Re: A quick Ethernet/Wireless straw poll please

["Mal Lansell" <mlansell@xxxxxxxxxxxxxx>]

You're right about USB WiFi - they are slave devices.

However, the CF cards can be used with microcontrollers - there is an
article in this months Circuit Cellar describing a data logging module that
communicates using a WiFi CF card.

I don't see a 10Mbit connection being a problem - the bandwidth is plenty
for this application, and the new faster hardware is surely going to be
backwards compatible (ie 10/100/1000)

Mal


----- Original Message -----
From: <ian.bird@xxxxxxx>
To: <ukha_d@xxxxxxx>
Sent: Friday, November 12, 2004 11:48 AM
Subject: RE: [ukha_d] A quick Ethernet/Wireless straw poll please



Thanks everyone.

>From the replies it is a 100% wired interface then.

USB is not an option for these as I think to run Ethernet interfaces the
USB controller needs to be a host rather than a slave. If this is the case
then this is very difficult to achieve in embedded hardware produced at
home. Same goes for PCMCIA both with hardware and the necessary coding
around supporting it. This is after all only a poor little 128kbyte micro
running at 14MHz with minimal resources. I would guess that a CF card
would suffer all the same problems.

By the time any of the above solutions had been designed, built, coded and
hardware bought I suspect there would be very little difference in cost to
the 80 quid plug it in and go embedded version.

Connecting external wireless hardware to the RJ45 port is fine although
products to do this are clumsy and not really cheap. I don't think an
access point would work for this but I am not an expert here.

Another question
How about a 10/100 interface. I had some chap from the States take a sharp
breath at _only_ 10Mbit saying that all new PC's over there are now
100/1000. Any thoughts? Basically these units would have to plug into a
switch or similar to reduce the throughput. Does anyone see this as an
issue over here in good old blighty?

Ian







"Paul Gordon" <paul@xxxxxxx>
12/11/2004 10:43
Please respond to ukha_d


To:     <ukha_d@xxxxxxx>
cc:     (bcc: Ian Bird/CV/Novartis)
Subject:        RE: [ukha_d] A quick Ethernet/Wireless straw poll
please



Hi Ian.

Couple of thoughts.

Personally, I'd always try to use a wired rather than a wireless I/F
whenever & wherever possible, and would only want to use wireless if
there
*really* wasn't any other way...

>From a flexibility & manufacturing POV, wouldn't it be better for
you to
just leave your device with a single wired interface, since anyone can
then connect that to an external wireless adapter if they wanted to.

Plus, given your projected price point, it seem as though it would
actually be cheaper for the end user to add their own off-board wireless
adapter; (after all, access points can be bought for as little as
£20-odd)...

As an alternative, rather than providing a built-in wireless interface,
couldn't you perhaps consider fitting either a PCMCIA or USB interfaces to
the board, and would this be significantly cheaper than fitting wireless?
- Again this would allow the end user to fit their own wireless interface,
and has the added benefit of giving them the choice of what wireless
interface they want to use...

This last point is my last comment on the flexibility aspect... - we all
know that current wireless hardware isn't necessarily 100% compatible
across all vendors.. - Different WiFi chipsets have interoperability
issues, certain manufacturers introduce proprietary features yadya-yada...
If you design in a wireless interface into the product, you are imposing
that choice on the end user, and potentially opening yourself up for
increased support burden when users can't get your particular flavour of
wireless to work on their flavour of wireless network...

Paul G.






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