titus-larsen-titus-1981-apple-interfacing

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2
CLR 20 2 CK
Si\17474
The device select circuit used in Experiment No. 2 is also used in
is experiment. If it has not been wired, wire it as shown in Fig. 6-4.
Wire the SN7474 flip-Hop as shown in Fig. 6-6. The 'T' noted at
e "D" input to the SN7474 means that a logic one ( +5 volts) is
lied to this input. Likewise, a "O" would indicate a logic zero, or
und connection. The 0 and 1 notations are used to distinguish
·c level connections from power-carrying connections. The Q outt
from the flip-Hop should be the only device connected to the
ic probe. Remember to make the power connections to the
7474 flip-flop; pin 14 to +5 volts and pin 7 to ground.
c
3
this circuit, the WR 49318 pulse (signal C) will dock the outof
the Hip-flop to a logic one, while the RD 49319 pulse (signal
} will clear it to a logic zero. Since a flip-fl.op is stable in either state,
e pulsed by RD 49319, its Q output will remain in the logic one
+5
GND
14
D
Q
TO LOGIC PROBE
FROM C
(WR 49318)
_n_ 3
CK
CLR
SN7474
FROM A tr
(RD 49319)