Chapter 4 Command Operation

Page 4 - 4

 

 

 

 

 

 

 

The Base Parameter Block

The Base

The Parameter Block is one of the basic building blocks of the RF3880

Parameter

command structures. It is designed to hold all facts relevant to a single

command.

 

 

 

 

 

 

Block

 

 

 

 

 

 

The same Parameter Block format is used whether the command is a Pass-

 

 

 

 

through command directed to a SCSI device, or a Board-control command to

 

 

be interpreted and acted on by the adapter. (The various flags and byte values

 

 

may have different meanings in each case though.)

 

 

 

 

All Board-control commands are described in detail in Chapter 7. More

 

 

information about how the RF3880 implements SCSI commands can be found

 

 

in Chapter 5. See a SCSI specification and vendor-supplied peripheral

 

 

documentation for details about particular SCSI commands.

 

 

Parameter

The Parameter Block format for all Pass-through and also adapter Board-

Block Format

control commands is illustrated below:

 

 

 

 

 

 

 

Address

 

 

Byte Memory Address

 

 

 

 

 

Offset

 

Offset + 0

Offset + 1

 

Offset + 2

Offset + 3

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

00H

 

 

Command Identifier

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

04H

 

 

 

 

 

Target/Adapter ID

 

 

 

 

 

 

 

 

 

 

 

 

08H

 

Command Options, Addresses, and Transfer Count

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0CH

 

 

 

 

 

 

 

 

 

 

10H

 

Command Code

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

14H

 

 

 

Command Descriptor Block

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

18H

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 17: Base Parameter Block

 

 

A brief description of each of the fields follows:

Command Identifier

When setting up a command structure, you use this field to distinguish a command in order to associate it with a returned Status Block. The value is a double-word and must be unique; the Command Identifier for each currently executing command should be different. Any unique four-byte value will work. You could, for example, use the command address or a Parameter Block Index pointer as the Command Identifier. Both Pass-through commands and adapter Board-control commands use this field for proper identification of status to be returned whether the command is issued in a Single Command structure or a Command List.

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User’s Guide

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Ciprico Rimfire 3880 manual Base, Parameter, Block Format