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NIRScan Nano Evm resets during scans

Jan Makowski
Prodigy 60 points
Other Parts Discussed in Thread: DLPC150

Hello,


we've been using the NirScan Nano EVM extensively over the last couple of months. However, it suddenly stopped working with a mysterious bug: On windows systems, the EVM resets after the software sends the command for sending a scan (NNO_PerformScan). On a Mac system, the same function at least activates the lamp, but the dlpspec_scan_interpReference function fails. A closer look at the data shows that the EVM only returned meaningless data.

Upgrading the software on the device as well as the PC/Mac to the V2.0.2 version did not produce a different result. What could be the matter here?

Jan

  • 0
    TI__Expert 6995 points

    Jan,

    First of all , ensure that the Tiva firmware and GUI are at the latest versions.

    The dlpspec_scan_interpReference function takes the stored reference scan and computers absorbance. The unit might not have a stored reference. To store a new reference:

    • ensure that bluetooth is off
    • click on the Utilities button
    • place reference material in front of sample window: we use a metal surface coated in a highly reflective material like Spectralon or Wite-Out. Refer to NIRscan Nano User's Guide Section 3.1.4 for more info.
    • then go to the Replace Reference Calibration and click on Scan under the “Update the factory Reference Calibration Data”
    • wait for the scan to complete, it takes about 30 seconds or so.

    Best regards,
    Pedro

  • 0 in reply to PedroGelabert
    Prodigy 60 points

    Pedro,

    thank you for the update. The firmware and gui both have the latest versions. Performing the reference scan from the utilities tab also triggers a reset, just like regular scan. All tests from the factory tab come back positive except the DLPR test. Starting the test triggers a the same reset as in the scans.

    On a Mac, where the scan was at least performed, I used a debugger to trace the contents of the m_scanResults variable. After a scan, it just seems to return random values.

    What's curious is that, the device worked for several hundred scans, but the stopped working. Which hardware defects or connector issues may trigger such a behavior? Which JTAG variables could provide further infos?

    best regards

    Jan

  • 0 in reply to Jan Makowski
    TI__Expert 6995 points

    Jan,

    Sounds like the DLPC150 is not booting properly. This could be caused by the following:

    • Not enough current on USB. During a scan the lamps and DLP subsystem are powered. For a small amount of time there is a current peak that can exceed 500ma. Some USB hubs or PC do not support high current output. Ensure the NIRscan Nano is powered from a powered hub or a PC/Mac that support 1A USB current output.
    • Long and high resistance USB cable. Some USB cables are not manufactured to USB tolerances. If they are too long, they might have a significant voltage drop at the voltage at the USB connector. When the lamps are powered, this voltage might drop further and cause a reset. Ensure a high quality and short USB cable is used to power the system. Try several short cables to rule out this issue.
    • Corrupted DLPC150 firmware. Please download  the DLPC150 firmware to the Nano using the GUI.
    • Loose connections between the Tiva and DLP Controller boards. Ensure that the boards are firmly set in their board to board connectors. If the boards were separated, inspect the connectors to ensure there are no bent pins.
    • Short in the cable to the Detector Board. Inspect the cable from the Tiva to the Detector board. We have seen the cable not seated properly or one of the wires pinched, causing electrical connection issues with the board.

    Best regards,
    Pedro

  • 0 in reply to PedroGelabert
    Prodigy 60 points

    Thank you for the help Pedro,

    turns out it was a combination of several of the above issues.


    Best

    Jan