SLVUDH7 December   2025

 

  1.   1
  2. 1Description
  3. 2Features
  4. 3Applications
  5.   5
  6. 4Evaluation Module Overview
    1. 4.1 Introduction
    2. 4.2 Kit Contents
    3. 4.3 SNSR-DUAL-ADC-EVM Specifications
    4. 4.4 Device Information
    5. 4.5 Getting Started With the SNSR-DUAL-ADC-EVM
  7. 5Hardware
    1. 5.1  Hardware Overview
    2. 5.2  Power Requirements
    3. 5.3  ADC Connections and Decoupling
    4. 5.4  Analog Inputs
      1. 5.4.1 ADC1 Analog Inputs
      2. 5.4.2 ADC2 Analog Inputs
    5. 5.5  Excitation Connections and Low Side Bridge Switch
    6. 5.6  Analog Sensor Connections
      1. 5.6.1 Pressure Sensor (Resistive Bridge) Application Examples
        1. 5.6.1.1 Measuring a Voltage-Excited 6-wire Bridge Using ADC1 and a Low-side Bias Resistor Using ADC2
        2. 5.6.1.2 Measuring a Voltage-Excited 6-wire Bridge Using ADC1 and a Current-Excited 2-wire RTD Using ADC2
        3. 5.6.1.3 Measuring a Current-Excited 4-wire Bridge Using ADC1 and a Voltage-Excited Thermistor Using ADC2
      2. 5.6.2 Temperature Sensor Application Examples
        1. 5.6.2.1 Measuring a Thermocouple Using ADC1 and an NTC for Cold-Junction-Compensation Using ADC2
        2. 5.6.2.2 Measuring One 3-wire RTD Using ADC1 and One 3-wire RTD Using ADC2
        3. 5.6.2.3 Measuring One 4-wire RTD Using ADC1 and One 4-wire RTD Using ADC2
      3. 5.6.3 General Purpose Application Examples
        1. 5.6.3.1 Measuring Generic Voltage or Current Inputs
    7. 5.7  MSPM0G1507
    8. 5.8  Digital Interfaces
    9. 5.9  Digital Connection Headers
    10. 5.10 Shift Register
    11. 5.11 Connecting External Output Boards to Header J2
  8. 6Software
    1. 6.1 Top Level Menu
      1. 6.1.1 Top-level Help Menu Terminal
    2. 6.2 System Sub Menu
      1. 6.2.1 SYS Help Menu Output
    3. 6.3 ADC Sub Menu
      1. 6.3.1 ADC Help Menu Output
      2. 6.3.2 adc help Menu Input and Output Examples
        1. 6.3.2.1 adc reset Example
        2. 6.3.2.2 adc wreg Daisy-Chain Example (Writing to a Single ADC )
        3. 6.3.2.3 adc wreg Daisy-Chain Example (Writing to Both ADCs)
        4. 6.3.2.4 adc rreg Daisy-Chain Example
        5. 6.3.2.5 adc stream Example
        6. 6.3.2.6 adc lowpwr Example
  9. 7Hardware Design Files
    1. 7.1 Schematics
    2. 7.2 PCB Layout
    3. 7.3 Bill of Materials
  10. 8Compliance Information
  11. 9References

5.6.2.1 Measuring a Thermocouple Using ADC1 and an NTC for Cold-Junction-Compensation Using ADC2

Figure 5-12 shows the EVM connection diagram to measure a thermocouple using ADC1 and an NTC for cold junction compensation using ADC2.

  1. Bias the thermocouple with external pullup and pulldown resistors to set a common mode voltage at mid supply. Alternatively, bias the thermocouple through an external wire from the REFOUT pin to SIGNAL+.
  2. Connect an external thermistor to the NTC+ and NTC- pins on the input header for cold-junction compensation of the thermocouple.
  3. Connect an external thermistor across NTC+ and NTC- for a differential measurement or NTC+ and GND for a single-ended measurement. The onboard 10kΩ (R29) bias resistor creates a voltage divider with the external thermistor.
ADS122S14EVM Measuring a Thermocouple Using ADC1 and an NTC for Cold-Junction-Compensation Using ADC2Figure 5-12 Measuring a Thermocouple Using ADC1 and an NTC for Cold-Junction-Compensation Using ADC2

The red lines indicate the sensor bias path and the blue lines indicate the sensor measurement path in Figure 5-12. Table 5-7 describes the applicable register settings to measure a thermocouple and an NTC for cold junction compensation. Recall that purple cells indicate ADC settings that are fixed by the hardware and yellow cells indicate ADC settings that the user must select.

Table 5-7 Suggested Register Settings for Application
ADC REGISTER (1) Value Description
ADC1MUX_CFG Register (07h)0x23hAINP = AIN2, AINN = AIN3
GAIN_CFG (08h)0x0DhGain = 128
REFERENCE_CFG (09h)0x00hREFOUT = 1.25V, Internal Reference
ADC2MUX_CFG Register (07h)0x01hAINP = AIN0, AINN = AIN1
GAIN_CFG (08h)0x01hGain = 1
REFERENCE_CFG (09h)0x03hREFOUT = 2.5V, Internal Reference
(1) See ADC1 and ADC2 Power-on and adc reset Register Settings for default EVM firmware settings.