Keyboard

Tanmatsu has a built-in QWERTY keyboard. Besides the letter, number and symbol keys it carries a row of colored function keys and an AltGr layer that gives direct access to accented letters and common symbols.

The keyboard matrix is scanned by the CH32V203 coprocessor; the ESP32-P4 receives decoded key events through the badge BSP. Each key event provides an ASCII byte, a UTF-8 string (already resolved for the active modifier layer) and a modifier bitmask.

Function keys

The colored keys along the top row are the navigation / function keys (BSP_INPUT_NAVIGATION_KEY_F1…F6). Their meaning is defined by the running application.

Symbol	Color	Event
✕	red	F1
△	orange	F2
☐	yellow	F3
◯	green	F4
☁	blue	F5
◇	magenta	F6

Applications reuse the same colored keys for their own actions — a chat app might put an emoji picker on the green ◯ and a special-character picker on the blue ☁, for instance.

AltGr layer

Hold AltGr and press a key to enter an accented letter or symbol directly. The default layout maps as follows (AltGr / AltGr+Shift):

Letters

Key	AltGr	+Shift		Key	AltGr	+Shift
Q	ä	Ä		A	á	Á
W	å	Å		S	ß	§
E	é	É		D	ð	Ð
R	®	™		F	ë	Ë
T	þ	Þ		J	ï	Ï
Y	ü	Ü		K	œ	Œ
U	ú	Ú		L	ø
I	í	Í		Z	æ	Æ
O	ó	Ó		X	·
P	ö	Ö		C	©	¢
				N	ñ	Ñ
				M	µ	±

Numbers and symbols

Key	AltGr		Key	AltGr
1	¡		8	¾
2	²		9	‘
3	³		0	’
4	¤		-	¥
5	€		[	«
6	¼		]	»
7	½		/	¿
			\	¬

Several keys (= ; ' , . and the shifted number row) carry combining diacritical marks on the AltGr layer, which combine with the next character rather than printing standalone.

The authoritative layout is the keymap table in badge_bsp_input.c. Whether a given character is displayed depends on the running application’s font coverage.

The keyboard layout is based on the US international with Alt Gr keyboard layout.