Adjusting trace timings and general troubleshooting

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This article will explain how the trace sample timing of the J-Trace Pro can be adjusted and some general troubleshooting steps if a setup does not work out-of-the-box as it would be typically expected.

Trace Timing Configuration

In some cases a target device or board design will output trace signals that do not follow the Arm trace timing requirements. If the issue is due to an incorrect sampling point in the time domain this can be fixed with J-Trace Pro's "Trace Timing Configuration" feature.

Configuration with Ozone

The recommended way is to use Ozone. It can be used directly to set the number of used trace pins and the trace sampling delay. To access this option simply open the trace project in Ozone and go to Tools->Trace Settings.

Here you can switch between different trace sources and the number of trace pins used. Default for ETM/PTM trace is Trace Source = Trace Pins and Trace Port Width = 4-bit.

To modify the trace sampling delays open the options under Trace Timing and set the the "Override Timings" checkbox. Now either one delay for all data lines can be selected or for each individually.

If you see trace data in the instruction trace window when the target device is halted and no trace related error message is printed in Ozone console the trace setup is currently stable.

Just make sure to restart the debug session each time you adjust the timing delays so they take effect.

General configuration

Via exec command

One more general way to set the delay that is Ozone independent is via an Exec Command. Such command can be used e.g. in a J-Link Script file.

Via webserver command

Common trace timings

Trace signal quality

The good

The bad

The ugly

FAQ