To be clear hard drive implementations only support an interrupt for SERVICE using a DMA protocol. As an aside we would be interested in receiving information on any ATAPI device that supports overlap and thus the use of the SERVICE function.
-----Original Message-----
From: Daniel J Colegrove [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, July 11, 2001 3:16 PM
To: [EMAIL PROTECTED]
Subject: [temp t13] Re: Service CMD question
** This is the quasi-official and semi-temporary T13 email list server. **
Sumit,
It is my understanding that both interrupts are required in case (2)
Service
Interrupt Enabled. The first is to indicate to the host that it is time to
read the
tag and set up the DMA engine. The second is the usual command
ending interrupt. Hard drive implementations do not support Service
Interrupt so I would defer to someone that has experience with Packet
queuing.
See figure 19 in ATA/ATAPI-6 state HI06:INTRQ_wait_B
Best Regards,
DC
Dan Colegrove
Senior Technical Staff Member
Storage Technology Division
IBM Corporation
702-614-6119
702-614-7955 fax
Tie Line 280-9959 (IBM internal)
[EMAIL PROTECTED]
Please respond to [EMAIL PROTECTED]
Sent by: [EMAIL PROTECTED]
To: "'[EMAIL PROTECTED]'" <[EMAIL PROTECTED]>
cc:
Subject: [temp t13] Service CMD question
** This is the quasi-official and semi-temporary T13 email list server.
**
Does anybody know the correct answer to his inquiry?
I don't know if this is addressed specifically in the ATA-6 spec.
thanks in advance for your help
- Sumit
We have a question regarding a SERVICE interrupt described in
ATA6 as following:
***************************************************************
8.50.21 Enable/disable SERVICE interrupt
Subcommand codes 5Eh and DEh allow a host to enable or disable
the asserting of an interrupt pending when DRQ is set to one in
response to a SERVICE command.
***************************************************************
Question::
In the case of (2), is it required that the INTRQ signal be
asserted necessarily twice? Or is it possible to omit the second
assertion (at the moment BSY gets low)?
We think that this description requires each signal be asserted
as following chart:
(1)When SERVICE interrupt is disabled
SERVICE Cmd Issue
|
| |----------------| Data Xfr
V___ ___
BSY __| |________________| |______
________________
DRQ ______| |__________
___
INTRQ ___________________________| |__
(2)When SERVICE interrupt is enabled
___ ___
BSY __| |________________| |______
________________
DRQ ______| |__________
___ ___
INTRQ _______| |_______________| |__
Question::
In the case of (2), is it required that the INTRQ signal be
asserted necessarily twice? Or is it possible to omit the second
assertion (at the moment BSY gets low)?
--
If you have any questions or wish to unsubscribe send a
message to Hale Landis, [EMAIL PROTECTED] To post to
this list server send your message to [EMAIL PROTECTED]
For questions concerning Thistle Grove Industries or TGI's
list services please send email to [EMAIL PROTECTED]
--
If you have any questions or wish to unsubscribe send a
message to Hale Landis, [EMAIL PROTECTED] To post to
this list server send your message to [EMAIL PROTECTED]
For questions concerning Thistle Grove Industries or TGI's
list services please send email to [EMAIL PROTECTED]
