RE: [SI-LIST] : IDE bus question

Farrokh Mottahedin (Farrokh.Mottahedin@quantum.com)
Fri, 5 Feb 1999 09:44:53 -0800

For the latest recommendations on ATA bus termination (the term IDE is not
used anymore), please refer to the Annex C of ATA/ATAPI-4 rev 18 or
ATA/ATAPI-5 rev 1 standard. You may find these standards at
ftp://fision.dt.wdc.com/x3t13.

While I would agree with your characterization of the IDE bus as unruly, I
would also point out that with proper signal integrity measures Quantum has
been able to quadruple the bus transfer rate in the last three years from
16.6 to 33 and now to 66 megabytes per second. It boils down to the
following measures:
1) careful I/O cell design with edge rate control (I would caution against
the use of F244 & F245)
2) use 33 Ohm series termination on data lines
3) for Ultra 66 MB/s use a special 80 conductor cable which provides 40
additional grounds but is downward compatible with the 40 conductor ATA
connector on the device or host.

Regards,

Farrokh Mottahedin
Quantum Corporation
(408) 324-7934
farrokh.mottahedin@quantum.com

> -----Original Message-----
> From: Robert Stuart [SMTP:jrs@meridian-audio.com]
> Sent: Friday, February 05, 1999 1:23 AM
> To: 'SI Post, News'
> Subject: [SI-LIST] : IDE bus question
>
> I am new to this list and apologise if this subject has been handled
> before.
>
> Can anyone point me to the recommended solution, or options on whether and
> how to terminate an IDE bus.
>
> We have implemented a card to control DVD ROM drives using HC or F 244 and
> 245.
>
> It seems to me that the IDE bus is a bit unruly and we can find
> combinations
> of drives and cable lengths that misbehave at high data-rates.
>
> I am concerned to know how to terminate this driver to have the minimum
> chance of problems in the future when clients change cables, drives or add
> more drives. Of course, we are not a computer company and this may all be
> well understood, but I would appreciate a pointer.
>
> Thanks
>
> Robert Stuart
> Meridian Audio
> Cambridge, England
>
> http://www.meridian-audio.com
>
>
>
> Robert Stuart
> Meridian Audio
> Cambridge, England
>
> Fax 01480 451587
> http://www.meridian-audio.com
>
>
> **** To unsubscribe from si-list: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> si-list, for more help, put HELP. si-list archives are accessible at
> http://www.qsl.net/wb6tpu/si-list ****

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****