/* * 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 */ }