C*Base PETSCII Viewer

Visual Studio Code extension for Commodore 64 PETSCII files

Renders C64 BBS sequence files directly in VS Code using the embedded C64 character ROM — no font installation required.

Part of the C*Base Larry Mod v3.1 development package.

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Features

• C64 bitmap rendering via embedded character ROM — zero anti-aliasing, pixel-accurate output
• Full 16-color palette with six presets sourced from authoritative references
• Uppercase/graphics and lowercase charset toggle
• MCI command display toggle (£-commands and @:-commands)
• CLS ($93) break indicator (.seq only)
• Variable column width with drag-to-resize (.seq only)
• VS Code theme-aware background
• Global settings persistence across all files in the workspace

File types

• .seq — PETSCII sequence files from C64 BBS systems (C*Base format)
• .petmate — Petmate JSON screen files with multi-page support

Getting started

1. Installation
2. Quick start

Documentation

• .seq viewer controls
• .petmate viewer controls
• Color palettes
• PETSCII control codes
• MCI commands
• Rendering
• Development and testing

Related tools

• BPP+ Preprocessor — Source-to-source compiler for C64 BASIC v2
• BPP+ Syntax Highlighting — Syntax highlighting and snippets for BASIC v2 and BPP+

GitHub repository

Source code, issue tracking, and releases: GitHub.