1、实验八 直流电机开环控制实验提高部分：1、 在分析掌握基于 SST89E554RC微控制器实现直流电机控制电路原理基础上，实现电机速度可调；本程序利用 ADC0808采样来改变 PWM波，从而实现电机的无极调速。【电路原理图 protues】AD7AD6AD5AD3AD4A2AD1AD0AD0AD1AD2AD3AD4AD5AD6AD7XTAL218XTAL119ALE30EA31PSEN29RST9P0./AD039P0.1/AD138P0.2/AD237P0.3/AD336P0.4/AD435P0.5/AD534P0.6/AD63P0.7/AD732P1.01P1.2P1.23P1.34P1
2、.45P1.56P1.67P1.78P3.0/RXD10P3.1/TXD1P3.2/INT012P3./INT113P3.4/T014P3.7/RD17P3.6/WR16P3.5/T115P2.7/A1528P2.0/A821P2.1/A92P2./A1023P2.3/A124P2.4/A1225P2.5/A1326P2.6/A1427U1AT89C51net=AD9OUT121AD B24AD A25AD C23VREF(+) 12VREF(-) 16IN31IN42IN53IN64IN75START6OUT58EOC7OE9CLOCK10UT220OUT74 UT615 UT817 UT4
3、18OUT319IN228IN127IN026ALE2U2ADC08080%RV11kU2(CLOCK)D1LED-BLUE2LED-BLUE3LED-BLUE4LED-BLUE5LED-BLUE6LED-BLUE7LED-BLUE8LED-BLUE+8.8【C 代码】/adc-motor.c/#include #define T_value (unsigned char)0xff / T 周期值 #define TL0_value (unsigned char)0xe7 / 定时器 T0 计数值（低） sbit pwm = P33;sbit oe=P32;sbit start=P30;sbi
4、t eoc=P31;unsigned char T_Count,T1_value=0x77,Tx; /Delay()/void Delay()unsigned char i;for(i=0; i200; i+);/time中断，重新赋初值并减 T_Count/void int_tim0() interrupt 1if(T1_value=0x00) pwm=0;else if(T1_value=0xff) pwm=1;else T_Count-;if(T_Count = 0) /跳变pwm = pwm;Tx = T_value - Tx; T_Count = Tx; /终于到 ADC这郁闷孩子的
5、时候/void ad_pwm() unsigned char getdata;oe = 0;start = 0;start = 1;start = 0;while (eoc = 0);oe = 1;getdata = P0;oe = 0;P1=getdata;if(getdata!=T1_value)T1_value=getdata;Tx=T_Count=T1_value;pwm=1;/ if(T1_value=0x00) pwm=0;/ else if(T1_value=0xff) pwm=1;/主函数 main.c/void main() T_Count = T1_value; Tx = T1_value;TMOD = 0x02; TH0 = TL0_value; TL0 = TL0_value;TCON = 0x10; IE=0x82;pwm = 1; while(1) ad_pwm();Delay();
