User manual

6. Debugging with hardware tools Raisonance Tools for ARM
6.4 Cortex Serial Wire Viewer (SWV) debugging features (Open4 RLink only)
Ride7 for ARM supports the SWV debugger for Cortex ARM based microcontrollers. The SWV uses
the low cost ARM CoreSight™ technology to obtain information from inside an MCU.
6.4.1 Introduction
SWV is the ability of the ARM™ core to send out real-time trace information via a single wire port
called the Serial Wire Output (SWO). This information is in several familiar formats (described in ARM
documentation) such as:
• Instrumentation Trace Macrocell (ITM) for application driven trace source that supports printf
style debugging.
We call these traces Software traces.
• Data Watchpoint and Trace (DWT) for variable monitoring and PC-sampling, which can in turn
be used to periodically output the PC (sampled) or various CPU internal counters and to obtain
profiling information from the target:
◦ Program Counter sampling,
◦ Data read and write cycles,
◦ Variable and peripheral values,
◦ Event counters,
◦ Exception entry and return.
We call these traces Hardware traces.
• Timestamps and CPU cycles which are emitted relative to packets.
6.4.2 Hardware requirements
SWV is only available with a special RLink version of the debug probe, embedded for example, into the
Evo and Open4 STM32 primers.
6.4.3 Configure Ride7 to use the SWV
Select SWV as debugging tool, and click on Advanced Options to open the Debug options.
- 32 -