SWRA679 January   2021 CC3200 , CC3220R , CC3220S , CC3220SF , CC3230S , CC3230SF , CC3235S , CC3235SF

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Basics of the SAR ADC Architecture
    2. 1.2 Introduction to the CC32XX ADC
      1. 1.2.1 Main Features
      2. 1.2.2 ADC Sampling Operation
      3. 1.2.3 ADC Additional Information
  3. 2ADC Application Examples
    1. 2.1 Battery Voltage Measurements
      1. 2.1.1 Important Considerations
        1. 2.1.1.1 Extra Current Draw
        2. 2.1.1.2 Droop Correction
        3. 2.1.1.3 Offset Adjustment
        4. 2.1.1.4 Least Squares Fit
        5. 2.1.1.5 Choosing the Capacitor (for droop correction)
        6. 2.1.1.6 First Measurement
        7. 2.1.1.7 Time Between Measurements
  4. 3AC Measurements
  5. 4Useful References
    1. 4.1 Smart Thermostat
    2. 4.2 Measuring Air Quality With the Winsen MP503 Analog Sensor
    3. 4.3 Touch Position Detection With HMI Through Resistive Touchscreen
  6. 5References

2.1.1.3 Offset Adjustment

Based on the chosen capacitor value and the approximate value of Vcc, the expected Vdrop across N samples can be calculated by using Equation 1. Then, the Vcc can be estimated as shown in Equation 2.

Equation 2. GUID-20201021-CA0I-KD8R-XC42-2BHG379CXV67-low.gif

The method can be recursively used to improve the value of Vcc, if there is no prior information on Vcc.