User manual

Example Projects

2.3.7 Project 7: Stepper Motor Control: Single Stepping, Half

Stepping and Microstepping

This project demonstrates the various ways to drive a bipolar stepper motor. There are

several ways to step a stepper motor, the most basic of which is single stepping, or

moving the motor in one-step increments. If a motor is specified as a 7.5

degrees-per-step motor, then single stepping the motor will result in moving the shaft

of the motor 7.5 degrees per step. Half stepping the same motor would result in a 3.75

degrees step.

Torque and current are linearly related for a stepper motor. Therefore, if two sinusoidal

currents are applied to the windings, offset by a 90 degree phase shift relative to one

another, then the stepper motor will have constant torque as it turns. This results in a

very smooth rotation of the shaft. Applying current to the windings in this way is referred

to as sine-cosine microstepping.

Objectives

1. Single-step a stepping motor.

2. Half-step the motor.

3. Micro-step the motor.

Applicable Technical Documents

Stepping Motor Fundamentals Application Note, AN907 (DS00907)

Stepper Motor Control Using the PIC16F684 Application Note, AN906 (DS00906)

Jumper Configuration

• AN0 (J13) to POT1 (J4)

• RA4 (J13) to SW2 (J4)

• RD7 (J10) to P1 (J1)

• RD6 (J10) to P2 (J1)

• RD5 (J10) to P3 (J1)

• RD4 (J10) to P4 (J1)

• CCP1 (J10) to PWM1 (J1)

• CCP2 (J10) to PWM3 (J1)

• Place three shunts (two pin jumpers) vertically on J2 where it is labeled “Connect

for Full-Bridge”.

• Place three shunts (two pin jumpers) vertically on J3 where it is labeled “Connect

for Full-Bridge”.

• Connect the BROWN lead of the stepper motor to Drive 1 (P9).

• Connect the ORANGE lead of the stepper motor to Drive 2 (P10).

• Connect the RED lead of the stepper motor to Drive 3 (P12).

• Connect the YELLOW lead of the stepper motor to Drive 4 (P11).

• Connect the right and center pins of JP8 using a shunt.