FYI - DEC fast ethernet compatibility

From: Dirk Grunwald <grunwald_at_foobar.cs.colorado.edu>
Date: Mon, 28 Apr 1997 09:54:37 -0600 (MDT)

In an earlier posting, someone quoted Mike Iglesias as saying...

> From: Mike Iglesias <iglesias_at_draco.acs.uci.edu>
>
> I've heard that any board with the TULIP chip works. You might try
> Kingston (www.kingston.com).

---
I'd just like to point out that this is not precisely correct.
Although the 21140 and related cards all report the same PCI vendor
and device ID (since that's part of the on-chip PCI configuration
information), the chip provides a set of eight "general purpose I/O"
pins. On DEC boards, a specific configuration of these pins is used
(best as I can tell) to sense the presence of a 100-Mbit carrier, to
kick an osscilator into 10/100Mbit and to signal the LED lights. The
assignment of pins is not specified in a standard, and some vendors
use a different mapping of pins to functions.
We bought some PC's that used the 21140 ethernet controller (as we
specified), but did not use the same DEC I/O pinout. This required
modifying the fast ethernet driver in Linux to use the cards. If you
didn't have Digital Unix source, you'd be up the creek, and it
wouldn't be obvious why for a while.
In general, when ordering you should specify FE cards that are known
to work in Digital Unix, or that are "fully compatible" with the
DE500.

Received on Mon Apr 28 1997 - 18:10:39 NZST