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29 WRITE BUFFER (3Bh)
Time Required to Load Code with WRITE BUFFER
As shown in Table 29-1, just over one minute is required to load new
microcode from the SCSI bus using a single WRITE BUFFER command.
Note:
Slightly more time may be required to load new microcode using
several WRITE BUFFER commands. This increase in time is
related to host overhead.
Table 29-1 Time Required to Load Code with WRITE BUFFER Command
Step
Time required (seconds)
Transfer the data across the SCSI bus
4
Validate image in buffer
19
Load new code into flash EPROMs
16
Perform a power-on reset and self-test
32
TOTAL
71 (approx.)
After the new code has been downloaded successfully, the EXB-8500 returns
Good status to the initiator that issued the WRITE BUFFER command. It
returns Check Condition status with the sense key set to Unit Attention (6h) to
commands sent by other initiators. The ASC and ASCQ fields will be set to
3Fh and 01h, and the Fault Symptom Code will be C3h.
29.1 Field Definitions
Byte 01, Bits 2 through 0 - Mode
The Mode field determines the type of operation to be performed. The only
operation supported by the EXB-8500 is downloading and saving the
microcode. The bits in this field must be set to 101b.
Byte 02 - Buffer ID
This field must be 0.
December 1991
29-3