A microcontroller (30) includes a processor (32), an embedded memory (46) operatively coupled to the processor (32), and a microcontroller test interface (34) operatively connected to the processor (32) and the memory (36). The microcontroller (30) responds to a reset signal to perform a reset initiation that causes an initial disabled state of the test interface (34) to be set and execution of initiation code with the processor (32). This code execution optionally establishes a further disabled state. The microcontroller (30) provides an enabled state of the test interface for memory (46) access through the test interlace (34) during microcontroller (30) operation subsequent to the reset initiation unless the further disabled memory (46) access state is established by execution of the initiation code.