Image Number 6 for United States Patent #7003699.
The present invention provides a data processing apparatus and method for generating trace signals. The data processing apparatus comprises a component whose behaviour is to be traced, and a trace generation unit for receiving input signals from the component indicative of the behaviour, and for generating from the input signals high priority and low priority trace signals for outputting to a trace receiving device. The trace generation unit is responsive to assertion of a suppression signal from the trace receiving device to suppress generation of the low priority trace signals, with the aim of avoiding overflow of the trace receiving device. Furthermore, in the event that multiple trace modules are provided within a data processing apparatus, embodiments of the present invention provide funnel logic to enable the trace signals generated by those various trace modules to be combined into a single trace stream having a bandwidth which is less than the collective maximum bandwidth of the individual trace streams generated by the multiple trace modules.