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TWL6030: TWL6030 + OMAP4430 Power off during a reboot

Avraham Bergel
Prodigy 40 points
Part Number: TWL6030
Other Parts Discussed in Thread: 4430

Hi All,

My configuration is OMAP 4430 with TWL6030, and this phenomena is happening in about 3-5% of the units of first production:

Our device is running TI-based Linux kernel 3.4.71 for OMAP4.

After rebooting the device by the command "reboot" in certain cases

we see that the device powers itself off in very unexpected places.

Several times we see the device goes down in the middle of kernel boot.

One time we interrupted normal boot flow and stopped in Uboot
to manually perform certain operation. The device suddenly powered
itself off in the middle of typing a U-Boot command.

You can help about this problem

Thx

  • 0
    TI__Prodigy 30 points
    Hi Avraham. Your question has been assigned to the expert on TWL6030. He will work to respond to your issue ASAP.
  • 0
    TI__Genius 17380 points

    Hi Avraham,

    Can you check the values in the PHOENIX_LAST_TURNOFF register? It may give a clue.

    Alternatively, have you measured VDD and PWRON during one of these shutdowns on an oscilloscope? If VDD is drooping it may explain it, or if PWRON is long key pressed it could shutdown. 

  • 0 in reply to Kevin LaRosa
    Prodigy 40 points

    Hi Kevin,

    Thank you for your response,

    1. We checked "PHOENIX_LAST_TURNOFF"  register value, and result was" 0x25". for unit  with problem of power off during a reboot

    and for unit without problem it was  0x01 .

    2. About the VDD  is stay on high during the reboot.

    ,"PWRON"  is not connected in my design but accordingly with DATA SHEET this input is with PU (Pullup) to "VIO" (this connect to" V1V8 SMPS" in my design) 

    Can you help me about this problem.

    Thank

  • 0 in reply to Avraham Bergel
    TI__Genius 17380 points

    Hi Avraham,

    Based on the PHOENIX_LAST_TURNOFF, it looks like there is a short being detected on one of the following: V1V29, V1V8, V2V1, VCORE1, VCORE2, VCORE3, VMEM, VANA, VAUX1, VAUX2, VAUX3, VCXIO, VDAC, VPP, VUSB.

    This can be the result of several possible cases. This issue only occurs during a reboot, correct? This would imply that it is not a physical short to GND (in which case it would not boot properly the first time), but more likely a higher than expected inrush or other problem.

    You may want to probe each voltage regulator during the reboot to see if any of them are not coming up properly. If the processor is broken and drawing too much current from any particular rail, it would shut down in this manner. You can find more about the short circuit protection circuit in the datasheet (~pg37).

  • 0 in reply to Kevin LaRosa
    Prodigy 40 points

    Hi Kevin,

    Thank you for your response,

    1. I checked and found all each voltage regulator during the reboot and they are good excepted:

     VPP is 0.3Volt (this floating??)


    2. Could you please say your opinion if :

    RESERVED1  ball: N15 connect to GND 
    RESERVED2  ball: K13 connect to "V2V1" and not to "VMMC_IN1" accordingly with data sheet ~pg10 (that it is connected to VBAT)
    RESERVED3  ball: B7   connect to "V2V1" and not to "VUSIM_IN1" (that it is connected to VBAT)

    Can you help me about this problem.

    Thank








  • 0 in reply to Avraham Bergel
    TI__Genius 17380 points
    Hi Avraham,

    You may need to take scope shots of each rail during a reboot when one of these unexpected shutdowns occurs to try to narrow down which rail is failing. If VPP isn't enabled, then it should not be causing the shutdown.

    Regarding the improper connection of the RESERVED balls, can you cut the traces to make them floating? Having these powered incorrectly could be having unexpected side effects.