TIDUEJ6A January   2019  – July 2022

 

  1.   Description
  2.   Resources
  3.   Features
  4.   Applications
  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 Support Resources
  10. 5About the Authors
  11. 6Revision History

2.3.1 MSP430FR6043

The MSP430FR604x family of ultrasonic sensing and measurement system on chips (SoCs) from TI are powerful highly-integrated MCUs that are optimized for gas and heat meters. The MSP430FR6043 MCU offers an integrated USS module, which provides high accuracy for a wide range of flow rates. The USS module helps achieve ultra-low-power metering, combined with lower system costs, due to maximum integration requiring few external components. The MSP430FR6043 MCU implements a high-speed, ADC-based, signal acquisition followed by optimized digital signal processing using the integrated LEA module, to deliver a high-accuracy metering solution with ultra-low power optimum for battery-powered metering applications.

The USS module includes a programmable pulse generator (PPG) and a physical interface (PHY) with a low-impedance output driver for optimum sensor excitation and accurate impedance matching, to deliver the best results for ZFD. The module also includes a programmable gain amplifier (PGA) and a high-speed, 12-bit, 8-Msps, sigma-delta (ΣΔ) ADC (SDHS) for accurate signal acquisition from industry standard ultrasonic transducers.

Additionally, the MSP430FR6043 MCU uses other peripherals to improve system integration for metering. The device has a metering test interface (MTIF) module, which implements pulse generation to indicate the flow measured by the meter. The MSP430FR6043 MCU also has the following:

  • On-chip 8-MUX LCD driver
  • RTC
  • 12-bit SAR ADC with up to 16 external channels
  • Analog comparator with up to 16 channels
  • Four eUSCI_A to implement universal asynchronous receiver/transmitter (UART)IrDA or serial peripheral interface (SPI)
  • Two eUSCI_B to implement I2C or SPI
  • Six 16-bit timers
  • Advanced encryption accelerator (AES256)
  • Cyclic redundancy check (CRC) module

The MSP430 ultra-low-power FRAM MCU platform combines uniquely embedded FRAM and a holistic, ultra-low-power, system architecture, letting system designers increase performance while lowering energy consumption. FRAM technology combines the low-energy fast writes, flexibility, and endurance of RAM with the nonvolatile nature of flash.

The TIDM-02003 design uses the MSP430FR6043 MCU to not only act as a host processor communicating with a PC GUI, but also to perform measurements in an automated process. The powerful peripherals of the MSP430FR6043 MCU, particularly the USS module, together with FRAM technology and the LEA, allow for an accurate and efficient implementation of an ultrasonic gas flow meter.