Hardware emulation is the process of imitating the behavior of one or more pieces of hardware (typically a system under design) with another piece of hardware, typically a special purpose emulation system. The goal is normally debugging of the system being designed. Often an emulator is fast enough to be plugged into a working target system in place of a yet-to-be-built chip, so the whole system can be debugged with live data.
The largest fraction of silicon integrated circuit re-spins are due to (at least in part) functional errors. Thus, comprehensive functional verification is key to reducing development costs and delivering a product on time. Functional verification of a design is most often performed using logic simulation and/or prototyping.
Logic simulation is easy, accurate, flexible, and low cost. However, simulation is often not fast enough for large designs and almost always too slow to run application software against the hardware design. FPGA-based prototypes are fast and inexpensive. But the time required to implement a large design into several FPGAs can be long.
The usual compromise is to use simulation early in the verification process when bugs and fixes are frequent, and prototyping at the end of the development cycle when the design is basically complete and speed is needed to get sufficient testing to uncover any remaining system-level bugs.
Prototyping is also very popular for testing software.


Critical Requirements for Prototyping :
1. Largest Density possible
2. Largest amount of I/O
3. Largest available Memory
4. Highest Performance
5. Powerful Tools
6. Volume Cost Reduction Path
Xilinx Virtex6 FPGA are offering the highest in each category with devices reaching 760K Flip-Flops, 38Mb of internal RAM,
2,000 DSP MAC’s running at 600Mhz, 11Gbps serial links to connect multiple devices and more then 1200 I/O’s to connect external interfaces,
To allow you to emulate and prototype your largest designs.
Virtex-6 LXT FPGA Features
