F81866A
commands to the system.
Input Buffer
The input buffer is an 8-bit write-only register at I/O address 60h or 64h. Writing to address 60h
sets a flag to indicate a data write; writing to address 64h sets a flag to indicate a command write.
Data written to I/O address 60h is sent to keyboard through the controller's input buffer only if the
input buffer full bit in the status register is “0”.
Status Register
The status register is an 8-bit read-only register at I/O address 64h that holds information about
the status of the keyboard controller and interface. It may be read at any time.
BIT
BIT FUNCTION
DESCRIPTION
0: Output buffer empty
1: Output buffer full
0
Output Buffer Full
0: Input buffer empty
1: Input buffer full
1
2
Input Buffer Full
System Flag
This bit may be set to 0 or 1 by writing to the system flag bit in the
command byte of the keyboard controller (KCCB). It defaults to 0 after
a power-on reset.
0: Data byte
1: Command byte
3
4
5
6
7
Command/Data
Inhibit Switch
0: Keyboard is inhibited
1: Keyboard is not inhibited
0: Muse output buffer empty
1: Mouse output buffer full
Mouse Output Buffer
General Purpose Time-out
Parity Error
0: No time-out error
1: Time-out error
0: Odd parity
1: Even parity (error)
Commands
COMMAND
FUNCTION
20h
Read Command Byte
86
Jan, 2012
V0. 12P
FINTEK [ FEATURE INTEGRATION TECHNOLOGY INC. ]
