SLAA475A October   2010  – March 2019 MSP430L092

 

  1.   MSP430x09x Analog Pool: Feature Set and Advanced Use
    1.     Trademarks
    2. 1 MSP430x09x Overview
    3. 2 Analog Pool (A-Pool)
      1. 2.1  Input Dividers
      2. 2.2  Internal Reference
      3. 2.3  Starting and Stopping the A-Pool
      4. 2.4  Comparator Function
      5. 2.5  8-Bit DAC Function
      6. 2.6  8-Bit ADC Function
        1. 2.6.1 ADC Conversion Using Ramp
          1. 2.6.1.1 ADC Conversion Without Error Compensation
          2. 2.6.1.2 ADC Conversions With Overdrive Compensation
          3. 2.6.1.3 ADC Conversions With Offset Compensation
          4. 2.6.1.4 ADC Conversions With Overall Compensation
          5. 2.6.1.5 Windowed ADC Conversion
        2. 2.6.2 ADC Conversion Using SAR
        3. 2.6.3 Multiple ADC Conversions
        4. 2.6.4 Comparison Between Different Measurement Methods
        5. 2.6.5 Error Dependencies
      7. 2.7  SVM Function
      8. 2.8  Use of Multiple Features
      9. 2.9  Temperature Measurements With the A-Pool
      10. 2.10 Fractional and Integer Number Use
      11. 2.11 APINTB and APFRACTB Use With ATBU and EOCBU
      12. 2.12 A-Pool Trigger Sources
      13. 2.13 Filtering ADC Conversions With Digital Filters
    4. 3 Summary
    5. 4 References
  2.   Revision History

2.6.1.5 Windowed ADC Conversion

If the voltage range of the input voltage is known, the ADC can also be used in a windowed mode. The counting of the ADC starts at a specific value and decreases the runtime of the ADC. For a comparison of the conversion methods, see Section 2.6.4. For an input voltage in a range of 250 mV to 500 mV, the following code can be used.

#include "msp430l092.h" unsigned char result; void main( void ) { // Stop watchdog timer to prevent time out reset WDTCTL = WDTPW + WDTHOLD; APCNF = CMPON+DBON+CONVON+APREFON; // Enable comparator on + // Enable DAC buffer + // Enable conversion + // Enable reverence APVDIV = A0DIV; // Set 500mV input range APINT = 0x80; // Start measurement at 250mV APIE |= EOCIE; // Enable end of conversion interrupt _BIS_SR(GIE); // Switch on global interrupts APCTL = CBSTP+SBSTP+APPSEL0+APPSEL2+OSEL; // Set DAC buffer output to PSEL + // Select output buffer + // Enable Comparator based stop + // Enable Saturation based stop + APCTL |= RUNSTOP; // Start conversion _BIS_SR(LPM0); // Go to LPM0 asm("nop"); while (1); } #pragma vector=APOOL_VECTOR // A-Pool interrupt service routine __interrupt void APOOL_ISR(void) { switch(__even_in_range(APIV,8)) // Add offset to PC and delete flag { case 0: break; case 2: result = APINT; // Save value in variable __bic_SR_register_on_exit(CPUOFF);// Exit LPM0 break; case 4: break; case 6: break; case 8: break; default: break; } }