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Quick Troubleshooting

Symptom Likely Cause What To Try
Port does not appear in Settings Board not enumerated, charge-only cable, wrong USB port, or board still rebooting after upload Unplug and reconnect the board, try a data-capable USB cable, wait a few seconds after upload, reopen the port list, and confirm the board appears in Arduino IDE.
ViewPoint cannot connect Another app owns the serial port Close Arduino Serial Monitor, Arduino Serial Plotter, PlatformIO monitor, terminal serial tools, or any other serial app, then reconnect.
Connects, but no plot appears Sketch is not sending ViewPoint data, the wrong sketch is running, or view.begin() / view.send() is missing Upload HelloPlotter, confirm the sketch includes <ViewPoint.h>, calls view.begin() in setup(), and calls view.addData(...) plus view.send() in loop().
Plot appears, but labels or configuration do not apply Data is arriving, but ViewPoint protocol configuration is not being negotiated Make sure the sketch uses the ViewPoint library, setLegacyMode(true) is not enabled, and the app was connected before or shortly after the sketch started.
Data appears, but scaling is wrong Axis bounds, auto-scale, log scale, or trace auto-scaling settings do not match the data Open Controls > Axis Configuration. Re-enable Auto-Scale, check manual Min/Max bounds, disable Logarithmic scale for zero or negative data, and confirm the trace has Affects Auto-Scaling enabled.
Trace is visible but changes the scale too much A noisy or outlier trace is included in auto-scaling Open Controls > Traces and turn off Affects Auto-Scaling for that trace, or use a fixed axis range.
Display modes are unavailable or do nothing Display modes require the right plot type and update mode Use Cartesian data in Frames mode. In sketches, call view.begin(frames, packetSize) or view.setMode(frames), then send a full frame before view.send().
Frames mode looks wrong send() is being called at the wrong time, or packet size does not match the frame In Frames mode, call addData(...) repeatedly to fill the frame, then call view.send() once per complete frame. Check that packetSize matches the number of points sent.
CSV capture is missing timestamps The sketch is not sending source timestamps, or CSV settings are using a different timestamp source ViewPoint can auto-supply timestamps; however, to send sketch timestamps, pass a timestamp to view.send(timestamp). Also check Settings > CSV Capture timestamp options.
CSV capture is missing expected traces Trace labels changed, traces were hidden, or capture started before data and configuration arrived Start capture after the plot is configured and visible. Confirm trace names in the legend and CSV Capture settings.
Screen recording is unavailable or low quality Recording backend is missing or limited JCodec works without setup but is limited to 10 FPS. Install FFmpeg for higher frame rates, better quality, and audio support, then confirm ViewPoint detects it in Settings > Screen Capture.
Serial Monitor shows data but the plot is wrong Raw serial format does not match ViewPoint's expected data or command protocol If using the library, compare against HelloPlotter. If writing a custom sender, see Appendix B: Serial Command Reference.
Arduino Serial Plotter works, but ViewPoint labels or configuration do not Sketch may be in legacy/data-only mode Disable view.setLegacyMode(true) when targeting ViewPoint. Legacy mode is for Arduino Serial Plotter compatibility and skips ViewPoint configuration commands.
After uploading firmware, connection drops The board disconnects and reconnects during upload Wait for the board to reappear, then reconnect. Enable Auto-Reconnect in Settings if you frequently upload while ViewPoint is open.