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8-6) Key Scan & Display Circuit Part
PANEL PCB
@ Key Scan and Display Operation
As is seen on each wave form of the following, send "HIGH" output in an
order of MICOM
PIN NO #3—-#4—-#5—#6—#7—#8 for 2msec in a cycle
of 12msec using six terminals of MICOM NO #3, 4, 5, 6, 7, 8. This signal
appears onto output terminal through input terminal of ICO5(UDN2981 or
KID65783AP). At this time, peak-to-peak voltage of the spherical wave is
about 11V(DC RMS1.5), and form of output wave form is like the drawing 1.
Mog
\
10msec
\
V
bute
la
as 3
GRID #1
[rv
VIG
i
GRID#2 | | |
; |
| |
Ce
r] ae
7]
GRID #3
bs
4
|
Vel
ae oe ai
;
|
GRID#4
| ' 3
|
| |
a
cae
7
7
GRID#S | i
toi
@) Key Scan
When the wave form of GRID#2 is outputted, this signal is provided to SW6 button
through the resistance of 10K0. When SW6 is pressed at this time, signal gets smaller
by R501(12k2), and about 4.5V of peak-to-peak voltage is applied to MICOM.
MICOM judges that the wave form of GRID#1 is inputted, and changes function
corresponding to SW6 KEY. In this way, each wave form of GRID is recognized.
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