CardKB firmware

Overview

In the conventional firmware, only the released key was retrieved.
The modifier key qualified the next key after clicking, and double-clicking locked it.

With the new firmware, it is now possible to acquire the pressed state of all keys.
This enables Software-side processing to detect is/was, Pressed, Released, Holding and Repeating.
(However, the input order of keys pressed at the same time cannot be identified)
In addition, key input while pressing the modifier key has been made possible, resulting in an operation feel similar to that of a normal keyboard.
As before, the modifier key can be locked by double-clicking.

Required library

Wire
Adafruit_NeoPixel

Protocrol

REG MAP(0x5F)		0	1	2	3	4	5	6	D	E	note
Scan	0x10 R	byte0 key	byte1 key	byte2 key	byte3 key	byte4 key	byte5 key	byte6 modifier			Scanned pressed key status
Mode	0x20 R/W	Mode									Operation mode 0x00:Conventional mode 0x01:M5UnitUnified mode
Hardware type	0xF0 R								type		Hardware 0x01:SKU:U035 0x11:SKU:U035-B
Firmware version	0xF0 R									version	Version: firmware version number

Mode

Value	Mode	Notes
0x00	Conventional	Compatible behavior with conventional firmware
0x01	M5UnitUnified	Key pressed status acquisition mode

Hardware type

Value	Type
0x01	SKU:U035 CardKB
0x11	SKU:U035-B CardKB v1.1

Scanned pressed key bits

Modifier

byte	Shift	Symbol	Function
byte 6	0x01	0x02	0x04

Key

Up to 48 bits valid as a key

byte	MSB key index	LSB key index
byte 0	7	0
byte 1	15	8
byte 2	23	16
byte 3	31	24
byte 4	39	32
byte 5	47	40

Key index

index	Key
0	ESC
1	1
2	2
3	3
4	4
5	5
6	6
7	7
8	8
9	9
10	0
11	BS
12	TAB
13	Q
14	W
15	E
16	R
17	T
18	Y
19	U
20	I
21	O
22	P
23	NO_KEY
24	LEFT
25	UP
26	A
27	S
28	D
29	F
30	G
31	H
32	J
33	K
34	L
35	ENTER
36	DOWN
37	RIGHT
38	Z
39	X
40	C
41	V
42	B
43	N
44	M
45	COMMA
46	PERIOD
47	SPACE

Examples with this firmware

How to write

In Japanese
- https://shikarunochi.matrix.jp/?p=2910
  This article for CardKB (ATmega328), If you write to CardKB v 1.1 then board setting is ATmega8.