An integrated digital processing device and method for examining the operation thereof

An integrated digital processing device and method for examining the operation thereof. An integrated multiple digital processing device has externally-accessible tag connections which provide signals representative of what circuit has access to external memory used by the processing device. The processing device includes a plurality of digital processor circuits, a DRAM refresh logic circuit, externally-accessible connections for receiving memory access signals from an external processor, and an arbitration circuit for determining which of the digital processor circuits, refresh logic circuit or external processor may have access to the external memory. The signals on the tag connections are provided by the arbitration circuit, and indicate which of the aforementioned circuits has access to the external memory at any moment. Preferably, an M-to-N line encoder is provided between the arbitration circuit and the externally-accessible tag connections to minimize the number of tag connections required to identify the circuit having access to the external memory.