hhkb: Revise doc
[tmk_keyboard.git] / keyboard / hhkb / doc / HHKB.txt
1 Internal of HHKB pro
2 =====================
3 HHKB pro has MCU and some chips on separate two PCBs.
4
5 Controller PCB
6 --------------
7 M38K07M4 Renesas MCU with USB function
8 http://documentation.renesas.com/eng/products/mpumcu/rej03b0192_38k0ds.pdf
9
10 (HHKB_controller.jpg)
11
12 Keyswitch PCB
13 -------------
14 HC4051 Analog Multiplexer: select a row line.
15 http://www.ti.com/lit/ds/schs122j/schs122j.pdf
16 LS145 BCD Decoder: select a column line.
17 http://www.ti.com/lit/ds/symlink/sn74ls145.pdf
18 BU9831 Non-volatile electronic potentiometer: for calibration?
19 https://www.spezial.com/doc/rohm-a/bu9831.pdf
20 TP1683/4 Capacitive Sensing controller: no datasheet available.
21
22 (HHKB_keyswitch.jpg)
23
24 Topre original chip?
25 (HHKB_TP1684.jpg)
26
27
28 Connector Cable
29 ---------------
30 Two PCBs are connected by 15 lines(13 in case of Pro2).
31 Vcc and GND use 3(2) lines each, other lines are for keyboard signaling.
32
33 HHKB connector lines:
34 JP Pro2 Pro Function Description TMK pin usage
35 --------------------------------------------------------------------------------------------
36 1 Vcc(5V) 5V
37 1 1 2 Vcc(5V) 5V
38 2 2 3 Vcc(5V) 5V
39 3 3 4 TP1684 ~KEY: Low(0) when key is pressed PD7 input(with pullup)
40 4 4 5 TP1684 HYS: High(1) when key is pressed PB7 output
41 5 5 6 HC4051 A(bit0)\ PB0 output
42 6 6 7 HC4051 B(bit1) > select row 0-7 PB1 output
43 7 7 8 HC4051 C(bit2)/ PB2 output
44 8 8 9 LS145 A(bit0)\ PB3 output
45 9 9 10 LS145 B(bit1) > select column 0-7 PB4 output
46 10 10 11 LS145 C(bit2)/ PB5 output
47 11 11 12 LS145 ~D(enable) Low(0) enables selected column PB6 output
48 12 12 13 GND GND
49 13 13 14 GND GND
50 15 GND
51 14 HC4051(Z2) ~Enable of Z2 row0-7 PC6
52 15 HC4051(Z3) ~Enable of Z3 row8-15 PC7
53
54 NOTE: Probably HYS changes threshold for upstroke and makes hysteresis in the result.
55 NOTE: HYS should be given High(1) when previous KEY state is Low(0).
56 NOTE: 1KOhm didn't work as pullup resistor on KEY. AVR internal pullup or 10KOhm resistor was OK.
57 NOTE: JP has two HC4051(Z2,Z3) and line 5, 6 and 7 are connected to both of them.
58
59 (HHKB_connector.jpg)
60
61
62 Keyswitch matrix
63 ----------------
64 HHKB switch matrix is ghost-free and bounce-free.
65
66 Pro/Pro2(8x8):
67 COL 0 1 2 3 4 5 6 7
68 ROW ---------------------------------------------------------------
69 0| 2 q w s a z x c
70 1| 3 4 r e d f v b
71 2| 5 6 y t g h n _NONE_
72 3| 1 Esc Tab Control LShift LAlt LMeta Space
73 4| 7 8 u i k j m _NONE_
74 5| \ ` Delete Return Fn RShift RAlt RMeta
75 6| 9 0 o p ; l , _NONE_
76 7| - + ] [ ' / . _NONE_
77
78
79 JP(16x8):
80 COL 0 1 2 3 4 5 6 7
81 ROW ---------------------------------------------------------------
82 0| ESC TAB LFn LShift LCtrl
83 1| 4 E MuHKN C D
84 2| 3 W LAlt X S
85 3| 1 HHK
86 4|
87 5| 5 R V F
88 6| 2 Q LGui Z A
89 7| 6 T Space B G
90 8| 9 I Kana , K
91 9| 8 U Henkan M J
92 A| 7 Y N H
93 B| 0 O RAlt . L
94 C| BS Right RShift Enter
95 D| \ [ Down Up ]
96 E| - P RFn / ;
97 F| ~ @ Left Ro :
98
99
100 Matrix diagram:
101
102 Pro/Pro2:
103 +-------------------------+-+-+-+-+-+-+-+ Vcc
104 |bias control? - - - - - - - - ---
105 | 3.9K*8 R R R R R R R R |
106 +--------^+ +--------+ - - - - - - - - |
107 | 3| | HC4051 <0-------|-|-|-|-|-|-|-|--|R|-+
108 | DIL-20 |capa. | <1-------|-|-|-|-|-|-|-|--|R|-+
109 | TP1684 |sense | <2-------|-|-|-|-|-|-|-|--|R|-+
110 | 20<------| <3-------|-|-|-|-|-|-|-|--|R|-+
111 | | | <4-------|-|-|-|-|-|-|-|--|R|-+
112 | | | <5-------|-|-|-|-|-|-|-|--|R|-+
113 >5~EN <-+ | <6-------|-|-|-|-|-|-|-|--|R|-+
114 | 2 4 | | | <7-------|-|-|-|-|-|-|-|--|R|-+
