FUJITSU M3097G User Manual

Page 119

Bit for distinguishing from other messages

1: The initiator does not permit disconnect
0: The initiator permits disconnect

1: Processed by the target alone
0: Processed by the target and logical unit

(Reserved)

Specifies a logical unit number
(for bit 4 = 0)
Specifies a process incorporated in
the target (for bit = 1)

This scanner does not support the target>incorporated process function. Therefore,
if a 1 is set in bit 5, the IDENTIFY message is rejected with the MESSAGE
REJECT message.

(9)

DISCONNECT (X©04π) : MESSAGE IN phase (target Æ initiator)

Sent from the target to the initiator, this message indicates that the current link
will be disconnected but it will later have to be reconnected to complete the current
process.

After successfully sending the DISCONNECT message, the target releases the BSY
signal to switch into the BUS FREE phase. The target assumes the message
transfer to be successful if it detects that the ATN signal as well as the ACK signal
from the DISCONNECT message are false.

This scanner issues the DISCONNECT message if bit 6 (DiscPriv) in the
IDENTIFY message from the initiator is 1 and if a long time is expected for
processing in the scanner (e.g. , when the scanner receives the READ command and
prepares data to be transferred to the initiator).

The link will not be disconnected if bit 6 in the IDENTIFY message is 0. Also, it
will not be disconnected if the IDENTIFY message is not issued in a given command
sequence. For disconnect to occur therefore, bit 6 in the IDENTIFY message must
be set to 1.

When performing the disconnection during data transfer, this scanner sends the
SAVE DATA POINTER message before sending the DISCONNECT message so
that the data pointer is saved.

4 $ 94