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

1.1 PWM Signal Capture Introduction

A PWM signal is widely used as the speed control or feedback in system design. The relatively high MCU CLK frequency is required to reach a high PWM capture accuracy. A MSPM0C110x series MCU benefits the system design with the variety of peripherals, but the MCU CLK is only 24MHz which can cause errors in PWM capture. This application report proposes the workaround for the PWM capture error with a MSPM0C110x series MCU with only one timer and one GPIO. This workaround can also identify 100% and 0% PWM duty cycle without any additional work.