device, or while trying to access the file system.

We already proved the design in a prototype board with same design. Now we are in production stage and assembled one board initially. In this board we are observing this inconsistency.

We have measured all the resistor values on the board w.r.t. design
We have also checked with different SD cards with working code.

When we tried to probe the Clock and data lines at the connector with CRO, 
we found that when the board boots properly, the Data and clock lines are alive
and when the IO error occurs, we see that clock and data lines go low.

We are unable to find out the cause for the issue, as we already have a board of same design with no issues.
Can anybody please help us with this.
How can we debug the issue and move forward.

Please find the attached schematics and error file for reference.

 

sd_IO_error.txt


Thanks & Regards,

Nanjunda M

  • 0
    Prodigy 210 points
    Just a suggestion, but I see your SD_WP pin is pulled high. Off the top of my head I think this prevents writing to the SD card. Check this first. In my experience booting fails when the card is in write protect.
  • 0 in reply to Tate Schaar1
    Expert 2485 points
    Hello,

    Thanks for the suggestion.
    But the design is already working in board. We have a board which is fully working, the design is fully proved, there was no issues found with the interface previously.

    The micro SD card is working sometimes, we are facing the consistency problem with this interface.

    Coming to software side, the code does not include this pin/signal in the code.
    So its clear that the pull-up given to SD_WP will not create any problem for Micro SD functionality.


    Is there any other possibilities of error ?
    Any possible way for debugging ?


    Thanks & Regards,
    Nanjunda M