K60P100M100SF2RM Datasheet, PDF (226/1809 Pages) Freescale Semiconductor, Inc – K60 Sub-Family Reference Manual

ITM
9.8 ITM
The ITM is an application-driven trace source that supports printf style debugging to
trace Operating System (OS) and application events, and emits diagnostic system
information. The ITM emits trace information as packets. There are four sources that can
generate packets. If multiple sources generate packets at the same time, the ITM
arbitrates the order in which packets are output. The four sources in decreasing order of
priority are:
1. Software trace -- Software can write directly to ITM stimulus registers. This emits
packets.
2. Hardware trace -- The DWT generates these packets, and the ITM emits them.
3. Time stamping -- Timestamps are emitted relative to packets. The ITM contains a
21-bit counter to generate the timestamp. The Cortex-M4 clock or the bitclock rate of
the Serial Wire Viewer (SWV) output clocks the counter.
4. Global system timestamping. Timestamps can optionally be generated using a
system-wide 48-bit count value. The same count value can be used to insert
timestamps in the ETM trace stream, allowing coarse-grain correlation.
9.9 Core Trace Connectivity
9.10 Embedded Trace Macrocell v3.5 (ETM)
The Cortex-M4 Embedded Trace Macrocell (ETM-M4) is a debug component that
enables a debugger to reconstruct program execution. The CoreSight ETM-M4 supports
only instruction trace. You can use it either with the Cortex-M4 Trace Port Interface Unit
(M4-TPIU), or with the CoreSight ETB.
The main features of an ETM are:
• tracing of 16-bit and 32-bit Thumb instructions
• four EmbeddedICE watchpoint inputs
• a Trace Start/Stop block with EmbeddedICE inputs
• one reduced function counter
• two external inputs
• a 24-byte FIFO queue
• global timestamping
K60 Sub-Family Reference Manual, Rev. 6, Nov 2011
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Freescale Semiconductor, Inc.