Byte Transfer Length (Cdb Bytes 6, 7, And 8); Download Microcode With Offsets (0110B); Download Microcode With Offsets And Save Mode (0111B) - Seagate SCSI Interface Product Manual

SCSI Interface Product Manual, Rev. J
5.51.4.2

Byte Transfer Length (CDB bytes 6, 7, and 8)

The Transfer Length in bytes of the downloadable code. This value must be the exact length of the download
data. A value of one signifies one byte of download data, etc.
5.51.5

Download Microcode with Offsets (0110b)

In this mode, the initiator may split the transfer of the vendor specific microcode or control information over two
or more Write Buffer commands. If the logical unit cannot accept this command because of some device condi-
tion, the logical unit shall terminate each Write Buffer command with this mode (0110b) with a Check Condition
status, a sense key of Illegal Request, and shall set the additional sense code to Command Sequence Error.
If the last Write Buffer command of a set of one or more commands completes successfully, the microcode or
control information shall be transferred to the control memory space of the logical unit. After a power-cycle or
reset, the device shall revert to a vendor specific condition. In this mode, the Data Out phase contains vendor
specific, self-describing microcode or control information.
Since the downloaded microcode or control information may be sent using several commands, when the logi-
cal unit detects the last Download Microcode with Offsets and Save mode Write Buffer command has been
received, the logical unit shall perform any logical unit required verification of the complete set of downloaded
microcode or control information prior to returning Good status for the last command. After the last command
completes successfully, the logical unit shall generate a Unit Attention Condition (see Section 4.6.5) for all initi-
ators except the one that issued the set of Write Buffer commands. When reporting the Unit Attention Condi-
tion, the logical unit shall set the additional sense code to Microcode Has Been Changed.
If the complete set of Write Buffer commands required to effect a microcode or control information change (one
or more commands) are not received before a reset or power-on cycle occurs, the change shall not be effective
and the microcode or control information is discarded.
The Buffer ID field identifies a specific buffer within the logical unit. The vendor assigns buffer ID codes to buff-
ers within the logical unit. A Buffer ID value of zero shall be supported. If more than one buffer is supported,
additional buffer ID codes shall be assigned contiguously, beginning with one. If an unsupported buffer ID code
is identified, the logical unit shall return Check Condition status and shall set the sense key to Illegal Request
with an additional sense code of Invalid Field in CDB.
The microcode or control information are written to the logical unit buffer starting at the location specified by the
buffer offset. The initiator shall conform to the offset boundary requirements. If the logical unit is unable to
accept the specified buffer offset, it shall return Check Condition status and it shall set the sense key to Illegal
Request with an additional sense code of Invalid Field in CDB.
The Parameter List Length specifies the maximum number of bytes that shall be transferred during the Data
Out phase to be stored in the specified buffer beginning at the buffer offset. The initiator should attempt to
ensure that the Parameter List Length plus the buffer offset does not exceed the capacity of the specified
buffer. (The capacity of the buffer can be determined by the buffer capacity field in the Read Buffer descriptor.)
If the Buffer Offset and Parameter List Length fields specify a transfer that would exceed the buffer capacity, the
logical unit shall return Check Condition status and shall set the sense key to Illegal Request with an additional
sense code of Invalid Field in CDB.
5.51.6

Download Microcode with Offsets and Save mode (0111b)

In this mode, the initiator may split the transfer of the vendor specific microcode or control information over two
or more Write Buffer commands. If the logical unit cannot accept this command because of some device condi-
tion, the logical unit shall terminate each Write Buffer command with this mode (0111b) with a Check Condition
status, a sense key of Illegal Request, and shall set the additional sense code to Command Sequence Error.
If the last Write Buffer command of a set of one or more commands completes successfully, the microcode or
control information shall be saved in a nonvolatile memory space (semiconductor, disk or other). The saved
downloaded microcode or control information shall then be effective after each power-cycle and reset until it is
supplanted by another Download Microcode and Save operation or Download Microcode with Offsets and
Save operation. In this mode, the Data Out phase contains vendor specific, self-describing microcode or con-
trol information.
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