Control Byte; Status - Seagate ST11200 Product Manual

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4.2.6

Control byte

Normally all zeros. Typically, the disc drive does not support the Flag and Link bit functions. It can be sup-
ported as a special factory installed option.
Bit 7
Byte(s)
LAST
0
*Bit Description
1 Flag bit - If the link bit is zero, then the flag bit shall be set to zero. If the link bit is one, and if the
command terminates successfully, the target shall send LINKED COMMAND COMPLETE mes-
sage if the flag bit is zero and shall send LINKED COMMAND COMPLETE (WITH FLAG) mes-
sage if the flag bit is one. Typically, this bit is used to cause an interrupt in the initiator between
linked commands.
0 Link bit - This bit is set to one to indicate that the initiator desires an automatic link to the next
command upon successful completion of the current command. Implementation of linked com-
mands is optional. If the link bit is one, upon successful termination of the command, the target
shall return INTERMEDIATE status and shall then send one of the two messages defined by the
flag bit (above).
4.3

Status

A status byte shall be sent from the target to the initiator during the STATUS phase at the termination of each
command as specified in Tables 4.3-1 and 4.3-2 unless the command is cleared by one of the following
conditions:
1. an ABORT message
2. a BUS DEVICE RESET message
3. a hard reset condition
4. an unexpected BUS FREE condition (see 3.1.1)
5. an ABORT TAG message
6. a CLEAR QUEUE message
Bit 7
Byte(s)
0
Product Manual - Disc Drive SCSI-2/SCSI-3 Interface (Vol. 2; Ver. 2), Rev. E
Table 4.2.6-1. Control byte
6 5
0 0
Table 4.3-1. Status byte
6 5
Reserved
4 3
0 0
4 3
Status Byte Code
2 1
Flag* Link*
0 0 or 1 0 or 1
2 1
Rsvd
0
0