4.1.1. How ECT works

The ECT provides an interface to the debug system as shown in Figure 4.1. This enables ARM/ETM subsystems to interact, that is cross trigger, with each other. The debug system enables debug support for multiple cores, together with cross triggering between the cores and their respective ETMs.

The main function of the ECT (CTI and CTM) is to pass debug events from one core to another. For example, the ECT can communicate debug state information from one core to another, so that program execution on both processors can be stopped at the same time if required.

Cross Trigger Interface (CTI)

The CTI combines and maps the trigger requests, and broadcasts them to all other interfaces on the ECT as channel events. When the CTI receives a channel event it maps this onto a trigger output. This enables subsystems to cross trigger with each other. The receiving and transmitting of triggers is performed through the trigger interface.

Cross Trigger Matrix (CTM)

This block controls the distribution of channel events. It provides Channel Interfaces (CIs) for connection to either CTIs or CTMs. This enables multiple CTIs to be linked together.

Figure 4.1. CoreSight CTI and CTM block diagram

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