Synchronous Data Transfer Request Message; Table 6-6: Wide Data Transfer Request - Tandberg Data SLR7-140 PROGRAMMER Manual

Byte
0
1
2
3
Transfer Width
Exponent
Byte
0
1
2
3
4
Table 6-7:
Tandberg Data
The Wide Data Transfer Request Message has the following
format:
Value Description
01h Extended Message
02h Extended Message Length
03h Wide Data Transfer Request Code
m Transfer Width Exponent
Table 6-6: Wide Data Transfer Request
Valid transfer widths are 8 bits (m=00h) and 16 bits
(m=01h).
6.3.2.

Synchronous Data Transfer Request Message

Synchronous Data
exchange can be initiated by the Initiator to change the
data transfer agreement. The default data transfer mode
is asynchronous data transfer mode.
An Initiator may initiate an SDTR message whenever it is
appropriate to negotiate a new data transfer agreement
(either synchronous
never respond to an SDTR message with a MESSAGE REJECT
message. Re-negotiation at every selection is not re-
commended, since
likely.
The Synchronous Data Transfer Request Message has the
following format:
Value Description
01h Extended Message
03h Extended Message Length
01h Synchronous Data Transfer Request Code
m Transfer Period (multiples of 4 ns)
x REQ/ACK Offset
Synchronous Data Transfer Request
6-8 Tandberg SLR Product Line SCSI Functional Specifications
Transfer Request
or asynchronous).
a significant performance
Message System
(SDTR) message
The Drive will
impact is