1 Sun to USB keyboard protocol converter
2 ======================================
3 Target MCU is ATMega32u4 but other USB capable AVR will also work.
4 Supported keyboards: Sun Type 5 Keyboard, CTCSP SHORT TYPE KEYBOARD(CKUB)
6 CTCSP SHORT TYPE KEYBOARD: http://imgur.com/a/QIv6p
24 ----------------------------------
37 Singnal: Asynchronous, Negative logic, 1200baud, No Flow control
38 Frame format: 1-Start bit, 8-Data bits, No-Parity, 1-Stop bit
40 AVR USART engine expects positive logic while Sun keyboard signal is negative.
41 To use AVR UART engine you need exteral inverter in front of RX and TX pin.
42 Otherwise you can software serial routine to communicate the keyboard.
44 This converter uses software method, you doesn't need any inverter part.
47 Commands From System To Keyboard
49 Keyboard responds with following byte sequence:
50 Success: 0xFF 0x04 0x7F
57 followed by LED status byte:
59 LED: CapsLk ScrLk Compose NumLk
61 Keyboard responds with 'Layout Response' 0xFE 0xXX
63 Commands From Keyboard To System
65 means no keys pressed.
67 0xFF Reset Response(followed by 0x04)
70 http://kentie.net/article/sunkbd/page2.htm
71 http://kentie.net/article/sunkbd/KBD.pdf
79 Then, load the binary to MCU with your favorite programmer.