EM351_12 Datasheet, PDF (218/244 Pages) Silicon Laboratories – High-Performance, Integrated ZigBee/802.15.4 System-on-Chip

EM351 / EM357
14 Data Watchpoint and Trace (DWT)
The EM35x integrates the standard ARM^® Data Watchpoint and Trace (DWT). The DWT provides hardware
support for profiling and debugging functionality. The DWT offers the following features:
 ^{PC sampling}
 ^{Comparators to support:}
• Watchpoints – enters debug state
• Data tracing
• Cycle count matched PC sampling
 ^{Exception trace support}
 ^{Instruction cycle count calculation support}
Apart from exception tracing, DWT functionality is counter- or comparator-based. Watchpoint and data trace
support use a set of compare, mask, and function registers. DWT-generated events result in one of two
actions:
 Generation of a hardware event packet. Packets are generated and combined with software events and
timestamp packets for transmission through the ITM/TPIU.
 ^{A core halt – entry to debug state.}
When exception tracing is enabled, the DWT emits an exception trace packet under the following conditions:
 ^{Exception entry (from thread mode or pre-emption of a thread or handler).}
 ^{Exception exit when exiting a handler.}
 ^{Exception return when re-entering a pre-empted thread or handler code sequence.}
The DWT is designed for use with advanced profiling and debug tools, available from multiple vendors.
Altering DWT configuration may conflict with the operation of advanced profiling and debug tools.
For further information on the DWT, 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-000 Rev. 1.2