DS32kHz conectado al MSP430

Las luces del coche fantástico con 4 leds. El bucle principal del programa avanza un led en cada ciclo y entra en LPM4. La interrupción del Timer se encarga de reanudar la ejecución.

src/grace/GPIO_init.c
P1.0 tiene que configurarse como TA0CLK.

/*
 *  ======== GPIO_graceInit ========
 *  Initialize MSP430 General Purpose Input Output Ports
 *
 *  The GPIO registers should be set in a specific order:
 *     PxOUT
 *     PxSEL or PxSELx
 *     PxDIR
 *     PxREN
 *     PxIES
 *     PxIFG
 *     PxIE
 *
 *     This will ensure that:
 *         - IFG doesn't get set by manipulating the pin function, edge
 *           select, and pull-up/down resistor functionalities (see
 *           Section 8.2.6 of the MSP430 User's manual)
 *         - Glitch-free setup (configuring the OUT register _before_
 *           setting the pin direction)
 *         - Pull-up/pull-down resistor enable with the correct direction
 *           (.up. vs. .down.)
 */
void GPIO_graceInit(void)
{
    /* USER CODE START (section: GPIO_graceInit_prologue) */
    /* User initialization code */
    /* USER CODE END (section: GPIO_graceInit_prologue) */

    /* Port 1 Output Register */
    P1OUT = 0;

    /* Port 1 Port Select Register */
    P1SEL = BIT0;

    /* Port 1 Direction Register */
    P1DIR = BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;

    /* Port 1 Interrupt Edge Select Register */
    P1IES = 0;

    /* Port 1 Interrupt Flag Register */
    P1IFG = 0;

    /* Port 2 Output Register */
    P2OUT = 0;

    /* Port 2 Port Select Register */
    P2SEL &= ~(BIT6 + BIT7);

    /* Port 2 Direction Register */
    P2DIR = BIT0 + BIT1 + BIT2 + BIT3 + BIT4 + BIT5 + BIT6 + BIT7;

    /* Port 2 Interrupt Edge Select Register */
    P2IES = 0;

    /* Port 2 Interrupt Flag Register */
    P2IFG = 0;
}

src/grace/Timer0_A3_init.c

/*
 *  ======== Timer0_A3_graceInit ========
 *  Initialize MSP430 Timer0_A3 timer
 */
void Timer0_A3_graceInit(void)
{
    /* 
     * TA0CCTL0, Capture/Compare Control Register 0
     * 
     * CM_0 -- No Capture
     * CCIS_0 -- CCIxA
     * ~SCS -- Asynchronous Capture
     * ~SCCI -- Latched capture signal (read)
     * ~CAP -- Compare mode
     * OUTMOD_0 -- PWM output mode: 0 - OUT bit value
     * 
     * Note: ~<BIT> indicates that <BIT> has value zero
     */
    TA0CCTL0 = CM_0 + CCIS_0 + OUTMOD_0 + CCIE;

    /* TA0CCR0, Timer_A Capture/Compare Register 0 */
    TA0CCR0 = 3199;

    /* 
     * TA0CTL, Timer_A3 Control Register
     * 
     * TASSEL_0 -- TACLK
     * ID_0 -- Divider - /1
     * MC_1 -- Up Mode
     */
    TA0CTL = TASSEL_0 + ID_0 + MC_1;
}

src/grace/InterruptVectors_init.c
La interrupción despierta al MCU. El cuerpo del programa está en main().

/*
 *  ======== Timer0_A3 Interrupt Service Routine ======== 
 */
#pragma vector=TIMER0_A0_VECTOR
__interrupt void TIMER0_A0_ISR_HOOK(void)
{
    /* USER CODE START (section: TIMER0_A0_ISR_HOOK) */
 // Continua con el programa principal
 __bic_SR_register_on_exit(CPUOFF);
    /* USER CODE END (section: TIMER0_A0_ISR_HOOK) */
}

main.c

unsigned int contador = 0;
int dir=1;

/*
 *  ======== main ========
 */
int main(void)
{
    Grace_init();                   // Activate Grace-generated configuration
    
    while (1) {
  contador = contador + dir;
  if (contador==4){
   dir = -1;
  }

  if (contador == 1){
   dir = 1;
  }

  P1OUT = (1 << contador);

  LPM4;
    }
}