Program 6:-

Now I am adding one more functionality in the program. Now instead of continuously running motor, motor will run till desired no. of revolutions entered. Means motor will automatically stops when it completes desired revolutions. One can increase or decrease revolutions in step of one (1, 2, 3 …).  I have used 6 keys and 5 LEDs.

In the first program we have limit the number of applied pulses to 200. Now again we shall load the number every time that will change number of applied pulses. There is no maximum limit but sure there is minimum limit that is 1 revolution.

Org 00h
mov 30h, #3Ch           ; make a table of
mov 31h, #1Eh           ; four load values
mov 32h, #14h           ; for variable delay
mov 33h, #0Fh
mov r1, #30h              ; initial location in r1
mov 2fh,#32h             ; initial load value
mov 2eh,#01h            ; for no. of rev.
mov r0,#01h               ; initialize key count
mov p1,#0ffh              ; P1 as input port
lop:   mov a,p1
cjne a,#0ffh,jmp
ajmp lop                       ; loop until any key is pressed

jmp:     clr p0.0                     ; indicates keypress
loop:    rrc a
jnc num                        ; get key no.
inc r0
sjmp loop
num: acall dely                  ; key debounce delay
setb p0.0
cjne r0,#01h,nxt
acall clkwise
sjmp over
nxt:  cjne r0,#02h,nxt2
acall aclkwise
sjmp over
nxt2: cjne r0,#03h,nxt3
acall incrpm
sjmp over
nxt3: cjne r0,#04h,nxt4
acall decrpm
sjmp over
nxt4: cjne r0,#05h,nxt5
acall increv
sjmp over
nxt5:cjne r0,#06h,over
acall decrev

over:   mov p2,#00h
mov p1,#0ffh
mov r0,#01h
sjmp lop
clkwise:
mov r1,2Fh              ; load variable count
go: clr  p0.1
mov p2,#01h          ; single coil
acall delay              ; excitation
mov p2,#02h
acall delay              ; variable delay
setb p0.1
mov p2,#04h
acall delay
mov p2,#08h;
acall delay
djnz r1,go
ret
aclkwise:
mov r1,2Fh
go1:clr p0.2
mov p2,#01h
acall delay
mov p2,#08h
acall delay
setb p0.2
mov p2,#04h
acall delay
mov p2,#02h
acall delay
djnz r1,go1
ret
incrpm:
clr p0.3                     ; indication
cjne r1,#33h,incr     ; if max limit is
ajmp noin                  ; reached no increase
incr: inc r1                      ; increase otherwise
acall dely
setb p0.3
noin:  ret                         ; led stays on for max limit

decrpm:
clr p0.3                    ; indication
cjne r1,#30h,decr   ; if min limit is
ajmp noin                 ; reached no decrease
decr: dec r1                   ; decrease otherwise
acall dely
setb p0.3
noin: ret                         ; led stays on for min limit
increv:
clr p0.4                    ; indication
inc 2Eh                    ; increment multiplying factor
mov a,#32h
mov b,2Eh
mul ab                      ; multiply it by load value
mov 2Fh,a                ; stores the new load value
acall dely
setb p0.4
ret
decrev:
clr p0.4
mov r4,2Eh
cjne r4,#01h,decn     ; check for min
ajmp out2                   ; limit of multiplying
decn: dec 2Eh                 ; factor. If not reached
mov a,#32h              ; decrease it
mov b,2Eh
mul ab                       ; multiply it with load
mov 2Fh,a                 ; value and store the
acall dely                  ; new load value
setb p0.4
out2: ret

delay:
mov 10h,@r1              ; load the count
lop2: mov r6,#FAh           ; from table
lop1: nop
nop
djnz 10h,lop1
djnz r5,lop2
ret

dely:
mov r5,#0C8h             ; load count 200
lop2: mov r6,#0FAh          ; for 200ms delay
lop1: nop
nop
djnz r6,lop1
djnz r5,lop2
ret
end

Program 7:-
This program adds two more things to above program. It changes the mode of operation of stepper motor also it adds jog control. It changes three different modes on pressing one key. All eight keys and eight LEDs are now used.

When J7 key is pressed first time the mode will change from single coil to double coil. When pressed second time mode will change from double coil to half step. And on pressing third time again the same mode will repeat. When J8 key is pressed the motor will rotate in previously selected direction. Means if motor was running in clockwise direction then the jog will be in same direction.

Program 8:-

In above program motor doesn’t rotate continuously. In this program motor rotates continuously and one can change the RPM and operating mode while running. 6 keys and 8 LEDs are used.

by
Ashutosh M Bhatt
www.multyremotes.com