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TMS320F28034: lower poewr in HALT mode

HS FAE Germany
Mastermind 32400 points
Part Number: TMS320F28034


Hello,
my customer uses the HALT mode to save power. Now he found out by chance that by additional switching off the ADC and Flash he can save a little more power in HALT mode. Why is this not documented? Are there any more hints to save more power in HALT mode?

Regards, Holger

  • 0
    Guru 30330 points
    Holger,

    This is known. Please see the "Power Consumption Summary" table in the datasheet SPRS584. The "TMS320F2803x Current Consumption at 60-MHz SYSCLKOUT" table describes the conditions for achieving the lowest power consumption in HALT mode: FLash is powered down and all peripheral clocks are off. Continuing through the chapter, the Reducing Current Consumption Section describes other methods of further reducing power. Footnote 3 of "Typical Current Consumption by Various Peripherals (at 60 MHz)" describes that disabling the ADC peripheral clock will also reduce the current on the VDDA supply.

    You can see the differences between the ADC and Flash being powered or not by comparing the Operational currents for the respective supplies against the HALT mode currents. It is clear that disabling the ADC and Flash will have significant impacts on the power consumption of the device.

    Thanks,
    Mark
  • 0 in reply to Mark Labbato
    TI__Mastermind 32400 points

    Mark,
    customer has to switch off the ADC clock and additional has to switch of the ADC in Control Register 1 bit ADCENABLE.
    The flahs has to switch off by setting the PWR bit to "Pump and bank sleep" in register FPWR. This has to be done out of RAM.

    You have to agree that the documentation is very limited here and could be improved.

    Regards, Holger

  • 0 in reply to HS FAE Germany
    Guru 30330 points
    The customer is following the proper procedure here.

    I will see if we can get some additional content there.

    -Mark
  • 0 in reply to Mark Labbato
    TI__Mastermind 32400 points

    Mark,
    any feedback?

    Regards, Holger

  • 0 in reply to HS FAE Germany
    Guru 30330 points
    Holger,

    I have filed a ticket to include the information that you have brought up. I wasn't aware there was additional follow up? I do not have an estimate of when the document will be released with the additions.

    Do you have additional questions that you would like me to address?

    -Mark
  • 0 in reply to Mark Labbato
    TI__Mastermind 32400 points
    Hello Mark,
    ok, please let me know the outcome of the ticket. Right now no additional questions.

    Regards, Holger
  • 0 in reply to HS FAE Germany
    Guru 30330 points
    Ok. I will make sure that you get notified when we get around to it. I am going to close this post for now.

    Just a key point about why this might have been missed. Our Characterization tests for LPM typically just power on then get the device into LPM. I can't think of one that actually initialized a system (including powering on the Flash and Analog) then reducing the currents to measure them. It is possible that this did not cross the mind of the person writing the text section to think about powering down the analog section. Obviously this is clear now that the usecase is brought up, we can add it. I will also feed this forward to other documentation as needed.

    -Mark