Embedded Trace Buffer (Etb) - Segger J-Link User Manual

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16.3

Embedded Trace Buffer (ETB)

The ETB is a small, circular on-chip memory area where trace information is stored during
capture. It contains the data which is normally exported immediately after it has been
captured from the ETM. The buffer can be read out through the JTAG port of the device
once capture has been completed. No additional special trace port is required, so that the
ETB can be read via J-Link. The trace functionality via J-Link is limited by the size of the
ETB. While capturing runs, the trace information in the buffer will be overwritten every time
the buffer size has been reached.
The result of the limited buffer size is that not more data can be traced than the buffer
can hold. Because of this limitation, an ETB is not a fully- alternative to the direct access
to an ETM via J-Trace.
J-Link / J-Trace (UM08001)
CHAPTER 16
© 2004-2017 SEGGER Microcontroller GmbH & Co. KG
Embedded Trace Buffer (ETB)