Design modifications in microprocessors to simplify their testing /

Abstract

Design modifications in microprocessors are recommended to simplify the task of testing them in the user's environment. The recommended design modifications are two additional instructions that can easily be incorporated into the architecture of any currently manufactured microprocessor. A test method is then given that makes use of these instructions and also utilizes some of the principles of Thatte and Abraham (given in their recently published paper). It is shown that the present test method is an improvement over the test method of Thatte and Abraham in at least three ways: the test generation procedures are simpler to use, the fault model allows the existence of larger number of faults, and the testing time is reduced significantly. To illustrate the application of the method, it is used to generate test sequences for an Intel 8085 microprocessor.