Integrated circuit internal test mode indicator circuit

摘要

The indicator circuit and method of this invention include an OR circuit having at least two inputs and an output. A signature mode signal input is connected to one input of the OR circuit and a special test mode signal input is connected to a second input of the OR circuit. A logic circuit for providing indicator signals has at least three inputs and at least two outputs. A first input to the logic circuit is connected to the output of the OR circuit. At least one signature address signal is connected to a second input of the logic circuit. The signal indicating the results of the special test mode is connected to a third input of the logic circuit. A first preprogrammed code indicator circuit has an input connected to a first output of the logic circuit and a second preprogrammed code indicator has an input connected to a second output of the logic circuit. The first preprogrammed code indicator may contain, for example, a manufacturer code. The second preprogrammed code indicator may contain, for example, a device code.