• State Resolved
  • Locked Locked
  • Replies 3 replies
  • Answers 1 answer
  • Subscribers 31 subscribers
  • Views 155 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

MSPM0L2228: Restart system from battery back-up mode

Koichiro Tashiro
Mastermind 22945 points

Part Number: MSPM0L2228

Tool/software:

Hi,

My customer wants to keep RTC values while the main power is lost and LFSS is kept on with backup battery.
When the main power is back, how the system is restarted? Is this the same as normal power-on?

In the customer's software, RTC is initialized at power-up sequence.
To keep RTC values after recovery from battery back-up mode, the software needs to skip the RTC initialization.
Do we have any mechanism to distinguish "a normal power-up" and "recovery from battery backup"?

Thanks and regards,
Koichiro Tashiro

  • 0
    TI__Expert 3800 points

    Hi,

    There are a couple different ways to do this:

    1) The customer could save something in the scratchpad memory. If VBAT power is lost, then the scratchpad is reset. --> They could check this memory to see if their flag is still there.

    2) They could check VBATGOOD to see if the VBAT domain is valid, and then check the RTC status. The RTC is reset on a VBAT power loss.

    -Matthew

  • 0 in reply to Matthew Komitsky
    TI__Mastermind 22945 points

    Hi Matthew,

    Thanks for your detailed answer!
    I understood #1 works.

    For #2, it seems VBATGOOD simply shows current status of VBAT, according to TRM description.
    Does the bit stay cleared if VBAT is once lost during the battery backup mode, then power is recovered?

    Thanks and regards,
    Koichiro Tashiro

  • +1 in reply to Koichiro Tashiro
    TI__Expert 3800 points

    Hi,

    I would like make some slight clarifications to my previous post.

    Whenever power to VBAT is lost, then VBAT will be completely reset.

    For example: If there is an RTC configuration set on VBAT, and VBAT power is lost --> that configuration will be lost.

    The customer could check for this configuration to know if there has been a power loss on VBAT.

    -Matthew