SPRUI30H November 2015 – May 2024 DRA745 , DRA746 , DRA750 , DRA756
Many devices have system-level trace capabilities. This capability is generally implemented in a top-level module called the STM. The STM collects software and hardware messages (the trace data) from various other system modules and subsystems through a dedicated STM bus (OCP compliant). The STM then formats these high-level trace messages into streams of MIPI® system trace protocol (STP) compliant messages. The STP messages are then transmitted to a dedicated STP receiver over a narrow (generally four pins), high-speed export interface.
The SCTM has an optional mode that provides an STM OCP interface and a mode where the state of the counters can be transferred through the STM.
Figure 8-23 shows a typical STM system configuration with the SCTM as a hardware master. The hardware master messages from the SCTM STM bus enter the L4 debug interconnect through an asynchronous bridge. Other system-level hardware masters are also writing messages to the STM through this interconnect. Software messages from applications running on the MCU or DSP to reach the STM message buffer through a bridge from L3 interconnect to the L4 interconnect. The STM orders and formats the high-level hardware and software messages into STP protocol messages and exports them to an off-chip trace receiver.