NEC PC-8201 - Keyboard Interface

3.1.7 Keyboard Interface
The keyboard is sensed by a software scan.
It transmits low signals (OUT -
B9. OUT BA)
to Port A or Port B at 81C55, and senses the depressed key by IN E8.
* Key board Interface Port
I
1011 1 1001 OUT B9
I
OUT BA
PA7- PA0
00000001
0000001 0
00000100
00001000
0001 0000
001 00000
01 000000
10000000
PB7
-PBO
00000001 CAPS --SHIFT
Key
L-z
K-A
I -Q
A/ - 0
8( - 1'
PAST , 9.)
INS
- DEL
BS
STOP --- I