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如何用單片機(jī)控制驅(qū)動(dòng)直流電機(jī)?當(dāng)我們還是個(gè)孩子的時(shí)候，玩的四驅(qū)動(dòng)車給上邊的直流電動(dòng)機(jī)裝上電池就嗖嗖的跑了，這是直流電機(jī)最簡(jiǎn)單的控制方式，只要調(diào)整正極和負(fù)極就能改變電機(jī)的轉(zhuǎn)向。在單片機(jī)控制時(shí)需要加驅(qū)動(dòng)電路，我至今還沒(méi)驅(qū)動(dòng)起直流電機(jī)，就是因?yàn)橹�前不知道怎么�?lái)連接驅(qū)動(dòng)電路。

什么是單片機(jī)：

單片機(jī)又稱單片微控制器,它不是完成某一個(gè)邏輯功能的芯片,而是把一個(gè)計(jì)算機(jī)系統(tǒng)集成到一個(gè)芯片上。相當(dāng)于一個(gè)微型的計(jì)算機(jī)，和計(jì)算機(jī)相比，單片機(jī)只缺少了I/O設(shè)備。概括的講：一塊芯片就成了一臺(tái)計(jì)算機(jī)。它的體積小、質(zhì)量輕、價(jià)格便宜、為學(xué)習(xí)、應(yīng)用和開(kāi)發(fā)提供了便利條件。同時(shí)，學(xué)習(xí)使用單片機(jī)是了解計(jì)算機(jī)原理與結(jié)構(gòu)的最佳選擇。單片機(jī)的使用領(lǐng)域已十分廣泛，如智能儀表、實(shí)時(shí)工控、通訊設(shè)備、導(dǎo)航系統(tǒng)、家用電器等。各種產(chǎn)品一旦用上了單片機(jī)，就能起到使產(chǎn)品升級(jí)換代的功效，常在產(chǎn)品名稱前冠以形容詞——“智能型”，如智能型洗衣機(jī)等。單片機(jī)更詳細(xì)介紹請(qǐng)看《什么是單片機(jī)?這一篇文章讓你徹底搞懂》這篇文章

控制直流電機(jī)的轉(zhuǎn)速的是用PWM波形來(lái)控制，就是控制高電平持續(xù)時(shí)間在一個(gè)周期中所占的比例，這個(gè)有個(gè)專用的名詞叫占空比。

用單片機(jī)得到PWM波形有三種方式

方式1：利用軟件延時(shí)，當(dāng)高電平延時(shí)時(shí)間到時(shí)的時(shí)候，對(duì)I/O口電平取反，然后咋延時(shí)，當(dāng)?shù)碗娖窖訒r(shí)時(shí)間到后，在對(duì)I/O口進(jìn)行取反，如此循環(huán)就得到PWM波形

方式2：利用的是定時(shí)器延時(shí)，控制方法同上

方式3：利用單片機(jī)自帶的PWM控制器

示例代碼：得到PWM波形

//利用軟件延時(shí)：并且用鍵盤掃描得到不同的PWM

#include

#define uint unsigned int

#define uchar unsigned char

sbit PWN = P1^1;

sbit key1 = P3^1;

sbit key2 = P3^2;

uchar num;

uint yanshi;

uchar code table[]={0xc0,0xf9,0xa4,0xb0,

0x99,0x92,0x82,0xf8,

0x80,0x90,0x88,0x83,

0xc6,0xa1,0x86,0x8e};

void delayms(uint z)

{

uint x,y;

for(x = z;x>0;x--)

for(y=110;y>0;y--);

}

void main()

{

while(1)

{

P3 = 0xff;

if(key1 ==0)

{

delayms(2);

if(key1 ==0)

{

while(!key1);

num++;

if(num ==7)

{

num =0;

}

yanshi = 200*num;

}

}

switch(num)

{

case 1:

{

PWN = ~PWN;

P0 = table[num];

delayms(yanshi);

}

break;

case 2:

{

PWN = ~PWN;

P0 = table[num];

delayms(yanshi);

}

break;

case 3:

{

PWN = ~PWN;

P0 = table[num];

delayms(yanshi);

}

break;

case 4:

{

PWN = ~PWN;

P0 = table[num];

delayms(yanshi);

}

break;

case 5:

{

PWN = ~PWN;

P0 = table[num];

delayms(yanshi);

}

break;

case 6:

{

P0 = table[num];

PWN = 1;

}

break;

}

}

}

示例代碼2：

#include

#define uint unsigned int

#define uchar unsigned char

#define TIME 600

sbit led1 = P1^1;

void delay(uint xx)

{

while(xx--);

}

void main()

{

uint x;

while(1)

{

for(x = 0;x

{

led1 = 0;

delay(TIME-x);

led1 = 1;

delay(x);

}

delay(65535);

for(x=TIME;x>0;x--)

{

led1 = 0;

delay(TIME-x);

led1 = 1;

delay(x);

