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

2.2 Outline of FR2xx/FR4xx ADC

In the MSP430FR4xx and MSP430FR2xx MCUs, a single-ended external analog input is selected by the analog input multiplexer from 12 external and 4 internal analog signals. The 1.2-V VREF can be output to a device-specific external channel. The on-chip temperature sensor can be internally connected to channel A12. The 1.5-V VREF can be internally connected to channel A13.

In both the FR2xx/FR4xx ADC and the ADC12_B, 8-, 10-, or 12-bit resolution can be selected. In the FR2xx/FR4xx ADC module, the ADCCTL2.ADCRES bit field is used, and the default setting is 10 bit. In the ADC12_B module, the ADC12CTL2.ADC12RES bit field is used, and the default setting is 12 bit.

In MSP430FR4xx and MSP430FR2xx MCUs, the DMA is not supported. In MSP430FR58xx, MSP430FR59xx, and MSP430FR6xx MCUs, the DMA is supported in the ADC12_B.

In MSP430FR4xx and MSP430FR2xx MCUs, the interrupt vector register ADCIV has six interrupt flag sources including three from the window comparator function. More ADC12_B interrupts are handled using the ADC12IV.

For the ADC clock source and sampling rate, MODOSC, ACLK, MCLK and SMCLK can be set as ADC clock. The conversion time can be calculated in (resolution bits + 2) × 1/fADCCLK. The sampling time can be set by ADCSHTx.ADCCTL0 to 4, 8, 16, and up to 1024 ADC clock cycles. The sampling time should be equal or larger than the minimum sampling time specified in MSP430FR4xx or MSP430FR2xx device-specific data sheet. This value is related to the equivalent internal and external resistance and capacitance, resolution, and voltage.