SLAA941 March   2020 TUSS4440 , TUSS4470

 

  1.   TUSS44x0 Software Development Guide
    1.     Trademarks
    2. 1 Introduction to High-Level Software Flow
    3. 2 Main Energia Sketch File
      1. 2.1 MCU Initialization
      2. 2.2 TUSS44x0 Configuration
        1. 2.2.1 TUSS44x0 Odd Parity Calculation
        2. 2.2.2 TUSS44x0 Settings
          1. 2.2.2.1 Driver Settings
          2. 2.2.2.2 Receiver Settings
      3. 2.3 Read Ultrasonic Time-of-Flight
        1. 2.3.1 Run Time-of-Flight
        2. 2.3.2 Post-Process Data
        3. 2.3.3 Convert Time-of-Flight to Distance
    4. 3 Energia Examples
      1. 3.1 GetDistance.ino - COM Terminal Input Example
      2. 3.2 VOUT_ADC_Capture.ino - Standalone Example
    5. 4 References

2.3.1 Run Time-of-Flight

The MCU initiates a time-of-flight command by sending the appropriate SPI write and GPIO/clock toggle of the IOx pins. The MCU is able to force burst pulses at any given time because there is no preset record length in the TUSS44x0. The MCU should wait a user-defined amount of time before attempting a subsequent time-of-flight command. The delay time between time-of-flight commands is crucial to allow the ultrasonic sound wave travel and return to the sensor because the speed of sound is much slower than the majority of modern MCUs. If the MCU attempts to read the ADC, O3, and/or O4 results too quickly or immediately after the time-of-flight burst is initiated, there will be limited or no information available. Depending on the transmission medium, the speed of sound varies. For example, the speed of sound through air at room temperature is approximately 343 m/s, while the speed of sound through sea water at room temperature is 1531 m/s.