So the lowest ever frequency timer2 can deal with (assuming 20MHz crystal oscillator) = 20000000 / (4 * 16 * 256) = 1220.7 Hz (approx 81.9 us period). It offers prescaler values up to 16 and this prescaler is a feature in timers that allows them to divide input frequency fed into them in order to achieve lower frequencies.

If it is less than 50Hz, then we can generate 50Hz or we will find another way.Įquation 2 is obvious, which is the period of that frequency.Įquation 3 is the number of 'ticks' that the timer will tick until it reaches the time 't' that we want, according to the settings we specified like prescaler and crystal frequency.ĬCP1 module when operated as PWM uses timer2, and this timer2 is an 8-bit timer. We will use it to determine the lowest possible frequency that the timer can produce. N = (t * F_crystal) / (4 * prescaler)Įquation 1 calculates timer frequency. F_timer = F_crystal / (4 * prescaler * resolution) So how can we determine all necessary values to achieve our own required frequency? When it is configured as PWM, it uses Timer2 as a timing module in order to calculate its Ton and Toff. For the typical application, we always should configure it to be PWM (this is the straightforward way which we must use by default). PIC MCUs have something called CCP module which is Capture-Compare-PWM module, meaning, you can configure it to work as one of these 3.

However, you can use the straightforward way (CCP as PWM) if you have a very slow oscillator like 32 KHz, because then timer2 can achieve 50 Hz directly without the need of what we will explain here. This tutorial is for those who has such very high oscillators which is the standard way of using microcontrollers. We will operate this PIC 20MHz oscillator.

Creating a sin wave in mplab xc8