Triple speed ethernet problem

I would suggest to use one of the software examples first (such as the simple sockets server). They use the Interniche TCP/IP stack and some ready made drivers. This will at least let you know if there is a problem on the hardware side and/or the interface between the TSE and the PHY. Once you got that working, you can start implementing your own solution if you want.

IIRC there are a few steps necessary before you can read/write data on the TSE, such as setting up the MAC address and configuring the link speed.

I also see that you are sending the preamble. You shouldn't do that, it is automatically added by the TSE.