
EM358x
Rev. 0.4
247
15 Data Watchpoint and Trace (DWT)
The EM358x 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 customer 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.
Summary of Contents for EMBER EM358 series
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