Quantum Instruments DLT 7000 User Manual
Page 84

SCSI Description
3-20
Quantum DLT 7000 Tape System
3.5.5.1 Asynchronous Data Transfer
Drive to Initiator Transfer Procedure
1.
The drive drives the DB (0-15, P, & P1) signals to their desired values.
2.
Drive delays at least one deskew delay plus a cable skew delay.
3.
Drive asserts the REQ signal.
4.
Initiator reads the DB (0-15, P, & P1) signals.
5.
Initiator indicates its acceptance of the data by asserting the ACK signal.
6.
When ACK is true at the drive, drive can change or release the DB (0-15,
P, & P1) signals.
7.
Drive negates the REQ signal.
8.
Initiator negates the ACK signal.
9.
Drive can continue the transfer by driving the DB (0-15, P, & P1) signals
and asserting the REQ signal (Steps 1 – 3).
Initiator-to-Drive Transfer Procedure
1.
Drive asserts the REQ signal.
2.
Initiator drives the DB (0-15, P, & P1) signals to their desired values.
3.
Initiator delays at least one deskew delay plus a cable skew delay.
4.
Initiator asserts the ACK signal.
5.
When ACK is true at the drive, drive reads the DB (0-15, P, & P1)
signals.
6.
Drive negates the REQ signal.
7.
Initiator can change or release the DB (0-15, P, & P1) signals.
8.
Initiator negates the ACK signal.
9.
Drive can continue the transfer by asserting the REQ signal (Step 1).