//******************************************************************************
//  MSP430F20x2 Demo - ADC10, Sample A1, 1.5V Ref, Set P1.0 if > 0.2V
//
//  Description: A single sample is made on A1 with reference to internal
//  1.5V Vref. Software sets ADC10SC to start sample and conversion - ADC10SC
//  automatically cleared at EOC. ADC10 internal oscillator times sample (16x)
//  and conversion. In Mainloop MSP430 waits in LPM0 to save power until ADC10
//  conversion complete, ADC10_ISR will force exit from any LPMx in Mainloop on
//  reti. If A1 > 0.2V, P1.0 set, else reset.
//
//                MSP430F20x2
//             -----------------
//         /|\|              XIN|-
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//        >---|P1.1/A1      P1.0|-->LED
//
//  L. Westlund
//  Texas Instruments Inc.
//  May 2006
//  Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.41A
//******************************************************************************
#include "msp430x20x2.h"

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  ADC10CTL0 = SREF_1 + ADC10SHT_2 + REFON + ADC10ON + ADC10IE;
  __enable_interrupt();                     // Enable interrupts.
  TACCR0 = 30;                              // Delay to allow Ref to settle
  TACCTL0 |= CCIE;                          // Compare-mode interrupt.
  TACTL = TASSEL_2 | MC_1;                  // TACLK = SMCLK, Up mode.
  LPM0;                                     // Wait for delay.
  TACCTL0 &= ~CCIE;                         // Disable timer Interrupt
  __disable_interrupt();
  ADC10CTL1 = INCH_1;                       // input A1
  ADC10AE0 |= 0x02;                         // PA.1 ADC option select
  P1DIR |= 0x01;                            // Set P1.0 to output direction

  for (;;)
  {
    ADC10CTL0 |= ENC + ADC10SC;             // Sampling and conversion start
    __bis_SR_register(CPUOFF + GIE);        // LPM0, ADC10_ISR will force exi
    if (ADC10MEM < 0x88)                    // ADC10MEM = A1 > 0.2V?
      P1OUT &= ~0x01;                       // Clear P1.0 LED off
    else
      P1OUT |= 0x01;                        // Set P1.0 LED on
  }
}

// ADC10 interrupt service routine
#pragma vector=ADC10_VECTOR
__interrupt void ADC10_ISR (void)
{
  __bic_SR_register_on_exit(CPUOFF);        // Clear CPUOFF bit from 0(SR)
}

#pragma vector=TIMERA0_VECTOR
__interrupt void ta0_isr(void)
{
  TACTL = 0;
  LPM0_EXIT;                                // Exit LPM0 on return
}