SLAA890A December   2019  – August 2021 MSP430FR2000 , MSP430FR2032 , MSP430FR2033 , MSP430FR2100 , MSP430FR2110 , MSP430FR2111 , MSP430FR2153 , MSP430FR2155 , MSP430FR2310 , MSP430FR2311 , MSP430FR2353 , MSP430FR2355 , MSP430FR2422 , MSP430FR2433 , MSP430FR2475 , MSP430FR2476 , MSP430FR2512 , MSP430FR2522 , MSP430FR2532 , MSP430FR2533 , MSP430FR2632 , MSP430FR2633 , MSP430FR2672 , MSP430FR2673 , MSP430FR2675 , MSP430FR2676 , MSP430FR4131 , MSP430FR4132 , MSP430FR4133

 

  1.   Trademarks
  2. 1Overview of the MSP430FR4xx and MSP430FR2xx ADC Module
  3. 2Comparison Between the FR2xx/FR4xx ADC and ADC12_B
    1. 2.1 Outline of ADC12_B
    2. 2.2 Outline of FR2xx/FR4xx ADC
    3. 2.3 FR2xx/FR4xx ADC Pin Selection and Board Design
    4. 2.4 Key Parameters Comparison
  4. 3Tailoring the ADC and Reference Voltages to Your Application
    1. 3.1 Reference Voltages
    2. 3.2 Internal and External Reference Voltage
    3. 3.3 Signal Resolution
    4. 3.4 Selecting the Right Sampling and Conversion Time to Achieve the Target Conversion Rate
    5. 3.5 Clock Selection
  5. 4Using the Window Comparator to Monitor a Signal Without CPU Intervention
  6. 5Calibration of VREF and the Internal Temperature Sensor to Improve Performance
  7. 6FR2xx/FR4xx ADC Example Code and Resources
  8. 7References
  9. 8Revision History

5 Calibration of VREF and the Internal Temperature Sensor to Improve Performance

Calibration can be done to improve ADC performance. On-board calibration provides the best performance as it accounts for temperature drift and voltage dependencies based on the room temperature point provided by on-chip TLV data and the highest temperature point OR the lowest temperature point according to the application system level requirement, but it can require additional test time or hardware on the board to test the ADC code at high and low temperatures.

During production, measurements can be done specific to the application and those calibration values stored, and later used by the code to calibrate.

The device also contains some calibration values programmed by Texas Instruments that can be used to improve performance. These values are stored in the Device Descriptor Table (TLV). The device-specific data sheet shows the TLV calibration values available on the device and the correction equations are provided in the Device Descriptor Table section of the MSP430FR4xx and MSP430FR2xx Family User's Guide. To calibrate using TLV values, the code needs to implement the correction equations. The ADC has a gain factor and offset stored in TLV that is programmed on the device based on measurements using an external reference at room temperature. When the calibration equations are applied, gain and offset error are improved as well as total unadjusted error. At room temperature, gain and offset error are improved to ±0.5 LSB, and the total unadjusted error is improved to less than ±3 LSB.