msp430x20x2_adc10_temp.c

C280x C/C++ Header Files and Peripheral Examples The DSP28xx C/C++ peripheral header files and exam

//******************************************************************************
//  MSP430F20x2 Demo - ADC10, Sample A10 Temp and Convert to oC and oF
//
//  Description: A single sample is made on A10 with reference to internal
//  1.5V Vref. Software sets ADC10SC to start sample and conversion - ADC10SC
//  automatically cleared at EOC. ADC10 internal oscillator/4 times sample
//  (64x) 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. Temperaure in oC stored in IntDegC, oF in IntDegF.
//  Uncalibrated temperature measured from device to device will vary with
//  slope and offset - please see datasheet.
//  ACLK = n/a, MCLK = SMCLK = default DCO ~1.2MHz, ADC10CLK = ADC10OSC/4
//
//                MSP430F20x2
//             -----------------
//         /|\|              XIN|-
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//            |A10              |
//
//  P.Thanigai
//  Texas Instruments Inc.
//  May 2007
//  Built with Code Composer Essentials Version: 2.0
//******************************************************************************
#include  "msp430x20x2.h"

long temp;
long IntDegF;
long IntDegC;

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  ADC10CTL1 = INCH_10 + ADC10DIV_3;         // Temp Sensor ADC10CLK/4
  ADC10CTL0 = SREF_1 + ADC10SHT_3 + 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();

  while(1)
  {
    ADC10CTL0 |= ENC + ADC10SC;             // Sampling and conversion start
    __bis_SR_register(CPUOFF + GIE);        // LPM0 with interrupts enabled

    // oF = ((A10/1024)*1500mV)-923mV)*1/1.97mV = A10*761/1024 - 468
    temp = ADC10MEM;
    IntDegF = ((temp - 630) * 761) / 1024;

    // oC = ((A10/1024)*1500mV)-986mV)*1/3.55mV = A10*423/1024 - 278
    temp = ADC10MEM;
    IntDegC = ((temp - 673) * 423) / 1024;

    __no_operation();                       // SET BREAKPOINT HERE
  }
}

// ADC10 interrupt service routine
__interrupt void ADC_ISR (void);
ADC10_ISR(ADC_ISR)
__interrupt void ADC_ISR (void)
{
  __bic_SR_register_on_exit(CPUOFF);        // Clear CPUOFF bit from 0(SR)
}

__interrupt void Timer_A(void);
TIMERA0_ISR(Timer_A)
__interrupt void Timer_A(void)
{
  TACTL = 0;
  LPM0_EXIT;                                // Exit LPM0 on return
}