Lpc 43s50FET256 processor and its connections
This device actually has two processor cores and includes many peripherals including an Ethernet MAC. It is not a development board it's an IC. By the way, it has no on-chip flash. 

Not wanting to be rude, but if you can't glean this from that datasheet, it sounds like a heck of an undertaking for you.

Why do you want to use this chip specifically?