Stepper Motor Drive

The Experiment 5 we will test Use PIC16F628 to Drive Stepper Motor, for Article & Types of Stepping Motors you and see links as Resources ,Tools & Related Menu below
This Experiment use Unipolar Motors 9-24 V 7.5 Degree/Step , and use IC ULN2003 for Drive

Assemble circuit as figure 5.1 and Download Program to PIC16F628 from Figure 5.1 VR 100k use for adjust frequency clock of PIC16F628 when run in mode ER
Source Code For Experiment 5

list p= 16 f 628 ; list directive to define processor
#include

; processor specific variable definitions
__CONFIG _CP_OFF & _WDT_OFF & _BODEN_ON & _PWRTE_ON & _ER_OSC_NOCLKOUT & _MCLRE_ON & _LVP_OFF
COUNT equ 0 x 20
DUMMY 1 equ 0 x 21
DUMMY 2 equ 0 x 22
org 0 x 000 ; Reset Vetor Address
bsf STATUS,RP 0 ; Set RB 4- RB 7 For Drive Stepper Motor
movlw b' 00001111 '
movwf PORTB
bcf STATUS,RP 0
Begin movlw .12 ; Loop 12 Time For 7.5 Degree/Step
; 4x12x7.5 = 360
movwf COUNT
Loop movlw b' 00010000 ' ; 1 Phase Full Step
movwf PORTB
call Delay ; Change Delay For Change Speed
movlw b' 00100000 '
movwf PORTB
call Delay
movlw b' 01000000 '
movwf PORTB
call Delay
movlw b' 10000000 '
movwf PORTB
call Delay
decfsz COUNT,f ; Check Loop = 12 Time ?
goto Loop ; If Not Loop Again
movlw .12 ; Reverse Move 12 Time
movwf COUNT
Loop 2 movlw b' 01000000 '
movwf PORTB
call Delay
movlw b' 00100000 '
movwf PORTB
call Delay
movlw b' 00010000 '
movwf PORTB
call Delay
movlw b' 10000000 '
movwf PORTB
call Delay
decfsz COUNT,f ; Check Loop = Time ?
goto Loop 2
goto Begin ; If Yes Start Again
Delay movlw 0 x 20 ; Delay Between Step
movwf DUMMY 1
Delay 1 clrf DUMMY 2
decfsz DUMMY 2 ,f
goto $-1
decfsz DUMMY 1 ,f
goto Delay 1
return
END ; end of program


Tools & Components
Name List Quantity
MPLAB -
PIC16F628 1
4MHz Crystal 1

Push Button Switch 1 PC 1
33pF Capacitors 2
4.7K Resistors 1
47K Resistors 1
100K Variable Resistors( VR) 1
ULN2003 1
Unipolar Motors 1