An access interface for accessing electrical nodes of an electronic circuit for programming, testing, and debugging the electronic circuit. The access interface includes a protocol generator and a data generator that may be programmed to apply control and/or data sequences directly to the electronic circuit. The access interface performs operational commands based upon a plurality of states included in a programmable state machine. By suitably programming the protocol generator, the data generator, and the state machine, electrical nodes of the electronic circuit can be accessed in reduced time using a reduced number of operations. The access interface is controlled by a test resource apparatus, which communicates with the electronic circuit connected to the access interface. The access interface may be implemented as a downloadable circuit, e.g., it may be programmed into a programmable logic device by the test resource apparatus. Alternatively, the access interface may be implemented as a fixed/permanent circuit in an ASIC.