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AM3351: Default state of PMIC_POWER_EN signal

Jack Cha
Mastermind 7196 points
Part Number: AM3351
Other Parts Discussed in Thread: AM3352, TPS65219

Hi AM3351 Champ

A customer built a custom board designed using AM3351 and TPS6521905RHBR.
Only two boards were assembled and tested, and all output voltages of the PMIC are not checked.

They downloaded the NVM file to PMIC, and checked the Up/Down Sequence using the scope in PMIC EVK, but it didn't seem to be a problem.
And PMIC_POWER_EN pin of AM3351 is connected to EN/PB/VSENE pin of PMIC, and it is messured as LOW.

Please check if the AM3352 works normally.

Thanks.

Regards, 

Jack

  • 0
    Mastermind 7196 points

    In addition, 

    Currently, SD/eMMC is not programmed with bootable binaries,
    When they disconnect the PMIC_PWR_EN signal pattern between AM3351 and PMIC, and connect the VSYS to the PMIC 25pin (EN/PB/VSENSE) with a pull-up 10k, the PMIC outputs the power normally.

    However, if the PMIC EN pin does not have Pullup, the Power Up sequence is not progressing.

    As a result of further experiments, they tested the following three things.

    Test 1
    - Download the NVM file sent by TI to EVK -> Power OFF/ON -> power on sequencing Normal

    Test 2
    - Download the NVM file sent by TI to EVK -> Remove R3 from EVK -> Power OFF/ON -> Voltage not measured.

    Test 3
    - Regarding the FSD function of PMIC, set the PU_ON_FSD bit of MFP_2_CONFIG Register (ADDRESS 0X20) as follows.

    - Download the modified NVM file to EVK -> Check that the download was successful by reading the DEVICE value.

    - Remove R3 of EVK -> Power OFF/ON -> Voltage not measured. (Power on sequencing normal with R3 resistance)

  • 0
    TI__Guru** 124058 points

    Hello Jack,

    Thank you for the query.

    The PMIC_POWER_EN is used along with the RTC. Not sure if this could be used with the PMIC you mentioned above,

    8.1.4.3.5 RTC-Only

    RTC-only mode is an ultra-low power mode which allows the user to maintain power and clocks to the real-time clock (RTC) domain while the rest of the device is powered down. All context and memories will be lost, and the only portion of the chip that will be maintained is the RTC. Only the RTC power supply must be ON. All the remaining supplies must be OFF. The RTC battery backup domain consists of the RTC subsystem (RTCSS), a dedicated, on-chip 32.768 Hz crystal oscillator and I/Os associated with the RTCSS: pmic_power_en and ext_wakeup.

    Regards,

    Sreenivasa

  • 0 in reply to Jack Cha
    TI__Guru** 124058 points

    Hello Jack, 

    Thank you.

    Jack Cha said:

    Currently, SD/eMMC is not programmed with bootable binaries,
    When they disconnect the PMIC_PWR_EN signal pattern between AM3351 and PMIC, and connect the VSYS to the PMIC 25pin (EN/PB/VSENSE) with a pull-up 10k, the PMIC outputs the power normally.

    However, if the PMIC EN pin does not have Pullup, the Power Up sequence is not progressing.

    I would expect this to work.

    Regarding the ruse of PMIC_POWER_EN to control the PMIC, this needs to be discussed with the PMIC team.

    Please start a new thread with title PMIC TPS65219 EN. Do not include the processor number in the title.

    Regards,

    Sreenivasa