fet140_adc12_01.c

msp430 149 的c程序 模版程序

//******************************************************************************
//  MSP-FET430P140 Demo - ADC12, Using 10 External Channels of Conversion
//
//  This example shows how to perform A/D conversion on up to 10 external
//  channels by showing that channels A8 and A9 can be used for conversion
//  of external signals. A single sequence of conversions is performed - one 
//  conversion on A8 and then one conversion on A9. Each conversion uses AVcc 
//  and AVss for the references. The conversion results are stored in ADC12MEM0 
//  and ADC12MEM1 respectively and are moved to 'results[]' upon completion of 
//  the sequence. Test by applying voltages to pins VeREF+ for A8 and 
//  VREF/VeREF- for A9, then setting and running to a break point at the 
//  "_BIC..." instruction in the ISR. To view the conversion results, open a 
//  watch window in C-Spy and view 'results' or view ADC12MEM0 and ADC12MEM1 in 
//  an ADC12 SFR window.
//
//  *NOTE*  When using channels A8 and A9 for external signals, internal
//  references must be used for the conversions. Refer to figure 15-1 in the 
//  MSP430x1xx Family User's Guide.
//
//
//                 MSP430F149
//             -----------------
//            |                 |
//            |          VeREF+ |<---- Vin1
//            |    VREF-/VeREF- |<---- Vin2
//
//
//  M.Mitchell
//  Texas Instruments, Inc
//  January, 2002
//  Built with IAR Embedded Workbench Version: 1.25A
//******************************************************************************

#include          "msp430x14x.h" // Standard Equations

static unsigned int results[2];         // Needs to be global in this example
                                        // Otherwise, the compiler removes it
                                        // because it is not used for anything.

void main(void)
{ 
  WDTCTL = WDTPW+WDTHOLD;               // Stop watchdog timer
  ADC12CTL0 = ADC12ON+MSC+SHT0_15;      // Turn on ADC12, set sampling time
  ADC12CTL1 = SHP+CONSEQ_1;             // Use sampling timer, single sequence
  ADC12MCTL0 = INCH_8;                  // ref+=AVcc, channel = A8
  ADC12MCTL1 = INCH_9+EOS;              // ref+=AVcc, channel = A9, end seq.
  ADC12IE = 0x02;                       // Enable ADC12IFG.1
  ADC12CTL0 |= ENC;                     // Enable conversions
  _EINT();                              // Enable interrupts  

  while(1)
  {
  ADC12CTL0 |= ADC12SC;                 // Start conversion
  _BIS_SR(LPM0_bits);                   // Enter LPM0 
   }
}

interrupt[ADC_VECTOR] void ADC12ISR (void)
{
  results[0] = ADC12MEM0;               // Move results, IFG is cleared
  results[1] = ADC12MEM1;               // Move results, IFG is cleared  
  _BIC_SR_IRQ(LPM0_bits);               // Clear LPM0, SET BREAKPOINT HERE
}