Lpc2000

On 1 Feb 2005 at 22:52, Rick Collins wrote:

> 
> 
> --- In lpc2000@yahoogroups.com, "Anton Erasmus" <antone@s...> wrote: >
> On 31 Jan 2005 at 5:07, Rick Collins wrote: > > [Lots of stuff
> snipped] > > > > I understand that the W3100A would be simpler to use,
> but I believe > > you said it did not support 100 base TX, right? The
> LAN91C111 is not > > an inexpensive chip, but it includes the PHY so
> all you need to add is > > the transformer and the connector and that
> end is ready to plug into a > > network.  Yes, it needs a lot more on
> the other side, but making a > > general app board, I want to be able
> to support 100 base TX.  Even if > > you don't need the data rate,
> this can be an advantage is some cases > > and it should still meet
> the selling price target of $99, qty 1.  > > > > I will need to
> project a parts list in the next couple of days, now > > that I have
> been promised samples of the AT91SAM7S64.  This is pin > > compatible
> with the SAM7S128 and SAM7S256 and will do for initial > > prototypes.
>  > > No the W3100A does support 100 base T. Although you need a
> seperate > PHY and of course the magnetics + connector. They have a
> module which > includes the W3100A device + the Realtek RTL8201L Phy.
> One only need > to add the magnetics. If you actually use the module,
> then you can offer > the board without the module at a reduced price,
> and people can later > add it. Nice when one is on a tight budget.
> 
> Unless you really need some speed.  You said it interfaces by I2C
> which is very slow by comparison, ~400 kbps vs. >10 Mbps.  

That is if you use the I2C bus - I would only use this on a legacy product 
that does not have enough pins for the parallel mode. The normal method
is to map it to a 8-bit 16K SRAM block. When one wants to send a packet,
one copies the data to the specific socket Tx buffer, and set a bit to transmit
the data. The hardware will handle any TCP/IP overhead. 
Normal frequency for bus timing is 25MHz, but a clock up to 50MHz can be
used. the device can easily do the full 100Mbps using the normal
parallel mode.

> I don't plan to sell the board in versions, that gets to be a PITA.
> But I will likely sell a bare board version if you want to
> do-it-yourself.  

I seldom buy these sort of products, hence I am obviously not the
target market, hence not in a position to say whether this is a good
or bad idea.

Regards
   Anton Erasmus

 
 
-- 
A J Erasmus