}

}

}

步進(jìn)電機(jī)：

步進(jìn)電機(jī)是將電脈沖信號(hào)轉(zhuǎn)變?yōu)榻俏灰坪途�位移的開(kāi)環(huán)控制元件，在非超載的情況下，電機(jī)的轉(zhuǎn)速，停止的位置，只取決于脈沖信號(hào)的頻率數(shù)，和脈沖數(shù)，而不受負(fù)載變化的影響

基本的步進(jìn)電機(jī)的驅(qū)動(dòng)程序：

#include

#define uint unsigned int

main()

{

uint i,j;

while(1)

{

P1 = 0x01;//0000 0001

for(i = 0;i<800;i++);

P1 = 0x02;//0000 0010

for(i = 0;i<800;i++);

P1 = 0x04;//0000 0100

for(i = 0;i<800;i++);

P1 = 0x08;//0000 1000

for(i = 0;i<800;i++);

}

}

綜合程序;用按鍵實(shí)現(xiàn)步進(jìn)電機(jī)的啟動(dòng)，停止，增速，減速，并在數(shù)碼管上顯示出來(lái)：

#include

#define uint unsigned int

#define uchar unsigned char

sbit dula = P2^7;

sbit wela = P2^6;

sbit key1 = P3^3;//這里是解決我的單片機(jī)上按鍵壞掉的問(wèn)題

sbit key2 = P2^4;

sbit key3 = P2^5;

sbit key4 = P2^1;

uchar aa,flag,speed,flag1,i;//flag 是用來(lái)標(biāo)記啟動(dòng)和停止的標(biāo)志位

//flag1 是用來(lái)標(biāo)記正轉(zhuǎn)還是反轉(zhuǎn)的標(biāo)志位

uchar code table[]={0x01,0x02,0x04,0x08};

uchar code table1[]={0x3f,0x06,0x5b,0x4f,

0x66,0x6d,0x7d,0x07,

0x7f,0x6f,0x77,0x7c,

0x39,0x5e,0x79,0x71};

void init()

{

TMOD = 0x01;

TH0 = (65536-2400)/256;

TL0 = (65536-2400)%256;

EA = 1;

ET0 = 1;

}

void delay(uint z)

{

uint x ,y;

for(x = z;x>0 ;x--)

for(y = 110 ;y>0;y--);

}

void display1()//on顯示函數(shù)

{

wela = 1;

P0 = 0xf7;

wela = 0;

P0 = 0;

dula = 1;

P0 = 0x3f;

dula = 0;

delay(5);

P0 = 0xff;

wela = 1;

P0 = 0xef;

wela =0;

P0 = 0;

dula = 1;

P0 = 0x54;

dula = 0;

delay(5);

}

void display2()//off顯示函數(shù)

{

wela = 1;

P0 = 0xf7;

wela = 0;

P0 = 0;

dula = 1;

P0 = 0x3f;

dula = 0;

delay(5);

P0 = 0xff;

wela = 1;

P0 = 0xef;

wela =0;

P0 = 0;

dula = 1;

P0 = 0x71;

dula = 0;

delay(5);

wela = 1;

P0 = 0xdf;

wela = 0;

P0 = 0;

dula = 1;

P0 = 0x71;

dula = 0;

delay(5);

P0 = 0xff;

}

void display()//顯示函數(shù)

{

uchar gw,sw;

gw = speed%10;

sw = speed/10;

wela = 1;

P0 = 0xfe;

wela = 0;

P0 = 0;

dula = 1;

P0 = table1[sw];

dula = 0;

delay(5);

P0 = 0xff;

wela = 1;

P0 = 0xfd;

wela =0;

P0 = 0;

dula = 1;

P0 = table1[gw];

dula = 0;

delay(5);

}

void key_scan()//鍵盤掃描函數(shù)

{

P3 = 0xff;

if(key2==0)

{

delay(5);

if(key2==0)

{

while(!key2)

{

{

display2();

}

flag = 0;

}

}

if(key1==0)

{

delay(5);

if(key1 ==0)

{

while(!key1)

{

display1();

display();

}

flag = 1;//步進(jìn)電機(jī)啟動(dòng)

}

}

if(flag==1)

{

if(key4 == 0)

{

delay(5);

if(key4==0)

{

while(!key4)

{

display();

display1();

}

speed --;

flag1 = 1;

if(speed ==-1)

speed = 20;

}

}

if(key3==0)

{

delay(5);

if(key3==0)

{

while(!key3)

{

display();

display1();

}

speed ++;

flag1 = 0;

if(speed==21)

{

speed = 1;

}

}

}

}

}

main()

{

init();

while(1)

{

key_scan();

if(flag == 1)

{

TR0 = 1;

display();

display1();

}

if(flag == 0)

{

TR0 = 0;

display2();

}

}

}

void time0() interrupt 1

{

TH0 = (65536-2400)/256;

TL0 = (65536-2400)%256;

aa ++;

if(aa ==speed)

{

aa = 0;

if(flag1 == 1)//正轉(zhuǎn)的標(biāo)志

{

i++;

if(i ==4)

i = 0;

P1 = table[i];

}

if(flag1 == 0)//反轉(zhuǎn)的標(biāo)志

{

i --;

if(i == -1)

i = 3;

P1 = table[i];

}

}

}