The Art of Prototyping

There is another huge advantage of using FPGA which I had left out in my previous post. In fact, this is one of the significant reasons the engineers are using the FPGAs. Seeing is Believing! Many IC Designers design their "designs" with simulation tools that cost them hundreds of thousand or even millions dollars, but sometimes all the simulation results before the first silicon is still not enough. So, the IC Designers work with the engineers who are familiar with the FPGA devices and tools to create a prototype for their designed IC using the RTL codes written by them. The prototype can reduce a lot of risk on the IC designed because if there is any bug found on the RTL codes, it can still be fixed, re-compiled on the FPGA tool and then verified on the FPGA again within a short period of time. As I told you in my previous post, the FPGA can be re-configured with any new design easily. In my working experience, the most impressive prototype that I had seen so far is the prototyping of a RF wireless chip in a Xilinx FPGA. Of course, the Xilinx FPGA only prototypes the digital portion of the RF chip, such as the microcontroller, JTAG (Joint-Test-Action-Group), etc.

The prototype can at least verify the functionalities of the new IC designed. But then you may ask, what is the difference between the FPGA prototype and the final product IC? Timing. It is difficult to match the timing between the FPGA and the ASIC (short form for the Application Specific IC, usually the IC designed has a specific application, such as graphics chip, USB device chip, etc) due to the different architectures inside the ASIC and the FPGA. Anyway, even if the FPGA cannot run as fast as the targetted ASIC frequency, it doesn't stop people from prototyping their final product in FPGA unless their final product is an analog device. You may also be curious, if that is the case, why don't the IC Design companies just sell their "ASICs" designs in the FPGAs? Well, the reason is simple, the cost is different. If they have the confidence that many people will love their ICs and their ASICs is going to make them a lot of money, then it is certainly very much more cost-efficient to go for ASICs. Two three years ago, FPGA vendors such as Altera and Xilinx have rolled out many low cost FPGAs such Cyclone series and Spartan series FPGAs. These low cost FPGAs certainly worth considered if the designs do not target very high frequency and high performance. However, if you are targetting the high-end FPGAs such as Stratix series or Virtex series FPGA, then you might consider selling your product with volume in ASIC because the high-end FPGAs are very expensive! Or, you may consider Altera HardCopy II as Altera promises "seamless" migration from FPGA to ASIC at NO pain!