Sharp MZ-80B Owner's Manual page 63

54
The relation between the strobe signals and bit data in keyboard scan is shown in Table 4.5.
Strobe signals are delivered to four terminals (A
3 ,
A
2 ,
A
1 ,
A
0 ),
and are fed into the demultiplexer
154, then delivered to 12 terminals of strobe inputs of keyboard. Keys are discriminated by strobe
signals and key data.
For instance, when the strobe is '6H' and key data 'FFH', then it is found that key 'S' is being
depressed.
Table 4.5 Key scanning
strobe signals and bit data
E MODE 0
1 2 3 4 5 6
7
4
FI F2 F3 F4
Fs
F6
F7 Fs
0
0
F9
FlO
8
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1
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4
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2
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