//******************************************************************************
//  MSP430F54x Demo - ADC12, 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 ADC12SC to start sample and conversion - ADC12SC
//  automatically cleared at EOC. ADC12 internal oscillator times sample
//  and conversion. In Mainloop MSP430 waits in LPM4 to save power until
//  ADC10 conversion complete, ADC12_ISR will force exit from any LPMx in
//  Mainloop on reti.
//  ACLK = n/a, MCLK = SMCLK = default DCO ~ 1.045MHz, ADC12CLK = ADC12OSC
//
//  Uncalibrated temperature measured from device to devive will vary do to
//  slope and offset variance from device to device - please see datasheet.
//
//                MSP430F5438
//             -----------------
//         /|\|              XIN|-
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//            |A10              |
//
//   W. Goh
//   Texas Instruments Inc.
//   November 2008
//   Built with CCE Version: 3.2.2 and IAR Embedded Workbench Version: 4.11B
//******************************************************************************
#include "msp430x54x.h"

volatile long temp;
volatile long IntDegF;
volatile long IntDegC;

void main(void)
{
  WDTCTL = WDTPW + WDTHOLD;                 // Stop WDT
  ADC12CTL0 = ADC12SHT0_8 + ADC12REFON + ADC12ON;
                                            // Internal ref = 1.5V
  ADC12CTL1 = ADC12SHP;                     // enable sample timer
  ADC12MCTL0 = ADC12SREF_1 + ADC12INCH_10;  // ADC i/p ch A10 = temp sense i/p
  ADC12IE = 0x001;                          // ADC_IFG upon conv result-ADCMEMO
  __delay_cycles(37);                       // 35us delay to allow Ref to settle
                                            // based on default DCO frequency.
                                            // See Datasheet for typical settle
                                            // time.
  ADC12CTL0 |= ADC12ENC;

  while(1)
  {
    ADC12CTL0 |= ADC12SC;                   // Sampling and conversion start

    __bis_SR_register(LPM4_bits + GIE);     // LPM0 with interrupts enabled
    __no_operation();

    // Temperature in Celsius
    // ((A10/4096*1500mV) - 894mV)*(1/3.66mV) = (A10/4096*410) - 244
    // = (A10 - 2438) * (410 / 4096)
    IntDegC = ((temp - 2438) * 410) / 4096;

    // Temperature in Fahrenheit
    // ((A10/4096*1500mV) - 829mV)*(1/2.033mV) = (A10/4096*738) - 408
    // = (A10 - 2264) * (738 / 4096)
    IntDegF = ((temp - 2264) * 738) / 4096;
    __no_operation();                       // SET BREAKPOINT HERE
  }
}

#pragma vector=ADC12_VECTOR
__interrupt void ADC12ISR (void)
{
  switch(__even_in_range(ADC12IV,34))
  {
  case  0: break;                           // Vector  0:  No interrupt
  case  2: break;                           // Vector  2:  ADC overflow
  case  4: break;                           // Vector  4:  ADC timing overflow
  case  6:                                  // Vector  6:  ADC12IFG0
    temp = ADC12MEM0;                       // Move results, IFG is cleared
    __bic_SR_register_on_exit(LPM4_bits);   // Exit active CPU
    break;
  case  8: break;                           // Vector  8:  ADC12IFG1
  case 10: break;                           // Vector 10:  ADC12IFG2
  case 12: break;                           // Vector 12:  ADC12IFG3
  case 14: break;                           // Vector 14:  ADC12IFG4
  case 16: break;                           // Vector 16:  ADC12IFG5
  case 18: break;                           // Vector 18:  ADC12IFG6
  case 20: break;                           // Vector 20:  ADC12IFG7
  case 22: break;                           // Vector 22:  ADC12IFG8
  case 24: break;                           // Vector 24:  ADC12IFG9
  case 26: break;                           // Vector 26:  ADC12IFG10
  case 28: break;                           // Vector 28:  ADC12IFG11
  case 30: break;                           // Vector 30:  ADC12IFG12
  case 32: break;                           // Vector 32:  ADC12IFG13
  case 34: break;                           // Vector 34:  ADC12IFG14
  default: break;
  }
}