RapiTime works by taking measurements of small sections of code executing on the target hardware. There are four different classes of tracing that are supported. The standard option is 2.

1. Software only
   Low setup cost, can have high overhead
   The software is automatically instrumented by RapiTime. Each instrumentation point writes to a memory buffer which can then be downloaded after testing via debugger/serial/Ethernet etc. Time-stamping is done on-target as part of the instrumentation point.
2. Software with hardware support
   Low overhead
   The software is automatically instrumented by RapiTime. Instrumentation points write a value to an IO port or memory address. The RapiTime TraceBox, a Logic Analyser, in-circuit emulator, ETM or Nexus interface timestamps data off the target. This is the standard way of using RapiTime. Explicit support is built into RapiTime for the TraceBox, and also for Tektronix logic analysers.
   View the TraceBox product description
3. Full hardware tracing support
   Very low overhead
   An in-circuit emulator, ETM or Nexus trace provides a trace of the executing code. This is not available on all targets and can have a higher integration cost.
4. Simulated
   Low cost and low overhead, but only approximate timings.
   A software simulator provides a full program counter trace or low-overhead instrumentation point capture. This can be a powerful way of providing early feedback on execution times, hot-spots and optimization.