USB device not found or already in use - JTAGICE3
Technical Note 68109
When using Atmel JTAGICE3 the following errors might occur:
Fatal error: USB device not found or already in use.
Fatal error: Failed to initialize USB driver: error 0x20000007 ("Internal system error")
Use IAR Embedded Workbench for AVR 6.21.3 or newer. Alternatively, see the AVR32 solution below.
Use IAR Embedded Workbench for AVR32 4.21.1 or newer.
Alternatively, downgrade the firmware to a version that is supported by IAR Embedded Workbench for AVR32. If you don't intend to use SAM D20 (ARM) with your JTAGICE3 , and the new firmware is causing trouble, one option is to downgrade your JTAGICE3 to the old V2 firmware again, using the firmware tool "atmelatfwsetup-61133".
After you install the tool, you will find a new entry "Downgrade connected JTAGICE3 to Firmware V2" on your start menu. Connect your JTAGICE3, and select this entry.
Note: It is possible to prevent Atmel Studio from upgrading your JTAGICE3. To prevent AS6.1.2730 from upgrading your JTAGICE3, you will have to replace \Program Files \Atmel\Atmel Studio 6.1\tools\JTAGICE3\jtagice3_fw.zip with \Program Files\Atmel\AtmelAtfw\jtagice3_fwv2.zip. Rename the zip to match the original name (remove v2 from the file name).
Atmel Studio 6.1.2 upgrades the JTAGICE3 firmware to version 3.8 that turns the JTAGICE3 into a CMSIS-DAP debugger. This firmware version will not work with IAR Embedded Workbench for AVR version 6.21 and IAR Embedded Workbench for AVR32 version 4.20 (or older).
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