How to Interface Stepper Motor with PIC16F877A Microcontroller?

PIC16F877A Pinout

Symbol

PIC16F877A Symbol

Footprint

PIC16F877A Footprint

3D Model

PIC16F877A 3D Model

The following diagram of PIC16F777A is given below

PIC16F877A Block Diagram

Microchip Technology PIC16F877A-I/P technical specifications, attributes, parameters and parts with similar specifications to Microchip Technology PIC16F877A-I/P.

A stepper motor is a type of motor that uses electrical pulses to generate mechanical movement. A stepper motor, unlike all other motors, moves in steps. The motor's steps are measured in degrees and can vary depending on the application. It takes one step at a time, and each step is the same size as the previous one.

A stepper motor has three excitation modes: wave drive, full drive, and a half drive. Only one winding is activated at a time in wave drive mode, whereas two phases are energized at the same time in full drive mode. In both wave and full drive modes, however, the number of steps is the same. Half drive mode combines wave drive and full drive, i.e. it alternately energizes one and two phases.

The following is a circuit diagram of a stepper motor connecting with a pic16f877a microcontroller:

Stepper Motor interfacing with PC16F877A microcontroller

The ULN2003 transistor array chip is the simplest way to connect a stepper motor to a Pic16F877A microcontroller. This IC  is used for high current torque motors and has seven Darlington transistor drivers. The four input pins  (1B, 2B, 3B, 4B) of the ULN2003  are linked to the lowest significant bits of the microcontroller's PORTD, while the output pins (1C, 2C, 3C, 4C  ) are connected to the stepper motor 's 'live' pins, as shown in the circuit diagram.
The stepper motor 's 'common' pins, as well as the ULN2003  's 'COM' pin, are connected to a 12V  battery supply.

In the mikroC code editor window, type the following code:

1. void main()

2. {

3. TRISD = 0b0000000; // PORT D as output port

4. PORTD = 0b1111111;

5. do

6. {

7. PORTD = 0b00000011;              // energizing two phases at a time

8. Delay_ms(500); // delay of 0.5s

9. PORTD = 0b00000110;

10. Delay_ms(500);

11. PORTD = 0b00001100;

12. Delay_ms(500);

13. PORTD = 0b00001001;

14. Delay_ms(500);

15. }while(1); // loop executed infinite times

16. }

The code above shows how a stepper motor in full drive mode works. The above code will need to be tweaked somewhat for wave drive and half drive modes. The circuit diagram, on the other hand, remains unchanged. The controller's PORTD has been designated as an output port, which is fed to the ULN2003 driver IC. The input pins of the IC receive the combination of bits from the controller's PORTD, allowing it to turn on and off the motor's various coils.

Stepper motors are widely employed in our everyday lives. Automobiles, digital photocopiers, computer printers, and other home appliances all use them to move the print head carriage. Industrial machines, security, and medical devices all employ stepper motors.