51 single chip microcomputer drives stepper motor (assembly language)

Here is an introduction to the method of using 51 single-chip microcomputer to drive stepper motor.
The driving voltage of this stepper motor is 12V, and the step angle is 7.5 degrees. A circle of 360 degrees requires 48 pulses to complete!!!
This stepper motor has 6 leads, arranged in the following order: 1: red, 2: red, 3: orange, 4: brown, 5: $, 6: black.
Use the method of 51 to drive ULN2003 to drive.
The drive of ULN2003 directly uses the 5V voltage of the single-chip microcomputer system, but the torque is not very large. You can increase the driving voltage to 12V by yourself.  ;****************************************************************** 　　;****************************Stepper Motor Drive*************************************** 　　; DESIGN BY BENLADN911 FOSC = 12MHz 2005.05.19 　　;--------------------------------------------------------------------------------- 　　; The driving signal of the stepper motor must be a pulse signal!!! The speed of rotation is proportional to the frequency of the pulse!!! 　　; The step angle of this stepper motor is 7.5 degrees. One circle of 360 degrees requires 48 pulses to complete!!! 　　;--------------------------------------------------------------------------------- 　　; Group A coil corresponds to P2.4 　　; Group B coil corresponds to P2.5 　　; Group C coil corresponds to P2.6 　　; Group D coil corresponds to P2.7 　　; Forward order: Group AB--Group BC--Group CD--Group DA (i.e. one pulse, forward 7.5 degrees) 　　;---------------------------------------------------------------------------------- 　　;----------------------------Forward-------------------------- 　　ORG 0000H 　　LJMP MAIN 　　ORG 0100H 　　MAIN: 　　MOV R3,#144 Forward rotation for 3 circles, a total of 144 pulses 　　START: 　　MOV R0,#00H 　　START1: 　　MOV P2,#00H 　　MOV A,R0 　　MOV DPTR,#TABLE 　　MOVC A,@A+DPTR 　　JZ START Judge A, when A = 0, then jump to START 　　MOV P2,A 　　LCALL DELAY 　　INC R0 　　DJNZ R3,START1 　　MOV P2,#00H 　　LCALL DELAY1 　　;-----------------------------Reverse rotation------------------------ 　　MOV R3,#144 Reverse rotation for one circle, a total of 144 pulses 　　START2: 　　MOV P2,#00H 　　MOV R0,#05 　　START3: 　　MOV A,R0 　　MOV DPTR,#TABLE 　　MOVC A,@A+DPTR 　　JZ START2 　　MOV P2,A 　　CALL DELAY 　　INC R0 　　DJNZ R3,START3 　　MOV P2,#00H 　　LCALL DELAY1 　　LJMP MAIN 　　DELAY: MOV R7,#40 Stepper motor speed 　　M3: MOV R6,#248 　　DJNZ R6,$ 　　DJNZ R7,M3 　　RET 　　DELAY1: MOV R4,#20 2S delay subroutine 　　DEL2: MOV R3,#200 　　DEL3: MOV R2,#250 　　DJNZ R2,$ 　　DJNZ R3,DEL3 　　DJNZ R4,DEL2 　　RET 　　TABLE: 　　DB 30H,60H,0C0H,90H Forward table 　　DB 00 Forward end 　　DB 30H,90H,0C0H,60H Reverse table 　　DB 00 Reverse end