mirror of
https://git.k-space.ee/arti/vt1200.git
synced 2026-10-31 12:05:05 +02:00
SDD
3fd1e13b2e
Distils public docs into reference/keyboard-mouse/PROTOCOL.md for the level-1 Keyboard (27) / Mouse (26) device tests: - keyboard: 4800 8N1 RS-423, self-test via FD -> 01 00 00 00 (errors 3D/3E) - mouse: 4800 8O1 RS-232, self-test via 'T' -> 4-byte report (errors 3D/3E, >=0x20 fatal) - separate ports: DUART2 A=keyboard, B=mouse (NOT daisy-chained) MAME already has an LK201 device (src/mame/dec/lk201.cpp/.h) but no DEC mouse.
59 lines
2.6 KiB
Markdown
59 lines
2.6 KiB
Markdown
# elkay
|
||
|
||
A USB HID converter for the DEC LK401 keyboard, built so that every key and LED works with
|
||
[veetee](https://github.com/issinoho/veetee), the DEC VT emulator, and with any other USB host.
|
||
|
||
The LK401 speaks DEC's LK201-family serial protocol (4800 baud, RS-423 levels, +12 V supply)
|
||
through a 4P4C modular cable. elkay is a small inline box: the keyboard's own cable plugs into
|
||
it, and a USB cable comes out. The keyboard itself is not modified.
|
||
|
||
```
|
||
LK401 ──4P4C──▶ ┌──────────────── elkay box ────────────────┐ ──USB──▶ host (veetee)
|
||
│ 12 V boost ◀── USB 5 V │
|
||
│ level shift/invert ◀─▶ ATmega32U4 UART │
|
||
│ ATmega32U4 USB ──▶ HID keyboard + LEDs │
|
||
└────────────────────────────────────────────┘
|
||
```
|
||
|
||
## Status
|
||
|
||
| Phase | What | State |
|
||
|-------|------|-------|
|
||
| 1 | Characterise the keyboard: pinout, current draw, signal levels ([procedure](docs/phase1-bench.md)) | next |
|
||
| 2 | Power and level-shifting circuit on a breadboard ([hardware](hardware/README.md)) | provisional design |
|
||
| 3 | Firmware: serial sniffer and command console, record every keycode | written, untested |
|
||
| 4 | Firmware: initialisation (LK401 mode, up/down modes, LEDs, click, bell) | console commands in place |
|
||
| 5 | Firmware: USB HID keyboard with LED feedback | — |
|
||
| 6 | Keymap for veetee ([keymap](docs/keymap.md)); veetee and Linux host side done | proposed |
|
||
| 7 | Enclosure, testing, write-up | — |
|
||
|
||
## Layout
|
||
|
||
| Path | Contents |
|
||
|------|----------|
|
||
| `firmware/` | PlatformIO project; Arduino Micro is the main target, Teensy 2.0 the alternative |
|
||
| `hardware/` | Interface circuit, bill of materials, wiring notes |
|
||
| `docs/protocol.md` | The LK201/LK401 protocol as the firmware uses it |
|
||
| `docs/keymap.md` | LK401 keycode → USB HID usage → veetee binding |
|
||
| `docs/phase1-bench.md` | Bench procedure for identifying the connector and signals |
|
||
| `host/linux/` | xkb option so Linux desktops see F13–F20 ([why](host/linux/README.md)) |
|
||
|
||
## Building
|
||
|
||
```sh
|
||
cd firmware
|
||
pio run # Arduino Micro
|
||
pio run -e teensy2 # Teensy 2.0
|
||
pio run -t upload # flash the Micro
|
||
pio device monitor # console at 115200 baud
|
||
```
|
||
|
||
## References
|
||
|
||
- *VCB02 Video Subsystem Technical Manual*, EK-104AA-TM-001 (the LK201 protocol, on bitsavers/manx)
|
||
- Linux `drivers/input/keyboard/lkkbd.c`, a working LK201/LK401 driver
|
||
|
||
## Licence
|
||
|
||
MIT.
|