EE 322 Lab 3

1
EE 322 Lab 3

• 1/31/08
• Simple Stepper Motor
• Report Due 2/5/08

2
Administrative

• "We cannot use the thinking that got us here to
  solve the problem, that is the reason we have the
  problem."
• Albert Einstein

3
Prelab

• Review the details of this lab carefully
• Design a Stepper Motor solution in VHDL
• Inputs and outputs are described in slide 9
• State Logic is described in slides 5, 6, and 7
• Express your design as done in class and Lab 1
• Use a block diagram to show details of the
  entity and architecture sections
• Use a state diagram to describe the stepping
  sequence in the synchronous logic portion of your
  architecture description
• Bring your design to Lab

4
Unipolar Stepper Motor

• 4 Windings
• Rotor Movement is a result of stepping through a
  sequence of energizing and de-energizing the
  windings
• Rotor Movement can be reversed by reversing the
  step sequence

5
Winding Arrangement
6
Forward Rotation Truth Table
7
Reverse Rotation Truth Table
8
Lab Assignment Objective

• Implement a Unipolar Stepper Motor Driver using
  the 22V10 as the state machine
• Implement a 4 phase step sequence that
• Can be stepped forward or back
• Can be disabled (disable all windings so the
  motor can be turned by hand)

9
Entity Description

• Inputs
• Enable
• Direction
• Clock

• Outputs
• PhaseA
• PhaseB
• PhaseC
• PhaseD

10
Architecture Description

• Signal StateCounter(1 down to 0)
• If (direction 1) then increment, else decrement
• If(StateCounter 0) then
• PhaseA 1
• PhaseB 0
• PhaseC 0
• PhaseD 1
• Etc.