I
Resume
- This signal
is
sent
to the external device to
show
that
the
CRAY-1
is
ready
for
the next data transmission.
Resume
is
a pulse
50
± 3 nanoseconds
wide
(at
the
50%
voltage points) sent in groups
of four.
For
any
group of
Resume
pulses, the time
from
the leading
edge
of
one
Resume
to the leading
edge
of the next
Resume
is
100
± 3 nsec.
Disconnect - This signal
is
sent
from
the external device to the
CRAY-1
and
indicates
that
the transmission
from
the external device
is
complete.
It
is
sent
after
the
last
Ready.
The
Input Dis-
connect pulse
must
be
transmitted
no
earlier
than
20
nsec
after
the leading
edge
of the final
Ready
pulse. Disconnect
is
a pulse
50
~
10
nanoseconds
wide
(at
the
50%
voltage
points).
Output channels
Table 6-5
illustrates
a general
view
of
an
output signal sequence.
Table 6-5.
16-bit
high-speed asynchronous output channel signal exchange
(DO
module)
CRAY-1
Externa 1
1. Activate channel
(set
CL
and
CA).
2.
Read
word
from
memory
and
advance
current
address.
3.
Data
2
63
_2
48
with
Ready
•
4.
Data
2
47
_2
32
with
Ready
•
5.
Data
2
31
_2
16
with
Ready
•
6.
Data
2
15
_2°
with
Ready
•
(with Disconnect
if
this
is
the
last
word)
7.
....
..
1------
Resume
8.
If
(CA)
f (CL),
go
to 2.
9. Set
interrupt
and
deactivate
channel.
Data
Bits
2°
through 2
15
-
Data
Bits 2°, 2
1
,
...
, 2
15
are
signals
carrying a
16-bit
parcel of data
from
the
CRAY-1
to
an
external
device.
They
are
all
sent
at
the
same
time, within 5 nanoseconds
of the leading
edge
of the
Ready
pulse.
Data
Bit
signals
remain
steady
on
the
lines
until
the next parcel
is
sent.
2240004
6-12 E
~
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