#8 CPU frequency bounces back to 100000



I am using the latest version of the avr-eclipse (at least software update does not give me a newer version).
If I read the cpu frequency from the device it gives me 1Mhz. Despite the device runs on 8Mhz. Don't know if it is a bug.
But if I set it manually to 8Mhz and aplly the settings close the properties dialogue and open it aain it is back at 1Mhz.

Could this be a bug?

My workaround is to set F_CPU by hand.


  • Thomas Holland

    Thomas Holland - 2010-01-21

    Hi Anonymous,

    sorry, but I missed your support request. Is it still valid?



  • Interactive Matter

    Yes, it is still valid.
    Unfortunately it appears to affect just one project. Can I help you by providing some project file or something?

  • Thomas Holland

    Thomas Holland - 2010-01-22


    first of all. the Plugin does not read the MCU clock frequency from the target MCU. It can only determine the MCU (a convenience featrue if you do not know the exact type)

    But nevertheless the clock frequency should not change itself. So this could be a bug and if you send me the affected project (or attach it to this support request item) I can check if I can reproduce the bug.


  • Mikko Saarisalo

    Mikko Saarisalo - 2010-01-22

    Hi Thomas,

    I am experiencing the exact same behavior. I am getting it apparently every time I create a project. (I am following these instructions: http://robertcarlsen.net/2009/10/31/arduino-in-eclipse-989). I'll upload a fresh project tar with zero source file in it. I'll do it on bug ID: 2934539. No intention to cross post. This one just had the 1MHz observation more precisely described then the ...539.

  • Thomas Holland

    Thomas Holland - 2010-01-26

    I checked the project you posted, but it works for me, i.e. all changes to the clock setting are saved as expected.

    For further troubleshooting could you check the file "{your Project}/.settings/de.innot.avreclipse.core.prefs". This is where the plugin stores the MCU type and clock frequency. Does the the avrtarget/ClockFrequency line in the file change when you 'Apply' or 'OK' a different clock frequency in the plugin?

    P.S. as a workaround to your problems you could edit the abpve mentioned line in the preferences file with Eclipse not(!) running to manually select a different clock frequency.

  • Mikko Saarisalo

    Mikko Saarisalo - 2010-01-27

    Hi Thomas,

    Thanks for helping!

    The clock speed value is not stored in the config file upon "Apply" or "Ok". I did edit the file manually and now the value of 16MHz is showing correctly on Eclipse side, as well.

    The config file mod is:
    -rw-r--r--@ 1 saarisal saarisal 784 27 Tam 06:41 de.innot.avreclipse.core.prefs
    and Eclipse process is owned by saarisal:
    saarisal 4955 107 0 0:14.17 ?? 1:05.00 /Applications/eclipse/Eclipse.app/Contents/MacOS/eclipse -psn_0_950504



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