Block Diagram - IBM 5150 Technical Reference

Several keyboard arrangements are available. These are
illustrated on the following pages. For information about the
keyboard routines required to implement non-U.S. keyboards,
refer to the Guide to Operations and DOS manuals.
Block Diagram
8255A5 LS322
PAO-------lOH OH'
PA1 OG
PA2 OF
PA3 OE
P A 4 - - - - - - I
P A 5 - - - - - - - l
P A 6 - - - - - - 4
P A 7 - - - - - - 4
PB7
PB6
Keyboard
Clock
1
0
IRQ1
Keyboard
2
0
Data
3
0
Reset
4
0
GND
0
5
+5V
PC LK
--'--I---l
Keyboard Interface Block Diagram
4-4 Keyboard