msp430x20x2_adc10_10.c


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//******************************************************************************
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//  MSP430F20x2 Demo - ADC10, DTC Sample A2-0, AVcc, Single Sequence, DCO
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//
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//  Description: Sample A3/A2/A1 as single sequence with reference to AVcc.
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//  Software sets ADC10SC to trigger sample sequence. In Mainloop MSP430 waits
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//  in LPM0 to save power until ADC10 conversion complete, ADC10_ISR(DTC) will
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//  force exit from any LPMx in Mainloop on reti. ADC10_ISR will force any LPMx
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//  exit. ADC10 internal oscillator times sample period (16x) and conversion
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//  (13x). DTC transfers conversion code to RAM 200h - 206h. P1.0 set at start
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//  of conversion burst, reset on completion.
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//
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//               MSP430F20x2
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//            -----------------
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//        /|\|              XIN|-
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//         | |                 |
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//         --|RST          XOUT|-
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//           |                 |
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//       >---|P1.3/A3      P1.0|-->LED
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//       >---|P1.2/A2          |
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//       >---|P1.1/A1          |
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//
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//  L. Westlund
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//  Texas Instruments Inc.
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//  May 2006
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//  Built with IAR Embedded Workbench Version: 3.41A
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//******************************************************************************
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#include  "msp430x20x2.h"
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void main(void)
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{
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  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
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  ADC10CTL1 = INCH_3 + CONSEQ_1;            // A3/A2/A1, single sequence
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  ADC10CTL0 = ADC10SHT_2 + MSC + ADC10ON + ADC10IE;
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  ADC10DTC1 = 0x03;                         // 3 conversions
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  ADC10AE0 |= 0x0E;                         // P1.3,2,1 ADC10 option select
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  P1DIR |= 0x01;                            // Set P1.0 output
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  for (;;)
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  {
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    ADC10CTL0 &= ~ENC;
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    while (ADC10CTL1 & BUSY);               // Wait if ADC10 core is active
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    ADC10SA = 0x200;                        // Data buffer start
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    P1OUT |= 0x01;                          // P1.0 = 1
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    ADC10CTL0 |= ENC + ADC10SC;             // Sampling and conversion start
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    __bis_SR_register(CPUOFF + GIE);        // LPM0, ADC10_ISR will force exit
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    P1OUT &= ~0x01;                         // P1.0 = 0
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  }
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}
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// ADC10 interrupt service routine
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#pragma vector=ADC10_VECTOR
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__interrupt void ADC10_ISR(void)
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{
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  __bic_SR_register_on_exit(CPUOFF);        // Clear CPUOFF bit from 0(SR)
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}