In this project an AVR microcontroller type ATtiny2313 acts as a variable frequency divider, giving a sequence of very stable reference frequencies with a 50% duty cycle and covering a frequency range of 0.1 Hz – 4 MHz in 1, 2, 4 or 8 steps. The circuit is very simple because everything is done inside the microcontroller. In the program 31 different frequencies are predefined and may be selected by switches according to a table.