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

5.6.2.2 Measuring One 3-wire RTD Using ADC1 and One 3-wire RTD Using ADC2

Figure 5-13 shows the EVM connection diagram to measure one 3-wire RTD using ADC1 and one 3-wire RTD using ADC2.

  1. Connect RTD1 leads 1, 2, and 3 as shown such that ADC1 measures the RTD output across SIGNAL+ and SIGNAL- on the input header.
  2. Connect an external RTD reference resistor (RREF) across SENSE+ and SENSE- to enable a ratiometric reference voltage configuration for ADC1.
  3. Connect additional jumper wires from IDAC to SIGNAL+ and from SENSE- to EXC-.
  4. Connect RTD2 leads 1, 2, and 3 as shown such that ADC2 measures the RTD output across NTC+ and NTC- on the input header. The onboard 4.02kΩ reference resistor (R38) enables a ratiometric reference voltage configuration for ADC2.
  5. Connect an additional external wire between RTD+ and NTC+ pins.
ADS122S14EVM Measuring One 3-wire RTD Using ADC1 and One 3-wire RTD Using ADC2Figure 5-13 Measuring One 3-wire RTD Using ADC1 and One 3-wire RTD Using ADC2

The red lines indicate the sensor bias path and the blue lines indicate the sensor measurement path in Figure 5-13. Table 5-8 describes the applicable register settings for measuring two 3-wire RTDs. 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 5-8 Suggested Register Settings for Application
ADC REGISTER (1) Value Description
ADC1MUX_CFG Register (07h)0x23hAINP = AIN2, AINN = AIN3
GAIN_CFG (08h)0x01hGain = 1
REFERENCE_CFG (09h)0x21hREFP_BUF_EN, REF_SEL = External Reference
IDAC_MAG_CFG (0Dh)0x0AhIDAC1 Magnitude 90x IUNIT
IDAC_MUX_CFG (0Eh)0x80hIDAC Unit = 10µA
I1MUX = AIN0
ADC2MUX_CFG Register (07h)0x01hAINP = AIN0, AINN = AIN1
GAIN_CFG (08h)0x01hGain = 1
REFERENCE_CFG (09h)0x21hREFP_BUF_EN, REF_SEL = External Reference
IDAC_MAG_CFG (0Dh)0x0AhIDAC1 Magnitude 90x IUNIT
IDAC_MUX_CFG (0Eh)0x86hIDAC Unit = 10µA
I1MUX = AIN6
(1) See ADC1 and ADC2 Power-on and adc reset Register Settings for default EVM firmware settings.