J11s\
______
_
~
945424-9701
Tabie i-iO. Modei
9ii
VDT Character Decoder
ROM
Table
ROM
INPUTS
ROM
OUTPUTS
x
0 0
0
0
0 0
0
0 0
0
0 0 0 +
128
x
0 0 0 0 0
0 0
0 0
63
+
227
x
0
0 0
I
0
0
0 0
0 0
I
90
+
218
I
x
0 0
0
0
BALL
DRIVE
0 0
0 0 0
82
+
210
x
0
0 0 0 0
0
0
79
+
207
I x
0
0 0
0
I I
0 0
0
0
0
1
I
74
+
202
*
ROM
IS
PROGRAMMED
TO
BE
INDEPENDENT
OF
Ul'USED
H
INPUT.
(A)1
36304
Composite Sync (CSQ) indicates
that
either HSQ
or
VSQ
is
high. Composite Sync
is
not,
however, the logical
OR
of
HSQ and VSQ. During vertical sync, Vertical Sync
is
serrated with
pulses simiiar
to
Horizontal Sync
to
maintain horizontai synchronization during vertical synchro-
nization. The positive transition
of
Composite Sync
is
always enabled at character time 82.
During vertical sync the negative transition occurs
at
the
next
character 74 time. Normally (not
during vertical sync), the negative transition occurs at character time 90.
1-88
Digitai
Systems Division
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