Flasher Support

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Basic Settings

  • Please check that you have selected the correct device from the device list.
  • Have you selected the correct programming mode?
  • Are higher programming voltages required? Please use our "Programming voltage adapter".
    https://www.segger.com/products/production/Flasher/accessories/adapters/segger-programming-voltage-adapter/
  • Please check the cable wiring. See XML file wiring diagram for your device.
  • Have you ensured that possible rx and tx lines are properly crossed?
  • Are all pins required for flashing accessible and not hard-wired to GND or VCC or other signals?

Chip state

  • Is it a brand new board or has it been already programmed?
  • Has the programming mode been switched or deactivated?
  • Was the chip irreversibly code protected? (e.g. RDP Level 2)
  • Firmwares can prevent the debug interface from being activated.

Keep in mind that high frequencies (MHz) are used

  • The cables should be shorter than 30 cm.
  • Try to use twisted and shielded cables.
  • Try to avoid plugs and similar junctions.
  • Ensure a good ground connection.
  • Route the cables separately from other cables and avoid proximity to higher (AC) voltages.

Signal quality

  • Is there any circuitry on the target hardware that could affect the signal quality?
  • Is this circuit within the specification for programming the chip?
  • The timing and data setup times must meet the requirements defined in the data sheet!
  • Are external watchdog circuits connected to the reset pin? Disconnect or disable these circuits during flashing.
  • Please check your signal quality using an oscilloscope. See our reference diagrams.
  • Try to reduce the frequency of the target interface.
  • Improve your wiring and positioning of the Flasher.

Power Supply

Self powered target systems

  • How long does it take for the power supply to charge the capacitors?
  • Adjust the set-up time for the "target power" to your design!
  • When using an external power supply, make sure that the GND of the Flasher is properly connected to the GND of the connected device.
  • Please note possible ground differences between the (PC) Flasher and the target hardware. If in doubt, please use our "USB isolator".
    https://www.segger.com/products/production/flasher/accessories/isolators/usb-isolator/

VTref pin of the Flasher connected to the Vcc pin of the target system?

  • If yes, please deactivate the option "Fixed VTref".
  • If not, please activate "Fixed Vtref" and enter your I/O voltage in mV manually.

Universal Flashloader

  • Many programming algorithms support a so-called "Verbosity Level". The higher the level is set, the more messages are displayed on the console.
  • High verbosity may lead to lost messages, if you use a serial terminal. Try to use the Telnet terminal in this case.
  • This gives us more information about the possible causes of your problem.

If you need help, please provide us the following information:

  • Your used Flasher variant
  • Your Flasher's serial number
  • The exact name of your target device
  • The programming mode you want to use
  • The target power mode you want tot use(Self powered or powered by the Flasher)
  • An excerpt from the wiring diagram for the target interface and the reset logic
  • A detailed photo of the wiring from the flasher to the target.
  • The settings you have chosen. Flasher.UNI or Flasher.CFG file and the J-Flash/UFL project file.
  • A data file that can reproduce the behavior.
  • An ASCII file containing the consoles output at the highest "verbosity level"
  • Oscillograms of at least the data and clock lines


Example oscillograms for good signal quality at different clock rates:

Oscilloscope with 100MHz Bandwidth:

At high clock rates you can clearly see the influence of the oscilloscope's bandwidth.

Oscilloscope with 350MHz Bandwidth: