README.md

Arduino Hardware Quadrature Generator

Uses an Arduino UNo to generate quadrature output on pins 9 & 10. Configurable freqnecy from ~122Hz to 4Mhz. (Lower freqencies possible) Confugrable phase shift from -180 deg to +180 deg.

Main function:

// freq_hz is frequency in hertz from 122 to 4,000,000
// shift_deg is phase shift between output A and output B in degrees (values outside -180 to +180 are normalized)

// Note that at frequencies above 44KHz you will loose precision on phase shift. At 4Mhz, everything is rounded to just 0 or +/-90 degrees.
// Note that all timing happens in 1/16Mhz increments, so frequencies that do not land on integer multipules of that will be aproximiate. 
// Use startWaveforms() directly for more precise control. 

void startQuadrature( unsigned long freq_hz , int shift_deg  );

Example outputs

  // 250Hz, B about 5us behind behind A 
  startQuadrature( 250 , 1);

  // 1KHz, A and B exactly in phase
  startQuadrature( 1000 , 0 );

  // 10KHz, A and B exactly out of phase
  startQuadrature( 10000 , 180 );     //(-180 same result)

  // 100KHz, A leads B by 90 degrees
  startQuadrature( 100000 , 90 );

  // 1MHz, B leads A by 90 degrees
  startQuadrature( 1000000 , -90 );