EM351 Datasheet, PDF (217/245 Pages) List of Unclassifed Manufacturers – High-Performance, Integrated ZigBee/802.15.4 System-on-Chip

EM351 / EM357
13 Instrumentation Trace Macrocell (ITM)
The EM35x integrates the standard ARM^® Instrumentation Trace Macrocell (ITM). The ITM is an application-
driven trace source that supports printf style debugging to trace software events and emits diagnostic system
information from the ARM^® Data Watchpoint and Trace (DWT). Software using the ITM generates Software
Instrumentation Trace (SWIT). In addition, the ITM provides coarse-grained timestamp functionality. The ITM
emits trace information as packets, and these packets are sent to the Trace Port Interface Unit (TPIU). Three
sources can generate packets. If multiple sources generate packets at the same time, the ITM arbitrates the
order in which the packets are output. The three sources, in decreasing order of priority, are:
 ^{Software trace. Software can write directly to ITM stimulus registers, emitting packets.}
 ^{Hardware trace. The DWT generates packets that the ITM emits.}
 ^{Time stamping. Timestamps are emitted relative to packets and the ITM contains a 21-bit counter to}
generate the timestamps.
The Ember software utilizes the ITM for efficiently generating debug data. Altering the ITM configuration may
conflict with Ember debug output.
For further information on the ITM, contact Silicon Labs support for the ARM^® Cortex^TM-M3 Technical
Reference Manual, the ARM^® CoreSight^TM Components Technical Reference Manual, the ARM^® v7-M
Architecture Reference Manual, and the ARM^® v7-M Architecture Application Level Reference Manual.
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Final
120-035X-000M