EM357-RTR datasheet(214/240 Pages) ETC2

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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 Ember support for the ARM® CortexTM-M3 Technical Reference

Manual, the ARM® CoreSightTM Components Technical Reference Manual, the ARM® v7-M Architecture

Reference Manual, and the ARM® v7-M Architecture Application Level Reference Manual.

13-1

120-035X-000D

Preliminary

EM357-RTR データシート(PDF) 214 Page - List of Unclassifed Manufacturers