TANDBERG SLR7, Справочное руководство, Страница: 80 / 118

Tandberg Data Hardware Interface
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8-12 Tandberg SLR Reference Manual
8.4.7. Data Exchange Phase
The Data Exchange Phase includes both the Data Out Phase and the Data In Phase. In both
cases the C/D and MSG lines will be deasserted, and BSY asserted.
The Data Out Phase allows data to be transferred from the Initiator to
the Target in the following way:
Ž
The Target deasserts
I/O.
p
For each byte, the
Target asserts REQ.
{
The Initiator responds
by placing data on the
bus and then assert-
ing ACK.
The Target reads the
byte and deasserts
REQ, whereupon the
Initiator deasserts
ACK.
-BSY
-SEL
-ATN
-MSG
-C/D
-I/O
-REQ
-ACK
min. 0
ns
First Data Out Last Data Out
min. 400 ns
min. 55 ns
min. 0 ns
-DB(0-7, P)
DB(8-15, P1)
Figure 8.6 Data Out Sequence
This completes the byte transfer. This cycle is repeated until the last data byte has been
transferred.