* * 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--;       /* decremnet ccw step number */         if (ccw_n !=0)          j--;          /* if not zero decrement index j */          else          {flag1&=~0x02; /* disable ccw() executon */           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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