3.5.4. Using the process ID signals

ETM7 Rev1 supports tracing of process IDs or overlay identifiers, using the PROCID[31:0] and PROCIDWR signals.ARM720T Rev3 provides a 32-bit register in the system control coprocessor (CP15) that contains the current process ID. The macrocell has output signals that correspond to this register called ETMPROCID[31:0] and ETMPROCIDWR. These must be connected directly to the PROCID[31:0] and PROCIDWR ETM inputs.Earlier ARM cores do not provide these signals directly, but it is possible for the process ID register to be put into a peripheral or another coprocessor, subject to software toolkit compatibility.


If you are using a processor that does not provide these signals, you must tie the unused ETM7 inputs LOW.

Future versions of the ARM trace debug tools will support the process ID extensions, to allow tracing of dynamically loaded memory and overlay systems. See Chapter 6 Software Considerations for Trace for more details.

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