115 +---V---^-+ | +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
116 KEY HYS | A B C +-----------------+
117 | | +-^----+ | | | | LS145 |
118 Vcc | | |BU9831| | | | +-^--^--^--^------+
119 --- | | +------+ | | | A B C D +-------+
120 | | | | | | | | | | | |
121 1-3 4 5 6 7 8 9 10 11 12 13-15 Pro |
122 1-2 3 4 5 6 7 8 9 10 11 12-13 Pro2|
123 +--------------------------------------------------+ |
124 | connector | ---
125 +--------------------------------------------------+ GND
126
127
128 JP:
129 +-----------------------------+-+-+-+-+ Vcc
130 |bias control? - - - - - ---
131 | 3.9K*5 R R R R R |
132 +--------^+ +--------+ - - - - - |
133 | 3| | HC4051 <0-----------|-|-|-|-|----|R|-+
134 | |capa. | Z2 <1-----------|-|-|-|-|----|R|-+
135 | TP1684 |sense | <2-----------|-|-|-|-|----|R|-+
136 | 20<---+--| <3-----------|-|-|-|-|----|R|-+
137 | | | | <4-----------|-|-|-|-|----|R|-+
138 | | ~En| <5-----------|-|-|-|-|----|R|-+
139 >5~EN | +----> <6-----------|-|-|-|-|----|R|-+
140 | 2 4 | | | | A B C <7-----------|-|-|-|-|----|R|-+
141 +---V---^-+ | | +-^-^-^--+ | | | | | |
142 KEY HYS | | | | | | | | | | |
143 | | | | +--------+ | | | | | |
144 | | | | | HC4051 <8-----------|-|-|-|-|----|R|-+
145 | | | | | Z3 <9-----------|-|-|-|-|----|R|-+
146 | | | +--| <A-----------|-|-|-|-|----|R|-+
147 | | | | <B-----------|-|-|-|-|----|R|-+
148 | | | | <C-----------|-|-|-|-|----|R|-+
149 | | | ~En| <D-----------|-|-|-|-|----|R|-+
150 | | | +-> <E-----------|-|-|-|-|----|R|-+
151 | | | | | A B C <F-----------|-|-|-|-|----|R|-+
152 | | | | +-^-^-^--+ 0 1 2 3 4 5 6 7 33K*8
153 | | | | | | | +-----------------+
154 | | | | | | | | LS145 |
155 Vcc | | | | | | | +-^--^--^--^------+
156 --- | | | | | | | A B C D +-------+
157 | | | | | | | | | | | | | |
158 1-2 3 4 14 15 5 6 7 8 9 10 11 12-13 |
159 +--------------------------------------------------+ |
160 | connector | ---
161 +--------------------------------------------------+ GND
162
163 TP1684-5(~EN) pin is connected with LS145-D/Connector-11.
164
165
166 Signals charts
167 --------------
168 While pressing space bar, watched HHKB Pro original controller signals by logic analyzer.
169 Row and column is looping between 0-7 each for selecting a key.
170 A key is scaned every about 15ms, so scan rate is 66Hz.
171
172 (HHKB_chart1.jpg)
173
174 Space bar locate at ROW:3 COL:7. A key is selected by HC4051(C,B,A) and LS145(C,B,A).
175 Key state can be read on TP1684(4) while asserting low on LS145(D).
176
177 (HHKB_chart2.jpg)
178
179
180 Signal of JP:
181
182 1) Select row
183 rowC ____~~~~____~~~~ 3.8/3.8ms(JP) 7.7/7.7ms(Pro) S2 of HC4051
184 rowB __~~__~~__~~__~~ 1.9/1.9ms(JP) 3.8/3.8ms(Pro) S1 of HC4051
185 rowA _~_~_~_~_~_~_~_~ 1.0/1.0ms(JP) 1.9/1.9ms(Pro) S0 of HC4051
186 0123456701234567 selected row(Pro)
187 0123456789ABCDEF selected row(JP)
188 rowEn0 ________~~~~~~~~ 7.7/7.7ms(JP only) ~Enable of Z2 HC4051(JP only)
189 rowEn1 ~~~~~~~~________ 7.7/7.7ms(JP only) ~Enable of Z3 HC4051(JP only)
190
191 2) Select column
192 colC ____~~~~____~~~~ 550/410us(JP) / us(Pro)
193 colB __~~__~~__~~__~~ 200/210us(JP) 450/460us(Pro)
194 colA _~_~_~_~_~_~_~_~ 100/110us(JP) 220/230us(Pro)
195 0123456701234567 selected column
196
197 3) Wait 5us after column select, then set prev, strobe colD to spit out key status and read it.
198 hys _~~~~_____ 20us if previous key state is low
199 colD ~~~__~~~~~ 10us strobe
200 key ~~~____~~~ 22us indicates current state of the key
201
202 NOTE: JP scans twice fast as Pro/Pro2 does. So Pro/Pro2 scans 8x8 matrix in 15.4ms while JP scans 16x8 in that time.
203
204
205
206 EOF
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