SC2500 User Guide Ver 2.1
May 6, 2003
Page 4 of 26
3. GENERAL DESCRIPTION
3.1 SCSI Interface
An intelligent SCSI controller from QLogic, the FAS209, handles the SCSI
interface for the SC2500. The FAS209 is SCSI-I and SCSI II compliant, and
automates much of the interface overhead. It has a 16 byte FIFO, a DMA
interface, and numerous command and control registers.
The SC2500 employs the following attributes:
1. Single-ended
drivers
2.
Termination power derived from cable or drive
3.
Parity on the interface
4.
"Hard" RESET implemented
5.
No reservation queuing
The SC2500 has implemented all mandatory SCSI-I and SCSI- II commands
and several optional commands to enhance functionality. The following is a
list of commands and their equivalent hexadecimal representation.
1.
Test Unit Ready
00h
M
2. Rezero
Unit 01h
O
3. Request
Sense
03h
M
4. Format
Unit 04h
M
5.
Read
08h
M
6.
Write
0Ah
O
7.
Inquiry
12h
M
8. Reserve
Unit 16h
M
9. Release
Unit 17h
M
10. Mode
Sense 1Ah
O
11. Send
Diagnostics
1Dh
M
12. Read
Capacity 25h
M
13. Extended
Read
28h
M
14. Extended
Write
2Ah
O
15.
Erase
2Ch
O
16.
Verify
2Fh
O
Notes:
O = Optional
M = Mandatory
The implemented messages on the SC2500 are as follows:
1. Command
Complete 00h
Generated
2. Extended
Message
01h
Both
3.
Init Detected Error
05h
Received
4. Abort
06h
Received
5. Message
Reject
07h
Generated
6. NoOp
Message
08h
Received
7.
Message Parity Error
09h
Received
8.
Bus Device Reset
0Ch
Received
9. Identify
80h
Received
