Datasheet

STM32F405xx, STM32F407xx Description
Doc ID 022152 Rev 2 37/167
Debug is performed using 2 pins only instead of 5 required by the JTAG (JTAG pins could be
re-use 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.
2.2.38 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
STM32F40x through a small number of ETM pins to an external hardware trace port
analyzer (TPA) device. The TPA is connected to a host computer using USB, Ethernet, or
any other high-speed channel. Real-time instruction and data flow activity can 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.