Legacy Circuit Mockups

Legacy circuit mockups

Create breadboard circuit mockups and visual diagrams for retro computing and electronics projects. Translate the requested circuit into component placement, pin-aware wiring, color conventions, and an HTML5 Canvas-style representation that a builder can follow.

When to invoke

• "Create a breadboard layout for this circuit."
• "Mock up a 6502 computer on a breadboard."
• "Draw a 555 timer LED blinker diagram."
• "Visualize the wire connections between these components."
• "Make an educational electronics diagram for a Ben Eater-style build."

Prerequisites and context

• Use bundled pinout and build references when exact chip behavior matters.
• Apply breadboard layout conventions: rows, columns, center channel, power rails, and consistent grid spacing.
• Treat diagrams as build aids, not certified electrical designs; preserve component polarity, power, and ground explicitly.

Supported components

Canvas model

Use a deterministic grid and object model so the diagram can be rendered or recreated.

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

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

Pinout quick reference

Build patterns

Formulas and conventions

Gotchas

• LED polarity matters: anode goes toward positive supply through a resistor; cathode goes toward ground.
• IC orientation matters: pin 1 and the notch/dot determine all subsequent pin positions.
• Power rails may be split: show jumpers that bridge rail breaks when the mockup assumes continuous +5V or GND.
• 6502 buses get unreadable fast: bundle address, data, and control wires by color and label bus ranges instead of drawing ambiguous spaghetti.

Troubleshooting

Progressive disclosure and bundled resources

Load bundled references only when the component, emulator, or build step is relevant.

• references/555.md: complete 555 timer IC specification.
• references/6502.md: MOS 6502 microprocessor details.
• references/6522.md: W65C22 VIA interface adapter.
• references/28256-eeprom.md: AT28C256 EEPROM specification.
• references/6C62256.md: 62256 SRAM details.
• references/7400-series.md: TTL logic gate pinouts.
• references/assembly-compiler.md: assembly compiler specification.
• references/assembly-language.md: assembly language specification.
• references/basic-electronic-components.md: resistors, capacitors, switches.
• references/breadboard.md: breadboard specifications.
• references/common-breadboard-components.md: comprehensive component reference.
• references/connecting-electronic-components.md: step-by-step (by-step) build guides with ceramic/electrolytic capacitor notes.
• references/emulator-28256-eeprom.md: emulating 28256-eeprom specification.
• references/emulator-6502.md: emulating 6502 specification.
• references/emulator-6522.md: emulating 6522 specification.
• references/emulator-6C62256.md: emulating 6C62256 specification.
• references/emulator-lcd.md: emulating a LCD specification.
• references/lcd.md: LCD display interfacing.
• references/minipro.md: EEPROM programmer usage.
• references/t48eeprom-programmer.md: T48 programmer reference.

Output template

## Circuit mockup — <circuit name>

**Status:** ready | needs clarification | blocked
**Format:** HTML5 Canvas plan | breadboard layout | wiring table
**Assumptions:** <supply voltage, breadboard type, component variants>

### Components
| Ref | Component | Value/model | Placement | Notes |
| --- | --- | --- | --- | --- |
| U1 | NE555 | timer IC | center channel, rows <range> | notch points left |

### Wiring
| Wire | From | To | Color | Purpose |
| --- | --- | --- | --- | --- |
| W1 | +5V rail | U1 pin 8 Vcc | Red | power |

### Canvas model
```javascript
<component and wire objects>
```

### Build notes
- <polarity, pinout, formula, or troubleshooting note>

Quality gate

• Every IC has model, package, orientation, power pins, and ground pins shown.
• LED, electrolytic capacitor, diode, and power polarity are explicit.
• Current-limiting resistors are present for LED loads.
• Wires use the color convention for power, ground, clock, buses, and controls.
• Bus labels such as A0-A15, D0-D7, R/W, PHI2, and RESB match the pinout.
• Formulas used for timing or resistors are shown with the chosen component values.
• Any referenced bundled file exists under references/ and was loaded only when needed.