đŸŽ¯ Mistic VLSI Layout Tool

Overview

Mistic is a powerful VLSI (Very Large Scale Integration) layout tool designed for creating and analyzing digital circuit layouts. It provides an intuitive interface for designing CMOS circuits with multiple layers including polysilicon, diffusion regions, metal interconnects, and more.

🎨 Available Layers

Polysilicon
Gate material for transistors
N+ Diffusion
NMOS transistor regions
P+ Diffusion
PMOS transistor regions
Contact/Via
Layer connections
Metal
Interconnect wiring
VCC/GND
Power connections
Probe
Test points

🔌 Contact Placement Rules

ℹī¸ Important Rule: Only one contact type can exist in a grid cell at any time. When you place a new contact (Probe, VCC, GND, or Via), any existing contact in that cell will be automatically cleared.

The following contact types are mutually exclusive:

💡 Tip: This automatic clearing ensures clean circuit layouts and prevents conflicts between different contact types. You can always place a different contact type in the same location by simply clicking on it.

⌨ī¸ Command Line Interface

The tool features a powerful command-line interface at the bottom of the screen for precise control and automation.

Basic Commands

clear - Clear the entire canvas
redraw - Redraw all tiles
help - Show available commands

Drawing Commands

draw <layer> at (x,y) - Single point placement
draw <layer> from (x,y) to (x,y) - Rectangle drawing

Examples

draw metal at (5,5) - Place metal at coordinate (5,5)
draw polysilicon from (3,3) to (6,3) - Draw polysilicon line from (3,3) to (6,3)
draw via at (5,1) - Place a via at (5,1)
draw VCC at (1,1) - Place VCC at (1,1)
draw probe at (10,10) - Place a probe at (10,10) (will prompt for label)
draw GND at (15,15) - Place ground at (15,15)

Layer Aliases

n+ = N+ diffusion
p+ = P+ diffusion
via = contact

🖱ī¸ Mouse Controls

🔧 Special Features

Assignment System

For authenticated users, the tool includes an assignment system with automatic grading. Complete assignments to test your circuit designs and receive grades.

NOT Gate Button

Click the Not button to automatically draw a complete NOT gate circuit with all necessary components.

Read Circuit

Use the Read Circuit button to generate draw commands that can replicate your current circuit design. This feature also provides speech synthesis for accessibility.

Layer Visibility

Click the Layers button to toggle layer visibility and control which layers are displayed.

💡 Tips & Best Practices

💡 Tip: Use the command line for precise placement and to create repeatable designs. The commands you type can be saved and reused later.
💡 Tip: Start with power connections (VCC/GND) and work your way down to the signal layers for better organization.
💡 Tip: Use the "Read Circuit" feature to verify your design and get the exact commands needed to recreate it.
💡 Tip: When placing probes, use meaningful labels like "A" for input and "Q" for output to make circuit analysis easier.

⚠ī¸ Important Notes

⚠ī¸ Warning: Contact/via layers only support single-point placement with the "at" command. They cannot be drawn as rectangles.
⚠ī¸ Warning: The grid size is currently 30x30. Coordinates outside this range will generate an error.
⚠ī¸ Warning: Placing a new contact will automatically remove any existing contact in the same grid cell. This is by design to maintain circuit integrity.

🔍 Troubleshooting

📚 Advanced Usage

For complex circuits, consider:

🎓 Assignment Features

For authenticated users, the tool includes:

Learning Resources

Happy circuit designing! 🚀

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About This Tool

This MISTIC VLSI tool is part of the Computer Architecture for Everybody course, available at www.ca4e.com