Cray CRAY-1 - Page 181

I
Disconnect
CRAY-1 and
complete.
Disconnect
points).
- This signal is sent from the external device to the
means that the transmission from the external device is
It is sent after the Resume is received for the last Ready.
is a pulse 50 ± 10 nanoseconds wide (at the 50% voltage
Channel Master Clear - This signal may be programmed (see description
of Programmed Master Clear later in this section) or may result from
a Clear I/O Signal.
Output channels
Table 6-3
illustrates a general view of an output signal sequence.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
Table 6-3.
16-bit asynchronous output channel signal exchange
(DK module)
CRAY-1
Externa 1
Activate
channel
(set CL and CA)
Read
word from memory and
advance current address
Data
2
63
_2
48
with Ready
•
...
Resume
Data
2
47
_2
32
\lJi th
Ready
•
...
Resume
Data
2
31
_2
16
with
Ready
..
...
Resume
Data 2
15
_2°
with
Ready
•
...
Resume
If (CA) f (CL), go to 2.
Disconnect
•
Set interrupt
and deactivate channel.
Data Bits 20 through 2
15
- Data Bits 20, 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
6-9 E