本此设计选择STC89C52单片机作为主控芯片，选取带有光电编码器的直流电机作为被控对象，利用单片机的T0定时器产生PWM信号并送到直流电机。在Proteus仿真环境下搭建了L298N直流电机驱动电路、矩阵键盘扫描电路以及LCD12864显示电路。实现了直流电机的启动、加速、正转、反转、制动等功能。同时，采用PID控制算法可实现电机速度在特定的场合实现自动切换。

单片机源程序如下:

#include

#include

#include

#include "lcd.h"

#include "Key.h"

#include "Motor.h"

#include "LCD12864.h"

#include "KeyBoard.h"

#include "LCD12864.h"

#include "LcdShow.h"

#include "PID.h"

extern uchar State_Flag;

extern uchar Fwd_Flag;

extern uchar Rev_Flag;

unsigned int KeyValue;

unsigned int idata pwm_t;//周期

unsigned int idata Impluse,Time_Count,ImpluseR;

uchar idata Stop_Flag,Run_Flag,Curve_Flag;

uint idata Set_Speed; // 设定转速

unsigned char idata Sz_Flag,Sr_Flag; // 记录A相触发后 ，B相高低电平的标志

float idata L_Speed,R_Speed,ReaSpeed;

uint idata PWM_Out,R_Duty,L_Duty,Turn_now;

sbit LSB_L = P1^0; // LSB_L

sbit LSB_R = P1^1; // LSB_R

void TimerInit(void) //@11.0592MHz

{

TMOD=0x01; //定时器模式

TL0 = 0x18; //初值 1ms

TH0 = 0xFC; //初值

IT0 = 1; //设置下降沿触发 还是低电平触发 0低电平

IT1 = 1; //设置下降沿触发 还是低电平触发 0低电平

EA = 1;

EX0 = 1;

EX1 = 1;

ET0 = 1;

TR0 = 1;

}

void main()

{

LED = 0;

Stop_Flag = 0;

Lcd_Initial();

TimerInit();

Set_Speed = 0;

Lcd_Clear();

while(1)

{

KeyValue = Get_Keyvalue(); // 矩阵键盘扫描

if(KeyValue == 14) // 输入速度

{

Set_Speed = SpeedInput();

KeyValue = 16;

}

Key_Process();

if(Run_Flag)

{

Set_Speed = 80;

Run_Flag = 0;

}

if(State_Flag && ~Stop_Flag)

{

PWM_Out = PID_Calculate(Set_Speed,abs(ReaSpeed));

R_Duty = PWM_Out + Turn_now;

L_Duty = PWM_Out - Turn_now;

}

else

PWM_Out = 0; // 停止

Lcd_Show();

}

}

//定时器0中断

void timer0() interrupt 1

{

static int i;

TL0 = 0x18; //初值

TH0 = 0xFC; //初值

pwm_t++;

Time_Count++;;

if(pwm_t == 500) //500ms

{

pwm_t = 0;

if(Stop_Flag)

{

i++;

L_Duty = 0;

R_Duty = 0;

if(i<31)

{

LED = ~LED;

if(i == 30)

{

Stop_Flag = 0;

i = 0;

Set_Speed = 30;

}

}

}

}

if( pwm_t

MotorL_Control();

else

MotorL_Stop();

if( pwm_t

MotorR_Control();

else

MotorR_Stop();

/*---------M法 测速------------*/

if(Time_Count == 100 ) // 100ms

{

Control();

Time_Count = 0;

Impluse = 0;

ImpluseR = 0;

}

}

void int0() interrupt 0

{

Impluse++;

if(LSB_L == 1)

Sz_Flag = 1; // 正反转标志位 A相下降沿，B相高电平

else Sz_Flag = 0;

LSB_L = 1;

}

void int1() interrupt 2 // 外部中断1 用于测 右轮的速度

{

ImpluseR++;

if(LSB_R == 1)

Sr_Flag = 1; // 正反转标志位 A相下降沿，B相高电平

else Sr_Flag = 0;

LSB_R = 1;

}