20 Quadrature Encoder Interface (QEI)

This section describes the Quadrature Encoder Interface (QEI) implemented in the dsPIC33AK256MPS306 family of devices. The QEI is typically used in motor control applications to detect the mechanical position, direction of rotation and speed of rotation of quadrature encoders. The following high-level features are covered in this section:

  • Four Input Pins: Two Phase Signals, an Index Pulse and a Home Pulse
  • Programmable Digital Noise Filters on Inputs
  • Quadrature Decoder Providing Counter Pulses and Count Direction
  • x4 Count Resolution
  • Index Pulse to Reset the Position Counter
  • General Purpose 32-bit Timer/Counter Mode
  • Interrupts Generated by QEI or Counter Events
  • 32-bit Velocity Counter
  • 32-bit Position Counter
  • 32-bit Index Pulse Counter
  • 32-bit Interval Timer
  • 32-bit Position Initialization/Capture/Compare High Word Register
  • 32-bit Position Initialization/Capture/Compare Low Word Register
  • 4X Quadrature Count Mode
  • External Up/Down Count Mode
  • External Gated Count Mode
  • External Gated Timer Mode
  • Interval Timer Mode
  • Direction Change Indication
  • Input Override Capability
    • Includes forced input override capability for use by Functional Safety-focused customers

  • Check Invalid Encoder Transition

The following high-level Hall decoder features are covered in this section:

  • Hall Sensor
    • Hall code detection
    • Check valid Hall transitions
    • Programmable event generation delay after a Hall transition
  • Window monitoring of Hall transitions