EM357-RTR datasheet(215/240 Pages) ETC2

215 / 240 page

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 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.

14-1

120-035X-000D

Preliminary

EM357-RTR 数据表(PDF) 215 Page - List of Unclassifed Manufacturers