MSP430F5510 LPM4 problem

Carloalberto,

As Jeff pointed out, many other devices or some MSP430 peripherals might be drawing current in unexpected ways. Even small LEDs can draw microamperes when turned off (dark current or other effects).

Gustavo

Jeff,

thank you very much for your suggestion. I added your 3 code lines and the power consumption dropped to 1.5 uA in LPM4. That's the value in the datasheet.

In LPM3 i measure 5.2 uA, value still a little bit higher than the datasheet one.

As you and Gustavo said, there could be other things which drain current. How can i disable all the modules in the MCU? I want to be sure that everything is off and turn on just what i need!

Any suggestion?

Thank you!

Regards,

Carloalberto

I don't know specifically in your case, but I would look at the user's guide. I believe most peripherals  are off, but you never know unless you check.

Sorry if I answear just now but i've been away.

My LPM3 testing code it's the same as the LPM4 cose except for __bis_SR_register(LPM3_bits);

As you suggest (thanks!) I connected ACLK to VLO

UCSCTL4 &= 0xF8FF;
UCSCTL4 |= SELA__VLOCLK;

and the power consumption dropped to 1.6 uA (before it was 5.2 uA) !

Disabling SVS and SVM with this code:

PMMCTL0_H = PMMPW_H;                // PMM Password
SVSMHCTL &= ~(SVMHE+SVSHE);         // Disable High side SVS
SVSMLCTL &= ~(SVMLE+SVSLE);         // Disable Low side SVS

the power consumption drop to 1.3 uA.

So i think we figured out the issue!

If i enable all the clocks i need in my application the power consumpion rise to 2.4 uA. Do you think is it ok or there is something more than i can improve (see the code below)?

The code it's the following:

void halMcuInit(void)
{
    // Stop watchdog
    WDTCTL = WDTPW + WDTHOLD;                // Stop watchdog timer

    // Set up clock system on MCU to fit your system
    // Target specific implementation
 
    P5SEL |= BIT4+BIT5;                        // Port select XT1
    UCSCTL6 &= ~XT1OFF;                        // Set XT1 On

    P5SEL &= ~(BIT2+BIT3);                  // Don't select XT2
    UCSCTL6 |= XT2OFF;                        // XT2 Off
    UCSCTL6 |= XCAP_3;                      // Internal load cap 12 pF

    // Loop until XT2 fault flag is cleared
    do
    {
        UCSCTL7 &= ~XT1LFOFFG;                      // Clear XT1 LF fault flags
    }while (UCSCTL7&XT1LFOFFG);                   // Test XT1 LF fault flag

    __bis_SR_register(SCG0);                  // Disable the FLL control loop
 
    UCSCTL3 = SELREF__XT1CLK + FLLREFDIV_0;      // XT1 as FLL ref, FLL reference divider at 1

    UCSCTL0 = 0x0000;                         // Set lowest possible DCOx, MODx

    UCSCTL1 = DCORSEL_2;                      // Select DCO range for 4 MHz operation
    UCSCTL2 = 30 + FLLD_2;                      // x (30 +1), x 4

    UCSCTL6 &= ~(XT1DRIVE_3);                 // Xtal is now stable, reduce drive strength to the lowest current consumption.

    UCSCTL4 = SELA__XT1CLK + SELM__DCOCLK + SELS__DCOCLK;     // Set ACLK = XT1, MCLK = DCOCLOCK, SMCLK  = DCOCLOCK,

    UCSCTL8 &= 0xF8;//~(ACLKREQEN | MCLKREQEN | SMCLKREQEN);
    UCSCTL6 |= 0x0001;
   
    __bic_SR_register(SCG0);                  // Enable the FLL control loop

    // Worst-case settling time for the DCO when the DCO range bits have been
    // changed is n x 32 x 32 x f_MCLK / f_FLL_reference. See UCS chapter in 5xx
    // UG for optimization.
    // 32 x 32 x [ 32768 x (30 + 1) x 4 Hz] / 32768 Hz = 126976 = MCLK cycles for DCO to settle
    __delay_cycles(126976);
   
    // Loop until XT1,XT2 & DCO stabilizes.
    do
    {
        UCSCTL7 &= ~(XT2OFFG + XT1LFOFFG  + DCOFFG);
        // Clear XT2,XT1,DCO fault flags
        SFRIFG1 &= ~OFIFG;                      // Clear fault flags
    }while (SFRIFG1&OFIFG);                   // Test oscillator fault flag
}

void main(void)
{   
    WDTCTL = WDTPW+WDTHOLD;                   // Stop WDT
   
    P1OUT  = 0;
    P1DIR  = 0xFF;                          // P1 & P2 
    P1SEL  = 0;
    P2OUT  = 0;
    P2DIR  = 0xFF;                          // P1 & P2 
    P2SEL  = 0;
    P4OUT  = 0;
    P4DIR  = 0xFF;                          // P1 & P2 
    P4SEL  = 0;
    P5OUT  = 0;
    P5DIR  = 0xFF;                          // P1 & P2 
    P5SEL  = 0;
    P6OUT  = 0;
    P6DIR  = 0xFF;                          // P1 & P2 
    P6SEL  = 0;
    PJOUT  = 0;   
    PJDIR  = 0xFF;                            // PJ

    USBKEYPID = USBKEY;
    USBPWRCTL = 0;
    USBKEYPID = 0;
   
    // Disable SVS
    PMMCTL0_H = PMMPW_H;                  // PMM Password
    SVSMHCTL &= ~(SVMHE+SVSHE);    // Disable High side SVS
    SVSMLCTL &= ~(SVMLE+SVSLE);      // Disable Low side SVS

    halMcuInit();
   
  __bis_SR_register(LPM3_bits);             // Enter LPM3
  __no_operation();                                      // For debugger
}

Do you think is it ok to disable SVS and SVM? Why would i enable them?

Thanks!

Regards,

Carloalberto