8051 – TRAINER BOARD

PS-TRAINER-8051 trainer kit is proposed to smooth the progress of learning and developing designs of MCU from Intel and NXP. It has the facility to connect PC’s 101/104 Keyboard, to enter user programs in Assembly languages. Serial communication achieved using 8051. It also supports C & assembly language in standalone kit (P89V51RD2). It’s designed as to facilitate On-board Programmer for NXP 8051 MCU through ISP on serial port.

STEPPER MOTOR

A stepper motor is a brushless, synchronous electric motor that converts digital pulses into mechanical shaft rotation. Every revolution of the stepper motor is divided into a discrete number of steps, and the motor must be sent a separate pulse for each step.

INTERFACING STEPPER MOTOR

Fig. 1 shows how to interface the Stepper Motor to microcontroller. As you can see the stepper motor is connected with Microcontroller output port pins through a ULN2803A array. So when the microcontroller is giving pulses with particular frequency to ls293A, the motor is rotated in clockwise or anticlockwise.

INTERFACING STEPPER MOTOR WITH 8051

We now want to control a stepper motor in 8051 trainer kit. It works by turning ON & OFF a four I/O port lines generating at a particular frequency.

The 8051 trainer kit has three numbers of I/O port connectors, connected with I/O Port lines (P1.0 – P1.7),(p3.0 – p3.7) to rotate the stepper motor. Ls293d is used as a driver for port I/O lines, drivers output connected to stepper motor, connector provided for external power supply if needed.

PIN ASSIGNMENT WITH 8051

CIRCUIT DIAGRAM TO INTERFACE STEPPER MOTOR WITH 8051

ASSEMBLY PROGRAM TO RUN THE STEPPER MOTOR USING 8051

ADDRESS	OP CODE	MNEMONICS	COMMENTS
8500	74 80	MOV A, #80H	Initialize 80HEX value to Accumulator
8502	90 40 03	MOV DPTR, #4003	Move 4003   to R1 register
8505	F0	MOVX @DPTR, A	Store ACC value into R1 register
8506	90 40 00	MOV DPTR, #4000	Move 4000   to R1 register
8509	74 66	MOV A, #66H	Move 66HEX value   to Accumulator
850B	F0	AGAIN:MOVX@DPTR, A	In AGAIN, Store ACC value into R1
850C	03	RR A	Rotate sequence for clockwise
850D	B1 11	ACALL DELAY	wait
850F	80 FA	SJMP AGAIN	Short Jump into AGAIN
8511	7D 05	DELAY:   MOV R5, #5	In DELAY, Load 5 value into R5
8513	7C 0F	H3:         MOV R4, #0F	In H3, Load 0F value into R4 register
8515	7B 43	H2:         MOV R3, #43	In H2, Load 43 value into R3 register
8517	DB FE	H1 :       DJNZ R3, H1	H1, Decrement R0& check if it’s not 0
8519	DC FA	DJNZ R4, H2	Decrement R4& Check if it’s not 0
851B	DD F6	DJNZ R5, H3	Decrement R5& Check if it’s not 0
851D	22	RET	Return

NOTE: To turn the motor in the reverse direction enter as (Rl A instead of RR A). The schematics sections given is, stepper motor connected to port 1 and the sample program is given based on 8255.