51单片机实现四相步进电机控制实例

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工作原理见书《51单片机应用及原理——基于KeilC和Proteus，陈海宴》P178-180

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步进电机控制应用实例

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设计要求：

采用定时中断方式控制步进机的转速，定时单位时长为10ms。 速度设置在1/2/3/4四个档位，1档最快，依次递减，能够控制步进电机的停、转和方向，同时显示步进机的当前档位。

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设计思路：

• 通过P1控制步进电机的转动，P1.0->a，P1.1->b，P1.2->c，P1.3->d，ULN2003A作为步进电机驱动
• P2.0-P2.3对应数码管显示（使用7447芯片对应将BCD码转换成7端LED数码管），通过7447简单驱动数码管（P2只需要发送1/2/3/4即可）
• 通过定时器计数，到达设定值时步进电机转动1/4圈，计数清零

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元件清单：

• AT89C51
• BUTTON
• MOTOR-STEPPER
• RESPACK-8
• 7SEG-COM-ANODE
• ULN2003A
• 7447

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实现代码：

1 #include <reg52.h>
  2 typedef unsigned char uchar;
  3 uchar direction = 0;  //0为正转,1为反转
  4 uchar onoff = 0; //关为0,开为1
  5 uchar n = 0; //每次定时器中断触发时n++,当n==max时电机转动1/4
  6 uchar max = 10;
  7 uchar index = 0; //通过index指示电机转动,AB,BC,CD,DA
  8 sbit LED = P3 ^ 7; //当n==max时LED闪烁提示
  9 int main()
 10 {
 11     /* LED */
 12     P2 = 0xff;
 13     /* 初始化中断 */
 14     EA = 1;
 15     EX0 = 1; //要用到的中断是两个外部中断和定时器中断0
 16     IT0 = 1;
 17     EX1 = 1;
 18     IT1 = 1;
 19     ET0 = 1;
 20     /* 定时器0 */
 21     TMOD = 0x01; //使用定时器0,方式1
 22     TH0 = (65536 - 10000) / 256; //12MHz晶振下,定时器为10ms触发中断,更方便观察转动情况
 23     TL0 = (65536 - 10000) % 256;
 24     TR0 = 1;
 25     while(1)
 26     {
 27         switch(P0)
 28         {
 29         case 0xfe: //11111110
 30             max = 1;
 31             P2 = 1;
 32             break;
 33         case 0xfd: //11111101
 34             max = 10;
 35             P2 = 2;
 36             break;
 37         case 0xfb: //11111011
 38             max = 50;
 39             P2 = 3;
 40             break;
 41         case 0xf7: //11110111
 42             max = 100;
 43             P2 = 4;
 44             break;
 45         }
 46     }
 47 }
 48 void Stop()interrupt 0
 49 {
 50     onoff++;
 51     if (onoff > 1)
 52         onoff = 0;
 53 }
 54 void int1()interrupt 2
 55 {
 56     direction++;
 57     if (direction > 1)
 58         direction = 0;
 59 }
 60 void delay50ms(void)
 61 {
 62     unsigned char a, b;
 63     for(b = 173; b > 0; b--)
 64         for(a = 143; a > 0; a--);
 65 }
 66 void time()interrupt 1
 67 {
 68     TH0 = (65536 - 10000) / 256;
 69     TL0 = (65536 - 10000) % 256;
 70     if (onoff == 1) //在开状态下
 71     {
 72         if (n == max) //设定档位速度,经过了max次中断后,步进电机转1/4圈
 73         {
 74             LED = 0; //每次n==max时LED闪烁
 75             delay50ms();
 76             LED = 1;
 77             if (direction == 0)
 78             {
 79                 switch(index) //正转时以AB,BC,CD,DA顺序
 80                 {
 81                 case 0:P1 = 0x03;break; //00000011 AB高电平
 82                 case 1:P1 = 0x06;break; //00000110 BC高电平
 83                 case 2:P1 = 0x0c;break; //00001100 CD高电平
 84                 case 3:P1 = 0x09;break; //00001001 DA高电平
 85                 }
 86                 index ++; 
 87                 if (index == 4) //步进电机转完一圈时index清零
 88                     index = 0;
 89                 n = 0; //到达max,n重置为0
 90             }
 91             if (direction == 1)
 92             {
 93                 switch(index) //反转时以DA,CD,BC,AB顺序
 94                 {
 95                 case 0:P1 = 0x09;break;
 96                 case 1:P1 = 0x0c;break;
 97                 case 2:P1 = 0x06;break;
 98                 case 3:P1 = 0x03;break;
 99                 }
100                 index ++;
101                 if (index == 4)
102                     index = 0;
103                 n = 0;
104             }
105             else n = 0;
106         }
107         n++; //n!=max时,n++
108     }
109     else n = 0; //在关状态下,n始终为0,无法触发电机转动
110 }