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Welcome to Zero Board Computer

The Zero Board Computer (ZBC) is a platform-agnostic hardware and system specification designed for bringing up compilers, debuggers, and libraries in a highly controlled, deterministic environment.

What is ZBC?

ZBC provides a minimal, standardized computing platform consisting of:

• A CPU (any architecture from 8-bit to 128-bit and beyond)
• RAM (dynamically sized based on address space)
• MC6847 Text Display (32×16 character console)
• RIFF-Based Semihosting Peripheral (memory-mapped host I/O)

With these four simple components and just two device drivers (display + semihosting), developers get immediate access to full libc support including file I/O, console output, and timing services—without the complexity of a full operating system.

Key Features

• Platform-Agnostic: Works on any CPU architecture
• Minimal Complexity: Only two well-defined devices to support
• Full libc Support: File I/O, console, timing via semihosting
• Deterministic: Predictable, repeatable execution environment
• Universal: Can be built in hardware (FPGA/ASIC), emulators, or simulators
• Open Specification: Not tied to any specific implementation

Getting Started

• What is Zero Board Computer? - Comprehensive introduction
• Getting Started - First steps with ZBC
• Design Goals and Use Cases - Why ZBC exists

Documentation

Foundation	Technical Documentation	Implementation	Reference
What is Zero Board Computer? Design Goals and Use Cases Getting Started Key Concepts	Architecture System Overview Memory Layout and Addressing Video Display (MC6847) Interrupt System (JP1 Jumper) Semihosting Semihosting Overview Device Registers RIFF Protocol Fundamentals Operation Modes	MAME Implementation Overview Hardware Implementation Guide Emulator Implementation Guide Running ZBC Systems Writing Programs for ZBC Troubleshooting	Complete Register Reference Memory Map Examples Syscall Quick Reference RIFF Chunk Reference Supported CPU List Glossary

Use Cases

• Compiler Bring-Up: Test code generation for new CPU architectures
• Debugger Development: Controlled environment for debugging tools
• Library Porting: Validate libc and runtime libraries
• CPU Emulator Testing: Standardized test harness (MAME uses ZBC to test 300+ CPUs)
• Education: Learn assembly and systems programming with immediate I/O feedback

Project Information

• License: Creative Commons Attribution 4.0 (CC BY 4.0)
• Specification: Platform-agnostic, implementation-independent
• Reference Implementation: MAME (Multiple Arcade Machine Emulator)
• Primary Use: Development, testing, and education

Zero Board Computer Documentation
Foundation	Architecture	Semihosting	Implementation	User Docs	Reference
What is Zero Board Computer? Design Goals and Use Cases Getting Started Key Concepts	System Overview Memory Layout and Addressing Video Display (MC6847) Interrupt System (JP1 Jumper) CPU Support and Initialization Quickload System	Semihosting Overview Device Registers RIFF Protocol Fundamentals CNFG Chunk CALL and PARM Chunks DATA Chunk RETN and ERRO Chunks Operation Modes Syscall Reference	MAME Implementation Overview zbcgen Tool Hardware Implementation Guide Emulator Implementation Guide Implementation Checklist	Running ZBC Systems Writing Programs for ZBC Using Semihosting Services Troubleshooting	Complete Register Reference Memory Map Examples Syscall Quick Reference RIFF Chunk Reference Supported CPU List Error Codes and Errno Values Glossary