Patent ID: 7676716

Claim:
A method of testing a tristate capability of a tristate element, the method comprising the steps of: applying a given logical value to an input of the tristate element, applying an opposite of the given logical value to a keeper element that is connected at an output of the tristate element, capturing a first logical value with a latch at a downstream position of the output of the tristate element, evaluating a second logical value at the output of the tristate element using the first logical value, comparing the second logical value to the opposite of the given logical value, producing a failure code for the tristate element when the second logical value is not equal to the opposite of the given logical value, applying the opposite of the given logical value to the input of the tristate element, applying the given logical value to the keeper element, capturing the first logical value with the latch, evaluating the second logical value at the output of the tristate element using the first logical value, comparing the second logical value to the given logical value, producing a failure code for the tristate element when the second logical value is not equal to the given logical value, and producing a passing code for the tristate element when a failure code has not been produced.