lS322
QH
QH1
QG
QF
QE
QD
QC
QB
QA
-OE
D1
+5V
DO
-ClR
+5V
ClK
-SE
DS
S/-P
-G
lS175
+5V
7407
lS175
PB6
PAO
-----------t
PA1
- - - - - - - - - - - 1
PA2
-----------t
PA3
--------~
PA4
-----------t
PA5
--------~
PA6
-----------t
PA7
-----------t
8255A-5
7407
PB7
83-Key Keyboard
4-5
-RESET - - -__- - - - - - - - - '
PClK - -....
-1---1
Keyboard Clock
Keyboard Data
-Reset
GND
+5V
Block Diagram
Keyboard Interface Block Diagram