MSP430FR2033功耗问题

看那个中断函数里有对io的操作，io也是要消耗电流的

yanqing zhou 说：

Hi all

          我在做一个项目，需要用到RTC的低功耗模式 ，但我实测发现上电后的功耗是0.4uA，但执行完第一次中断程序后，之后不管进入多少次中断，进入RTC低功耗模式都是12.6uA。我试过和定时时间没关系，第一次中断前都是0.4uA。请问是我需要在每次再次进入低功耗时都需要重新配置下RTC吗？

//   MSP430FR413x Demo - RTC, device enter LPM3.5 and toggle P1.0 in RTC interrupt handling every 1s
//
//
//   Description: Device enter LPM3.5 after configuring the RTC. The RTC wakes
//   the device up from LPM3.5 every second and toggles P1.0.
//   It also stores the state of P0OUT in the Backup RAM Registers.
//
//   ACLK = XT1 = 32kHz, MCLK = SMCLK = default DCODIV = ~1MHz.
//
//            MSP430FR4133
//         -----------------
//     /|\|                 |
//      | |                 |
//      | |        XIN(P4.1)|--
//      --|RST              |  ~32768Hz
//        |       XOUT(P4.2)|--
//        |                 |
//        |             P4.5|-->LED
//
//  Wei Zhao
//  Texas Instruments Inc.
//  March 2015
//  Built with IAR Embedded Workbench v6.20 & Code Composer Studio v6.1
//******************************************************************************
#include <msp430.h>

void initGpio(void);

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

    initGpio();                             // Configure GPIO

    // Initialize XT1 32kHz crystal
    P4SEL0 |= BIT1 | BIT2;                  // set XT1 pin as second function
    do
    {
        CSCTL7 &= ~(XT1OFFG | DCOFFG);      // Clear XT1 and DCO fault flag
        SFRIFG1 &= ~OFIFG;
    } while (SFRIFG1 & OFIFG);              // Test oscillator fault flag

    // First determine whether we are coming out of an LPMx.5 or a regular RESET.
    if (SYSRSTIV == SYSRSTIV_LPM5WU)        // When woken up from LPM3.5, reinit
    {
        // If MCU wakes up from LPM3.5, re-init and then return to LPM3.5 again.

        // Restore P1OUT value from backup RAM memory, keep P1OUT after LPMx.5 reset
        P4OUT = *(unsigned int *)BKMEM_BASE;

        __enable_interrupt();               // The RTC interrupt should trigger now...
    }
    else
    {
        // Device powered up from a cold start.
        // It configures the device and puts the device into LPM3.5

        // Configure backup memory
        *(unsigned int *)BKMEM_BASE = 0;

        // Initialize RTC
        // Interrupt and reset happen every 1024/32768 * 32 = 1 sec.
        RTCMOD = 960-1;
        RTCCTL = RTCSS__XT1CLK | RTCSR | RTCPS__1024 | RTCIE;

        // Store P1OUT value in backup memory register before enter LPM3.5
        *(unsigned int *)BKMEM_BASE = P4OUT;
    }

    // Enter LPM3.5 mode with interrupts enabled. Note that this operation does
    // not return. The LPM3.5 will exit through a RESET event, resulting in a
    // re-start of the code.
    PMMCTL0_H = PMMPW_H;                    // Open PMM Registers for write
    PMMCTL0_L |= PMMREGOFF;                 // and set PMMREGOFF
    __bis_SR_register(LPM3_bits | GIE);
    __no_operation();

    return 0;
}

void initGpio(void)
{
		P1DIR |= 0x1F;
		P2DIR |= 0xFF;
		P3DIR |= 0xFF;
		P4DIR |= 0xFF;
		P5DIR |= 0xFF;
		P6DIR |= 0xFF;
		P7DIR |= 0xFF;
		P8DIR |= 0xFD;

		P1OUT |= 0x1F;
		P2OUT |= 0xFF;
		P3OUT |= 0xFF;
		P3OUT &= ~0x87;
		P4OUT |= 0xFF;
		P5OUT |= 0xFF;
		P6OUT |= 0xFF;
		P7OUT |= 0xFF;
		P8OUT |= 0xFD;

		P8DIR &= ~0x02;
		P8REN &= ~0x02;

		//Motor P1.6 1.7 1.5
		P1DIR &= ~0xE0;
		P1REN &= ~0xE0;

		P2DIR &= ~0xF3;
		P2REN &= ~0xF3;

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

#if defined(__TI_COMPILER_VERSION__) || defined(__IAR_SYSTEMS_ICC__)
#pragma vector = RTC_VECTOR
__interrupt void RTC_ISR(void)
#elif defined(__GNUC__)
void __attribute__ ((interrupt(RTC_VECTOR))) RTC_ISR (void)
#else
#error Compiler not supported!
#endif
{
    switch(__even_in_range(RTCIV, RTCIV_RTCIF))
    {
        case RTCIV_NONE : break;            // No interrupt pending
        case RTCIV_RTCIF:                   // RTC Overflow
            // Toggle LED on P1.0
            P4OUT ^= BIT5;

            // Store P1OUT value in backup memory register
            *(unsigned int *)BKMEM_BASE = P4OUT;
            __bis_SR_register(LPM3_bits | GIE);
            break;
        default:          break;
    }
}

LPM3.5功耗是比较低，但是从LPM3.5唤醒之后需要做一些初始化，这段时间比较耗电，如果应用唤醒频率不是很低的话建议用 LPM3. 操作简单，功耗也低。