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How to Interface Stepper Motor with 8051 Development Board

8051 Development Board

The 8051 Development board is specifically designed to help students to master the required skills in the area of embedded systems. The kit is designed in such way that all the possible features of the microcontroller will be easily used by the students. The kit supports in system programming (ISP) which is done through serial port.

NXP’s 8051 (AT89V51RD2), 8051 Development Kit is proposed to smooth the progress of developing and debugging of various designs encompassing of speed 8-bit Microcontrollers.

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 ULN2003 array. So when the microcontroller is giving pulses with particular frequency to ULN2003, the motor is rotated in clockwise or anticlockwise.

Interfacing Stepper Motor to Microcontroller


Interfacing Stepper Motor with 8051

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

The 8051 Development Board has four numbers of I/O port lines, connected with I/O Port lines (P0.0 – P0.3) to rotate the stepper motor. ULN2003 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

Source Code

The Interfacing stepper motor control with 8051 program is very simple and straight forward, that control the stepper motor in clockwise, counter clockwise and also a particular angular based clockwise by using switches. The I/O port lines are used to generate pulses for stepper motor rotations. C programs are written in Keil software.

C Program to control stepper motor using 8051


Title : Program to control stepper motor rotations


#include <reg51.h> //Define 8051 registers #include<stdio.h> void DelayMs(unsigned int); //Delay function //----------------------------------// Main Program//---------------------------------- void Clockwise (void) { unsigned int i; for (i=0;i<30;i++) { P0 = 0x01;DelayMs(5); //Delay 20msec P0 = 0x02;DelayMs(5); P0 = 0x04;DelayMs(5); P0 = 0x08;DelayMs(5); } } void AntiClockwise (void) { unsigned int i; for (i=0;i<30;i++) { P0 = 0x08;DelayMs(5); //Delay 20msec P0 = 0x04;DelayMs(5); P0 = 0x02;DelayMs(5); P0 = 0x01;DelayMs(5); } } void main (void) { P0 = 0; //Initialize Port0 while(1) //Loop Forever { Clockwise (); DelayMs (100); P0 = 0; AntiClockwise (); DelayMs (100); P0 = 0; } } //--------------------------------- // Delay Function//--------------------------------- void DelayMs(unsigned int n) { unsigned int i,j; for(j=0;j { for(i=0;i<800;i++); } }