Patent ID: 8046648

Claim:
Apparatus of an electronic device for carrying out a test mode of operation and a functional mode of operation of the electronic device wherein the test mode of operation has already been established and wherein the apparatus of the device includes a number of device digital functional input and output connections, functional circuitry for carrying out a functional mode of operation and test circuitry for carrying out externally conducted continuity test operations, the test circuitry including exclusively combinational logic coupling between a number of the digital functional inputs and outputs, control circuitry for switching between the test and functional modes of operation, output circuitry for selectively applying outputs of either the test circuitry or the functional circuitry to digital functional output connections, the apparatus further comprising: (a) test circuitry having functionality for performing both continuity testing and any one of a number of other test functions, wherein a plurality of the number of digital functional input connections used in continuity testing are also used in the any one of the number of other test functions; (b) mode control circuitry included in the test circuitry for switching between the test and functional modes of operation; and, (c) control circuitry included in the test circuitry operatively coupled to the functional circuitry and the test circuitry, to control functional and test operations in direct response to combinations of signals superfluous to performing continuity testing that are applied to the plurality of the number of digital functional inputs.