6 Thread on Geekhack: https://geekhack.org/index.php?topic=88439.0
11 Just `make` to build firmware. And consult with wiki for further information.
13 https://github.com/tmk/tmk_keyboard/wiki
20 | board | board |Description |Schematic |ATmega32u4
21 |--------|-----------|--------------------------------------|-----------|------------
23 | 2 |19 | GND |GND |GND
24 | 3 |18 | GND |GND |GND
25 | 4 |17 | 3.3V |V33 |3.3V/5V
27 | 6 |15 |*Z6-TP1684-4-HYS(o) |FBSTB |PC7
28 | 7 |14 |*Z6-TP1684-2-KEY(i) |OUT |PC6
29 | 8 |13 |*Z2-AD5258-5-SCL(I2C) |SCL |PD0(TWI)
30 | 9 |12 |*Z2-AD5258-4-SDA(I2C) |SDA |PD1(TWI)
31 |10 |11 |*Z4-LV4051A-6-~EN(Col 0-7) |INH_1 |PB4
32 |11 |10 |*Z5-LV4051A-6-~EN(Col 8-F) |INH_2 |PB3
33 |12 | 9 |+Z7-LV07A-5 (LV4051A-9-C) |SEL_C |PB2
34 |13 | 8 |+Z7-LV07A-1 (LV4051A-10-B) |SEL_B |PB1
35 |14 | 7 |+Z7-LV07A-3 (LV4051A-11-A) |SEL_A |PB0
36 |15 | 6 |+Z3-LVC138A-3-C |COL4 |PD6
37 |16 | 5 |+Z3-LVC138A-2-B |COL3 |PD5
38 |17 | 4 |+Z3-LVC138A-1-A |COL2 |PD4
39 |18 | 3 |+Z3-LVC138A-4-~G2A Z6-TP1684-5-~EN |COL1 |PD7
40 |19 | 2 |+Z7-LV07A-11-~InsertLED |LED1 |PB5
41 |20 | 1 |+Z7-LV07A-13-~CapsLED |LED2 |PB6
48 - Connector on Switch board: https://i.imgur.com/Zi89xO5.jpg
49 - Connector on Controller board: https://i.imgur.com/9SZUzYo.jpg
54 Row5-7 have no key, you can omit scaning on those lines. Topre original controller scans those rows for some reason.
56 | |0 |1 |2 |3 |4 |5 |6 |7 |8 |9 |A |B |C |D |E |F |
57 |----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|
58 | 0|Q |W |E |Tab |R |U |T |Y |O |P |[ |I |] | |\ |Del |
59 | 1|1 |2 |3 |Esc |4 |7 |5 |6 |9 |0 |- |8 |= | |BSpc|Ins |
60 | 2| |LWin|LAlt|LCtl| | | |Spc |RAlt| |RCtl| |Fn |Down|Left|Rght|
61 | 3| |Z |X |LSft|C |N |V |B |, |. |/ |M |RSft|Up | | |
62 | 4|A |S |D |Caps|F |J |G |H |L |; |' |K | | |Entr| |
63 | 5| | | | | | | | | | | | | | | | |
64 | 6| | | | | | | | | | | | | | | | |
65 | 7| | | | | | | | | | | | | | | | |
68 - http://i.imgur.com/9XoNTev.png
69 - https://i.imgur.com/5FCP1Ay.png
71 This code emuluates what original cotnroller does for matrix scan.
72 - https://github.com/tmk/tmk_keyboard/blob/master/keyboard/fc660c/fc660c.c
76 LV138A(Z3) selects a row line and gives strobe by enabling with ~G2A(18).
90 ### Column designation
91 LV4051A(Z4, Z5) select one of 16 column lines to sense capacitance of switches.
93 |Col |A/14|B/13|C/12|Z4-EN/10|Z5-EN/11|
94 |----|----|----|----|--------|--------|
115 https://fccid.io/RPKFC660C
117 - schematic: https://fccid.io/pdf.php?id=1888185
118 - part list: https://fccid.io/pdf.php?id=1888184
123 - Hirose DF14A-20P-1.25H: http://www.mouser.com/ds/2/185/DF14_catalog-939195.pdf
124 - LV07A: http://www.ti.com/lit/ds/symlink/sn74lv07a.pdf
125 - LV138A: http://www.ti.com/lit/ds/symlink/sn74lvc138a.pdf
126 - LV4051A: http://www.ti.com/lit/ds/symlink/sn74lv4051a.pdf
127 - AD5258: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf
132 LV07A and LVC138A are 5V-tolerant and can be powered with 5V, the keyboard will work only with 5V power supply. It may not be completely safe to operate LV138A with 5V Vcc, its datasheet says:
134 > Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
138 Controller can operate AD5258 via I2C to change actuation point of keys. This may make keyboard unusable accidentally and it will be difficult to recovery in some situation. For safety firmware doesn't support it at this point, though.
140 Lower value of RDAC register causes shallower actuation point.
144 - Pics: https://imgur.com/a/UTR8Z