Detection of a network connection on a switch

[ptitnain]

Hello

I am currently designing an ethernet driver on a PowerPC 8280. I'm using the evaluation board PQ2FADS-ZU.

To validate the issue of my ethernet frame, I connected with a crossover cable, my evaluation board to a PC with wireshark running. This configuration works. Frames are correctly sent and received on the distant PC. All my frames are displayed on wireshark.

My problem is this.
When I try to connect my evaluation board to a cisco switch (to send frames to multiple PCs), the switch (a Cisco Catalyst 2950) did not not detect the presence of a connection, the LED is off desperately.

So to sumarize, my PC network card can receive my ethernet frames, but my cisco switch can't. I don't know why.

In advance thank you.


PS: The connection is configured for full duplex 100M.

[jasmine01smith]

More detailed about cisco 2950 switch, wish can help you.

[ptitnain · Accepted solution]

Hello

I post this in case of someone would have the same problem as me.

I finally succeeded to solve my problem. The problem was  the "scrambler" function which was bypassed on the PHY interface.

I add some informations about the scrambler :

The scrambler is required to control the radiated emissions (EMI) by spreading the transmit energy across the frequency spectrum at the media connector and on the twisted pair cable in 100Base-TX operation.
By scrambling the data, the total energy presented to the cable is randomly distributed over a wide frequency range. Without the scrambler, energy levels on the cable could peak beyond FCC limitations at frequencies related to repeated 5B sequences like continuous transmission of IDLE symbols. The scrambler output is combined with the NRZ 5B data from the code group encoder via an XOR logic function. The result is a scrambled data stream with sufficient randomization to decrease radiated emissions at critical frequencies. 

This is an extract of the PHY interface documentation (DAVICOM DM9161). This PHY is used on the PQ2FADS-ZU evaluation board.

Regards.