The ETM monitors the ARM core buses and outputs compressed information through the trace port to a Trace Port Analyzer (TPA). The on-chip ETM contains trigger and filter logic to control what is traced. The ETM implemented in the Excalibur provides signals (DEBUG_EXTIN[3:0] and DEBUG_EXTOUT[3:0]) that provide you with access to logic within the PLD. However, the supplied PLD images do not make use of these signals. See the Excalibur ARM-Based Embedded Processor PLD Hardware Reference Manual.

The TPA is an external device that stores information from the trace port.

This is a protocol converter that converts debug commands from the debugger into JTAG messages for the ETM. The JTAG unit might be a separate device or might be incorporated within the TPA.

The Trace Debug Tools (TDT) is an optional component of the ARM Developer Suite (ADS) that runs on a host system. It is used to set up the filter logic, retrieve data from the analyzer, and reconstruct an historical view of processor activity. For further information, see the ADS Trace Debug Tools User Guide.