//******************************************************************************
//  MSP430x11x1 Demo - Comp_A, Output Reference Voltages on P2.3
//
//  Description: Output Comparator_A reference levels on P2.3. Program will
//  cycle through the on-chip comparator_A reference voltages with output on
//  P2.3. Normal mode is LPM0, TA0_ISR will interrupt LPM0.
//  ACLK = n/a, MCLK = SMCLK = default DCO ~800kHz
//
//		            MSP430F1121
//             -----------------
//         /|\|              XIN|-
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//            |         P2.3/CA0|--> Vref
//            |                 |			
//
//  M. Buccini / Z. Albus
//  Texas Instruments Inc.
//  May 2005
//  Built with Code Composer Essentials Version: 1.0
//*****************************************************************************

#include  <msp430x11x1.h>

void delay(void);                           // Software delay

void main (void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  CAPD  |= 0x08;                            // Disconnect port pins
  CACTL2 = P2CA0;                           // P2.3 = +comp
  CCTL0 = CCIE;                             // CCR0 interrupt enabled
  TACTL = TASSEL_2 + ID_3 + MC_2;           // SMCLK/8, cont-mode
  _EINT();                                  // enable interrupts

  while (1)                                 // Loop
  {
    CACTL1 = 0x00;                          // No reference voltage
    _BIS_SR(LPM0_bits);                     // Enter LPM0
    CACTL1 = CAREF0 + CAON;                 // 0.25*Vcc on P2.3, Comp. on
    _BIS_SR(LPM0_bits);                     // Enter LPM0
    CACTL1 = CAREF1 + CAON;                 // 0.5*Vcc on P2.3, Comp. on
    _BIS_SR(LPM0_bits);                     // Enter LPM0
    CACTL1 = CAREF1 + CAREF0 + CAON;        // 0.55V on P2.3, Comp. on
    _BIS_SR(LPM0_bits);                     // Enter LPM0
  }
}

// Timer A0 interrupt service routine
__interrupt void Timer_A (void);
TIMERA0_ISR(Timer_A)
__interrupt void Timer_A (void)
{
    _BIC_SR_IRQ(LPM0_bits);                 // Clear LPM0 bits from 0(SR)
}