RTC Magazine

Imagine if a single-board design could fulfill the needs of every project. What if you could configure an entire board, or several boards in the same platform, to meet the needs of any part of a system or all needs of a complete system? What if you could rapidly fashion system hardware components like microprocessors; peripherals; filters; control loops; (add your desired functionality here); and UART, SPI and I2C controllers in the right mix to specifically and exactly meet the needs of your application?

Ten years ago this would have seemed like pie-in-the-sky thinking, when most standard logic blocks like Ethernet, CAN and USB controllers; microprocessors and memory controllers; and UARTs were still relegated to off-the-shelf hard logic silicon devices. However, FPGAs are now achieving attractive volume price points and sizes, such that even a full 32-bit microprocessor constitutes only a small fraction of overall cost and size. FPGAs now represent a more viable option than ever for tackling nearly any type of application imaginable. This includes designing FPGAs into products, using FPGAs to test products or even using FPGA-based hardware for controlling and manufacturing products.

FPGAs are everywhere, and with the availability of an enormous amount of FPGA-targeted intellectual property (IP) blocks from FPGA hardware vendors, third-party IP suppliers and the FPGA community, you can take an idea from paper to silicon more rapidly than you would think. With the task of creating all but application-unique IP blocks out of the way, most of the work in creating a completely unique system targeted to your specific needs becomes more of the integration and assembly process itself. FPGA vendors and companies with FPGA-based products have even taken this to the next level of productivity by introducing new levels of abstraction with higher-level design tools that integrate IP components and I/O through graphical block diagrams.

The value of using FPGAs goes beyond simply being able to tackle many applications with one board because you also can solve problems with more degrees of freedom. Previous board solutions generally contained a fixed microprocessor or application-specific standard product (ASSP) and associated hard logic in a rigid architecture, limiting the ways in which performance could be achieved; an FPGA-based board has an architecture that can be tuned for accelerated performance. Tasks can be optimally moved between hardware and software and implemented to operate in parallel—by adding more soft microprocessors to the mix, by duplicating hardware function blocks or by a mixture of these by adding coprocessing components directly to the microprocessors themselves. The combination of performance and flexibility provides clear benefits for any given application, and whether you are working with embedded designs, test equipment or control systems, FPGAs have become an integral part of our world today.

FPGAs in Embedded Designs

It is clear that FPGAs are employed in a wide range of applications today. You are probably already considering an FPGA for your next design for many of its basic benefits such as flexibility and integration. However, as the available IP catalog continues to grow, more FPGA designs are beginning to look like system-on-a-chip (SoC) designs. With the majority of SoC designs containing a microprocessor, it is no small coincidence that one of the most recent arrivals on the FPGA IP scene is the embedded 32-bit microprocessor. Creating application-specific embedded designs using FPGAs as the base technology is gaining traction. A Gartner report shows that by 2010, more than 40 percent of all FPGA designs will contain an embedded microprocessor.

Based on processing speeds, with more than 200 MHz for soft processor implementations and hard block implementations exceeding twice that amount, nearly 80 percent of all embedded 32-bit application needs are addressable inside an FPGA. Having the microprocessor inside the FPGA does not imply compromises either. As an example, Xilinx offers a soft 32-bit microprocessor called MicroBlaze with configurable instruction and data cache sizes, which includes an optional memory management unit (MMU) for protected memory accesses. While this soft core can be targeted to any of its FPGA devices, Xilinx also offers a hard 32-bit PowerPC processor in its higher-end Virtex line. With the open standard processor local bus (PLB) interface present on both of these processors, they can connect to a large number of supplied peripherals and acceleration logic (Figure 1).