1. An apparatus for collecting trace data, comprising: a trace data input for receiving trace data from a data processor; first and second trace circuit portions for processing the received trace data, one of said first and second trace circuit portions coupled to said input, said first and second trace circuit portions cooperable for producing processed trace data for trace analysis; and reset logic coupled to said first and second trace circuit portions; wherein, in response to receipt of a reset signal under a first condition, said reset logic resets said first trace circuit portion without resetting said second trace circuit portion; and wherein, in response to receipt of said reset signal under a second condition, said reset logic resets said second trace circuit portion.