Here are some practical tips on how to develop software for FPGA embedded processors. s product designs increase in complexity, there is a need to use integrated components, such as application-specific standard products (ASSPs), to address design requirements. Years ago, engineers chose individual components for processor, memory and peripherals, and then pieced these elements together with discrete logic. More recently, they would search through catalogs of ASSP processing systems attempting to find the nearest match to meet system requirements. When they need additional logic or peripherals, they often mate an FPGA with an ASSP to complete the solution. Indeed, surveys indicate that FPGAs are now a part of 50 to 70 percent of all embedded systems. Over the last few years, FPGA sizes have increased, providing sufficient space to accommodate complete processor and logic systems within a single device. Software engineers are now faced with developing and debugging code targeting a processor inside of an FPGA—and in some cases they fear doing so. But a grasp of FPGA basics and an understanding of how to create and debug code for FPGA embedded processors will go a long way to settle their nerves.
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WHAT IS AN FPGA? A field-programmable gate array (FPGA) is an integrated circuit containing logic that may be configured and connected after manufacturing, or “in the field.” Where in the past engineers purchased a variety of logic devices from a catalog and then assembled them into a logic design via connections on a printed-circuit board, today hardware designers can implement complete designs within a single device. In their simplest form FPGAs contain: ■
Configurable logic blocks consisting of AND, OR, Invert and many other logic functions
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Configurable interconnect enabling logic blocks to be connected together
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I/O interfaces
With these elements, users may create an arbitrary logic design. Second Quarter 2011
Xcell Journal
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