Sharp MZ-80B Owner's Manual page 61

54
The relationship between strobe signals and bit data during keyboard scan is shown in Table 4.5.
Strobe signals are delivered to four terminals (A
3
,
A 2 , A
1
,
A
0 ) ,
fed into demultiplexer 154, then
delivered to 12 keyboard strobe input terminals. Keys are discriminated by strobe signals and key
data.
For instance, when the strobe is ' 6H' and the key data is 'F7H', it indicates that the ' S' key is
being pressed .
Table 4.5 Key scanning strobe signals and bit data
E MODE
0
1
2
3 4
5
6 7
~
F I F 2 F 3 F4 Fs F 6 F 7 F s
0
0
F9 F IO
8
9 00
•
+
-
1
1
0
1
2
3 4
5
6 7
2
1
TAB
SPACE
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G G
I
BREAK
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3
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d e f
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~
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f--
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f--
D
T
E
:r
F
f--
G
R=
4
2
-+
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•
f--
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h
I
i
J
j
K
k I
M
m
n
0
nr
~ f-- ~
L
iF
-
N
f--
0
PI=
5
3
F=
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p
Q
q
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r
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s
T
t
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v w
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3
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2
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5
6 7 8
4
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