Sharp MZ-800 Service Manual page 29

From keyboard
Key data
PBO
input pin
I
(a-p)
PB7
VBlNK
PC7
556
OUT
PC6
PC2
READ
PC5
MOTOR
PC4
MOTOR
PC3
ON
WRITE
PCl
PCO
To keyboard
PA7
PA3
Key data
strobe
PA2
(10-p)
lS
145
PAl
PAO
a) Key scan
Ports PAD-PAa of the 8255 are connected via the
CD @ @
@
@
Do
8255
28
MZ-800
07 07
I
I
DO
DO
Al Al
AO
AO
RD
WR
KEY
RESET
55
RESET
LS145 decoder, and PSD-PS7 are connected to the
key matrix directly.
@