CoreSight™ is an on-chip debugging and tracing technology designed
by ARM. The device manufacturer can implement CoreSight features in
various combinations. For a list of advantages refer to Streaming Trace.
CoreSight features can be accessed through a JTAG or Serial Wire
interface. Debugging in JTAG and Serial Wire mode at the same time is
not possible. Cortex-M processor-based devices can include a:
The supported debug modes are:
JTAG Debug is the industry-standard interface
that allows device chaining.
Serial Wire Debug is a 2-pin interface with an
optional Serial Wire Trace Output. Contrary to JTAG, devices cannot
The Serial Wire-JTAG Switch (SWJ) synchronizes the debugger
adapter and the CoreSight debug interface. ULINKpro uses
this option to generate sequences for switching between Serial Wire
Debug and JTAG Debug mode.
The Debug Interface communicates with the
Run Control: allows the user to start, stop, and
single-step through the source code.
Breakpoint Unit: allows the user to set breakpoints even
while the processor is running.
Memory Access Unit: allows the user to read or write to
memory and peripheral registers even while the program is
The Trace Interface encodes and provides trace information
The Serial Wire Trace Output (SWO) pin, which
can be used only in combination with the Serial Wire Debug mode.
SWO does not support ETM trace data.
The 4-Pin Trace Output, which has a greater
bandwidth than the Serial Wire Trace Output and uses 5 functional
The Embedded Trace Buffer (ETB), which provides on-chip
storage of trace data using 32-bit RAM. Data is accessed through
registers. No additional output-pins are needed.
The Trace Interface communicates with the following
Embedded Trace Macrocell (ETM): provides instruction
tracing to debug historical sequences, for software profiling and
code coverage analysis. ETM data are output through an extra 4-bit
Instrumentation Trace Macrocell (ITM): provides
application information like debug printf(), RTOS information, unit
test, or UML annotation.
Data Watchpoint & Trace Unit (DWT): provides PC
sampling, event counters, timing, and interrupt execution
information. In addition, it allows Access
Breakpoints for up to four memory addresses.
The two standard connectors are recommended:
Debug for JTAG or Serial Wire Debug and Trace.
Debug+ETM connector adds to the Cortex Debug connector ETM
The manufacturer's device data sheet describes the implemented
The chapter Debug
Driver describes the ULINKpro configuration options for
the Debug Interface.
The chapter Trace
Configuration describes the ULINKpro configuration
options for the Trace Interface.