Abstract: An integrated circuit including operational circuitry operable in response to at least one control signal asserted to an external node from an external source, and test circuitry coupled to the external node and the operational circuitry. In response to data asserted to the external node from an external source, the test circuitry enters a test mode in which it tests, configures, or reconfigures the operational circuitry. The test circuitry also asserts to the operational circuitry each control signal received at the external node (or an amplified or translated version thereof). Other aspects of the invention include test circuitry for use in a circuit having an access node and methods for performing on-chip testing, configuration, and control of operational circuitry within a chip in response to test data and at least one control signal asserted from an external source to an external node.