Browse Prior Art Database

RAPID SYSTEM TESTING OF EMBEDDED SYSTEMS

IP.com Disclosure Number: IPCOM000009696D
Original Publication Date: 2000-Jan-01
Included in the Prior Art Database: 2002-Sep-11
Document File: 3 page(s) / 155K

Publishing Venue

Motorola

Related People

Craig Schaefer: AUTHOR

Abstract

Testing the functionality of embedded automo- tive control unit in a real-time environment is a dif- ficult task. Testing involves setting every possible combination of the units input and output for each stated behavior. When the stated behaviors of the unit are large the number of unique test cases is exponentially larger, simply due to combinatorial mathematics. Therefore the time to test a unit is also significantly long.

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0 M MO-LA Technical Developments

RAPID SYSTEM TESTING OF EMBEDDED SYSTEMS

by Craig Schaefer

  The switch box contains an array of switches
that the unit controls and monitors that the test per- DETAILED DESCRIPTION
son can manipulate to exercise the tests. This meant
that tests were subject to human error and hard to
reproduce in a real-time environment.

SOLUTION SUMMARY

  An automated test harness has been produced to alleviate the problems of running consistent repro- ducible tests and to run many tests quickly on any typical micro-controller containing embedded soft- ware. The automated test harness consists of super- visory control and data acquisition hardware, which is driven.by a group of software modules. The hard- ware has been arranged to plug into most types of automotive control units. The software modules provide a generic ANSI C application-programming interface (API) from which a test person can record controlled test files. The automated test harness is called Hardware in the Loop (HWIL).

BACKGROUND

  Testing the functionality of embedded automo- tive control unit in a real-time environment is a dif- ficult task. Testing involves setting every possible combination of the units input and output for each stated behavior. When the stated behaviors of the unit are large the number of unique test cases is exponentially larger, simply due to combinatorial mathematics. Therefore the time to test a unit is also significantly long.

  The other aspect of the problem is that tests were performed with a variety of devices, usually a switch box and serial analyzer. There was no one solution that could control and measure all the units I/O simultaneously.

        Unit Under Test I ,

Fig. 1 The Software and Hardware Layers of HWIL

  HWIL exhibits the system architecture shown in Figure 1. Figure 1 shows the hardware layer that forms the test harness of HWIL. This sits between the software layer and the device under test. Figure 1 also shows the software layer, which is used to control the test harness and execute test scripts.

HARDWARE LAYER

  The hardware layer consists of three major sub- assemblies as shown in Figure 2. The first major sub-assembly encapsulates digital I/O, analogue I/O and pulse width modulated I/O by employing the use of National Instruments (NI) SCXI modules mounted in a SCXI chassis. The SCXI modules are at the front-end for the DAQ control card. The DAQ control card, mounted in the dedicated PC, also contains additional hardware for timers, coun-

Q Motmola. In.2 mm I21 January 2wo

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Technical MO-LA @ Developments

ters and fast I/O. The second major sub-assembly contains the serial bus communication hardware consisting of two RS-232 ports that interface with Vehicle Serial Interface (VSI) boxes. The RS-232 ports are mounted in a dedicated PC for HWIL. The third sub-assembly contains a General-Purpose Interface Bus...