Ciprico Rimfire 3880 manual Example 2Inquiry Pass-through Command, Example Pass-through command PB

Chapter 4 Command Operation

Some Example Single Commands Page 4 - 15

Example 2:Inquiry Pass-through Command

This example describes the issue of a Initiator Pass-through command. The SCSI Inquiry command is fully described in the SCSI specification.

This example shows you how to use the Single Command structure to issue an Initiator Pass-through command.

1.The set-up of a Pass-through command is the same as for a Board- control command. You must select a portion of system memory for the Single Command structure. You will need 52-bytes of space to hold the Parameter Block, Interrupt and Reserved fields, and the Status Block that make up a Single Command structure. For this example we’ll use the same memory address.

Example Memory Address = 822F4H

2.Fill in the Parameter Block information. (Detailed Parameter Block information for Initiator Pass-through commands is given in Chapter 5. For information about the SCSI Inquiry command, you must reference a SCSI specification or drive manual.)

These are the Parameter Block values for this example:

Address		Byte Memory Address
Offset	Offset + 0	Offset + 1	Offset + 2	Offset + 3
00H		Command Indentifier = 000822F4H
04H	Flags-2 = 0	Flags-1 = 0	Addr Mod = 3DH	ID = 01H
08H		VME Memory Address = 00099450H
0CH		Transfer Count = 24H
10H	Command = 12H	LUN = 0	Reserved = 0	Reserved = 0	Inquiry
					6-Byte
14H	Allocation = 24H	Flag/Link = 0	0	0
					Command
18H	0	0	0	0	Descriptor
					Block

Table 23: Example Pass-through command PB

Command Identifier = 822F4H - Even though the Status Block is part of the Single Command structure and easily identified it is good to provide a value here in order to be consistent with Command List structures. The value chosen is the address of the Single Command structure.

ID = 01H - Indicates to the RF3880 adapter that this Pass-through command should be directed to device ID 1.

Address Modifier = 3DH - This value indicates Standard Supervisory Data Access mode will be used to execute the Inquiry command.

Flags-1 = 0 - This byte is used to control aspects of command operation. None of the features are enabled for this command.

Flags-2 = 0 - This byte offers further command control options. None of the additional features are enabled for this example.

VME Memory Address = 99450H - System Memory address to which the Inquiry data will be returned.

Transfer Count = 24H - This value is the number of bytes of data that will be transferred for this command. The Inquiry data returned by this device is contained in 36 (24H) bytes.

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