Understanding the Basics of Trace Functionality
Having a good grasp of how trace functionality works in Lauterbach Trace32 is essential. The purpose of trace data is to capture the sequence of executed instructions or data transfers. Real-time trace involves capturing these events as they happen, without affecting your system's real-time behavior.
The data can be captured using different methods, including ETM (Embedded Trace Macrocell), PTM (Program Trace Macrocell), or ITM (Instrumentation Trace Macrocell). Ensure that you have the correct trace settings for your specific setup.
Verifying the Hardware Setup
Ensure the Lauterbach Trace32 hardware is correctly connected to your target board. Loose or incorrect connections can lead to data capture issues.
Check the trace connector and cables for any physical damage that might be disrupting signal integrity.
Verify that the trace signals have proper termination on your board and are routed according to the signal integrity guidelines relevant for high-speed signals.
Configuring Trace32 for Real-Time Trace
Load the appropriate Trace32 configuration scripts specific to your microcontroller or microprocessor. This ensures that Trace32 is aware of the correct CPU architecture and trace capabilities.
The configuration script often includes settings for the trace clock, data pins, and buffer sizes. Modify these settings based on your system's real-time requirements. An example configuration might look like:
; Set up the Trace clock and data pins
SYStem.CONFIGURE.CLOCK 200MHz ; Set the trace clock to 200MHz
SYStem.CONFIGURE.DATA TracePortSize 4 ; Trace data port size
; Set up trace buffer
TRACe.BUFFER.Mode.Set Oversize ; Use oversize buffer if available
Adjusting Trace Buffer and Bandwidth
The buffer size is critical for capturing real-time trace data. Evaluate whether the existing buffer size is sufficient; if not, consider increasing it to avoid overflow, which leads to data loss.
Bandwidth settings need adjustment according to the data being captured. If too much data is being captured for the bandwidth, consider filtering or compressing trace data.
Testing for Signal Quality Issues
Use an oscilloscope or logic analyzer to test the quality of the trace signals. Look for signal degradation such as ringing, skew, or excessive jitter, which can impact the quality of captured trace data.
Analyze if there is any Electromagnetic Interference (EMI) affecting the trace signal, and make necessary adjustments by re-routing traces or providing better shielding.
Debugging Trace Through Lauterbach Tools
Check the status of the Trace32 by running diagnostic commands to see if there are any errors or warnings reported:
PRACTICE diagnostic.trc
View the captured trace data to verify it is sensible and aligns with expected program behavior. Use PRinT.TBar.Data to print specific parts of the trace buffer for review:
PRinT.TBar.Data <start_address> <end_address>
Firmware Considerations
Ensure that your firmware is not inadvertently disabling trace stimulus. Some embedded systems allow program parts to disable trace to save power or reduce noise.
The firmware must also be optimized for real-time operation. Unoptimized code can affect the trace capture. Ensure critical sections of the code are kept efficient.
Consult Documentation and Support
Every firmware project is unique, and specific nuances may require consulting the Lauterbach documentation or reaching out to their support team for help.
Consider joining forums or user groups for Lauterbach users to gain insights from developers who may have experienced similar issues.
By methodically verifying both hardware and software configurations, diagnosing signal integrity, and consulting with available technical resources, you'll be better equipped to address real-time trace data capture issues in Lauterbach Trace32.