![]() This means writing 0 to value just clears the pin while writing 255 sets the pin. Interestingly, the function takes values zero and 255 as extremes: if (val = 0) The rest of the code is just the same bits repeating for the other timers on other Arduino boards. connect pwm to pin on timer 1, channel B connect pwm to pin on timer 1, channel A connect pwm to pin on timer 0, channel B connect pwm to pin on timer 0, channel A Here’s some part of the function: void analogWrite(uint8_t pin, int val) The function definition resides on wiring_analog.c on the Arduino core. To answer the question above, we will look at how analogWrite() is implemented. Will this do anything? Dissecting the AnalogWrite Function Here, we set the value parameter to 30000 which is obviously beyond 255 but within the limits of the int variable. This one uses Timer1 but is this possible? analogWrite(9, 30000) While this uses Timer2: analogWrite(11, 100) So this uses Timer0: analogWrite(5, 100) In fact, the timer used depends on the PWM pin you specify: The Arduino UNO contains three timers: two 8-bit (Timer0 and Timer2) and one 16-bit (Timer1). However, the documentation specifies that the value parameter must be between 0 and 255, which makes it essentially an 8-bit variable. ![]() Both parameters are of int type, a 16-bit data type. The function accepts two parameters: pin and value and returns nothing. Most of us are familiar with Arduino’s analogWrite() function in generating PWM: analogWrite(pin, value) The most common are dimming a LED or controlling the speed of a DC motor. PWM has a lot of uses in the microcontroller world. Ever since I wrote about timer interrupts, a number of readers have asked me on how to generate a 16-bit pulse width modulation (PWM) signal with Arduino. ![]()
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