There are several possible reasons why the data trace results might be empty:
- Clock speed mismatch: make sure that the frequency specified in the `cpuSpeed` field of the `<debugConf>` matches the actual speed of the MCU.
- Invalid SWO pin config: ensure that the SWO pin is configured in SWO mode and isn't used otherwise in your target code.
- Clock configuration is taking too long: the MCU clock configuration in your target code must be performed as soon as possible after the power-on reset. Once initialized, the main clock (CPU clock) must not be changed for the duration of the test.
- Use of low-power mode: you cannot use deep sleep modes while using data trace since the high frequency clock must be running all the time.