SBOA444 November   2020 TMCS1100

 

  1.   Trademarks
  2. 1Introduction
  3. 2Implementation Block Diagram
  4. 3Hardware Implemenation
    1. 3.1 Analog Inputs
      1. 3.1.1 Voltage Measurement Analog Front End
      2. 3.1.2 Current Measurement Analog Front End
    2. 3.2 MSP432 LaunchPad Connections
    3. 3.3 PCB Layout Recommendations
  5. 4How to Implement Software for Metrology Testing
    1. 4.1 Setup
      1. 4.1.1 Clock
      2. 4.1.2 UART Setup for GUI Communication
      3. 4.1.3 Real-Time Clock (RTC)
      4. 4.1.4 Direct Memory Access (DMA)
      5. 4.1.5 ADC Setup
    2. 4.2 Foreground Process
      1. 4.2.1 Formulas
        1. 4.2.1.1 Standard Metrology Parameters
        2. 4.2.1.2 Power Quality Formulas
    3. 4.3 Background Process
      1. 4.3.1 per_sample_dsp( )
        1. 4.3.1.1 Voltage and Current ADC Samples
        2. 4.3.1.2 Pure Waveform Samples
        3. 4.3.1.3 Frequency Measurement and Cycle Tracking
      2. 4.3.2 LED Pulse Generation
      3. 4.3.3 Phase Compensation
  6. 5Metrology Accuracy Testing
    1. 5.1 Test Setup
    2. 5.2 Results
  7. 6Schematics
  8. 7References

3.2 MSP432 LaunchPad Connections

This design has a LaunchPad connector that allows supporting connections to different microcontrollers. The Implemented LaunchPad Connections figure shows the implementation of the LaunchPad connector in this design:

GUID-20201005-CA0I-NFQN-JGV8-VJDCG3T2BS44-low.gif Figure 3-6 Implemented LaunchPad™ Connections.
To support multiple microcontroller LaunchPads, there are two options for where to connect the SYNC/RESET (J32 pin 18 or J33 pin 3), SPI_CS (J33 pin 6 or J33 pin 5), and DRDY pins (J32 pin 20 or J33 pin 7). Each of these options have a resistor footprint that can be populated with a 0-Ω resistor for the options that are selected and depopulated for the options that are not selected.

For communication to the MSP432 LaunchPad specifically, the SYNC/RESET pin should be brought out to J33 pin 3, SPI_CS should be brought out to J33 pin 5, and DRDY should be brought out to J33 pin 7. These connections to the MSP432 LaunchPad is supported by populating resistors R71, R72, and R77 while depopulating resistors R78, R79, and R73, as is shown in the Implemented LaunchPad Connections figure.

The LaunchPad Connection Mappings table shows the connections that are used on the MSP432 LaunchPad for this design:

Table 3-1 LaunchPad™ Connection Mappings
LaunchPad™ PIN FUNCTION
J33 pin 7 (P5.6) ADS131M08 DRDY
J33 pin 5 (P2.4) ADS131M08 Chip Select
J33 pin 3 (P2.6) ADS131M08 Reset/Sync
J33 pin 12 (P1.6) ADS131M08 DIN (UCB0SIMO)
J32 pin 13 (P1.5) ADS131M08 SPI Clock
J33 pin 14 (P1.7) ADS131M08 DOUT(UCB0SOMI)
J33 pin 13 (P2.3) EUSCIA0 UART RX for PC GUI communication
J33 pin 4 (P2.5) EUSCIA0 UART RX for PC GUI Communication
J32 pin 15 (P4.6) Active Energy Pulse Output
J32 pin 10 (P4.2) Reactive Energy Pulse Output
J32 pin 14 (P4.5) Voltage Zero Crossing Pin