HP Test Development Software

This section describes the HP E1496A Test Development Software for the HP 75000 Model D20 Functional Test System. The steps that are required to create a physical test will be described. The E1496A is a software package that allows a user to either enter test vectors manually in a spreadsheet or import test vectors from a HP PCF file. While developing a test for a particular chip, the user may enter a few vectors in the spreadsheet to debug the settings. Some examples of settings include pin assignments, pin group definition, and timing information. After verifying that the settings are correct, the test vectors from the PCF file can be imported to perform the real test. Tests can be run from within the software or a text file with a series of SCPI commands for the D20 test system can be exported and loaded into the tester. In general, tests are run from within the software during the test development stage. After the test has been verified, then the commands can be exported to a text file and loaded into the D20 hardware with VEE Test. The use of VEE Test will be discussed in the next section.

Figure 7 is the main screen of the HP E1496A Test Development Software. The E1496A software is installed on the HP 700i Workstation and the command to load it is hp75000d20. After entering the command, the screen on Figure 7 appears. As shown by the figure, there are two separate sub-windows within the E1496A. The one in the back is a spreadsheet with test vectors. The one in the front is for entering timing information and the timing of control signals.

Figure 7: Main Screen of HP E1496A Test Development Software

The flow chart on Figure 8 shows the steps required to setup a digital test in the E1496A software. The steps are as follows:

1. Define Pin Groups
   As discussed in an earlier section, a pattern I/O pin group can range from 1-32 pins. Control pin groups should be defined in this step as well. Pin groups must be defined first before other tasks can be performed. To define pin groups, select Configure->Define Pin Groups from the menu bar and a dialog box will appear. The dialog box prompts for the following information: pin group name, number of pins, type (pattern I/O, control), mode (stimulus, record, compare) and the timing cycle. There can be a maximum of 6 stimulus timing cycles and 6 response timing cycles. But in general, only one of each will be required.
2. Assign Hardware Connections
   After defining pin groups, the hardware connections (pattern and timing pods) are automatically assigned. However, these connections can be changed by selecting Configure->Change Hardware Connections.
3. Enter Timing Information/Setup Control Signals
   After defining pin groups, the timing information and the timing of control signals can be entered in the timing window. On the left of the window is a list of the stimulus/response groups and control signals. By clicking on the right mouse button, a menu appears. The menu allows the user to specify when control signals should be high or low, when stimulus test vectors should be valid, and when responses should be sampled and the end of the timing cycle. A timing cycle is the length of time that a test vector is valid and it is divided into four or more sub-cycles. The length of a sub-cycle is called the resolution and can range from 6.25 ns to 409.6 us. There can be a maximum of 1023 sub-cycles in a timing cycle.
4. Enter/Import Test Vectors
   Test vectors can be either entered into the spreadsheet window manually, or imported from a PCF file. To import a PCF file, select File->Import.
5. Run Test/Debug
   Tests can be run from the E1496A software by selecting Debug->Run Test. Pattern I/O output pins can also be forced to a certain value from the run test dialog box. The current value of the response pins can be read as well. Of course, before the test can be run from within the E1496A software, both the power sources and the relays on the CMC Test Head must be turned on. This can be done from HP VEE Test and the procedure will be discussed in the next section.
6. Export Test in SCPI Format
   After verifying that the timing information and test vectors are correct, the test can be exported as a sequence of SCPI commands to be loaded into the D20 hardware by HP VEE Test. To export a test, select File->SCPI from the menu. The test can be saved by selecting File->Save or File->SaveAs.

Figure 8: Steps to Develop a Digital Test in E1496A

The 74LS165 example will describe the steps in Figure 8 in detail. The next section is a description of HP VEE Test and how it can be used to perform physical testing of ICs.