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Synchronising startup of two AM335x processors (with independent TPS65910A31/TPS65910A3)

Jaroslaw Karwik
Prodigy 205 points

Hi,

I have system with two independent modules - each has AM335x with own TPS65910A31.

They are connected with each other, so I wanted to be sure they start same time ( to avoid electrical issues related to driving i/o pins)

I have something like that:

PMIC_RESETOUTN  is ANDed with external signal ( which is PMIC_RESETOUTN  from second module). The gate is wide voltage tolerant ( up to 6V regardless of supply). I do not use RTC-only mode.

Few questions:

- Is it correct approach ? 

- I have selected VAUX1 as 1.8V supply for the gate ( it seems to be one of early 1.8V supplies)

- I do not use RTC-only mode ( only RTC timer functionality ). Do I understand it correctly that in such case it does not  really matter whether I use TPS65910A31 or TPS65910A3 - I mean that once I never go to sleep mode I do not need external LDO for VRTC in TPS65910A3 configuration ?

  • 0
    TI__Expert 6090 points

    Hi

    For your uest 1 , its hard to comment if this is a correct approch or not . the device will send a reset signal how the system control it externally is completely in control of the users,

    for your question 3 if RTC of the PMIC is not connected to any thing on AM335 then you can use any varient.

     

  • 0 in reply to Puneet Sehgal
    Prodigy 205 points

    About 1 - let me put it more clearly

    I have two systems ( AM335x + PMIC) which I want to synchronise ( during hard power on).

    In normal case reset signal from PMIC ( NRESPWRON from TPS65910A31 ) is connected directly to processor PWRONRSTn(porz) . But as I want these systems to start simultaneously I  create logical "and" of two PMIC reset signals - this creates reset delay for the faster system ( as it is unlikely they will have same timings).

    Basically - just wanted to be sure that delaying PWRONRSTn does not cause any side effects.