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| AT89C2051驱动步进电机的电路和源码 
 
 
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 程序
 
 stepper.c
 stepper.hex
 /*
 * STEPPER.C
 * sweeping stepper‘s rotor cw and cww 400 steps
 * Copyright (c) 1999 by W.Sirichote
 */
 #include c:\mc51\8051io.h /* include i/o header file */
 #include c:\mc51\8051reg.h
 register unsigned char j,flag1,temp;
 register unsigned int cw_n,ccw_n;
 unsigned char step[8]={0x80,0xc0,0x40,0x60,0x20,0x30,0x10,0x90}
 #define n 400
 /* flag1 mask byte
 0x01 run cw()
 0x02 run ccw()
 */
 main()
 {
 flag1=0;
 serinit(9600);
 disable(); /* no need timer interrupt */
 cw_n = n; /* initial step number for cw */
 flag1 |=0x01; /* initial enable cw() */
 while(1){
 {
 tick_wait(); /* wait for 10ms elapsed */
 energize(); /* round-robin execution the following tasks every 10ms */
 cw();
 ccw();
 }
 }
 }
 cw(){
 if((flag1&0x01)!=0)
 {
 cw_n--; /* decrement cw step number */
 if (cw_n !=0)
 j++; /* if not zero increment index j */
 else
 {flag1&="0x01; /* disable cw() execution */
 ccw_n = n; /* reload step number to ccw counter */
 flag1 |=0x02; /* enable cww() execution */
 }
 }
 }
 ccw(){
 if((flag1&0x02)!=0)
 {
 ccw_n--; /* decremnent ccw step number */
 if (ccw_n !=0)
 j--; /* if not zero decrement index j */
 else
 {flag1&="0x02; /* disable ccw() execution */
 cw_n = n; /* reload step number to cw counter */
 flag1 |=0x01; /* enable cw() execution */
 }
 }
 }
 tick_wait(){ /* cputick was replaced by simpler ASM code 10ms wait */
 asm‘ JNB TCON.5,*‘; /* wait for TF0 set */
 asm‘ CLR TCON.5‘; /* clear TF0 for further set */
 asm‘ ORL TH0,#$DC‘; /* reload TH0 with $DC, TL0 = 0 */
 }
 energize(){
 P1 = step[(j&0x07)]; /* only step 0-7 needed */
 }
 
 
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