Meaning
Real-time diagnostic data streams capture the execution history and state changes of an embedded processor without stopping its execution. By implementing trace telemetry, engineers can monitor the internal variables, instruction sequences, and interrupt events of a system in real time. This information is gathered by dedicated hardware trace units inside the processor, allowing developers to analyze complex software bugs under real-world operating conditions.
Data Extraction
Extracting trace data from a running processor requires specialized interfaces. Embedded systems use trace ports or serial links to transmit trace telemetry to a debug probe.
Bandwidth Budget
The generation rate of execution trace data can easily exceed the bandwidth limits of standard debugging interfaces. To manage trace telemetry, the internal capture logic compresses the instruction and data trace before transmission. This compression relies on transmitting only branch targets and packet headers, which reduces the required transmission bandwidth and prevents packet loss on the trace port.
Hardware Overhead
Dedicated debug blocks require physical space and power on the silicon die. Silicon designers must balance the diagnostic benefits of trace telemetry against the hardware cost, which often leads to the inclusion of trace logic in development models but its removal or disabling in production units. This distinction is specified in the technical datasheet, enabling the purchaser of the assembly to select the appropriate microcontroller variant for each product stage.
