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Control Unit Response to Select-Out (Continued)
The channel
acknowledges the
control-unit-busy
sequence
The fall of
status-in
completes the
control-unit
por:tion of this
sequence
Th& control
~itiontQ
cl ear, a need
for service, or
another selection
sequence
The byte on bus
out need not
be
valid ofter the
fall of the in tag
The fall of address out
completes this signal
sequence.
The byte on bus
No
out must hove
been valid for at
least 100 ns prior
to the raising of
the out tog
The fall of releot In
completes this signal
equence.
The channel now awaits
a request for polling or
a
new command
c_______
he channel now awaih
NOTE: All mention of select out assumes
proper operation
of
hold out as well.
Thus, select out up means select out
and hold out up, and select out down
means either select out or hold out
d~n
118
S/360
a request for polling or
a new command
Y
Suppress out is normcilly
dropped at the start of on
interface sequence
if
it
was up for the purpose of
indicating chaining
The byte on bus in must
be
valid within 100 ns after the
raising of the in tag
IBM CONFIDENTIAL
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