430FR6972低功耗LPM4功耗降不下来

只看该作者 · 2018-5-27 16:30

我的板子不焊接CPU整板功耗40uA左右焊接CPU，进入LPM4后，整板功耗170uA左右，CPU功耗有130uA左右

LPM4模式下  CPU and all clocks are disabled ，官方数据手册该模式下只有0.4uA的功耗
数据手册有这样一句说明 Although the I/O register contents are lost, the I/O pin states are locked upon LPMx.5 entry

所以不排除IO口默认值引起一些功耗，但是单独针对某一可能的IO口尝试各种置位处理，功耗反而会升上去(1.4mA左右)........

求指点，怎么把CPU功耗降下去！！！

主要测试程序如下；
Sys_Init();

LED_ON();
__delay_cycles(800000); // Wait 8,000,000 CPU Cycles
LED_OFF();

LPM4;

//==============================

void  Sys_Init ( void )
{

  WDTCTL = WDTPW | WDTHOLD;                // Stop WDT

  // Configure GPIO
  P1OUT &= ~BIT0;                         // Clear P1.0 output latch for a defined power-on state
  P1DIR |= BIT0;                         // Set P1.0 to output direction

  PJDIR |= BIT2;
  PJSEL0 |= BIT2;                         // Output ACLK
  PJSEL1 &= ~BIT2;

  P7DIR |= BIT4;
  P7SEL1 |= BIT4;                         // Output SMCLK
  P7SEL0 |= BIT4;

  // Disable the GPIO power-on default high-impedance mode to activate
  // previously configured port settings
  PM5CTL0 &= ~LOCKLPM5;

  // Clock System Setup
  CSCTL0_H = CSKEY >> 8;                   // Unlock CS registers
  CSCTL1 = DCOFSEL_6;                      // Set DCO to 8MHz
  CSCTL2 = SELA__VLOCLK | SELS__DCOCLK | SELM__DCOCLK;  // Set SMCLK = MCLK = DCO
                                          // ACLK = VLOCLK
  CSCTL3 = DIVA__1 | DIVS__1 | DIVM__1;    // Set all dividers to 1
  CSCTL0_H = 0;                            // Lock CS registers

}