PS/2 to USB keyboard converter
==============================
This firmware converts PS/2 keyboard protocol to USB and supports only Scan Code Set 2.
PS/2 signal handling implementations
------------------------------------
Following three methods are used to implement PS/2 signal handling.
### Simple and stupid busy-wait(ps2_busywait.c)
This is expected to implemented with portable C code for reference.
### Interrupt driven(ps2_interrupt.c)
Uses pin interrupt to detect falling edge of clock line.
### USART hardware module(ps2_usart.c)
Uses AVR USART engine to receive PS/2 signal.
To select method edit Makefile.
Connect Wires
-------------
In case of Teensy2.0(ATMega32U4):
1. Connect Vcc and GND.
2. Connect Clock and Data line.
- Busywait: Clock is on PD5 and Data on PD2.
- Interrupt: Clock is on PD1 and Data on PD2.
- USART: Clock is on PD5 and Data on PD2.
3. Optionally you need pull-up register. 1K-10K Ohm is OK.
To change pin configuration edit config.h.
Build Firmware
--------------
Just run `make` :
$ make
To select keymap:
$ make KEYMAP=[plain|jis|spacefn|...]
Keymap
------
Several version of keymap are available in advance but you are recommended to define your favorite layout yourself. To define your own keymap create file named `keymap_<name>.c` and see keymap document(you can find in top README.md) and existent keymap files.
V-USB Support
-------------
You can also use this converter on ATmega(168/328) with V-USB instead of Teensy.
The converter on V-USB lacks some features for now: USB NKRO and System/Media control.
Circuit:
+---+ +---------------+
USB GND | | ATmega168 |
=== C3 | |
5V < ------- + -------- + --- | Vcc , AVCC | PS / 2
R1 | | ====
D- < ---- + -- + -----R2----- | INT1 RXD | ------- > DATA
D+ < ---- | --- + ----R3----- | INT0 XCK | ------- > CLOCK
Z1 Z2 | | ->5V
GND< ---- + --- + -- + -- + ----- | GND | - > GND
| | | |
| C2-+--|XTAL1 |
| X1 | |
+--C3-+--|XTAL2 |
+---------------+
R1: 1.5K Ohm
R2,R3: 68 Ohm
Z1,Z2: Zenner 3.6V
C1,C2: 22pF
C3: 0.1uF
X1: Crystal 20MHz(16MHz/12MHz)
