A professional serial terminal with dual ASCII/HEX view, real-time plotting, binary/frame decoding, data converter, and configurable macro buttons. Built with Python and PyQt5.

• Auto-detect serial ports with device name and VID:PID display
• Configurable baud rate (9600 to 921600), data bits, parity, stop bits, flow control
• Auto-reconnect when an unplugged USB device reappears (View > Auto-Reconnect)
• Visual connection indicator (DB-9 connector icon: green = connected, red = disconnected)
• Live status bar with RX/TX throughput (bytes/sec), totals, and baud rate
• Timestamped logging to file (Record button / Ctrl+R), one log line per device line

• ASCII and HEX views side by side, updated in real-time (batched at ~30 fps, so the GUI stays responsive at high baud rates)
• Color-coded: red for received data, blue for sent data
• Scroll position and text selection are preserved while data streams in; the view only auto-scrolls when already at the bottom
• Search/highlight in scrollback (Ctrl+F)
• Resizable splitter between the plot and data views

• Three send modes: ASCII, HEX, BINARY
• Configurable line endings: None, LF, CR, CR+LF
• Command history with Up/Down arrow keys
• 8 macro buttons for quick-send (right-click to edit label and payload)

• 1 to 12 channels with auto-scaling Y-axis
• Configurable scrolling window (10 to 10,000 points)
• High-throughput rendering: samples are batched into preallocated numpy buffers and each curve redraws once per display frame (~30 fps) with peak-preserving downsampling, independent of the incoming sample rate. Binary streams are decoded vectorized (np.frombuffer, no per-sample Python), so the plot keeps up with multi-MB/s USB-CDC sources, far beyond any real serial baud rate
• Dual Y-axes: right-click a legend entry to move a channel to Y2 (dashed)
• Per-channel show/hide toggle checkboxes below the plot
• Per-channel scale / offset / unit (right-click a legend entry): plotted value = raw x scale + offset, with the unit shown in the legend and crosshair
• Time-based X-axis ("Time X" checkbox): label the axis in seconds using the measured sample rate, instead of the sample index
• Math/computed channels with numpy expressions (e.g. ch0 * ch1); expressions are validated against a whitelist and compiled once
• FFT frequency spectrum view (Hann window, amplitude-normalized)
• Pause button and oscilloscope-style trigger mode (level + edge, centered)
• Crosshair cursor showing all channel values at the mouse position
• Right-click legend entries to rename channels or change colors
• Right-click plot area for axis settings (auto-range, manual Y-axis limits)
• Clear Plot button to reset all data
• Export plot as PNG image
• Export plot data as CSV with channel name headers

ASCII (default) -- Parses newline-delimited text values for plotting.

Supports labeled values (e.g., temp:23.5,hum:45.2). A non-numeric or empty field is plotted as a gap so the remaining values stay on their own channels.

Binary Stream -- Decodes continuous raw binary data.

Each sample is channels x sizeof(type) bytes. In this mode, the left panel shows color-coded decoded channel values.

Custom Frame -- Decodes framed binary packets.

Frame structure: [Start Byte(s)] [Optional Size Field] [Payload] [Optional Checksum]

• Real-time conversion between HEX, ASCII, Decimal, and Binary
• 12 conversion combinations
• Input/output with arrow indicator

• All settings saved automatically to AxxTerm_settings.json (writes are debounced so rapid changes coalesce into one disk write)
• Includes: serial port config, decode mode, plot settings, channel names/colors/axes/visibility, math channels, macros, dark mode, and window/splitter geometry
• File > Save Settings / Load Settings for explicit save/load to custom files

• Python 3.8+
• PyQt5 >= 5.15
• pyqtgraph >= 0.13
• NumPy >= 1.24

git clone https://github.com/AxxAxx/AxxTerm.git
cd AxxTerm
pip install -r requirements.txt
python AxxTerm.py

No Python installation is needed on the target machine. Build a single portable executable with PyInstaller:

pip install pyinstaller
pyinstaller --onefile --windowed --name AxxTerm --clean AxxTerm.py

This creates dist/AxxTerm.exe. Copy it anywhere and run.

• The .exe resolves config files relative to the executable location, not the temp folder
• First launch creates AxxTerm_settings.json next to the executable when you change any setting
• File size is typically 30-50 MB (includes Python runtime and all dependencies)

The tests run headless via Qt's offscreen platform (no display needed) and use a throwaway settings file:

QT_QPA_PLATFORM=offscreen python tests/test_axxterm.py

On Windows PowerShell:

$env:QT_QPA_PLATFORM = "offscreen"; python tests/test_axxterm.py

They cover the binary/frame/ASCII decoders (including chunk boundaries and resync), the hex formatter, the math-expression sandbox, per-channel scale/offset, the time-axis sample-rate measurement, and a settings round-trip.

AxxTerm_settings.json is auto-created and contains:

{
  "dark_mode": false,
  "auto_reconnect": true,
  "window": { "geometry": "<hex>", "splitter": [300, 400] },
  "plot": {
    "mode": "ASCII",
    "num_channels": 4,
    "num_points": 100,
    "show_plot": false,
    "show_fft": false,
    "delimiter": "Auto",
    "channel_names": {},
    "channel_colors": {},
    "channel_axes": {},
    "channel_scale": {},
    "channel_offset": {},
    "channel_units": {},
    "hidden_channels": [],
    "x_time_mode": false,
    "y_auto_scale": true,
    "math_channels": [],
    "binary": { "data_type": "float32", "endianness": "little" },
    "frame": { "sync_word": "AA", "size_field": "fixed", "frame_size": 12, "checksum": false }
  },
  "serial": {
    "baud_rate": "115200",
    "data_bits": 3,
    "parity": 0,
    "stop_bits": 0,
    "flow_control": 0
  },
  "macros": [
    { "label": "0x7F", "hex": "7F" }
  ]
}

MIT License. See LICENSE for details.