User’s Guide 21020285 D
Chapter 5 Initiator Mode Pass-through Commands
Initiator Pass-through Parameter Block Format Page 5 - 3
Initiator Pass-through Parameter Block Format
In Chapter 4, a Base Parameter Block was introduced and explained in a general
context. Parameter Blocks are the same size, with the same general fields,
whether you are issuing a Pass-through command or an adapter Board-control
command. The information specific to Initiator Pass-through commands will
be covered in this section.
Command
Format
Use this format when issuing a Parameter Block containing an Initiator Pass-
through command:
Description of
the Fields
The Initiator Pass-through commands Parameter Block fields can be explained
as follows:
Command Identifier
The Command Identifier field is used to identify the Status Block associated
with a Parameter Block.
It must be a unique value.
Target ID
This value identifies the Target ID of the device th at is to r eceive the command
contained in the SCSI Command Descriptor Block.
Address Modifier
This value further defines the VMEbus Address specified for a data transfer.
Note
Valid Address Modifier
values can be found by
referring to a VME
Specification, Revision
D.
Addr Mod Address Modifier - These six bits inform the RF3880 adapter
what Address Modifier it should use for data transfer.
Address
Offset Byte Memory Address
Offset + 0 Offset + 1 Offset + 2 Offset + 3
00H Command Identifier
04H Flags-2 Flags-1 Addr. Mod. Target ID
08H VME Memory Address
0CH Transfer Count
10H 0 (OP Code) 1 2 3 SCSI 6, 10 or
12 byte
Command
Descriptor
Block
14H4567
18H 8 9 10 11
Table 25: Initiator Pass-through Parameter Block
BITS
76543210
00 Addr Mod
Table 26: Bit-meanings of Address Modifier Fiel d