The Cortex-M4 processor implements a complete hardware debug solution and provides high system visibility of the processor and memory through either a traditional 4-pin JTAG port or a 2-pin Serial Wire Debug (SWD) port, which is ideal for microcontrollers and other small-package devices. The SWJ-DP interface combines the SWD and JTAG debug ports into one module, which allows a seamless switch between the 2-pin and 4-pin modes of operation, depending on application needs.
For system trace, the processor integrates an Instrumentation Trace Macrocell (ITM) alongside data watchpoints and a profiling unit. To enable simple and cost-effective profiling of the system trace events, a Serial Wire Viewer (SWV) can export a stream of software-generated messages, data trace, and profiling information through a single pin.
For detailed specifications and information on the programmer's model for the Cortex-M4 CPU and the associated peripherals mentioned throughout Section 6.2, see the appropriate reference manual at www.arm.com.