Microcontroller breathing light program and waveform demonstration

I found a breathing light program on the Internet and wrote it myself.
I used a timer to generate pwm to realize the breathing light
. I can also control the speed of the DC motor by referring to the breathing light program. You can go to this page to see https://www.zhihu.com/tardis/sogou/art/83373994

pwm waveform:

The microcontroller source program is as follows:

#include

#define uint unsigned int

#define uchar unsigned char

bit flag; //Determine whether to brighten or darken based on flag

uchar count; //Enter interrupt times

uchar pwm; //Turn on or off according to this value

uint updata; //Update the duty cycle according to this value, period 120ms

sbit LED=P2^0; //LED pin

void timer0();

/*********Timer initialization function***********/

void timer0_init()               

{

        TMOD=0x02; //Timer 0, mode 2

        TH0=0xa3; //Assume the crystal oscillator is 11.0592M, the timing is 100us

        TL0=0xa3;               

        ET0=1; //Open timer 0 interrupt

        EA=1; //Open the general interrupt

        TR0=1; //Start the timer

}

void main()

{

        flag=0; //Initial duty cycle rise

        count=0;

        pwm=10; //Pulse period is 2ms, initial duty cycle is 50%

        updata=0;

        LED=1;

        timer0_init();

        while(1);

}

void timer0() interrupt 1

{

        count++;

        updata++;

        if(count==pwm)

                LED = 0;

        if(count==20)

        {

                LED=1;

                count=0;

        }

        if((updata==1200)&&(flag==0)) //120ms arrives, update the duty cycle according to flag

        {

                updata=0;

                pwm++; //Add 1 each time, the duty cycle increases by 5%

                if(pwm==19)

                        flag=1;

        }

        if((updata==1200)&&(flag==1))

        {

                updata=0;

                pwm--;

                if(pwm==1)

                        flag=0;

        }

}

3-Basic parameters of PWM

In the figure above, the value of frequency F is 1/(T1+T2), and the value of duty cycle D is T1/(T1+T2). Frequency modulation can be achieved by changing the number of pulses per unit time; voltage regulation can be achieved by changing the duty cycle. The larger the duty cycle, the larger the average voltage and the larger the amplitude; the smaller the duty cycle, the smaller the average voltage and the smaller the amplitude. The dynamic diagram is shown in Figure 4.