This warning indicates that the serial trace link between the target and the TRACE32 debugger was unstable during a trace recording. Specifically, the connection was lost at least once between the trace states "Arm" and "OFF".

Possible Scenarios:

The warning may appear in any of the following cases:

• The trace link was never established (always down).

• The trace link went down once and did not recover.

• The trace link went down once but recovered.

• The trace link went down and recovered multiple times.

If you are using a PowerTrace Serial with a TRACE32 software version from December 2023 or newer, additional details about the cause of the issue are displayed together with the warning. For example:

Serial trace connection had errors (link always down)

Troubleshooting Steps:

1. Check the Physical Connection

Ensure that all hardware components are correctly and securely connected.

Moreover, common causes of instability include:

• Faulty or low-quality trace connectors

• Custom adapters

• Extension cables that introduce signal degradation

2. Verify Trace Port Configuration

Open the TRACEPORT.state window and check the following settings:

• Lane count

• Lane speed

• Reference clock source and frequency (RefClock)

Make sure these parameters match the configuration required by your target processor. Refer to the processor's documentation or your board’s hardware reference manual for the correct settings.