JAJU680A January   2019  – July 2022

 

  1.   概要
  2.   Resources
  3.   特長
  4.   アプリケーション
  5.   5
  6. 1System Description
    1. 1.1 Key System Specifications
  7. 2System Overview
    1. 2.1 Block Diagram
    2. 2.2 Design Considerations
      1. 2.2.1 Flow Measurement
      2. 2.2.2 ToF Measurement
        1. 2.2.2.1 ADC-Based Acquisition Process
        2. 2.2.2.2 Ultrasonic Sensing Flow-Metering Library
      3. 2.2.3 Low-Power Design
        1. 2.2.3.1 Energy-Efficient Software
        2. 2.2.3.2 Optimized Hardware Design
        3. 2.2.3.3 Efficient Use of FRAM
        4. 2.2.3.4 The LEA Advantage
    3. 2.3 Highlighted Products
      1. 2.3.1 MSP430FR6043
      2. 2.3.2 OPA836 and OPA838
      3. 2.3.3 TS5A9411
    4. 2.4 System Design Theory
      1. 2.4.1 Signal Processing for ToF
  8. 3Hardware, Software, Testing Requirements, and Test Results
    1. 3.1 Required Hardware and Software
      1. 3.1.1 Hardware
        1. 3.1.1.1 EVM430-FR6043
      2. 3.1.2 Software
        1. 3.1.2.1 MSP Driver Library (MSP DriverLib)
        2. 3.1.2.2 Ultrasonic Sensing Flow Metering Library
        3. 3.1.2.3 Application
          1. 3.1.2.3.1 Application Customization
          2. 3.1.2.3.2 LCD Stand-Alone Mode
        4. 3.1.2.4 USS Design Center (PC GUI)
      3. 3.1.3 Transducer and Meter
        1. 3.1.3.1 Frequency Characterization of Transducer and Meter
    2. 3.2 Testing and Results
      1. 3.2.1 Test Setup
        1. 3.2.1.1 Connecting Hardware
        2. 3.2.1.2 Building and Loading Software
          1. 3.2.1.2.1 Using Code Composer Studio IDE
          2. 3.2.1.2.2 Using IAR Embedded Workbench IDE
        3. 3.2.1.3 Executing Application
        4. 3.2.1.4 Configure Device and Observe Results Using GUI
        5. 3.2.1.5 Customization and Optimization
      2. 3.2.2 Test Results
        1. 3.2.2.1 Single-Shot Standard Deviation
        2. 3.2.2.2 Zero-Flow Drift
        3. 3.2.2.3 Absolute Time of Flight Measurements
        4. 3.2.2.4 Variability in Zero Flow Drift Across Transducers
        5. 3.2.2.5 Flow Measurements
        6. 3.2.2.6 Average Current Consumption
        7. 3.2.2.7 Memory Footprint
  9. 4Design and Documentation Support
    1. 4.1 Design Files
      1. 4.1.1 Schematics
      2. 4.1.2 Bill of Materials
      3. 4.1.3 PCB Layout Recommendations
        1. 4.1.3.1 Layout Prints
      4. 4.1.4 Altium Project
      5. 4.1.5 Gerber Files
      6. 4.1.6 Assembly Drawings
    2. 4.2 Software Files
    3. 4.3 Related Documentation
    4. 4.4 Terminology
    5. 4.5 Trademarks
    6. 4.6 サポート・リソース
  10. 5About the Authors
  11. 6Revision History
3.1.2.3.1 Application Customization

The ultrasonic gas-flow meter application included in this reference design is provided in source code to let developers customize it according to their needs. Although developers can customize the functionality and behavior of the application as needed, the most common customizations are:

  • Changing the default USS configuration

    Although the Design Center GUI lets developers modify different ultrasonic configuration parameters, as described in Section 3.1.2.4, the application includes source code of configuration files, which can be modified to customize the default configuration of the system.

  • Customizing the hardware

    The application is designed in a modular way, including a hardware abstraction layer (HAL) to encapsulate hardware interactions. This feature allows for easier customization of different hardware requirements from developers and an easier migration between TI platforms.

  • Customizing data processing

    The library includes proprietary algorithms, which are used to process captured ADC waveforms and obtain flow rate information. However, it is possible for developers to implement custom algorithms to add a proprietary IP or attempt to optimize the performance of the system.

  • Changing the default application configuration

    The application supports several features that can be enabled, disabled, or customized by developers. Table 4-1 lists the features.

Table 4-1 Configuration of Application Features
FeatureDescriptionDefinitions
Resonator calibrationThe application periodically calibrates the resonator using the 32-kHz crystal as a reference. The resulting value is used as a correction term for ToF calculations.USS_APP_RESONATOR_CALIBRATE
USS_APP_RESONATOR_CALIBRATE_INTERVAL
Automatic gain controlThe application periodically calculates the optimal gain setting.USS_APP_AGC_CALIBRATE
USS_APP_AGC_CALIBRATE_INTERVAL
DC offset cancellationThe application calculates and cancels the DC offset of the captured ADC signals.USS_APP_DC_OFFSET_CANCELLATION
USS_APP_DC_OFFSET_CANCELLATION_INTERVAL

Application Software (SW) for MSP430FR6043-Based Ultrasonic Gas Flow Meter describes application customization in more detail.