Gherkin keyboard driver, created for the VT2040 terminal
Z and Enter function as normal shift keys, accessing the upper-case letters. The two space keys and V access three further cases, labelled in orange, purple and green respectively. In the code they're called the mega, super and ultra cases.
I first discovered the Gherkin keyboard after I got a Unihertz Titan Pocket, and found that its 29-key keyboard was surprisingly usable once I got the Z and Enter keys working as shift keys.
The mega-case numbers and symbols match the labels on the Unihertz Titan Pocket keys, which I can't change. I don't think matching the phone keyboard is necessarily the best option here; typing numbers with one hand is possible but uncomfortable, and they're upside-down compared to a regular numeric keypad.
The super case contains all the other symbols on a "normal" keyboard, plus æ. Finally, the ultra case has the arrow keys on HJKL (I'm a vi user), and other cursor movement and Ctrl-* keys:
- Q Escape
- W Reverse-video mode
- E End
- R Rotate screen
- T Brightness down
- Y Brightness up
- U Delete to beginning of line
- I Tab
- A Ctrl-A
- S Home
- D Ctrl-D
- F Page Down
- Z Ctrl-Z
- C Ctrl-C
- B Page Up