Enabling ECP...

John Lohmeyer lohmeyer at t10.org
Fri Sep 7 07:32:02 PDT 2001


* From the T10 Reflector (t10 at t10.org), posted by:
* John Lohmeyer <lohmeyer at t10.org>
*
At 04:09 PM 8/29/2001, Mike Kosco wrote:
>* From the T10 Reflector (t10 at t10.org), posted by:
>* Mike Kosco <Mike at ChipCraft.com>
>*
> From SPI-4 rev06, annex G:
>
>G.4 Enabling ECP
>Following a hard reset (see 12.4), a communicative expander shall
>function as a simple expander for each
>initiator until the initiator enables ECP as follows:
>1) negotiate asynchronous transfer mode and a transfer width of 8 bits
>to some target; and
>2) issue a WRITE BUFFER command to that same target with the MODE field
>set to echo buffer plus
>enable ECP (see SCSI Primary Commands-2 standard).
>
>What does "plus enable ECP" mean?  I believe ecp is enabled by
>
>1) negotiate asynchronous transfer mode and a transfer width of 8 bits
>to some target; and
>2) issue a WRITE BUFFER command to that same target with the MODE field
>set to echo buffer, and
>3) issue  echo buffer write data with an expander function header
>containing the expander signature followed by SEDB(s)/LEDB... etc
>
>Am I missing something here?,

Mike,

The accepted ECP proposal (T10/00-257r3) expanded the WRITE BUFFER command 
MODE field to 5 bits and included some new MODE field values:

   1Ah  Echo buffer plus enable ECP
   1Bh  Disable ECP

These values were accepted for inclusion in SPC-3 at the September 14, 2000 
meeting of T10 under agenda item 10.3.1 (see 00-308r1).  I just noticed that 
00-257r3 is NOT in Ralph's list of stuff to be included in SPC-3, so I am 
copying him on this email.  Thanks for asking about this!

Regards,
John


--
John Lohmeyer                  Email: lohmeyer at t10.org
LSI Logic Corp.                Voice: +1-719-533-7560
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