A programme-controlled unit comprises a crossbar with a multiplicity of ports, a multiplicity of devices which are connected to the ports of the crossbar and can exchange data via the crossbar, and debug resources for detecting the events and states occurring in the programme-controlled unit. The programme-controlled unit described can be characterized by the fact that the ports of the crossbar comprise a diagnostic port, that the addresses, data and/or control signals which are transmitted between two other ports of the crossbar are additionally also supplied to the diagnostic port, and that the debug resources are connected to the diagnostic port of the crossbar.