Test scripting — An alternative approach to realtime instrument control

In many test applications involving high speed digital data buses, the time required to receive data from a Unit Under Test (UUT), process that data, and provide a response to the UUT may be small enough to preclude use of the computer controlling the overall test system, even if the nature of that data processing is not very complex. In these situations, Test Program Set (TPS) developers can use local computing power that is embedded in a particular test instrument. However, developing test programs to run on this embedded computing power can be difficult and involve purchasing additional software tools beyond what is provided with the test system. In addition, the embedded computer program does not run independently, but rather in tandem with and under the control of, the test program running on the test system computer. So, in addition to developing the algorithms to receive, process, and transmit data, the TPS developer must also provide the framework by which the overall test program can control these operations. The solution proposed in this paper helps simplify the TPS development effort by; 1) providing a simple scripting language that TPS developers can use to create test scripts that execute on the test instrumentation, 2) providing them with tools to code and compile those test scripts, 3) providing the necessary framework for them to allow the overall test program to control the operation of the test scripts, and relieving the TPS developers of that burden, and 4) providing an alternative to them having to purchase expensive, real-time programming tools. This paper identifies test applications where test scripting may be used effectively in reducing overall TPS development time, lists basic features of a test scripting language, describes the capabilities needed of the accompanying tool set, and how the test scripts would be developed and integrated into a TPS. The paper also includes a practical example of a test script used to dynamically modify data as part of a Fibre Channel based test application.