Of all the gin joints in all the towns in all the world, Jason Thorpe had to
walk into mine and say:

> On Sat, 29 Jan 2000 13:50:23 -0500 (EST) 
>  wpaul@ee.columbia.edu (Bill Paul) wrote:
> 
>  > I asked the Davicom people why the problems with the DM9102 weren't
>  > documented in their datasheet in an errata section. They told me that
>  > they didn't consider it an issue because typically their customers that
>  > use the DM9102 chip also use the drivers that Davicom provides them,
>  > which are written by Davicom engineers and have workarounds for the
>  > problems. I harrassed them a bit over this; hopefully it will have some
>  > effect.
> 
> Well, that's annoying!  :-)
> 
> I have some DM9102 boards on the way from Davicom, but they're apparently
> stuck in customs!  Grumble.  Anyhow, I'll keep this in mind when adding
> support for the chip.

They sent me two DM9102A cards recently that took a couple of weeks to
arrive. The DM9102A is essentially the same as the DM9102 except it has
an external MII interface. The eval boards they sent me have both
fast ethernet and HomePNA interfaces, with the HomePNA PHY connected
to the external MII interface. However, the way they did it, the
external MII management interface is separate from the internal one,
meaning that when you flip the port selection bit in CSR6, you can
see either the interal PHY or the external one, but not both at the
same time. In fact, the internal and external PHYs are wired to MII
address 1.

This struck me as a bit goofy since it means you need to do two MII
bus probes in order to find both PHYs, and you need two miibus device
handles to handle both buses.
 
>  > Believe it or not, there is also a 3com clone chip. The Sundance Technologies
>  > ST201 chip uses a programming interface that's a close copy of the 3c90xB.
>  > It also allows arbitrary byte alignment for RX DMA buffers, like the 3c90xB,
>  > which makes it the only chip other than the 3Com boomerag/cyclone/etc,
>  > the Intel 82557/8/9 and the Texas Instruments ThunderLAN that does this.
>  > (Well, the gigE cards do it too, but that's another class of adapter.)
> 
> Can you please point me at a datasheet for the ST201, and tell me which
> card has it?  So far, Sundance hasn't responded to my requests for a
> datasheet and demo board.

I originally got a preliminary copy of the ST201 datasheet from D-Link,
who is apparently using it on a card called the DFE-550TX. I was told this
card would appear on the U.S. market eventually, but I haven't seen it
yet. D-Link sent me two sample cards. If you can't get one from Sundance,
I can probably part with one of mine. However, don't let Sundance off the
hook too easily. I originally had my copy of the datasheet on www.freebsd.org
(which I normally do for datasheets from companies who don't already have
manuals on their web sites -- since I don't sign NDAs, if they give me
something, then I feel justified in doing anything I damn well want with
it), however the Sundance people complained and asked me to take it away
from there. I told them that I would only do it if they made it readily
available on their own server, and if they didn't, then I would put it
back.

Since they don't seem to have gotten them message, I'm putting it back.
You can find it at http://www.freebsd.org/~wpaul/Sundance/st201.pdf.
If they don't like it, they can go to hell.

Note: there is one gotcha. On pages 50 and 51, the MACCTRL register
is described as being a single 32-bit register. However the register
summary on page 44 shows it as being two adjacent 16-bit registers.
The register summary page is correct: it actually is two 16-bit
registers. Trying to to treat it as a single 32-bit register doesn't
work. This means you need to divide up the bit definitions into two
16-bit sets instead of one 32-bit set. Not a big deal really, but I got
really confused by this initially and it took me a while to figure out
where I'd gone wrong. They may have fixed this in later versions of
the manual. (Though I wouldn't bet real money on it.)

-Bill

-- 
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-Bill Paul            (212) 854-6020 | System Manager, Master of Unix-Fu
Work:         wpaul@ctr.columbia.edu | Department of Electrical Engineering
Home:  wpaul@skynet.ctr.columbia.edu | Columbia University, New York City
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"Mulder, toads just fell from the sky!" "I guess their parachutes didn't open."
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