SLAAE30 July   2021 MSP430FR2355

 

  1.   Abstract
  2.   Trademarks
  3. 1PIR Design Description
    1. 1.1 PIR Sensor
    2. 1.2 PIR Signal Chain
      1. 1.2.1 Traditional Motion Detection Signal Chain Design
      2. 1.2.2 Capacitor-Free Signal Chain Design
  4. 2Software
    1. 2.1 Software Architecture
    2. 2.2 Software Flow Chart
    3. 2.3 Power Profile
    4. 2.4 Data Processing
      1. 2.4.1 Digital Signal Conditioning
      2. 2.4.2 Low-Pass Filter for Temperature Drift
      3. 2.4.3 Spikes and Noise
      4. 2.4.4 Motion Detection Function
  5. 3Hardware and Schematic
    1. 3.1 MSP430FR2355
    2. 3.2 Schematic
  6. 4Results
    1. 4.1 Distance: 15 ft (4.5 m)
    2. 4.2 Distance: 22.5 ft (6.9 m)
    3. 4.3 Distance: 36.5 ft (11.1 m)
  7. 5Summary
  8. 6References

3.1 MSP430FR2355

The main MCU leveraged to enable this innovative PIR Motion Detector Design is the MSP430FR2355. The MSP430FR2355 is part of the MSP430™MCU value line portfolio of ultra-low-power low-cost devices for sensing and measurement applications. MSP430FR235x MCUs integrate four configurable signal-chain modules called smart analog combos, each of which can be used as a 12-bit DAC or a configurable programmable-gain Op-Amp to meet the specific needs of a system while reducing the BOM and PCB size. The device also includes a 12-bit SAR ADC and two comparators. The MSP430FR215x and MSP430FR235x MCUs all support an extended temperature range from –40°C up to 105°C, so higher temperature industrial applications can benefit from the devices' FRAM data-logging capabilities. The extended temperature range allows developers to meet requirements of applications such as smoke detectors, sensor transmitters, and circuit breakers.

  • Microcontroller
    • 16-bit RISC architecture up to 24 MHz
    • Extended temperature: –40°C to 105°C
    • Up to 48-MHz clock speed
  • Low-power ferroelectric RAM (FRAM)
    • Up to 32KB of nonvolatile memory
    • Built-in error correction code (ECC)
    • Configurable write protection
  • Optimized low-power modes (at 3 V)
    • Active mode: 142 µA/MHz
    • Standby: – LPM3 with 32768-Hz crystal: 1.43 µA (with SVS enabled)
  • High-performance analog
    • One 12-channel 12-bit analog-to-digital converter (ADC)
    • Two enhanced comparators (eCOMP)
    • Four smart analog combo (SAC-L3)
      • Supports General-Purpose Operational Amplifier (OA)
      • Configurable PGA mode supports
      • Built-in 12-bit reference DAC for offset and bias settings

Features: MSP430FR235x MCUs are supported by an extensive hardware and software ecosystem with reference designs and code examples to get your design started quickly. TI provides the MSP430FR2355 LaunchPad™ development kit and also free MSP430Ware™ example software, which is available within TI Resource Explorer.