Microcontrollers (MCU)

MSP430™ ultrasonic & rotary flow sensing microcontrollers

Ultra-low-power SoCs for water, gas and heat meters

System-on-chip MSP430™ ultrasonic and performance sensing MCUs are designed for high-accuracy water, heat and gas flow measurement applications. The MCUs feature integrated peripherals including an ultrasonic sensing analog front end, extended scan interface and DSP capabilities, and all MCUs feature a real time clock, LCD driver, 12-bit SAR ADC and comparator.

Ultrasonic sensing SoCs

  • High-precision ultrasonic flow sensing
  • Ultrasonic MCUs with integrated AFE
  • Integrated 8 MSPS sigma-delta ADC
  • Metering test interface (MTIF)

Rotary flow sensing SoCs

  • Ultra-low power extended scan interface peripheral
  • Supports up to 3 LC rotation detection sensors
  • Supports TMR, GMR, Hall-effect and optical sensors

Signal processing MCUs

  • Integrated low-energy math engine
  • 40x the performance of Arm® Cortex®-M0+ MCUs
  • Efficient FIR and FFT filter implementations

Why ultrasonic sensing for flow meters?

Ultrasonic sensing uses the time of flight (TOF) of an ultrasonic wave within any liquid or gas medium and its dependency on the flow rate to measure and calculate volume flow. This technique uses the difference in the propagation time of the ultrasonic wave when transmitted into and against the direction of the flow. This technology is robust and accurate in measuring volume flow rates across a wide dynamic range. 

ultrasonic sensing for flow meters

Ultrasonic flow meter features

Ultrasonic sensing provides: 

  • High accuracy <±1% of flow measurement
  • No moving parts or wear and tear for longer operational life and cost effectiveness with less service/maintenance
  • Resistant to vibration, infrared radiation and EMI

Works well on fluids including: 

  • Water
  • Oil
  • Paint

Works well on gases including: 

  • Air
  • Carbon dioxide
  • Oxygen
  • Methane

Our waveform capture-based approach for ultrasonic sensing

MSP430 ultrasonic sensing SoCs facilitate a unique waveform capture based technique, where the entire response of the transducer is captured in time domain for both the upstream and downstream conditions. Post-processing on these waveforms determine the differential time of flight (TOF). 

ultrasonic water meter diagram

Benefits of the waveform approach

  • Robustness to signal amplitude variation (transducer-transducer variation, different material compositions, high flow rates, noise, temperature variation, etc.)
  • Leak detection combined with very high accuracies at low-flow rates
  • Suppression of noise to achieve higher accuracy and reduced variations
  • 3V drive capabilities for transducers using standard MCU voltage levels
  • Ability to extend to material and composition analysis
  • Additional capabilities for meter diagnostics over time to:
    • Detect slow variation in envelop due to transducer aging, adjusts transducer-transducer resonant frequency variation
    • Eliminate periodic calibration over the lifetime of a product

Ultrasonic sensing solution analog front end (AFE)

The Ultrasonic sensing sub-system peripheral is anintegrated analog front end that can directly excite a wide range of transducers and has an integrated PHY for impedance matching. It also has an integrated programmable gain amplifier (PGA) and a high speed 8MSPS sigma-delta ADC in the receive section, which enables waveform capture in real time. 

Ultrasonic analog front end diagram

Features of the ultrasonic sensing AFE

  • Direct interface to a variety of transducers
  • Programmable pulse excitation for a wide range of transducers
  • PHY for transducer impedance matching
  • Programmable gain amplifier (PGA) for signal amplification up to 35dB
  • Real-time waveform capture using an integrated high-speed 8MSPS sigma-delta analog-to-digital converter (ADC)

Get started with our newest ultrasonic sensing SoCs

Integrated SoC for ultrasonic sensing and measurement

Unique high-speed ADC-based ultrasonic sensing technique 

  • High accuracy, high precision measurements 

  • Low power  (~ 3uA) for 1meas/ sec for water flow

  • Low flow rate detection (<1L/h) 

Ultrasonic design center

One-stop-shop for ultrasonic sensing development

  • Real-time waveform capture and plot of key parameters for added intelligence

  • Software library

  • GUI for ease of development 

Ultrasonic gas measurement evaluation module

Easy interface to ultrasonic transducers

  • BoosterPack™ Plug-in Module connectors to add functionality: RF, battery management, temperature measurement, etc.

  • Power consumption analysis and LCD display capabilities 

  • On-board programming and debug

Signal processing MCUs

The integrated low-energy accelerator (LEA) module is a 32-bit hardware engine designed for operations that involve vector-based signal processing such as FIR, IIR and FFT. These operations are done without CPU intervention and trigger an interrupt when the operation is completed. The LEA module supports multiple commands, which are issued by the CPU and performs vector math operations up to 40x faster than Arm Cortex-M0+ MCUs running the CMSIS DSP library and minimal energy consumption.

Low energy accelerator diagram

Benefits of signal processing MCUs

  • 32-bit hardware engine
  • No CPU intervention – triggers an interrupt when operation is complete
  • Performs math operations up to 40x faster than Arm Cortex-M0+ MCUs
  • Little DSP expertise required with free optimized DSP Library
  • Vector-based signal processing: FIR, IIR, FFT
  • Supports 16-bit and 32-bit fixed point operations in both the real and complex domains

Rotary flow sensing SoCs

For water, gas and heat meters that use conventional mechanical technologies, flow is determined by a spinning wheel that rotates at a speed proportional to the flow rate. Extended scan interface (ESI) is an analog-front-end (AFE) integrated in the MSP430FR6989 MCU family to automatically measure linear or rotational motion of sensors with the lowest possible power consumption. 

extended scan interface diagram

Benefits of rotary flow sensing SoCs

  • Robust state machine enables run-time calibration and sensor detection, etc.
  • Direct interface with different sensors including inductive (LC), Hall-effect, magneto-resistive (GMR and TMR) and optical transducers. 
  • Accurately measures linear or circular motion across a wide-dynamic range of flow rates
  • Works with sensors without CPU intervention to deliver measurements at the lowest power