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HALO XYZ Plotter Simulation

Explore a three-axis XYZ plotter motion system with independent stepper control, homing, end-limit detection, GPIO control, and simulator-based waveform visualization.

Robotics XYZ Plotter 3-Axis Stepper GPIO
Overview Theory Architecture Source Code Pinout Examples

Overview

The HALO XYZ Plotter is a 3-axis virtual hardware system designed for learning, simulating, and validating digital control of a plotter-style motion system.

The system provides three independent stepper channels for X, Y, and Z motion. Each axis includes dedicated control signals and hardware limit switches for homing and end-of-travel detection.

Each stepper driver uses ENABLE, DIR, and STEP control signals. Because the required control signals exceed the capacity of a single 8-bit GPIO block, the system distributes the signals across GPIO0 and GPIO1.

Key Features

  • Three independent stepper channels
  • X-axis motion control
  • Y-axis motion control
  • Z-axis motion control
  • ENABLE, DIR, and STEP control signals
  • Home limit switches for all three axes
  • End-limit switches for all three axes
  • Two GPIO ports for control signal expansion
  • Integrated simulator
  • Waveform visualization for debugging motion behavior

Axis Summary

HALO XYZ Plotter Axis Structure
X Axis
Stepper X
→
Y Axis
Stepper Y
→
Z Axis
Stepper Z
→
Plotter

Applications & Use Cases

  • XYZ plotter motion control
  • Stepper motor control experiments
  • Digital motion-control learning
  • Axis homing experiments
  • End-of-travel limit detection
  • GPIO-based motion control
  • Waveform debugging
  • Educational robotics and embedded control
HALO XYZ Plotter Control Flow
Controller
→
GPIO0 / GPIO1
→
X / Y / Z
→
Stepper Drivers
→
XYZ Plotter

Theory

The HALO XYZ Plotter uses three independent stepper-driven axes to control movement along the X, Y, and Z directions.

Each axis is controlled using three digital signals: ENABLE, DIR, and STEP. Hardware HOME and END switches provide position boundary detection.

Motion Control

XYZ Motion Control
X Axis
+
Y Axis
+
Z Axis
→
Plotter Position

Stepper Control 

ENABLE → Enables the stepper driver

DIR    → Selects the direction of motion

STEP   → Generates step pulses

HOME   → Detects the home position

END    → Detects the end-of-travel position

Architecture

The HALO XYZ Plotter consists of a controller, two GPIO register blocks, three stepper motor drivers, three motion axes, and hardware limit switches.

Controller
→
GPIO0
→
X Axis

GPIO0
→
Y Axis
→
Stepper Y

GPIO1
→
Z Axis
→
Stepper Z

Control Signals

  • ENABLE — Enables the stepper motor driver
  • DIR — Selects the direction of axis motion
  • STEP — Generates step pulses
  • HOME — Detects the axis home position
  • END — Detects the axis end limit

Source Code

Example GPIO configuration for the HALO XYZ Plotter controller.

GPIO0 Configuration 

// GPIO0: Outputs on bits 0,1,2,5,6,7
// Inputs on bits 3,4

WRITE_REGISTER(0x40000000, 0xE7);

GPIO1 Configuration 

// GPIO1: Outputs on bits 2,3,4
// Inputs on bits 0,1,5,6
// Bit 7 unused

WRITE_REGISTER(0x40000400, 0x1C);

X Axis Control 

X_ENABLE → Enable X stepper
X_DIR    → Select X direction
X_STEP   → Generate X step pulse
X_HOME   → Detect X home
X_END    → Detect X end limit

Y Axis Control 

Y_ENABLE → Enable Y stepper
Y_DIR    → Select Y direction
Y_STEP   → Generate Y step pulse
Y_HOME   → Detect Y home
Y_END    → Detect Y end limit

Z Axis Control 

Z_ENABLE → Enable Z stepper
Z_DIR    → Select Z direction
Z_STEP   → Generate Z step pulse
Z_HOME   → Detect Z home
Z_END    → Detect Z end limit

Pinout

GPIO register mapping for the X, Y, and Z stepper controlled axes and their hardware limit switches.

GPIO0

Bit 0
X_ENABLE
Bit 1
X_DIR
Bit 2
X_STEP
Bit 3
X_HOME

Bit 4
X_END
Bit 5
Y_ENABLE
Bit 6
Y_DIR
Bit 7
Y_STEP

GPIO1

Bit 0
Y_HOME
Bit 1
Y_END
Bit 2
Z_ENABLE
Bit 3
Z_DIR

Bit 4
Z_STEP
Bit 5
Z_HOME
Bit 6
Z_END
Bit 7
Unused

Register Addresses

GPIO0 MODE
0x40000000
GPIO0 IN
0x40000004
GPIO0 OUT
0x40000008

GPIO1 MODE
0x40000400
GPIO1 IN
0x40000404
GPIO1 OUT
0x40000408

Examples

Example exercises for the HALO XYZ Plotter.

  • Move the X axis using stepper pulses
  • Move the Y axis using stepper pulses
  • Move the Z axis using stepper pulses
  • Perform X-axis homing
  • Perform Y-axis homing
  • Perform Z-axis homing
  • Detect X-axis end limits
  • Detect Y-axis end limits
  • Detect Z-axis end limits
  • Generate coordinated XYZ motion
  • Analyze stepper control waveforms
  • Debug motion behavior using the waveform viewer