Datasheet

Flyport Wi-Fi and Ethernet Programmer's guide framework 2.3 (rev 1.0) www.openpicus.com

PWM function

There are 4 basic PWM functions:

Initialize the pin as PWM →PWMInit(BYTE pwm, float freq, float dutyc);

It is a mandatory to call the initialize function to setup the a PWM module

Parameters:

pwm: PWM id (from 1 up to 9)

freq: the frequency of the PWM signal in Hertz

duty: new duty cycle desired (from 0 up to 100, it is expressed in percentage)

Activate a PWM signal →PWMOn(Byte io, BYTE pwm);

Parameters:

io: io pin to assign at pwm functionality (p1, p2, p3...)

pwm: PWM id (from 1 up to 9)

Change Duty Cycle →PWMDuty(float duty, Byte pwm);

This function can be used to change the pwm duty cycle “on the fly”.

Parameters:

duty: new duty cycle desired (from 0 up to 100, it is expressed in percentage)

pwm: PWM id (from 1 up to 9)

To Turn Off the PWM →PWMOff(BYTE pwm);

This function can be used to turn off a PWM.

Parameters:

pwm: PWM id (from 1 up to 9)

A simple application of PWM can be changing the brightness of a LED. In fact, by changing the PWM

duty cycle we change the root mean square (RMS) voltage of the signal, so we can change the

brightness of a LED with PWM.

For example:

PWMInit(1, 1000, 100); //Initialize PWM1 to work

//at 1000 Hz, 100% of duty (always on)

PWMOn(p5, 1); //Turns on PWM1, and set it to p5

PWMDuty(50, 1); //Change the duty at 50% (about half bright)

PWMDuty(0,1); //Change the duty at 0% (off)

PWMOff(1);