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TPS65216: Connection of TPS65216 nPFO, nWAKEUP, nINT pins for AM3356 processor

Sota Inoue
Prodigy 40 points
Part Number: TPS65216
Other Parts Discussed in Thread: AM3356, , AMIC110, AMIC120

Dear TI expert team,

Now I'm working on a hardware design of AM3356 custom board powering with TPS65216.

I have checked TI User's Guide (SPRUIP2: Powering AMIC110, AMIC120, AM335x, and AM437x with TPS65216), and still have a question about some pin connection of TPS65216.

Q1.
There's no descriptions about nPFO and nWAKEUP in SPRUIP2.
Do you have any suggestions for connection of these pin?
It is my guess that EXT_WAKEUP pin of AM3356 should be connected to nWAKEUP or other pin, but is it correct? 

Note:
An external RTC IC (R2051S02 Nisshinbo microdevice) is used on our board, so we don't need AM3356's RTC function when the board is power-off state.

Q2.
nINT pin is connected to AM335x GPIOx in SPRUIP2, but what GPIO pin?
There's no specific GPIO (any GPIO pin is OK)? Or it depends on the software?
Our software will be based on TI AM335x Processor SDK Linux version.  

 

Also if you can provide an example schematics of AM335x processor and TPS65216 design, it would be a greate help for our design.
Anyway I'm looking forward to hearing from you.

Thanks!

  • +1
    TI__Mastermind 22531 points

    Hi,

    Thank You for using E2E. Below are the responses to the questions in the previous message. I recommend reviewing the AM335x connections with the Sitara processor team once the schematic is ready. 

    • The power fail comparator is an optional feature that can be used to monitor the pre-regulator with the PMIC. It could be connected to a GPIO (i.e E18 when using ZCZ) from the processor.
    • PMIC nWAKEUP can be used to drive EXT_WAKEUP. Please make sure the correct pull-up supply is used to match the corresponding power domain on the processor.
    • PMIC nINT can be used to drive EXTINT on the processor. 

    Thanks,

    Brenda

  • 0 in reply to Brenda Diaz
    Prodigy 40 points

    Dear Brenda-san,

    Thank you for your quick reply!

    Following your advice, we will connect nPFO, nWAKEUP, and nINT pin as below. 
     - nPFO ---> AM3356 GPIOx (eg. gpio1_8)
     - nWAKEUP ---> AM3356 EXT_WAKEUP
     - nINT ---> AM3356 EXTINT

    And let me ask one more thing about TPS65216 nINT behaviour.
    Is there any possibility that TPS65216 asserts (pulls low) nINT pin during power-up and power-down sequence even the TPS65216 is under normal conditions?

    According to AM335x datasheet, AM335x EXTINT pin is used as NMI.
    So I'm concerned that AM3356 may stops its boot/shutdown by detecting an interrupt from TPS65216 nINT if above behaviour could be occured.

    Sorry to bother you again but I look forward to your advice.

    Thanks,

  • +1 in reply to Sota Inoue
    TI__Mastermind 32030 points

    Hello, 

    The TPS65216 should not assert nINT pin during normal power-up and power-down sequences. The MASK registers (REG0x03 and 0x04) can also be used to mask certain events from generating an INT at nINT pin.

    For example, the AC_DET and PB (push-button) pins issue an interrupt when the pin status changes in ACTIVE mode. These interrupts can be masked using the ACM and PBM bits in INT_MASK1 register (subaddress 0x03).  

    Best Regards,

    Garrett

  • 0 in reply to Garrett Kreger
    Prodigy 40 points

    Dear Garrett-san,

    Thank you for your expertise!

    All of my concern has been solved, so I would like to close the issue.
    We really appreciate your support!

    Best regards,