FC980C Alt controller
=====================
2017/07/21

This controler replaces original controller of Leopold FC980C and makes the keyboard programmable.

Discuss this here: https://geekhack.org/index.php?topic=90681.0

The keyboard is very similar electronically to its sibling model FC660C you can also refer this.

FC660C Alt Controller: https://geekhack.org/index.php?topic=88439.0


Hardware
--------
This project uses common and familiar ATmega32u4 but any microcontroller with 5V I/O will work.

- Schematic of Alt controller: schematic.pdf


Pin configuration
-----------------
Connector bridging between switch board and controller is Hirose DF14A-20P-1.25H.

    |Switch  |Controller |
    |  board |     board |Description                           |Function   |ATmega32u4
    |--------|-----------|--------------------------------------|-----------|------------
    | 1      |20         | FG                                   |FG         |GND
    | 2      |19         | GND                                  |GND        |GND
    | 3      |18         | GND                                  |GND        |GND
    | 4      |17         | 3.3V                                 |V33        |3.3V/5V
    | 5      |16         | 5V                                   |Vcc        |5V
    | 6      |15         |*Z6-TP1684-4-HYS(o)                   |KEY_HYS    |PC7
    | 7      |14         |*Z6-TP1684-2-KEY(i)                   |KEY_STATE  |PC6
    | 8      |13         |*Z7-AD5258-5-SCL(I2C)                 |I2C_SCL    |PD0(TWI)
    | 9      |12         |*Z7-AD5258-4-SDA(I2C)                 |I2C_SDA    |PD1(TWI)
    |10      |11         |*Z5/4-LV4051A-6-~EN(Lo:Z5 Hi:Z4)      |COL_bit3   |PB3
    |11      |10         |+Z3-LV07A-5 (LV4051A-9-C)             |COL_bit2   |PB2
    |12      | 9         |+Z3-LV07A-1 (LV4051A-10-B)            |COL_bit1   |PB1
    |13      | 8         |+Z3-LV07A-3 (LV4051A-11-A)            |COL_bit0   |PB0
    |14      | 7         |+Z1-LVC138A-3-C                       |ROW_bit2   |PD6
    |15      | 6         |+Z1-LVC138A-2-B                       |ROW_bit1   |PD5
    |16      | 5         |+Z1-LVC138A-1-A                       |ROW_bit0   |PD4
    |17      | 4         |+Z1-LVC138A-4-~G2A  Z6-TP1684-5-~EN   |KEY_ENABLE |PD7
    |18      | 3         |+Q4-NPN-B-NumLock_LED(Hi:On)          |LED_NUML   |PB4
    |19      | 2         |+Q3-NPN-B-CapsLock_LED(Hi:On)         |LED_CAPS   |PB5
    |20      | 1         |+Q2-NPN-B-ScrollLock_LED(Hi:On)       |LED_SCRL   |PB6

```
* 5V intferface
+ 3.3V interface
```


Switch matrix
-------------

    |    |0   |1   |2   |3   |4   |5   |6   |7   |8   |9   |A   |B   |C   |D   |E   |F   |
    |----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|----|
    |   0|Left|RCtl|RAlt|    |Down|P.  |Righ|P0  |X   |LGui|`   |V   |    |Esc |M   |Spc |
    |   1|Fn  |.   |    |    |P1  |PEnt|P2  |P3  |Z   |LAlt|LCtl|C   |K   |    |N   |B   |
    |   2|'   |/   |,   |    |P4  |P+  |P5  |P6  |D   |A   |LSft|F   |J   |F1  |H   |G   |
    |   3|RSft|;   |L   |]   |Up  |    |    |    |S   |Q   |Caps|R   |I   |F3  |U   |T   |
    |   4|    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |    |
    |   5|=   |-   |0   |\   |NLck|BSpc|P/  |P*  |3   |2   |    |4   |9   |F2  |7   |6   |
    |   6|[   |P   |O   |Ent |P7  |P-  |P8  |P9  |W   |1   |Tab |E   |8   |F4  |Y   |5   |
    |   7|F11 |F10 |F9  |F12 |Del |PgDn|Ins |PgUp|    |    |    |    |F8  |F5  |F7  |F6  |


Row designation
---------------
LV138A(Z1) selects one of 8 row lines and gives strobe by enabling with ~G2A(17).

    |ROW |bit0|bit1|bit2|
    |----|----|----|----|
    |0   |0   |0   |0   |
    |1   |1   |0   |0   |
    |2   |0   |1   |0   |
    |3   |1   |1   |0   |
    |4   |0   |0   |1   |
    |5   |1   |0   |1   |
    |6   |0   |1   |1   |
    |7   |1   |1   |1   |


Column designation
------------------
LV4051A(Z4, Z5) select one of 16 column lines to sense capacitance of switches.

    |COL |bit0|bit1|bit2|bit3|
    |----|----|----|----|----|
    |0   |0   |0   |0   |0   |
    |1   |1   |0   |0   |0   |
    |2   |0   |1   |0   |0   |
    |3   |1   |1   |0   |0   |
    |4   |0   |0   |1   |0   |
    |5   |1   |0   |1   |0   |
    |6   |0   |1   |1   |0   |
    |7   |1   |1   |1   |0   |
    |8   |0   |0   |0   |1   |
    |9   |1   |0   |0   |1   |
    |A   |0   |1   |0   |1   |
    |B   |1   |1   |0   |1   |
    |C   |0   |0   |1   |1   |
    |D   |1   |0   |1   |1   |
    |E   |0   |1   |1   |1   |
    |F   |1   |1   |1   |1   |


Firmware
--------
Just `make` to build firmware. And consult with wiki for further information.

- https://github.com/tmk/tmk_keyboard/tree/master/keyboard/fc660c
- https://github.com/tmk/tmk_keyboard/wiki


Datasheets
----------
- Hirose DF14A-20P-1.25H: http://www.mouser.com/ds/2/185/DF14_catalog-939195.pdf
- LV07A: http://www.ti.com/lit/ds/symlink/sn74lv07a.pdf
- LV138A: http://www.ti.com/lit/ds/symlink/sn74lvc138a.pdf
- LV4051A: http://www.ti.com/lit/ds/symlink/sn74lv4051a.pdf
- AD5258: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5258.pdf
- JST S5B-PH-SM4: http://www.jst-mfg.com/product/pdf/eng/ePH.pdf
- Hirose UX60SC-MB-5S8: https://www.hirose.com/product/en/products/UX/UX60SC-MB-5S8%2880%29/
- TYU TU1252WNR-05S: http://php2.twinner.com.tw/files/tyu/TU1252series.pdf
- Tr(E42) for LED?: http://cj-elec.com/txUpfile/2013614923661845.pdf


3.3V power supply
-----------------
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:

> Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.


Digipot AD5258
--------------
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.

Lower value of RDAC register causes shallower actuation point.


USB connector board
-------------------
The keyboard has USB receptacle on small separate 1.0mm-thick PCB. USB receptacle is Hirose UX60SC-MB-5S8 while wire-to-PCB connector is TYU TU1252WNR-05S.

http://i.imgur.com/Nucn6h9.jpg


Resources
---------
- Pics: http://imgur.com/a/HhyIq
