MSP430f5529 low power issues

Hi Patrick,

I tried running the 'MSP430F55xx_LPM4.c' example code on the MSP430F5529 LaunchPad (no USB connected, no jumpers connected), and I saw current consumption (displayed on the bench power supply) shown as less than 1 mA for VCC=3.3V. This code does disable VUSB LDO. Can you describe how you're measuring the current? Are you using a LaunchPad or a custom board?

Keep in mind that the MSP430 goes to sleep in the LPMx modes, so this results in discontinuous, pulsed currents. These pulses are typically difficult for a multimeter to measure (too slow), as discussed in these two threads.

The most accurate way to measure the power consumption would be to use the EnergyTrace feature in CCS with the MSP-FET. However, this which would require a target board or custom board to be used, since the MSP-FET can't be used directly with the MSP430F5529 LaunchPad. An alternative (cheaper) approach could be using the MSP432 LaunchPad, since its on-board XDS-110 emulator supports EnergyTrace, as described here.

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//******************************************************************************
//   MSP430x552x Demo - Enters LPM4, LFXT1, REF0 disabled,
//                      VUSB LDO and SLDO disabled, SVS disabled
//
//   Description: Configure ports and enter LPM4. Measure current (~1.2uA).
//   MCLK = SMCLK = default DCO
//
//                MSP430F552x
//             -----------------
//        /|\ |              XIN|-
//         |  |                 | 32kHz
//         ---|RST          XOUT|-
//            |                 |
//
//   F. Chen
//   Texas Instruments Inc.
//   December 2012
//   Built with CCS Version: 5.3.0 and IAR Embedded Workbench Version: 5.51.1
//******************************************************************************

#include <msp430.h>

int main(void)
{
  WDTCTL = WDTPW | WDTHOLD;                 // Stop WDT

 // Setup UCS
  UCSCTL4 = SELA_1;                       // Ensure VLO is ACLK source

  // Port Configuration
  P1OUT = 0x00;P2OUT = 0x00;P3OUT = 0x00;P4OUT = 0x00;P5OUT = 0x00;P6OUT = 0x00;
  P7OUT = 0x00;P8OUT = 0x00;PJOUT = 0x00;
  P1DIR = 0xFF;P2DIR = 0xFF;P3DIR = 0xFF;P4DIR = 0xFF;P5DIR = 0xFF;P6DIR = 0xFF;
  P7DIR = 0xFF;P8DIR = 0xFF;PJDIR = 0xFF;

  // Disable VUSB LDO and SLDO
  USBKEYPID   =     0x9628;           // set USB KEYandPID to 0x9628
                                      // access to USB config registers enabled
  USBPWRCTL &= ~(SLDOEN+VUSBEN);      // Disable the VUSB LDO and the SLDO
  USBKEYPID   =    0x9600;            // access to USB config registers disabled

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

  __bis_SR_register(LPM4_bits);             // Enter LPM4
  __no_operation();

}

Regards,

James

MSP Customer Applications