Signal Processing at Warp Speed

FPGAs Allow Industrial OEMs to Eliminate Signal Processing Speed as a Design Constraint

There are now more FPGA design starts than ASIC design starts, and two FPGA companies are among the top 10 chip suppliers.

Manufacturing semiconductor chips is a complex process that was heretofore best left to chip vendors. Of late, there are improvements in Field Programmable Gate Arrays (FPGAs) that create a viable way for I/O vendors and for industrial machine, robot, and skid-builder OEMs to create their own silicon.

FPGAs are user-programmable semiconductor chips. The advantages to creating a custom silicon-based solution are amazing gains in speed, substantial cost savings, and incredible reductions in size, power consumption, and heat generation. These gains materialize because it is often possible to replace an application-specific integrated circuit (ASIC) chip, a printed circuit board, or even a board set with a single FPGA.

FPGAs have been around for decades, but their use largely was limited to niche applications such as prototyping and emulation systems. The number of logic gates per chip was too low to implement real products and FPGAs were just too expensive. In the past four years, FPGA technology has improved significantly and this, in turn, is increasing their popularity and changing the way FPGAs are applied.

FPGAs are now being incorporated into mainstream applications such as networking, consumer electronics, and signal processing. There are now more FPGA design starts than ASIC design starts, and two FPGA companies are among the top 10 chip suppliers. Find some background on this at (http://www.techonline.com/pdf/pavillions/standards/trenz_fpga.pdf).

So, what does this mean to industrial OEMs? At the vendor level, I/O products are now much easier and cheaper to produce. "We are developing a new stepper-motor controller that has the CPU, floating-point processor, dedicated counting hardware, and dedicated pulse output hardware on one FPGA," says Robert Oglesby, president of Host Engineering (http://www.hosteng.com), a technology provider to AutomationDirect. A bigger, faster CPU could accomplish the same thing, but at a price, power, and size premium."

Because I/O vendors are now exploiting FPGA technology to make better products, industrial OEMs can expect faster product introductions, lower costs, and increased performance for off-the-shelf I/O modules. This is exciting news, but the most significant benefit of FPGA-based I/O for machine builders will be customized I/O signal-processing modules.

Have you ever had a requirement for an I/O module that just could not be met by available devices? Maybe you needed a particular speed requirement, or a custom communication protocol was required, or perhaps a precise synchronization was necessary. Maybe it was a combination of all these factors.

Typically, the only available solution was tp specify custom hardware and/or custom software. As everyone is aware, customization increases costs and leadtimes in virtually all cases, and is not technically feasible for many industrial OEMs. I/O vendors are happy to customize, but non-recurring engineering costs can be exorbitant.

When a machine builder has a special I/O signal processing requirement, vendors are now using FPGAs to meet their needs. The vendor no longer has to approach an ASIC vendor or a printed-circuit board vendor for a custom product.

All I/O vendors are already using FPGAs to create custom and standard I/O signal processing and signal conditioning products, and at least one firm now provides tools that enable OEMs to customize I/O products using FPGAs.

Most FPGA programming is done with a hardware description language called Verilog (http://www.verilog.com). While Verilog is fine for chip designers and programmers, in practice it is somewhat arcane for most OEMs.

National Instruments (http://www.ni.com) has addressed this market disconnect with a product called Reconfigurable I/O (RIO). RIO lets OEMs program FPGAs with the high-level graphical programming found in National Instrument's LabView product.

National Instruments sells RIO-enabled 8 or 16-channel modules for voltage, current, RTD, strain gauge, or frequency inputs. Each module contains user-programmable FPGA chips. LabView also provides tools to simplify FPGA programming. "After writing an FPGA application,the code is automatically compiled to synthesize digital logic and downloaded to the FPGAs," says Brian MacCleery, the industrial control and measurement product manager with National Instruments.

Many I/O signal-processing tasks require high speed and precise synchronization. Traditional solutions that pass I/O signals to a main processor often cannot meet high-speed requirements. ASICs and custom boards are a solution, but it is very difficult to implement iterative designs with these "hard-wired" solutions.

FPGAs allow OEMs to virtually remove speed as a design constraint, and iterative design is a given because FPGAs can be reprogrammed again and again. Once speed is removed as a constraint, entirely new and better methods of designing I/O signal processing and control systems can be used.

In addition to processing I/O signals, FPGAs mounted on combo I/O boards with inputs and outputs are being used to create full custom silicon-based controllers with unprecedented processing speed and lighting-fast execution times.

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