Blink with Timer MSP430

Blinking the Internal LED on MSP430F5529LP: To blink the internal LED (LED1) on the MSP430F5529LP Launch Pad, you can use a timer interrupt. Here’s an example code snippet that achieves this:

#include <msp430.h>
#include <msp430f5529.h>

unsigned int timerCount = 0;

void main(void) {
    WDTCTL = WDTPW + WDTHOLD; // Disable watchdog
    P1DIR |= BIT0; // Set P1.0 (LED1) to output direction
    P1OUT &= ~BIT0; // Turn off the LED initially

    TA0CCR0 = (32768 - 1); // Set timer period (32768 cycles for 1 second)
    TA0CCTL0 = (CCIE + OUTMOD_6); // Enable interrupts for CCR0, toggle output
    TA0CTL = (TASSEL_0 + MC_1 + ID_3 + TACLR); // SMCLK, div 8, up mode, clear timer

    __enable_interrupt(); // Enable global interrupts

    for (;;) {
        // Do nothing while waiting for interrupts. Ideal place to use low power modes!
    }
}

#pragma vector = TIMER0_A0_VECTOR
__interrupt void Timer0_A0_ISR(void) {
    timerCount = (timerCount + 1) % 3;
    if (timerCount == 0) {
        P1OUT ^= BIT0; // Toggle LED1
    }
}

1. Make sure to initialize the timer and interrupt correctly. The example above uses Timer A0 and toggles the LED every third interrupt. Adjust the timer settings as needed¹.
2. Using LPM3 for Delay and Wake-Up: If you want to generate a delay using Low-Power Mode 3 (LPM3) and wake up after the delay, follow these steps:
   • Initialize a global counter value in your main loop.
   • Increment the counter in the timer’s ISR until you reach the desired delay.
   • Use __bic_SR_register_on_exit(LPM3) to exit LPM3 after the ISR².
3. Troubleshooting MSP430FR2311 Issues: If you’re facing issues after flashing the MSP430FR2311, ensure that you’ve configured the device correctly. Here’s an example snippet that puts the device into LPM4.5:

// Configure P2.6 and P2.7 as input direction pins
P2DIR &= ~(BIT6 + BIT7);
// Configure P2.6 and P2.7 as pulled-down
P2OUT &= ~(BIT6 + BIT7);
// Enable resistor register for P2.6 and P2.7
P2REN |= (BIT6 + BIT7);
// Set low-to-high edge for P2.6 and P2.7
P2IES &= ~(BIT6 + BIT7);
// Clear all P2 interrupt flags
P2IFG = 0x00;
// Enable interrupts for P2.6 and P2.7
P2IE |= (BIT6 + BIT7);

Feel free to ask if you need further assistance or have additional questions! 😊

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