Command Word; Flag Word 1 - Adaptec AHA-1740A Technical Reference Manual

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Command Word

The command word is a 16-bit structured field used to identify the operation to be
performed by the host adapter.
Command Word Structure
F E D
Options
Operation Code
Code (hex)
00
01
05
06
08
09
0A
10
Option Flags
The option flags (bits 14-12) are used to modify the meaning of the operation code
and/or the control block fields associated with the operation code. The meaning of
these flags are dependent upon the operation code that uses them.

Flag Word 1

Flag word 1 is a 16-bit structured field used to specify execution parameters for this
control block.
F E D
A D
R S
S B
Fields that are empty are reserved and should be set to zero.
6-4
C B A 9 8
Description
No Operation
Initiator SCSI Command
Run Diagnostic Test
Initialize SCSI Subsystem
Read Sense Information
Download Firmware
Read Host Adapter Inquiry Data
Target SCSI Command
C B A 9 8
S S
/ E
G S
AHA-1740A/1742A/1744
7 6 5 4 3
Operations Code
7 6 5 4 3
D
I
2 1 0
2 1 0
C
N
E