Why can I not debug in IAR Embedded Workbench for AVR?

Introduction

This Technical Note focues on failures to start an IAR Embedded Workbench for AVR debug session.

Message

When using IAR Embedded Workbench for AVR version 5.xx the following error might occur:

Failed to initialize USB driver: error 0x20000009 ("No valid license")

Situation 1 + Solution

If an old version of Atmel AVR Studio was installed before IAR Embedded Workbench for AVR version 5.xx was installed, then the above error might occur.

Both IAR Embedded Workbench for AVR v 5.11A and AVR Studio uses Jungo WinDriver to create USB drivers. The version of the driver installed by the old Atmel AVR Studio is not compatible with IAR Embedded Workbench for AVR version 5.xx.

To resolve the problem you can install the latest version of Atmel AVR Studio (v 4.14 at time of writing).

Situation 2 + Solution

After installing IAR Embedded Workbench for AVR 5.40 (or later), the above error might occur in versions older than 5.40.

Installing IAR Embedded Workbench for AVR 5.40 (or later) installs a new version of the Jungo driver.

To solve this, open any project in IAR Embedded Workbench for AVR 5.40 (or later), and start a C-SPY session. Now, the Jungo driver will be started. Exit IAR Embedded Workbench for AVR 5.40 (later).

After this, open your project in IAR Embedded Workbench for AVR older than 5.40. The Jungo driver is already started, and should now work.

Note that if you reboot your PC, the above has to be repeated, that is, to start the Jungo driver.

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