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MSP430g2553 low power mode power consumption problem

Alex Hsieh
Prodigy 20 points
Other Parts Discussed in Thread: MSP430G2553

hello everyone,

The TI company claims that the MSP430 launchpad consumes only few micro ampere current in the low power mode such as LPM3.
However in my case, I use a easy code just as following

I think that it was a very simple work for the launchpad and that it would consume little power (about few micro ampere),
but in my case, it consumed about 7mA current which extremely exceeded my expectation.
Did I forget to turn off any block such as Clk or CPU?
Or it's just a normal case to run this code?

By the way I have also tried the Blink sample code, and the current flowed in the Vcc pin was about 29~32mA when Vcc = 3.54V.
Can anyone tell me how to run the launchpad in a more low power way?

  • 0
    TI__Expert 6760 points

    Hello,

    Here is a blink led example that places the device in low power mode using Watchdog interrupt.

     

    8322.msp430g2xx3_lpm3.zip

    Regards,

    Arthi Bhat

     

  • 0 in reply to Arthi Bhat1
    Prodigy 20 points

    Thanks for your reply, Bhat.

    I have tried your code ,but the result wasn't  well.
    I used source meter to measure the power consumption of MSP430 launchpad.
    I set Vcc = 3.54V and then get current  around 18~20mA.
    I connect the circuit as the picture below,
    Could you tell  me what was the problem?

  • 0 in reply to Alex Hsieh
    Expert 1740 points

    Hi, the reasons for higher current consumtion:

    1. Any lighting LED will consume a few mA

    2. Your power supply feeds not only MSP430G2553 but also other part of board (programmer/debugger chips).

    3. MSP430 CODE EXAMPLE  above needs  32 kHz XTAL you do not have on the board.

    Br 

  • 0 in reply to Alex Hsieh
    Guru 227245 points

    Oleg is right - from the picture one can see that you didn’t remove the VCC jumper. So you power the MSP but also the other MSP on the FET side. Also, you operate the 5V to 3.6V regulator on the FET side backwards and therefore the the USB/SER converter too. And the power LED.

    Pull the VCC jumper (and also the other jumpers between target and FET side, to avoid any cross-currents) and see how the current goes down.

  • 0 in reply to Jens-Michael Gross
    Prodigy 20 points

    Hi,

    i've been running the same demo program on my Launchpad with a MSP430G2553.

    after programming through Code Composer (Version: 6.0.1.00040)  i then disconnect the target side from the FET side and ran the target board off of a battery supply ~2.85V. the red LED blinks periodically with the expected frequency but i'm measuring a current of 58.2uA when the LED is not blinking and the MCU is presumably in LPM3. i've tried sourcing the clock for the WDT from the VLO and from the external crystal but it seems to make no difference. All pins are in output and set to low and there's nothing else connected to the Launchpad.

    i've also recently upgraded my version of Code Composer from 5.5.0  just to see if there was some small chance something in there could be responsible so i'm pretty desperate at this point.

    my questions are is if this thread's problem has been resolved and/or if anyone else is getting this high a current reading for LPM3 with MSP430G2553? any reasoned suggestions are welcome at this point.

  • 0 in reply to rolo tumazi
    Prodigy 20 points

    Hi,

    success! i've managed to get something and i can understand it (bonus). i simply moved the MCU over to a breadboard and attached a 10k pullup to the RST pin. that seems to have done the trick. current consumption went down to 0.2uA - which is as low as my multimeter will read.

    now what is on the launchpad board that draws so much current? the switch attached to P1.3 of course. disconnecting pin P1.3 from the board showed the same low current draw as the breadboard.  adding:

    P1OUT = BIT3;

    in the setup() also did the trick.

  • 0 in reply to rolo tumazi
    Prodigy 20 points

    Ha! This must be my problem too! Thank you for the hint. The bloody switch pullup, yes.

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