FPGAs? Yes... Maybe

July 22, 2002
Why just build peripherals when it's possible to construct an entire SoC using an FPGA? Companies such as Altera, Xilinx, and Actel deliver low-complexity FPGAs with enough logic to implement a CPU and its peripherals (see "Programmable Logic...

Why just build peripherals when it's possible to construct an entire SoC using an FPGA? Companies such as Altera, Xilinx, and Actel deliver low-complexity FPGAs with enough logic to implement a CPU and its peripherals (see "Programmable Logic Challenges Traditional ASIC SoC Designs," electronic design, April 15, p. 44).

Actel's largest flash memory-based ProASIC Plus series incorporates over 1 million gates and almost 200 kbits of RAM. This is more than sufficient to implement a RISC processor and a host of peripherals, although on-board programming requires an off-chip processor. Altera and Xilinx have multimegagate, SRAM-based technologies that have been used to implement complex processors and peripherals.

There are two problems with this approach, however. One is the amount of expertise required to configure a large FPGA. The other is that implementing a processor via an FPGA is less efficient than using a fixed CPU core.

FPGA configuration is often done using register transfer logic (RTL) or Verilog. This makes the design transferable to a custom ASIC once the design has been proven or volumes increase. The downside is that this level of design is beyond most embedded developers. Routing problems are significant when dealing with very large logic arrays versus smaller FPGAs found in an architecturally mixed environment.

Although many of the chips covered in this article use an FPGA, configuration of peripherals is frequently done with libraries of components instead of a fully customizable solution. This lets developers deal with peripherals from a logical standpoint instead of a low-level logic implementation.

About the Author

William G. Wong | Senior Content Director - Electronic Design and Microwaves & RF

I am Editor of Electronic Design focusing on embedded, software, and systems. As Senior Content Director, I also manage Microwaves & RF and I work with a great team of editors to provide engineers, programmers, developers and technical managers with interesting and useful articles and videos on a regular basis. Check out our free newsletters to see the latest content.

You can send press releases for new products for possible coverage on the website. I am also interested in receiving contributed articles for publishing on our website. Use our template and send to me along with a signed release form. 

Check out my blog, AltEmbedded on Electronic Design, as well as his latest articles on this site that are listed below. 

You can visit my social media via these links:

I earned a Bachelor of Electrical Engineering at the Georgia Institute of Technology and a Masters in Computer Science from Rutgers University. I still do a bit of programming using everything from C and C++ to Rust and Ada/SPARK. I do a bit of PHP programming for Drupal websites. I have posted a few Drupal modules.  

I still get a hand on software and electronic hardware. Some of this can be found on our Kit Close-Up video series. You can also see me on many of our TechXchange Talk videos. I am interested in a range of projects from robotics to artificial intelligence. 

Sponsored Recommendations

Comments

To join the conversation, and become an exclusive member of Electronic Design, create an account today!