4.
CB 41, CB 42, CB 43 (Main Control Panels
Left, Center, Right)
These boards carry the switch recognition and the activaing
of the LEDs. Furthermore, the CB 42 carries the
LCD display plus outputting IC 1 (HC 174). And on the
CB 43 there is the on/off switch with integrated bi-color
LED.
The switches (and their appropriate LEDs) are arranged in
5 groups with 24 switches each. If no switch is depressed,
both the SENSE and the KD output of the respective pair of
comparators are set to +5 V.
AM 320-01-808
A momentary switch closure results in a Sense and
KD pulse, which is applied to the CPU's data
bus. This sense pulse occupies a specific time
slot in the CPU's sequence program and
instructs the CPU to initiate the function for
that time slot. The CPU, in turn, sends a
serial data code to the appropriate shift
register (74 HCT 164), designating the LEDs
to light up.
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