请教 FR系列 写变量到fram中的问题 掉电不丢失的变量

可以参考这个帖子http://www.deyisupport.com/question_answer/microcontrollers/msp430/f/55/t/74926.aspx

Guo Yan 说：

我知道有几种方法定义到FLASH(FRAM)里 

比如：const int x @ 0x3333 = 123;

不过好像只能是const的，我想把一些变量也放到FRAM里，程序运行的过程中，可以随时更改，这样就不用检测电源掉电了。

如果掉电，复位电路复位后重新运行程序，在FRAM里读取这些变量就可以了。

不知道怎么把变量也定义到FRAM里，请各位指教下。IAR环境，谢谢了～

用 

__persistent 来定义

 *******************************************************************************
 *
 *                       MSP430 CODE EXAMPLE DISCLAIMER
 *
 * MSP430 code examples are self-contained low-level programs that typically
 * demonstrate a single peripheral function or device feature in a highly
 * concise manner. For this the code may rely on the device's power-on default
 * register values and settings such as the clock configuration and care must
 * be taken when combining code from several examples to avoid potential side
 * effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
 * for an API functional library-approach to peripheral configuration.
 *
 * --/COPYRIGHT--*/
//******************************************************************************
//   MSP430FR243x Demo - FRAM write, use #pragma PERSISTENT to initialize variable in FRAM.
//
//   Description: Program use #pragma PERSISTENT(in CCS) or __persistent(in IAR) 
//                to statically-initialize variable Port_event in FRAM.
//                Download and run the program. Program automatically enters
//                LPM4.5 and measure the current. Use button S1 (or P1.3) on the
//                target board to wake the device up from LPM4.5 and toggle the 
//                LED (on P1.0). The interrupt times will be recorded in FRAM
//                and blink the LED (on P1.0) if more than 5 times.                
//
//                This demo was tested on MSP-EXP430FR2433 target board.
//
//   ACLK = XT1 = 32kHz, MCLK = SMCLK = default DCODIV = ~1MHz.
//
//            MSP430FR2433
//         -----------------
//     /|\|                 |
//      | |                 |
//      | |                 |
//      --|RST              |
//        |                 |
//        |                 |
//        |             P1.0|-->LED
//        |                 |
//        |             P1.3|<--- S1 push-button
//
//  Ling Zhu
//  Texas Instruments Inc.
//  Aug 2015
//  Built with IAR Embedded Workbench v6.10 & Code Composer Studio v6.0.1
//******************************************************************************
#include <msp430.h>

// Statically-initialized variable
#ifdef __TI_COMPILER_VERSION__
#pragma PERSISTENT(Port_event)
unsigned long Port_event = 0;
#elif __IAR_SYSTEMS_ICC__
__persistent unsigned long Port_event = 0;
#else
// Port the following variable to an equivalent persistent functionality for the specific compiler being used
unsigned long Port_event = 0;
#endif

void initGpio(void);

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

    // Configure GPIO
    initGpio();

    // Determine whether we are coming out of an LPMx.5 or a regular RESET.
    if (SYSRSTIV == SYSRSTIV_LPM5WU)        // MSP430 just woke up from LPMx.5
    {

        // Add the variable Port_event in FRAM to record the button event
        SYSCFG0 = FRWPPW | DFWP;            // Program FRAM write enable
        Port_event++;                       // Record the port event in FRAM
        SYSCFG0 = FRWPPW | PFWP | DFWP;     // Program FRAM write protected (not writable)

        do
        {

            P1OUT |= BIT0;                  // P1.0 = toggle
            __delay_cycles(100000);
            P1OUT &= ~BIT0;                 // P1.0 = toggle
            __delay_cycles(100000);

        }while (Port_event >= 5);           // Recorded 5 port interrupts?

    }

    // Device powered up from a cold start.
    // It configures the device and puts the device into LPM4.5

    P1DIR &= ~(BIT3);                       // Configure P1.3 as input direction pin
    P1OUT |= BIT3;                          // Configure P1.3 as pulled-up
    P1REN |= BIT3;                          // P1.3 pull-up register enable
    P1IES |= BIT3;                          // P1.3 Hi/Low edge
    P1IFG = 0;                              // Clear all P1 interrupt flags
    P1IE |= BIT3;                           // P1.3 interrupt enabled

    // Explicitly clear RTC control registers to disable it
    // just incase if the RTC was previously enabled
    RTCCTL = 0;

#ifdef __MSP430_HAS_LCD_E__
    // Explicitly disable the LCD module
    // just incase if the LCD was previously enabled
    LCDCTL0 = 0;
#endif

    PMMCTL0_H = PMMPW_H;                    // Open PMM Registers for write
    PMMCTL0_L |= PMMREGOFF;                 // and set PMMREGOFF
    PMMCTL0_H = 0;                          // Lock PMM Registers

    // Enter LPM4 Note that this operation does not return. The LPM4.5
    // will exit through a RESET event, resulting in a re-start
    // of the code.
    __bis_SR_register(LPM4_bits | GIE);
}

void initGpio()
{
    P1DIR = 0xFB; P2DIR = 0xFF; P3DIR = 0xFF; 
    P1REN = 0xFF; P2REN = 0xFF; P3REN = 0xFF; 
    P1OUT = 0x00; P2OUT = 0x00; P3OUT = 0x00; 

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