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BVE-700A control panel unit
. The control panel unit performs the two main functions
of generating key code and displaying received data
from processor unit.
Key code is generated by a latch consisting of two ICs
(IC303, IC304) on the keyboard unit and a buffer IC
(IC305).
Key data is read from IC305 after setting an output from
IC303 and IC304 to low. For example, when the output 1
of IC304 is set to low, all keys from ALL STOP key to
FF key can be checked.
The knob operation data is obtained by reading IC206
and IC207 periodically. The dial operation data is
obtained by reading IC205 periodically.
. Data indication on display is realized by sending data to
the respective circuit boards from CPU on the IF-23
board in serial format.
20 ICs from IC401 on the keyboard unit to IC102 on the
DP-425 board are connected in serial. When display data
is sent from CPU, the display data is set to all of these
ICs.
If all display data are indicated on display all at the same
time, not only power consumption exceeds the power
supply capacity but also efficiency is poor. Therefore,
several ICs only are turned on and the groups of the
illuminating ICs are switched one group after another.
However, the ICs that become dark by the dynamic
illumination method are turned on all the time as IC101.
These ICs are connected to the CPU bus through which
parallel data are set.
. Power to the control panel unit is supplied from proces-
sor unit through D-sub 15-pin cable connected to
processor. (Note: The D-sub 25-pin is used when BVE-
700 is connected.) The +12 V power that is supplied
from processor unit is shifted to +5 V by DC-DC
converter on the IF-23 board.
Control panel unit and processor unit are connected by
RS-422A serial interface. Display data and commands
are sent to control panel unit from processor unit with
this interface.
From control panel unit, data regarding the pressed key
or data indicating the dial operation are sent to processor
unit.
From processor unit, message is sent at the timing of
every video field and control panel unit receives message
at the timing of every video field so that processing is
executed in synchronism with the corresponding video
field.
1-38 (E)
BVE-700A
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