To use trace, the target board must have an Arm Cortex or a RISC-V device with the ETM/PTM/N-Trace trace pins—usually named TraceCLK and TraceDxx—and these pins must be connected to the debug connector. Because trace pins are multiplexed on some devices, take care not to connect these pins to other logic devices on the PCB to minimize the loading and improve signal integrity.

C-SPY will initialize and enable all necessary registers on the MCU to allow the ETM/N-Trace port to function properly so that no special user code instrumentation is necessary. However, ensure that the running application code does not interfere (read, write, etc.) with the GPIO pins used for the ETM/N-Trace trace.

The TRC LED on the I-jet Trace debug probe will turn green when trace data is being collected. This usually happens after trace is enabled in C-SPY and the Run command is issued.

For more information about trace, see the C-SPY Debugging documentation.