(The procedure for the 8 bit timer0 and timer2 is analog.) For the time controlled pulse you need the so called “CTC Mode”. Schematic, Arduino code and pictures are also included. With this a LED should light up in a 50 Hz cycle. In the following, the triggering of Arduino Timer Interrupts is shown with the 16-bit timer1. Practical example LED should light up with 50Hz This would be 16000000/1024=15625 increments per second and thus with an 8 bit timer 15625/256= 61.035 overflows per second (~61 Hz clock rate of the timer). For example, a prescaler of 1024 would increase the timer registers by 1 only at the 1024th system clock pulse. It allows you to divide the system clock (16MHz) by the selected factor and set a lower clock rate for the timers. A prescaler can be set to the values 1, 8, 64, 256 or 1024. Therefore there is a trick to slow down the clock rates. This is likely too fast for most timer applications! At 256 an overflow occurs and the timers start again from 0. For example, the 8 bit timers count from 0 to 255 each time. This means Timer0, Timer1 and Timer2 increase 16 million times per second. The system clock of the Arduino Uno is 16 MHz (CPU frequency).
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