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DM365 PRTCSS used for controlled power down sequence

rmiller
Prodigy 90 points

I would like to use the PRTCSS to control the DM365's  3.3V then 1.8V then 1.35V power off sequence, but have some questions:

According to SPRUFJ0A, Section 3.4, the power off sequence provides two output signals, PWCTRO0 and PWCTRO1, that control RESET and Power Down. Is this hard-coded, or if it is simply a recommended configuration?  I need at least 3 output signals to perform the power down sequence on my board.

I would like the DM365 to tell the PRTCSS to initiate a power down sequence, the PRTCSS would then need to disable all of the board's supplies in the correct order (as we are using individual regulators/switchers as opposed to a monolithic chip). Is this even possible? It appears that the DM365 must write/read from the PRTCIF which then controls the PRTCSS, but it is not clear to me if the PRTCSS can run entirely on its own.

 

Thanks for the help!

Rick

  • 0
    Intellectual 985 points

    Rick, we have struggled with this over the last month.  TI has come back and indicated that the sequencing functionality is not defined properly and they are not planning on supporting that feature.  We ended up using a small MSP430 to manage the sequencing, which controls the enables to a TPS65051. It could easily work with individual regulators as well.

    I'm pretty sure you aren't going to be able to use the PRTCSS the way you want.  Or at least you aren't going to get a lot of support from TI on that functionality because it all seems to be not completely understood internal to TI.

    Good luck!

  • 0 in reply to DJH
    Prodigy 90 points

     

    DJH said:

    Rick, we have struggled with this over the last month.  TI has come back and indicated that the sequencing functionality is not defined properly and they are not planning on supporting that feature.  We ended up using a small MSP430 to manage the sequencing, which controls the enables to a TPS65051. It could easily work with individual regulators as well.

    I'm pretty sure you aren't going to be able to use the PRTCSS the way you want.  Or at least you aren't going to get a lot of support from TI on that functionality because it all seems to be not completely understood internal to TI.

    Good luck!

    We also decided to use a small external micro to sequence the power supply rails. 

    Good to hear we're in the same boat.

     

    -Rick