ATtiny85 Low Frequency Oscillator

The ATtiny85 microprocessor outputs Sinewave, Triangle wave, Ramp Up, Ramp Down and Squarewaves, selectable by a Potentiometer.

The Speed of these waveforms is also variable via another Potentiometer.

I made it possible to use either the raw PWM (pulse-width modulation) for driving an LED, or a Filtered Low Frequency Oscillator (LFO) as an output to opamps, etc.