fpga4fun

Hi

I saw this cool project on fpga4fun on 10baseT ethernet. it's so cool
needs only 2 lines. like rs-232.
I like to try it, but my board has this LXT972 chip (ethernet PHY
thingy, like those MAXxxxx rs-232 voltage convertor thingy) sitting
between my
x2cv2000 fpga and the connector. it has so many pins that i don't know
what to do with them.

Can someone know about voltage and stuff tell me how to do.
can i rewire say 2 of the 5 rs-232 lines to be used as Ethernet_TDp
and Ethernet_TDm ?



thanks.

If your board RJ45 connector is hard-wired to the PHY chip, you can't use
it, you need to buy a separate RJ45 connector and wire it manually to 2 IOs
of the FPGA.
Jean

On 18 Jan 2004 10:17:25 -0800, paulw@mmail.ath.cx (Paul) wrote:

>Hi
>
>I saw this cool project on fpga4fun on 10baseT ethernet. it's so cool
>needs only 2 lines. like rs-232.
>I like to try it, but my board has this LXT972 chip (ethernet PHY
>thingy, like those MAXxxxx rs-232 voltage convertor thingy) sitting
>between my
>x2cv2000 fpga and the connector. it has so many pins that i don't know
>what to do with them.

It's called MII, and is quite a simple interface.  Had you tried
reading the datasheet?
http://www.intel.com/design/network/products/lan/datashts/24918603.pdf
Note: the LXT972 does 4B5B code conversions (when in 100Base-T mode)
or Manchester encoding (when in 10Base-T mode).  It is not a simple
voltage level converter like a MAX232.

>Can someone know about voltage and stuff tell me how to do.
>can i rewire say 2 of the 5 rs-232 lines to be used as Ethernet_TDp
>and Ethernet_TDm ?

If you want a truly Ethernet standard interface you should stick with
the hardware you have.  Otherwise, you can use Jan's interface if you
have access to some spare I/O pins.

Regards,
Allan.