Legacy Circuit Mockups

When to Use This Skill

• User asks to "create a breadboard layout" or "mockup a circuit"
• User wants to visualize component placement on a breadboard
• User needs a visual reference for building a 6502 computer
• User asks to "draw a circuit" or "diagram electronics"
• User wants to create educational electronics visuals
• User mentions Ben Eater tutorials or retro computing projects
• User asks to mockup 555 timer circuits or LED projects
• User needs to visualize wire connections between components

Prerequisites

• Understanding of component pinouts from bundled reference files
• Knowledge of breadboard layout conventions (rows, columns, power rails)

Supported Components

Microprocessors & Memory

Logic & Timer ICs

Passive & Active Components

Grid System

// Standard breadboard grid: 20px spacing
const gridSize = 20;
const cellX = Math.floor(x / gridSize) * gridSize;
const cellY = Math.floor(y / gridSize) * gridSize;

Component Rendering Pattern

// All components follow this structure:
{
  type: 'component-type',
  x: gridX,
  y: gridY,
  width: componentWidth,
  height: componentHeight,
  rotation: 0,  // 0, 90, 180, 270
  properties: { /* component-specific data */ }
}

Wire Connections

// Wire connection format:
{
  start: { x: startX, y: startY },
  end: { x: endX, y: endY },
  color: '#ff0000'  // Wire color coding
}

Step-by-Step Workflows

Creating a Basic LED Circuit Mockup

1. Define breadboard dimensions and grid
2. Place power rail connections (+5V and GND)
3. Add LED component with anode/cathode orientation
4. Place current-limiting resistor
5. Draw wire connections between components
6. Add labels and annotations

Creating a 555 Timer Circuit

1. Place NE555 IC on breadboard (pins 1-4 left, 5-8 right)
2. Connect pin 1 (GND) to ground rail
3. Connect pin 8 (Vcc) to power rail
4. Add timing resistors and capacitors
5. Wire trigger and threshold connections
6. Connect output to LED or other load

Creating a 6502 Microprocessor Layout

1. Place W65C02S centered on breadboard
2. Add 28C256 EEPROM for program storage
3. Place W65C22 VIA for I/O
4. Add 7400-series logic for address decoding
5. Wire address bus (A0-A15)
6. Wire data bus (D0-D7)
7. Connect control signals (R/W, PHI2, RESB)
8. Add reset button and clock crystal

Component Pinout Quick Reference

555 Timer (8-pin DIP)

W65C02S (40-pin DIP) - Key Pins

28C256 EEPROM (28-pin DIP) - Key Pins

Formulas Reference

Resistor Calculations

• Ohm's Law: V = I × R
• LED Current: R = (Vcc - Vled) / Iled
• Power: P = V × I = I² × R

555 Timer Formulas

• Frequency: f = 1.44 / ((R1 + 2×R2) × C)
• High time: t₁ = 0.693 × (R1 + R2) × C
• Low time: t₂ = 0.693 × R2 × C
• Duty cycle: D = (R1 + R2) / (R1 + 2×R2) × 100%

• Pulse width: T = 1.1 × R × C

Capacitor Calculations

• Capacitive reactance: Xc = 1 / (2πfC)
• Energy stored: E = ½ × C × V²

Color Coding Conventions

Wire Colors

LED Colors

Build Examples

Build 1 — Single LED

1. Insert black jumper wire from power GND to row A5
2. Insert red jumper wire from power +5V to row J5
3. Place LED with cathode (short leg) in row aligned with GND
4. Place 220Ω resistor between power and LED anode

Build 2 — 555 Astable Blinker

1. Place 555 IC straddling center channel
2. Connect pin 1 to GND, pin 8 to +5V
3. Connect pin 4 to pin 8 (disable reset)
4. Wire 10kΩ between pin 7 and +5V
5. Wire 100kΩ between pins 6 and 7
6. Wire 10µF between pin 6 and GND
7. Connect pin 3 (output) to LED circuit

Troubleshooting

References

• 555.md - Complete 555 timer IC specification
• 6502.md - MOS 6502 microprocessor details
• 6522.md - W65C22 VIA interface adapter
• 28256-eeprom.md - AT28C256 EEPROM specification
• 6C62256.md - 62256 SRAM details
• 7400-series.md - TTL logic gate pinouts
• assembly-compiler.md - Assembly compiler specification
• assembly-language.md - Assembly language specification
• basic-electronic-components.md - Resistors, capacitors, switches
• breadboard.md - Breadboard specifications
• common-breadboard-components.md - Comprehensive component reference
• connecting-electronic-components.md - Step-by-step build guides
• emulator-28256-eeprom.md - Emulating 28256-eeprom specification
• emulator-6502.md - Emulating 6502 specification
• emulator-6522.md - Emulating 6522 specification
• emulator-6C62256.md - Emulating 6C62256 specification
• emulator-lcd.md - Emulating a LCD specification
• lcd.md - LCD display interfacing
• minipro.md - EEPROM programmer usage
• t48eeprom-programmer.md - T48 programmer reference