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THE OUTPUTS OF THESE CIRCUITS GO LOW TO INDICATE A CHANGE IN THE SIGNAL FROM CHI. WHEN THE
HP-IB INTERRUPT PULSE IS SENT TO THE MICROCOMPUTER THE U62 FLIP FLOPS ARE CLOCKED. THE "NEW"
DATA THEN BECOMES THE "OLD" DATA, AND THE MONITORS WAIT FOR THE NEXT CHANGE. TO CHECK
THE MONITORS, LOOK FOR A STREAM OF PULSES AT BOTH MONITOR OUTPUTS (TO STATUS BYTE MUX
AND TO INTERRUPT NAND GATE) WHILE RUNNING THE FOLLOWING PROGRAMS.
LISTEN
8
'
o n d
7 ?
U /;" ?
10
SEND 7
;
UHL LISTEN 5
»
20 GOTO
10
l:
9to
0
30 END
TALK
0 i
red
705?T
10
SEND 7
UNT TALK 5
t:
91 o
8
28 GOTO
18
30 END
TRANSMIT ENABLE (T.E.1)
0 !
c 1 i
i'
1 s
G i'i d
7 ?
E
£*
*
Wt 1
0 s
7
?
w
t i
7
3
128
3:
wt i
8?
7 ? w
t i
7
?
132
42
• j fl F-1
— 2
10 SEND 7
;
UNT
15 RESUME 7
20 GOTO
18
38 END
TALK
Figure 5-40.
Listen, Talk, Transmit Enable Monitor Circuits (Sheet 1 of 2)
5-56
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