AN 669: Drive-On-Chip Design Example for Cyclone V Devices

ID 683466
Date 5/15/2022
Document Table of Contents

9.5. Quadrature Encoder Interface

The Drive-On-Chip Design Example quadrature encoder interface monitors and decodes the A, B and I signals from a quadrature encoder. The resulting output is a count value representing the position of the motor shaft.

The quadrature encoder interface allows you to:

  • Program maximum count value to match a wide range of encoders.
  • Increment or decrement the counter on each A or B input edge.
  • Capture the latest count value on an index pulse.
  • Reset the count value on an index pulse.
  • Reverse the direction of the count, equivalent to swapping the A and B inputs.
  • Capture the latest count by an external strobe to synchronize with the PWM module and ADC sampling.