User manual

Raisonance Tools for ARM 6. Debugging with hardware tools
Cycle counter:
• Every x cycles : enables periodic sampling of the Program Counter or the Cycle Counter value,
based on the CPU Cycle Counter. The period of the event can be choose from 64 cycles up to
16K cycles. The highest values will probably not work because the SWO communication
bandwidth is not big enough to handle that much flow of data.
• Reset cycle counter : causes the cycle counter to be set to zero, when validating the dialog box
by clicking on the OK button.
Time stamps: the Cortex debug module enables time stamp for every ITM or DWT event or group of
events. Use the resolution drop-down list to choose the resolution of the time stamp value. Four values
are available: CPU clock / 1; CPU clock / 4; CPU clock / 16; CPU clock / 64.
These correspond, for example, to 13ns, 55ns, 222ns, 888ns for a 72MHz CPU clock.
The lowest resolution is only useful if the time between each event packet is long: a time stamp is
automatically sent if there is no event and the time counter overflows (every 26ms, 110ms, 440ms or
1776ms at 72MHz).
Synchronization: causes ITM synchronization packet to be sent every time the specified period
elapses. It allows the system to resynchronize with the SWV flow in case of lost events, or bad event
reception. Three periods are available: 16M; 64M; 256M cycles.
These correspond, for example, to 233ms, 933ms and 3.7s at 72MHz.
To stop losing events, you can increase the synchronization period, but be aware that this also
increases the time before resynchronizations.
Profile counter events: the DWT unit contains a few profiling counters which cause trace samples to
be generated on overflows of these counters (every 256 of corresponding instructions).
Five counters can be monitored individually:
• Folded instructions counter,
• Load Store Unit operation counter,
• Sleep overhead counter,
• Interrupt overhead counter,
• CPI counter.
Interrupt log events: turn on tracing of exception entries and exits.
Note: These configurations are saved within the project.
- 35 -