3 port Ethernet Splitter on LPC213X

Started by radim100 April 5, 2006
I have question, regarding ETHERNET splitter, passive hub. I am
designing hardware with
LPC213X and ENC28J60 Ethernet chip . PC is going to talk from NIC to
this controller
TCP/IP (UDP) . Beside this LPC213X is going to communicate with modem
which has Ethernet port . Also PC will be able directly talk to modem
( configuration etc. )
So basically 3 Ethernet devices communicating ( LPC213X board, PC NIC
and Modem).
Is there any simple way ( passive connection etc. ) so I could have 2
RJ45 Ethernet connectors on my LPC213X board and plug-in one of them
PC and then Modem into second one and be able communicate each to
another ?
I know that I could use 3 port hub but if I could use something like
above I would prefer that solution.
Thanks Radim.

An Engineer's Guide to the LPC2100 Series

Hi Radim,

> Is there any simple way ( passive connection etc. ) so I could have 2
> RJ45 Ethernet connectors on my LPC213X board and plug-in one of them
> PC and then Modem into second one and be able communicate each to
> another ?

The KS8993 might meet your needs:
http://www.micrel.com/page.do?page=product-info/fastether_sw_unman.jsp#

One port allows direct connection to EMAC.
Another option is using an LPC2148 implementing USB RNDIS (MS technology).
This presents device as an Ethernet Adaptor to Windows. Then you would only
need to accommodate the modem. I have RNDIS running on LPC2148 now. Or you
could implement Linux Ethernet Gadget profile for multiple platform support.
Joel
--- In l..., "Joel Winarske" wrote:
>
> Hi Radim,
>
> > Is there any simple way ( passive connection etc. ) so I could
have 2
> > RJ45 Ethernet connectors on my LPC213X board and plug-in one of
them
> > PC and then Modem into second one and be able communicate each to
> > another ?
>
> The KS8993 might meet your needs:
> http://www.micrel.com/page.do?page=product-
info/fastether_sw_unman.jsp#
>
> One port allows direct connection to EMAC.
> Another option is using an LPC2148 implementing USB RNDIS (MS
technology).
> This presents device as an Ethernet Adaptor to Windows. Then you
would only
> need to accommodate the modem. I have RNDIS running on LPC2148
now. Or you
> could implement Linux Ethernet Gadget profile for multiple
platform support.
> Joel
>

Hi Joel,

Can you give some hints on USB RNDIS implementation as I like to
have a closer look at it and I think other people will be interested
too. In terms of time and effort how big the project is?

Jan
Hi Jan,

> Can you give some hints on USB RNDIS implementation as I like to
> have a closer look at it and I think other people will be interested
> too. In terms of time and effort how big the project is?

It wasn't exactly straight forward, and took some sleuthing. There is a
hacked RNDIS implementation in Linux under the guise of Linux Ethernet
Gadget class configuration two. I would suggest steering clear of this,
although it had one piece of the puzzle.

If there is commercial interest I will offer source for sale. My current
build is for IAR/LPC2148.

The RNDIS specification can be found here:
http://www.microsoft.com/whdc/device/network/NDIS/usbrndis.mspx
Joel