fet140_sd16_tempsingconv.c

msp430f14x 系列片内外设的实例代码

//******************************************************************************
//  MSP-FET430P140 Demo - SD16, Using the temperature sensor
// 
//  This example shows how to use the intergrated temperature sensor channel A6
//  to measure temperature. In this example, a single conversion is performed of 
//  the temperature sensor.  
//  The temperature is then calculated in degrees C and F, based on the 
//  conversion value. Test by setting and running to a break point at "_NOP()"
//  To view the temperature open a watch window in C-Spy and view DegC and 
//  DegF.
//
//               MSP430FE427
//             ---------------
//            |             A6|
//            |               |
//
//
//  Harman Grewal
//  Texas Instruments, Inc
//  Oct, 2004
//  IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include          "msp430xE42x.h"        // Standard Equations

static unsigned int ADCresult; 
static unsigned long int DegC, DegF, DegK;

void main(void)
{ 
  volatile unsigned int i;
  
  WDTCTL = WDTPW+WDTHOLD;               // Stop watchdog timer
  FLL_CTL0 |= XCAP14PF;                 // Set load capacitance for xtal.
  for (i = 0; i < 20000; i++);          // Delay - to allow watch crystal to stabilize.
  SD16CTL = SD16REFON+SD16SSEL0;        // Turn on SD16 Ref,SMCLK
  SD16CCTL2 |= SD16SNGL+SD16IE ;        // Single Conv, Enable Interrupt
  SD16INCTL2 |= SD16INCH_6;             // Select Channel A6
  _EINT();                              // Enable interrupts
  for ( i=0; i<0xFFFF; i++)             // Delay for reference start-up
  {
  }               
  
  while (1)
  {  
   SD16CCTL2 |= SD16SC;                 // Start conversion
   _BIS_SR(LPM0_bits);                  // Enter LPM0
   
//  DegK = (Vsensor)/1.32mV/K
//  DegC = DegK - 273, Vref = 1200 mV
//  Vsensor = (Vref)*(ADCresult-32768)/65536)
//  DegK -> ((ADCresult - 32768)*909)/65536
    DegK = ((((long)ADCresult-32768)*909)/65536);
    DegC = DegK - 273;
    DegF = ((DegC * 9/5)+32);           // Calculate DegF
    _NOP();                             //SET BREAKPOINT HERE
  }
}  
#pragma vector=SD16_VECTOR
__interrupt void SD16ISR (void)
{
  ADCresult = SD16MEM2;                 // Move results, IFG is cleared
  _BIC_SR_IRQ(LPM0_bits);               // Clear LPM0
}