The ETM9 is designed to be connected directly to the ARM core that it is tracing, and not to the main AMBA system bus. This is because it must closely track the instructions that the ARM core is executing, and this information is only available on the ARM processor pins.

Cached and other ARM products, such as ARM946E-S, ARM966E-S, and ARM920T (Rev 1) provide a trace interface to bring out the required trace signals from the ARM core to the periphery of the macrocell. This enables an ETM9 to be connected directly to it without further modifications being required.

The trace interface is described in ETM9 to ARM9 connection guide.

A small amount of glue logic is required to connect the ETM9 to an ARM processor. For example, glue logic is required if clock-gating is implemented (see Using the PWRDOWN output), or to OR debug requests (see Debug request output wiring). This glue logic is provided for most processors in the ETM Integration Kit described in Chapter 6 ETM Integration Testing.