COMMANDS (I/O ADDRESS HEX 64)
COMMAND
20
60
FUNCTION
Read Command Byte of Keyboard Controller
Write Command Byte of Keyboard Controller
BIT BIT DEFINITIONS
7
Reserved
6
IBM PC Compatible Mode
5
IBM PC Mode
4
Disable Keyboard
3
Inhibit Override
2
System Flag
1
Reserved
0
Enable Output Buffer Full Interrupt
AA
Self-test
BIT BIT DEFINITIONS
00
No Error Detected
01
K/B Clock Line is Stuck Low
02
K/B Clock Line is Stuck High
03
K/B Data Line is Stuck Low
04
K/B Data Line is Stuck High
AB
AD
AE
C0
D0
D1
E0
F0-FF
Interface Test
Disable Keyboard Feature
Enable Keyboard Interface
Read Input Port
Read Output Port
Write Output Port
Read Test Inputs
Pulse Output Port
12