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AM5728: eMMC Cold Boot issue

Michael DU
Prodigy 125 points
Part Number: AM5728
Other Parts Discussed in Thread: SYSBIOS

Hi,

I am facing a strange issue.

Setup : Custom Board with Phytec AM5728 SOM

Cold boot with SD Card (MMC1) is no problem,

Warm boot (reset) ok with either SD Card (MMC1) and eMMC (MMC2)

Cold boot with eMMC Ok with some boards, not OK with other boards, sometimes OK if not waiting too long before rebooting.

sysboot lines PU/PD resistors : 10k, on Phytec Module. priority setting is SD->eMMC.

Sysbios - All code in A15.0

processor_sdk_rtos_am57xx_6_03_00_106 - CCS 8.1 in linux environment.

I don't know how to narrow it down, please help ...

Michel

  • 0
    TI__Genius 10180 points

    Michel,

    What are the failure log you are seeing from RTOS?  Can you attach your schematic of the MMC2 (eMMC) connection? 

    Any chance you can connect and dump MMC2 registers at point of failure?

    Thanks & Regards,

    Shiou Mei

  • 0 in reply to Shiou Mei Huang
    Prodigy 125 points

    Hi Shiou,

    Thanks to take care of our issue.

    I slightly progress in the understanding, not sure this is linked to emmc. What I realized is if I insert an SD card (MMC1) without SBL, the ROM bootloader recognizes this is not a SD Boot card, then switch to eMMC boot as it should and everything starts correctly !

    But if no SD card is present, then the Bootload stucks and did not even try to load the SBL from eMMC.

    How can I debug as all this happens during ROM bootloader execution ?

    Where can I find the source code of the ROM bootloader to try to understand what is happening ?

    Thanks in advance for helping, this is a serious situation for us !

    Best regards.

    Michel

    MMC1 schematics, X_MMC1_SD is pulled-up to VDD_SD (3.3V), not shown here :

  • 0
    TI__Genius 10180 points

    Michael,

    Please remove the PU resistor on the MMC1 CLK lane.  Moreover, if you can connect to JTAG, then you can dump out the PC register values to gain more understanding on where the point of failure is.  Waveform captures of the MMC1 CLK, DAT0, and CMD with high resolution will also be beneficial for debug.

    Best Regards,

    Shiou Mei