----------------
Data bits are LSB first and Pairty is odd. Clock has around 60us high and 30us low part.
- ____ __ __ __ __ __ __ __ __ __ ________
- Clock \____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/
+ ____ __ __ __ __ __ __ __ __ __ _______
+ Clock \_____/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/ \_/
____ ____ ____ ____ ____ ____ ____ ____ ____ ____
Data ____/ X____X____X____X____X____X____X____X____X____X________
Start 0 1 2 3 4 5 6 7 P Stop
Start bit: can be long as 300-350us.
Inhibit: Pull Data line down to inhibit keyboard to send.
-Timing: Host reads bit while Clock is hi.
+Timing: Host reads bit while Clock is hi.(rising edge)
Stop bit: Keyboard pulls down Data line to lo after 9th clock.
| `-----`--- scan code
`------------- enable bit(0: enable repeat, 1: enable break)
- 00-77 Enable repeat(78-7F: invalid scancode)
- 80-F7 Enable break(F8-FF: invalid scancode)
+ 00-79 Enable repeat
+ 80-F9 Enable break(FA-FF are used as other commands, see above.)
FE Resend(011ah) no need to use
FF End(0114h) exits FC command mode.
Response from keyboard:
FD Out of bound - Invalid scancode
+ -- OK - No response means that command is accepted.
Examples:
To enable break code of all keys.