fet140_sd16_grpchsingconv_lpm.c

msp430f14x 系列片内外设的实例代码

//******************************************************************************
//  MSP-FET430P140 Demo - SD16, Enter LPM after Single Conversion on Group of 
//                         Channels
// 
//  This example shows how to perform a single SD16 conversion on a group of 
//  channels and then enter Low Power mode. It uses internal reference and 
//  performs a single conversion on channels 0,1&2. The conversion results are
//  stored in SD16MEM0,1 &2. Test by applying a voltage to channels, then 
//  setting and running to a break point at the mentioned instruction. To view 
//  the conversion results, open watch window in C-Spy and view the contents of
//  "results".
//
//  This example uses the Interrupt vector to determine the source of the
//  Interrupt
//               MSP430FE427
//             ---------------
//            |               |
//            |           I1+ |<---- Vin 1+
//            |           I1- |<---- Vin 1-
//            |           I2+ |<---- Vin 2+
//            |           I2- |<---- Vin 2-
//            |           V1+ |<---- Vin 3+
//            |           V1- |<---- Vin 3-
//            |               |
//
//
//  Harman Grewal
//  Texas Instruments, Inc
//  Oct, 2004
//  IAR Embedded Workbench Version: 2.21B
//******************************************************************************

#include          "msp430xE42x.h"       // Standard Equations

static unsigned int results[3];         // Needs to be global in this example
                                        // Otherwise, the compiler removes it
                                        // because it is not used for anything.

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.
  P1DIR = 0xFF;
  P1OUT = 0;
  P2DIR = 0xFF;
  P2OUT = 0;
  SD16CTL = SD16REFON+SD16SSEL0;        // Turn on SD16 Ref,SMCLK
  SD16CCTL0 |= SD16SNGL+SD16GRP+SD16IE; // Enable Grouping with next higher channel,
                                        // Single Conv
  SD16CCTL1 |= SD16SNGL+SD16GRP+SD16IE; // Enable Grouping with next higher channel,
                                        // Single Conv
  SD16CCTL2 |= SD16SNGL+SD16IE;         // Single Conv, Interrupt Enable
 

  _EINT();                              // Enable interrupts
  for ( i=0; i<0x3600; i++);            // Delay for reference start-up
  
  while (1)
  {  
   SD16CCTL2 |= SD16SC;                 // Start conversion
   _BIS_SR(LPM0_bits);                  // Enter LPM0
  }
}

enum
{
  NO_INT = 0,
  SDM0 = 4,
  SDM1 = 6,
  SDM2 = 8
};  
#pragma vector=SD16_VECTOR
__interrupt void SD16ISR (void)
{
  switch (SD16IV)
  {
    case NO_INT: break;
    case SDM0: results[0] = SD16MEM0; break; // Move results, IFG is cleared 
    case SDM1: results[1] = SD16MEM1; break; // Move results, IFG is cleared
    case SDM2: results[2] = SD16MEM2; SD16CTL= 0;LPM3;break; 
                                             // Move results, IFG is cleared    
                                             // LPM3 or 4              
    default: break;                           
  }
  
}