A data processing system and method generates debug messages by permitting an external debug tool to have real-time trace functionality. A data processor executes a plurality of data processing instructions and uses a memory for information storage. Debug module generates debug messages including address translation trace messages. A memory management unit has address translation logic for implementing address translation to translate addresses between virtual and physical forms. The debug module includes message generation module that is coupled to the memory management unit for receiving notice when one or more address translation mappings are modified. The message generation module generates an address translation trace message in response to a detection of a modification of an address translation mapping occurs and provides the address translation trace message external to the debug module.