fet140_adc12_10.c

基于IAR Workbench for MSP430 的MSP430c语言例程,

//******************************************************************************
//  MSP-FET430P140 Demo - ADC12 Sample A10 Temp and Convert to oC and oF  
//
//  Description; A single sample is made on A10 with refernce 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 LPM0 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 ~ 800kHz, ADC12CLK = ADC12OSC
//
//  Uncalibrated temperature measured from device to devive will vary do to
//  slope and offset variance from device to device - please see datasheet.
//
//                MSP430Fx49
//             -----------------
//         /|\|              XIN|-  
//          | |                 |
//          --|RST          XOUT|-
//            |                 |
//            |A10              |
//
//  M.Buccini
//  Texas Instruments, Inc
//  January 2004
//  Updated for IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include  <msp430x14x.h>
int long temp;
int long IntDegF;
int long IntDegC;

void main(void)
{ 
  WDTCTL = WDTPW + WDTHOLD;             // Stop WDT
  ADC12CTL0 = SHT0_8 + REFON + ADC12ON;
  ADC12CTL1 = SHP;                      // enable sample timer   
  ADC12MCTL0 = 0x01A;
  ADC12IE = 0x001;
  
  while(1)
  {
    ADC12CTL0 |= ENC + ADC12SC;         // Sampling and conversion start
    _BIS_SR(CPUOFF + GIE);              // LPM0 with interrupts enabled
 
//  oF = ((x/4096)*1500mV)-923mV)*1/1.97mV = x*761/4096 - 468 
//  IntDegF = (ADC12MEM0 - 2519)* 761/4096   
    IntDegF = (temp - 2519) * 761;         
    IntDegF = IntDegF / 4096;    

//  oC = ((x/4096)*1500mV)-986mV)*1/3.55mV = x*423/4096 - 278 
//  IntDegC = (ADC12MEM0 - 2692)* 423/4096
    IntDegC = (temp - 2692) * 423;         
    IntDegC = IntDegC / 4096;    

    _NOP();                             // << SET BREAKPOINT HERE
  }
}

#pragma vector=ADC_VECTOR
__interrupt void ADC12ISR (void)
{
    temp = ADC12MEM0;                   // Move results, IFG is cleared
    _BIC_SR_IRQ(CPUOFF);                // Clear CPUOFF bit from 0(SR)
}