Sun to USB keyboard protocol converter
======================================
Target MCU is ATMega32u4 but other USB capable AVR will also work.
Supported keyboards: Sun Type 5 Keyboard, CTCSP SHORT TYPE KEYBOARD(CKUB)
CTCSP SHORT TYPE KEYBOARD: http://imgur.com/a/QIv6p
Connector
---------
8Pin mini DIN
___ ___
/ |_| \
/ 8 7 6 \
| 5 4 3 |
\_ 2 1 _/
\_____/
(receptacle)
Wiring:
Pin mini DIN MCU
----------------------------------
1 GND GND
2 GND GND
3 5V
4 RX/TX(Mouse)
5 RX PD3
6 TX PD2
7 GND GND
8 5V VCC
Protocol
--------
Signal: Asynchronous, Negative logic, 1200baud, No Flow control
Frame format: 1-Start bit, 8-Data bits, No-Parity, 1-Stop bit
AVR USART engine expects positive logic while Sun keyboard signal is negative.
To use AVR UART engine you need external inverter in front of RX and TX pin.
Otherwise you can software serial routine to communicate the keyboard.
This converter uses software method, you doesn't need any inverter part.
Commands From System To Keyboard
0x01 Reset
Keyboard responds with following byte sequence:
Success: 0xFF 0x04 0x7F
Fail: 0x7E 0x01 0x7F
0x02 Bell On
0x03 Bell Off
0x0A Click On
0x0B Click Off
0x0E LED
followed by LED status byte:
bit: 3 2 1 0
LED: CapsLk ScrLk Compose NumLk
0x0F Layout
Keyboard responds with 'Layout Response' 0xFE 0xXX
Commands From Keyboard To System
0x7F Idle
means no keys pressed.
0xFE Layout Response
0xFF Reset Response(followed by 0x04)
Reference
http://kentie.net/article/sunkbd/page2.htm
http://kentie.net/article/sunkbd/KBD.pdf
Build Firmware
--------------
Just use 'make'
$ cd sun_usb
$ make
Then, load the binary to MCU with your favorite programmer.
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