If we take as example the ATmega328P CPU clock (16Mhz) the prescaler would be able to receive this clock speed and output a scaled down version of it, this is useful because since our timer register ...

#define FREQ_CLK 1000000 // Clock frequency (default setting for the ATmega328P -- 8 MHz internal clock with divide-by-8 This program blinks an LED at set frequencies. The timing is handled completely ...