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Linux/TPS659037: How to start up AM5748 use TPS6590378 without PWRON buttom

user5320730
Prodigy 90 points
Part Number: TPS659037
Other Parts Discussed in Thread: AM5748,

Tool/software: Linux

Hi,

We use TPS6590378 as the PMIC for AM5748 and our product is edge computing gateway.

As the reference design, system starts up after pushing down the bottom on PWRON.

But most of our customer want the gateway start up whenever power supplies without any push bottom action.

So how to treat with such situation？

Thank you.

BR.,

Ivan

  • 0
    TI__Genius 10885 points
    Hi Ivan,

    They should be able to boot automatically by connecting PWRHOLD (GPIO7) to VRTC with a pull-up. Looping in the device expert to confirm.

    Best Regards,
    Rick S.
  • 0 in reply to Richard Solarski
    TI__Genius 10000 points

    Hi Ivan,

    Rick is correct. However, if you tie PWRHOLD (GPIO_7) to VRTC, please ensure that you have a method to disable the PMIC before disconnecting power. RESET_IN or POWERDOWN could be options for this.

    Thanks,

    Nastasha

  • 0 in reply to Nastasha
    Prodigy 90 points

    Hi，Nastasha：

    As it mentioned in AM574x Sitara Processors Silicon Revision 1.0, i862 Reset Should Use PORz & i863 MMC2 Has PU/PD Contention Immediately after Release from Reset.

    We want to use the  Implementation 2 of i862: Additional circuit implemented that generates porz withoutPMIC support, cause this would be the suitable solution to treat with both software reset and eMMC.

    If that，the PWRHOLD(GPIO_7) should always keep low which would be a conflict with your suggestion.

    Do we have anymore reasonable solution?

    It's urgent, thank you so much.

    BR.,

    Ivan

  • 0 in reply to user5320730
    TI__Genius 10000 points

    Ivan,

    I am not sure I understand your question. The PMIC has a BOOT option that will toggle the PORz after the power sequence completes to address the i863 errata of the processor. Is this what you are looking for?

    Thanks,

    Nastasha

  • 0 in reply to Nastasha
    TI__Intellectual 2935 points

    Hi, Nastasha,

    Still have two questions:

    1. Can we use the sch as followed to power up the TPS659037?

    2. If we need a external Low Level Signal to trig the PWRON pin, how about the pulse width for the low voltage level?

  • 0 in reply to Wu JW
    TI__Intellectual 2935 points
    Can we floating the PWRON PIN without using the PWRON function?
  • 0 in reply to Wu JW
    TI__Genius 10000 points

    hi,

    If you don't want to use PWRON, you can leave it floating. having a pullup on PWRON will not turn the device on since it needs a high to low level transition on PWRON to enable the PMIC.

    The other option to turn on the PMIC is to use an enable signal on GPIO_7 (POWERHOLD). When this GPIO is high the device will be on, when it is set low, the device will power off.

    Thanks,

    Nastasha