MSP-EXP430FR5994: Power Consumption of Out-of-Box Example in LPM3 Mode

I don't know much about the FR5994 OOB example, but from what the Launchpad UG (SLAU678A) says I suspect it wasn't built as an exemplar of LPM3 consumption.

The LPM3 power rating is best case, meaning that Everything is turned off. At minimum, in the OOB the UART is running, and maybe the ADC as well. [Ref Data Sheet (SLASE54B) Sec. 5.10]

I also don't see any power gating in the schematics for the SD card, which will be a bit of a power hog even in standby.

Example msp430fr599x_lpm3_02.c (Examples suite SLAC710A) might be a better starting point.

Hi Bruce,

 Thanks for your suggestion on 'msp430fr599x_lpm3_02.c'. I tried the code below from 'msp430fr599x_lpm3_03.c' in my project. But still the power consumption seems to be 3.1 milli Watts (See attached image). No SD Card was inserted in this test or the earlier one (hence no power consumption for SD card). The below code starts immediately at the beginning of the main() function. Any suggestion on attaining the actual claimed datasheet power consumption figures?

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#if(POWER_CONSUMPTION_IN_LPM3_MODE_TEST)

   // LFXT, 1s interrupts

   WDTCTL = WDTPW | WDTTMSEL | WDTSSEL_1 | WDTIS_4;

   SFRIE1 |= WDTIE;                        // Enable WDT interrupt

   // Configure GPIO

   P1OUT = 0;

   P1DIR = 0xFF;

   P2OUT = 0;

   P2DIR = 0xFF;

   P3OUT = 0;

   P3DIR = 0xFF;

   P4OUT = 0;

   P4DIR = 0xFF;

   P5OUT = 0;

   P5DIR = 0xFF;

   P6OUT = 0;

   P6DIR = 0xFF;

   P7OUT = 0;

   P7DIR = 0xFF;

   P8DIR = 0xFF;

   P8OUT = 0;

   PJOUT = 0;

   PJSEL0 = BIT4 | BIT5;                   // For XT1

   PJDIR = 0xFFFF;

   // Disable the GPIO power-on default high-impedance mode to activate

   // previously configured port settings

   PM5CTL0 &= ~LOCKLPM5;

   // XT1 Setup

   CSCTL0_H = CSKEY_H;                     // Unlock CS registers

   CSCTL1 = DCOFSEL_0;                     // Set DCO to 1MHz

   CSCTL2 = SELA__LFXTCLK | SELS__DCOCLK | SELM__DCOCLK;

   CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1;   // Set all dividers to 1

   CSCTL4 &= ~LFXTOFF;                     // Enable LFXT1

   do

   {

       CSCTL5 &= ~LFXTOFFG;                // Clear XT1 fault flag

       SFRIFG1 &= ~OFIFG;

   } while (SFRIFG1 & OFIFG);              // Test oscillator fault flag

   CSCTL0_H = 0;                           // Lock CS registers

   __bis_SR_register(LPM3_bits | GIE);

   __no_operation();

#endif

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Regards

Soumyajit

Hi Bruce,

"I don't have a crystal on my Launchpad so I used LPM3_02 which only relies on VLOCLK" - As per the MSP-EXP430FR5994 schematic, I find that the external high speed crystal is not soldered on the board but the 32.768 kHz crystal is populated on the board (You may refer to Q1 & Q2 in the schematic). So, did you mean that the high speed crystal in not there on your board or the 32 kHz one? Did you remove (de-solder) the 32 kHz crystal from your board?

"I also removed the LED" - Did you remove the RED LED (LED1 on schematic) by removing the J7 jumper or you de-soldered the GREEN LED (LED2 on schematic) as well?

I will try to replicate your setup and see if I can attain 0.0017mW as is the power consumption in your case.

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Thanks

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Regards

Soumyajit

Hi Bruce,

 Thanks for your help in the matter. Would you mind running the attached code in your launchpad? I have attached the code I have used to test at my place. This code I have tested at my end resulting into a power consumption of 2.6 mW. I am curious to know whether you will also get the same results.

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Thanks

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Regards

Soumyajit

BlinkLED_MSP430FR5994.zip

Hi Bruce,

  Following your suggestion, I copied the 'lpm3_03.c' file content to a new CCS project. Running the code, the power consumption still remains at 2.6 mW. Am not understanding what might be going wrong. LED P1.0 jumper is removed as well as RXD & TXD jumpers. Super Capacitor jumpers were removed too. No SD card in SD card slot.

  I am attaching the code/project I just used in my test. Requesting you to run the same at your end and see if still you are getting the low power consumption (which I am not getting at my end).

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Thanks

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Regards

Soumyajit

msp430fr599x_lpm3_03.zip

Hi Kostas,

 Thanks for your comments. I am still waiting for the PCB tests (power consumption related) to be conducted. It's of severe priority that the MCU consume the power as per figures indicated in the datasheet. This is because the entire project depends on the low power consumption of the MCU (along with additional circuitry). In this regard, I will need to solve the power issue at all cost. I am expecting that the power consumption tests will be over by mid February 2019. You may go ahead closing the thread (in this case I will open up a new thread to discuss the power consumption issues faced in the custom PCB).

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Thanks

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Regards

Soumyajit Das