QtSpecem

A modern Qt6-based ZX Spectrum 48K emulator with a companion debugger, focused on accuracy and developer-friendly features.

© 2020-2025 Rui Fernando Ferreira Ribeiro
Z80A core emulation © 1991-2025 Rui Fernando Ferreira Ribeiro

Features

• Accurate Z80 Emulation

  • Ported from legacy WSpecem/emz80 emulators
  • Full support for documented and undocumented Z80 functionality (including Q/WZ/MEMPTR registers)
  • Successfully passes all 2023 ZXEALL and Z80TEST validation tests
  • Floating bus behavior implemented (passes Ramsoft's floatspy tests)

• Video & Sound

  • Real-time emulation with accurate timing
  • Timex video modes + ULAplus support
  • Standard Spectrum 48K sound

• Input & Peripherals

  • Full keyboard emulation
  • Gamepad support (Kempston interface currently implemented)
  • Early support for Timex cartridges

• Developer Tools

  • Companion Z80 debugger available at: https://github.com/ruyrybeyro/debugZ80
  • Memory dump and inspection features
  • Snapshot saving for debugging

File Format Support

Category	Supported Formats
Snapshots	SNA, Z80, SNX, SLT, SIT
Tapes	TAP
Memory Files	RAW, ZX, PRG, ACH, ROM, DAT, SCR, SEM

Usage

Basic Operation

• Launch the emulator using ./QtSpecem (Linux), open QtSpecem.app (macOS) or QtSpecem.exe (Windows)
• Drag and drop supported files into the emulator window

Loading Files

• TAP files: After drag & drop, enter LOAD "" in the emulator
• SNA/Z80/other snapshots: Simply drag & drop to instantly load

Controls

• Kempston Joystick: Use ALT + cursor keys or controller gamepad
• Function Keys:
  • F2: Save Z80 snapshots to /tmp (incremental filenames)
  • F5: Save TAP file dump to /tmp (incremental filenames)
  • F12: Save screen snapshot to /tmp (incremental filenames)

Building from Source

Prerequisites

• C++ development environment
• Qt6 development framework (6.2 or newer)
• SDL2 development libraries

macOS

# Install dependencies
brew install qt@6 sdl2

# Clone repository
git clone https://github.com/ruyrybeyro/QtSpecem
cd QtSpecem

# Build command line or load QtSpecem.pro into Qt Creator
# Command line:
qmake    # or ./do_qmake
make

# For deployment as self-contained executable
macdeployqt QtSpecem.app

Linux (Red Hat based)

# Install dependencies
sudo dnf install epel-release git
sudo dnf groupinstall "C Development Tools and Libraries"
sudo dnf install SDL2 SDL2-devel mesa-libGL-devel
sudo dnf install qt6-qtbase qt6-qtbase-devel qt6-qtdeclarative qt6-qtdeclarative-devel qt6-qtmultimedia qt6-qtmultimedia-devel

# Clone repository
git clone https://github.com/ruyrybeyro/QtSpecem
cd QtSpecem

# Build command line or load QtSpecem.pro into Qt Creator
# Command line:
qmake    # or ./scripts/do_qmake.sh
make

Linux (Debian/Ubuntu based)

# Install dependencies
sudo apt install git build-essential libsdl2-dev
sudo apt install qt6-base-dev qt6-base-dev-tools qt6-declarative-dev qt6-multimedia-dev

# Clone repository
git clone https://github.com/ruyrybeyro/QtSpecem
cd QtSpecem

# Build command line or load QtSpecem.pro into Qt Creator
# Command line:
qmake    # or ./do_qmake.sh
make

# If icons don't appear
sudo apt install adwaita-icon-theme breeze-icon-theme

Windows

# Prerequisites:
# - Qt framework with 64-bit MinGW GCC compiler
# - SDL2 development libraries
# - pkg-config for Windows

# 1. Download SDL2 from https://github.com/libsdl-org/SDL
#    (Version 2.x recommended)

# 2. Extract the 64-bit version to a folder (e.g., D:\Qt\projectos\QtSpecem\SDL2)

# 3. Download pkg-config for Windows and add it to system PATH

# 4. Set environment variable, for example:
#    PKG_CONFIG_PATH=D:\Qt\projectos\QtSpecem\SDL2\bin;D:\Qt\projectos\QtSpecem\SDL2\lib\pkgconfig

# 5. Clone repository
git clone https://github.com/ruyrybeyro/QtSpecem
cd QtSpecem

# 6. Build using Qt Creator or command line
#    - Qt Creator: Open the .pro file and build
#    - Command line: Use qmake and mingw32-make

Cross-compiling for Windows (from Ubuntu)

This method is preserved for reference but may require updates for newer Qt versions.

# Add MXE repository
echo "deb [arch=amd64] https://pkg.mxe.cc/repos/apt focal main" | sudo tee /etc/apt/sources.list.d/mxe.list
sudo apt update
sudo apt install mxe-x86-64-w64-mingw64.static-qt6

# Clone and build
PATH=/usr/lib/mxe/usr/bin:$PATH
git clone https://github.com/ruyrybeyro/QtSpecem
cd QtSpecem
/usr/lib/mxe/usr/x86_64-w64-mingw32.static/qt6/bin/qmake
make

If successful, a self-contained binary will be created at release/QtSpecem.exe.

Platform Compatibility

Platform	Tested Versions
macOS	Sequoia
Linux	Debian 12/13, Ubuntu 22.04+, Fedora 38+
Windows	Windows 10, Windows 11

Known Issues

• SHIFT + 0-9 combinations do not work in macOS due to Qt limitations (use Command + 0-9 instead)
• Loading a TAP file introduces temporary patches to the ROM, which will cause ROM checksum validation to fail
• Some ULAplus applications may display color artifacts

Project Vision

QtSpecem aims to serve as a comprehensive emulator framework for hosting independent utilities that run as separate programs on the same machine. The current implementation includes a command-line debugger, with plans to expand the toolkit for ZX Spectrum developers and enthusiasts.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.

Acknowledgments

• Thanks to all contributors and testers
• Thanks to Emanuel Santos for helping making it compile under Windows
• Original Z80 documentation authors