msp430fr413x_lpm4_5_01.c

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 *
 *                       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--*/
//******************************************************************************
//   MSP430FR413x Demo - LPM4.5, Device enters LPM4.5 waiting for a port
//                       interrupt on P1.2
//
//   Description: Download and run the program. Program automatically enters
//                LPM4.5 and measure the current. Use button S1 (or P1.2) on the
//                LaunchPad board to wake the device up from LPM4.5. This enables
//                the LFXT oscillator and blink the LED (on P1.0).
//
//                This demo was tested on MSP-EXP430FR4133 LaunchPad.
//
//   ACLK = XT1 = 32kHz, MCLK = SMCLK = default DCODIV = ~1MHz.
//
//            MSP430FR4133
//         -----------------
//     /|\|                 |
//      | |                 |
//      | |        XIN(P4.1)|--
//      --|RST              |  32768Hz
//        |       XOUT(P4.2)|--
//        |                 |
//        |             P1.0|-->LED
//        |                 |
//        |             P1.2|<--- S1 push-button (MSP-EXP430FR4133)
//
//  William Goh
//  Texas Instruments Inc.
//  July 2014
//  Built with IAR Embedded Workbench v5.60 & Code Composer Studio v6.0
//******************************************************************************
#include <msp430.h>

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
    {

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

        P1DIR &= ~(BIT2);                   // Configure P1.2 as input direction pin
        P1OUT |= BIT2;                      // Configure P1.2 as pulled-up
        P1REN |= BIT2;                      // P1.2 pull-up register enable
        P1IES |= BIT2;                      // P1.2 Hi/Low edge
        P1IFG = 0;                          // Clear all P1 interrupt flags
        P1IE |= BIT2;                       // P1.2 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);
    }

    // Now blink the LED in an endless loop.
    while (1)
    {
        P1OUT ^= BIT0;                      // P1.0 = toggle
        __delay_cycles(100000);
    }
}

void initGpio()
{
    P1DIR = 0xFB; P2DIR = 0xFF; P3DIR = 0xFF; P4DIR = 0xFF;
    P5DIR = 0xFF; P6DIR = 0xFF; P7DIR = 0xFF; P8DIR = 0xFF;
    P1REN = 0xFF; P2REN = 0xFF; P3REN = 0xFF; P4REN = 0xFF;
    P5REN = 0xFF; P6REN = 0xFF; P7REN = 0xFF; P8REN = 0xFF;
    P1OUT = 0x00; P2OUT = 0x00; P3OUT = 0x00; P4OUT = 0x00;
    P5OUT = 0x00; P6OUT = 0x00; P7OUT = 0x00; P8OUT = 0x00;

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