IBM Series 1 User Manual page 159

Figure 5-1. Digital I/O feature simplified data flow
USER ATTACHMENT
External sync
16 points DI/PI
Ready
External sync
16 points DI/PI
Ready
External sync
16 points DO
Ready
External sync
16 points DO
Ready
5-2
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I
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I
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I
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GA34-0033
INTEGRATED DIGITAL I/O FEATURE CHANNEL
~
Group 0
Ext sync interrupt
~
DI
~
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data
v
v
reg
Process interrupt
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PI
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data
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reg
v
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1
Ext sync interrupt
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data
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reg
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PI
data
Process interrupt
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reg
Group 2
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Ext sync interrupt
•
DO
data
reg
Group 3
"I
1<
Ext sync interrupt
-'"
DO
data
reg
l..,....-oo.