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TPS65217CEVM: Does TPS65217C support RTC Mode at AM335x?

Mert Samast1
Prodigy 120 points
Part Number: TPS65217CEVM
Other Parts Discussed in Thread: TPS65217, AM3358

Hello,

I am designing a board around AM335x. I am using TPS65217C PMIC. I want to keep the Real time when the PMIC power down (day/month/year).

According to my research, TPS35217C does not support to RTC. 

But acoording to my another researc, there are some ways to use RTC at PMIC and AM335X.

I still have questions about this topic. 

Is there any way to use RTC mode? How can I do this?

Note: I took the BBB schematic as an example in my project.

 

Thank you for your answers.

 

Best Regards,

 

Mert SAMAST

  • 0
    TI__Mastermind 30260 points

    Mert,

    The TPS65217 -C version can power the RTC domain of AM335x with LDO1.

    If you refer to Figure 24. Global State Diagram on page 39 the TPS65217 datasheet, the SLEEP state of the PMIC is a mode of operation in which LDO1 is enabled but all other regulators are disabled. If an AC adapter or USB cable is connected, the battery charger will also be active. The software should have multiple low-power modes, but RTC-only mode is essentially the same as shutting down the system but keeping power applied. So you should be able to enter a simply Linux command to test it:

    • sudo shutdown now

    And then you will need to press the push-button connected to the PB_IN pin of the PMIC to wake the system back up. You can verify this by setting the clock before you shutdown the system and by checking the clock when the system wakes back up.

    The schematic wiring for VDDS_RTC, RTC_KALDO_ENn, and CAP_VDD_RTC on the AM335x processor also needs to be correct for this to work. Refer to the below diagram:

    The LDO_PGOOD pin on the PMIC can be connected to RTC_PWRONRSTn on the processor, which is a dedicated push-pull output on the PMIC intended for this purpose (logic HIGH when LDO1 or LDO2 is enabled and within regulation).

    You could also ask this question to the Sitara team by submitting the question with AM3358 as your part number, but from the PMIC side we expect to support RTC-only mode.