INQUIRY Data field to report transceiver type
John Lohmeyer
john.lohmeyer at symbios.com
Wed Sep 9 19:15:15 PDT 1998
* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* John Lohmeyer <john.lohmeyer at symbios.com>
*
T10/98-215 r0
September 9, 1998
To: T10 Technical Committee
From: John Lohmeyer, LSI Logic Principal Member of T10
Subj: INQUIRY Data field to report transceiver type
Currently SCSI has no standard way for target devices to
report their transceiver types. This proposal would define a
byte (56) in the INQUIRY Data to permit reporting of the
device's transceiver capabilities and to report the current
transceiver mode.
There are two benefits to adopting this proposal: 1) multi-
mode devices can report all of their transceiver capabilities
and 2) it may assist domain validation in detecting expanders,
particularly those that translate between transceiver modes.
I am proposing that byte 56 be defined as protocol-specific.
For parallel, this byte would be used as documented below.
For serial interfaces, byte 56 would remain reserved.
+------+-------+-------+-------+-------+-------+-------+-------+-------+
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
|Byte | | | | | | | | |
+------+-------+-------+-------+-------+-------+-------+-------+-------+
| 56 | reserved | LVD_C | HVD_C | SE_C | Tmode |
+------+---------------+-------+-------+-------+-----------------------+
An LVD_C bit of one indicates that the device is capable of
supporting low-voltage differential drivers and receivers. An
HVD_C bit of one indicates that the device is capable of
supporting high-voltage differential drivers and receivers. An
SE_C bit of one indicates that the device is capable of
supporting single-ended drivers and receivers. If all of
these bits are zero, the device does not support this
reporting function.
The Tmode field is defined as follows:
Tmode Description
------- --------------------------------------------
000b Device does not support this field or cannot
determine its driver/receiver type
001b Device is in single-ended mode
010b Device is in high-voltage differential mode
011b Device is in low-voltage differential mode
100b-111b Reserved
--
John Lohmeyer Email: john.lohmeyer at symbios.com
LSI Logic Corp. Voice: +1-719-533-7560
4420 ArrowsWest Dr. Fax: +1-719-533-7036
Colo Spgs, CO 80907 BBS: +1-719-533-7950
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