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 Analog Pool (A-Pool)

The A-Pool module in the MSP430x09x supports several analog functions at 0.9 V, depending on the user software. The reference voltage for the A-Pool is supplied by an internal 256-mV reference or by an external reference that can be input through a port pin. The clock frequency can be selected from several clock sources and can also be divided within the A-Pool. The A-Pool provides these analog functions:

  • Comparator
  • 8-bit elementary DAC
  • 8-bit ADC
  • Supply voltage monitor (SVM)
  • Temperature sensor
  • Ultra-low-voltage reference

The core of the A-Pool is a comparator and two multiplexers. The multiplexers are used to select the signals for the positive and negative inputs of the comparator. In addition, a counter and specific start and stop logic are used for the ADC and DAC operations. The inputs to the A-Pool can be divided to select the correct voltage range. Table 1 shows the different levels for the input channels.

fbd_apool_slaa475.gifFigure 2. Functional Block Diagram of the Analog Pool

The A-Pool can be a powerful tool when used to implement and execute analog functions. To enable better performance and to avoid unintended behavior, the recommendations in this application report should be taken into account.