A VT52 emulator in the browser, for use with the Feersum Technology MicroBeast z80 retrocomputer.
Plug in your retrocomputer then visit https://blowback.github.io/beasTTY/ in a Chrome-based browser.
You may not. Only Chrome supports WebSerial, upon which this TTY is based.
Render a crips modern display with "Clean" or go for a more vintage CRT look with "Green", "Amber" or "White".
The special "Graphics Mode" characters are not available in "Clean" mode, which uses Jetbrains Mono Regular or falls back to whatever monospaced font is locally available.
As well as it's own builtin 16x8 font, the TTY includes a version of the original VT52 font,
including the special "Graphics mode" characters accessible by ESC F. This font comes from
the fritzm/vt52 github repo.
The fonts Cushion, Insigbyte, and You Square come from the excellent ZX Origins where there are many many more examples of DamienG's meticulous work.
All shortcuts are intercepted only when the terminal area has focus. Bare keys (no modifier listed) encode normally to the host as VT52 bytes — the table only lists chords and special keys with UI-side meaning.
| Shortcut | Action |
|---|---|
| Ctrl+Alt+T | Toggle theme (CRT ↔ Clean) |
| Ctrl+= / Ctrl++ | Zoom in (1× → 4×) |
| Ctrl+- | Zoom out |
| Ctrl+0 | Reset zoom to 1× |
| Ctrl+Shift+C | Copy current selection to clipboard |
| Ctrl+Shift+V | Paste from clipboard (subject to rate limit) |
| Ctrl+Shift+Esc | Clear an established selection |
| Shortcut | Action |
|---|---|
| Shift+PageUp | Scroll back one page |
| Shift+PageDown | Scroll forward one page |
| Shift+Home | Jump to oldest scrollback line |
| Shift+End | Snap to live tail (cancel scroll-back) |
Any keypress that produces an outbound byte while scrolled-back also snaps the viewport to the live tail before the byte is sent.
Esc is context-sensitive. The first matching rule wins:
| Context | Effect of Esc |
|---|---|
| Ctrl+Shift+Esc (any time) | Clear established selection |
| Mid-drag (mouse button still down) | Cancel the in-flight selection |
| Paste pump still running | Cancel paste |
| Otherwise | Encode 0x1B to host |
Chromium claims Ctrl+W (close tab), Ctrl+N (new window), Ctrl+T (new tab)
and Ctrl+Shift+T (reopen closed tab) at the OS layer. Map those control codes
to a different chord on the MicroBeast side if you need them.
Yes, download the repo then build it:
scripts/build.sh
then run it with:
python3 -m http.server -d www 8000