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TPS650830: How to disable FLT functionality

Part Number: TPS650830
Other Parts Discussed in Thread: USB2ANY

Hi,

Is there any way to disable the feature of emergency shutdown triggered by pressing power button (driving PWRBTN low)?  The purpose is not triggering emergency shutdown no matter how long that PWRBTN is driving low.

Thanks!

Antony

  • Hi,

    I have assigned your request to responsible Applications Engineer and we will get back to you as soon as possible.

    Regards,

    Murthy
  • Hi Antony,

       Emergency shutdown initiated by PWRBTN is not implemented by hardware; it's decided by host processor software code. The procedure is described below:

    1. Pushing power button makes the PWRBTN pin low;
    2. PWRBTN pin low makes is PWRBTN bit low;
    3. PWRBTN bit low can generate an interrupt and this interrupt can be masked by bit-0 of register IRQLVL1msK (address = 0x13);
    4. The time of power button being pushed down recorded by PBCONFIG register (address = 0x14) FLT[5:0];
    5. When the time of power button being pushed down reaches the FLT[5:0] setting time, an another interrupt can be generated to assert the bit-5 (FCO) of register RESETIRQ1; and this interrupt can be masked by bit-5 (MFCO) of register RESETIRQ1MASK;
    6. Finally, the host processor software code can read the FCO bit and then determine if push power button cause the emergency shutdown. 

        Please let me know if you have any further questions. 

    Thanks!

    Phil

  • HI Phil,

    Thanks!  I'm not sure if I understood this correctly.  

    It looks to me that the only purpose of FLT[5..0] setting is to trigger FCO interrupt when PWRBTNIN is driven low longer than FLT[5..0] setting??  So, to cause an emergency shutdown the I2C host need to do something (setting SDWN bit to '1'??) after receiving FCO interrupt? I FCO is masked (MFCO is '1') or the I2C host ignore FCO interrupt, actually PMIC would not enter emergency shutdown itself?

    Thanks!

    Antony

  • Hi Antony,

    Yes, you understood this correctly; but software force shutdown has two ways:
    1. SHUTDOWNZ pin pulled-low;
    2. Setting SDWN bit to '1'.

    Thanks!
    Phil
  • HI Phil,

    I tried to verify this on my TPS650830EVM, and found PMIC enter emergency shutdown (all power rails are turned off except LDO3/LDO5) simply by press power button (S1) for 31 seconds. (FLT default setting is 31 seconds.)  During the test, there's no USB2ANY connected, so there's no I2C access at all. It looks to me this is a pure HW behavior.  Can you double check this?

    Thanks!

    Antony

  • Hi Antony,

      I just double checked; you're right. After checking with designers, the explanation is: power button shutdown is implemented by hardware; but it can be disabled by setting the FLT[5:0]<2S (Need to update datasheet later for this function). 

    Thanks!

    Phil