Firmware development methodologies for synthetic test instrumentation

Traditional test equipment typically offers a fixed set of pre-determined functionality that is exposed to the test engineer by one or more fixed application programming interfaces. When building a general purpose test system using traditional test equipment, it is common to include a separate piece of test equipment for each supported protocol or bus type. As a result, these purpose-built test systems tend to have a large footprint, are difficult to maintain, and have a high obsolesce risk. To combat these issues, many system integrators are moving towards synthetic test instrumentation that can provide the functionality of several traditional test instrument With the increasing popularity of synthetic test instrumentation, many instrument vendors allow test engineers develop their own FPGA firmware to create custom runtimedefined test instruments better suited to the specific needs of each application. Custom firmware allows a single synthetic instrument to support multiple standard and proprietary protocols, add non-standard functionality to standard protocols, insert application specific test capability. Custom FPGA firmware development has not traditionally been the responsibility of test engineers. As a result, developing FPGA firmware for synthetic test instrumentation often presents a new development challenge that must be met. Many synthetic test instrument manufacturers have acknowledged this challenge and provide various methods to assist the test engineer in creating custom firmware. Methods include development tools and applications, graphical programming environments, integration with third party development tools, firmware template applications, and example source code. Each firmware development methodology has its own benefits and limitations, and provides varying levels of ease use, flexibility, portability, and functionality. When choosing synthetic test instrumentation, it is important that a test engineer take into account the available firmware- development methodologies and ensure that they are a good match for their current and future development requirements. This paper compares and contrasts some of the various development methodologies currently available.