Functional overview STM32L452xx
3.35 Development support
3.35.1 Serial wire JTAG debug port (SWJ-DP)
The Arm
®
SWJ-DP interface is embedded, and is a combined JTAG and serial wire debug port that enables either a serial wire debug or a JTAG probe to be connected to the target.
Debug is performed using only two pins instead of the five required by the JTAG (JTAG pins can be reused as GPIO with alternate function): the JTAG TMS and TCK pins are shared with SWDIO and SWCLK, respectively, and a specific sequence on the TMS pin is used to switch between JTAG-DP and SW-DP.
3.35.2 Embedded Trace Macrocell™
The Arm ® Embedded Trace Macrocell™ provides a greater visibility of the instruction and data flow inside the CPU core by streaming compressed data at a very high rate from the
STM32L452xx through a small number of ETM pins to an external hardware trace port analyzer (TPA) device. Real-time instruction and data flow activity be recorded and then formatted for display on the host computer that runs the debugger software. TPA hardware is commercially available from common development tool vendors.
The Embedded Trace Macrocell™ operates with third party debugger software tools.
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DS11912 Rev 7
