Epson S5U1C88348T, Manual

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2 BOARD CONFIGURATION AND CONTROL OF EACH UNIT
S5U1C88348T HARDWARE MANUAL
EPSON
II-5
2.4 S5U1C88348T Key Board
The 50 keys on this board comprise a 5
×
10 key matrix. Figure 2.4.1 provides the key layout, while Table
2.4.1 provides the configuration for the key matrix.
Esc
1
!
Q
*
A
_
-Y +Y
-M +M
Z
<
Erase
Caps
2
“
W
/
S
`
X
>
BS
Del
Shift
3
#
E
+
D
,
C
4
$
R
-
F
.
V
5
%
T
=
G
\
B
Space
6
&
Y
?
H
^
N
Char
7
‘
U
;
J
·
M
Mode
Submode
8
(
I
:
K
°
←
Prev
9
)
O
[
L
¥
↑
↓
On/Off
0
@
P
]
Enter
C-Return
→
Next
Fig. 2.4.1 Key Layout
Table 2.4.1 Key Matrix
KO0 (P15)
KO1 (P16)
KO2 (P17)
KO3 (R27)
KO4 (R34)
KI0 (K00)
Esc
1
Q
A
Z
KI1(K01)
Caps
2
W
S
X
KI2 (K02)
Shift
3
E
D
C
KI3 (K03)
4
R
F
V
Erase
KI4 (K04)
5
T
G
B
BS
KI4 (K05)
6
Y
H
N
Space
KI6 (K06)
7
U
J
M
Char
KI7 (K07)
Mode
8
I
K
←
KI8 (K10)
9
O
L
↑
↓
KI9 (K11)
On/Off
0
P
Enter
→
In
Out
Each key comprises the key-scan circuit shown in Figure 2.4.2.
In a program, one KO signal is set low and all KI signals are read. When a key is depressed, the corre-
sponding KI signal is 0; when no key is depressed, the KI signal is 1.
This is performed for all KO signals. To eliminate the noise caused by chattering and such, some correc-
tive measures such as multiple key reads should be incorporated in a program.
KOx KIx
Fig. 2.4.2 Key-Scan Circuit