左侧开关减速，右侧加速。l293d芯片驱动直流电机
![KN)Q9CAC4HKWED]K$K2%(YM.png](http://c.51hei.com/d/forum/202003/01/082140rcigw317g9xzphxc.png "KN)Q9CAC4HKWED]K$K2%(YM.png")
单片机源代码：
- #include<reg51.h>
- #define Tpwm 0xfc18//PWM周期对应的计数值1ms，基于12MHz晶振
- unsigned int duty[]={0,/*0*/
- 0xff9c/*100us*/,0xff38/*200us*/,0xfed4/*300us*/,\
- 0xfe70/*400us*/,0xfe0c/*500us*/,0xfda8/*600us*/,\
- 0xfd44/*700us*/,0xfce0/*800us*/,0xfc7c/*900us*/,\
- 0xfc18/*1000us*/};//PWM高电平时间
- unsigned char i=0;
- sbit P32 = P3^2;
- sbit P33 = P3^3;
- sbit PWMOUT = P2^0;
- sbit PWMIN1 = P2^1;
- sbit PWMIN2 = P2^2;
- bit flag = 1;//PWM输出电平状态，1为输出高电平时间，0为输出低电平时间
- void delay10ms(int n);
- void main(void)
- {
- PWMOUT = 0;//初始化L293D ，停止电机
- PWMIN1 = 0;
- PWMIN2 = 1;
- EA = 1; //开总中断
- IT0 = 1; //中断方式为跳变
- IT1 = 1;
- EX0 = 1; //打开外部中断0
- EX1 = 1; //打开外部中断1
- ET0 = 1; //开定时器0中断允许
- TMOD = 0x01; //设置定时方式
- while(1) //等待中断
- {
- /*在此可以实现其它任务*/
- }
- }
- //10ms延时函数
- void delay10ms(int n)
- {
- int i=0,j;
- while(n--)
- {
- for(i=0;i<10;i++)
- {
- for(j = 0; j < 125; j++);
- }
- }
- }
- void keySpeeddownISR() interrupt 0 //按键中断服务程序
- {
- EA = 0; //关中断
- delay10ms(2); //延时消抖
- if (!P32) //确认按键按下，滤除键盘抖动干扰
- {//减少PWM高电平时间
- if(i>0)
- i--;
- if((TR0=1) && (i == 0))
- {
- TR0 = 0;
- PWMOUT = 0;
- }
- }
- EA = 1;
- }
- void keySpeedupISR() interrupt 2 //按键中断服务程序
- {
- EA = 0; //关中断
- delay10ms(2); //延时消抖
- if (!P33) //确认按键按下，滤除键盘抖动干扰
- {//增加PWM高电平时间
- if(i<=10)
- i++;
- if((TR0 == 0) && (i > 0))
- {//启动PWM,电机顺时针旋转
- PWMIN1 = 0;
- PWMIN2 = 1;
- PWMOUT = 1;
- TH0 = duty[i]>>8;
- TL0 = duty[i]&0xff;
- TR0 = 1;
- flag = 1;
- }
- }
- EA = 1;
- }
- void T0ISR() interrupt 1 //定时器0中断服务程序
- {
- EA = 0; //关中断
- if(flag)
- {//高电平时间结束，输出低电平补齐PWM周期
- PWMOUT = 0;
- TH0 = (65535-(duty[i]-Tpwm))>>8;
- TL0 = (65535-(duty[i]-Tpwm))&0xff;
- flag = 0;
- }else
- {//周期结束
- PWMOUT = 1;
- TH0 = duty[i]>>8;
- TL0 = duty[i]&0xff;
- flag = 1;
- }
- EA = 1;
- }
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PWM.rar
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