Browse Prior Art Database

Test Device for Logic Cards

IP.com Disclosure Number: IPCOM000086590D
Original Publication Date: 1976-Oct-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Related People

Drinkhouse, EW: AUTHOR [+2]

Abstract

Logic cards in data processing machines must be tested for both DC conditions to detect circuit errors and for AC conditions to ensure that the logic will perform properly at functional speed. Recent logic cards incorporate a complete microprocessor, and the test devices required are both large and expensive. If both DC and AC speed testing could be accomplished on the same tester, test costs would be reduced.

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Test Device for Logic Cards

Logic cards in data processing machines must be tested for both DC conditions to detect circuit errors and for AC conditions to ensure that the logic will perform properly at functional speed. Recent logic cards incorporate a complete microprocessor, and the test devices required are both large and expensive. If both DC and AC speed testing could be accomplished on the same tester, test costs would be reduced.

When the microprocessor is provided with a memory containing a diagnostic program for the processor, the tester, shown above, will provide for both the AC and DC tests and will be substantially cheaper than the conventional test process for a card. The saving is due to the use of the microprocessor to test itself and its card. The test control section 1 is connected by a cable 2 and edge socket 3 to the card 4 under test. Another set of cables 5 are plugged into the top card connectors 6. An array of probes 7 are also extended to selected points on the card 4 for DC tests at those points. The tester is then run through its cycle to perform the required DC logic and resistivity checks, and probes 7 are then rendered ineffective. The oscillator in microprocessor module 8 is then allowed to start functioning.

The tester then provides the signals on cables 2 and 5 to cause the microprocessor module 8 to cycle through its diagnostic cycles at its functional speed. The tester can vary the input signals to introduce such errors as are n...