18.1 Introduction

This section describes the Resolver-to-Digital Converter (RDC) implemented in the dsPIC33AK256MPS306 family of devices. The primary function of the RDC is to produce excitation signals for the resolver and demodulate the resulting output signals. It includes a Cascaded Integrator Comb (CIC) filter for demodulation and filtering, and a Coordinate Rotation Digital Computer (CORDIC) block for computing error signals.

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

• Square wave excitation signal generator
• Resolver output signal demodulation
• Configurable signal processing via integrated second-order CIC filter
  • Digital filter for oversampling
  • Two CIC channels for filtering and demodulation
  • Detection of invalid input samples (out of range)
  • Input from internal register or external signal
• Error signal calculation based on CORDIC algorithm