SDAA040 July   2025 MSPM0C1104

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 PWM Signal Capture Introduction
    2. 1.2 MSPM0C110x Introduction
  5. 2PWM Signal Capture
    1. 2.1 PWM Signal Capture Methods
    2. 2.2 PWM Signal Capture with TIMx CC Block
    3. 2.3 PWM Signal Capture with GPIO Interrupt
    4. 2.4 Comparison of Different PWM Signal Capture Design
  6. 3Software Realization
    1. 3.1 Identifying Rising and Falling Edge
    2. 3.2 Time Order Classification
    3. 3.3 Signal Filter and Result Calculation
  7. 4System Test
    1. 4.1 Test Setup
    2. 4.2 Variable Monitor
    3. 4.3 PWM Signal Capture Resolution Test and Comparison
  8. 5Summary
  9. 6References

Abstract

PWM signal is used as the speed control or feedback in system design, it is important that the PWM signal is measured accurately in a wide range of period to meet the system control accuracy requirement. Normally speaking the high MCU clock frequency is needed to realize the high resolution PWM signal capture. This application note achieves less than 1% capture error of the input PWM duty cycle and period from 100Hz to 10KHz frequency range with MSPM0C1104 running on 24MHz MCU clock frequency, which highly benefits the system design with low power consumption.