Adrian Freed

This table-based digital audio oscillator implementation illustrates a few useful techniques on 8-bit microprocessors such as the Atmel parts supported by the Arduino/Wiring IDE. A timer is used to establish the sample rate clock and PWM is used to output an 8-bit signal. Human hearing has impressive frequency precision so accumulation is done on 32-bit integers. The code is a lesson in how to used fixed point representations and careful sizing of tables as powers of 2. This reduces the computational cost of the inner loop of the oscillator to a single 8-bit multiply, table lookup and