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LMH6881 eval issue

Lee Szymanski
Prodigy 90 points

Other Parts Discussed in Thread: LMH6881, USB2ANY

Hi

I'm using a USB2ANY to control the LMH6881 eval board. The attenuation works correctly and it's mostly reliable however the Product ID is incorrect (1 when it should be 32) and the device locks up with this error

d1172

Error calling method TI.eLAB.EVM.USB2ANY.SPI_WriteAndRead, (System.ArgumentNullException: Key cannot be null.
Parameter name: key) <append><b>System.ArgumentNullException</b> in USB2ANY.lvlib:Set SPI Read-Write Register.vi->LMH688x_EVAL_GUI.vi

Any ideas? Win7 with labview package installed

  • 0
    TI__Genius 15975 points

    Hi Lee,

    Is it possible for you to try to unplug the USB cable from the USB2ANY and try to re-plug the cable back again? Are you using the Labview control software used for the eval board: http://www.ti.com/lit/ug/snau128c/snau128c.pdf ? It might be that due to power down of LMH6881 board, and a read during this time might have caused the USB2ANY to not receive the proper SPI signals due to which the USB2ANY might have gotten jammed.

    Please let me know if the issue is resolved or not.

    Best Regards,

    Rohit

     

  • 0 in reply to Rohit Bhat
    Prodigy 90 points

    Hi Rohit

    I've re-installed the software, rebooted and tried every USB port on my PC. Still get the errors. 

    I'm using the parallel interface now.

    Regards

    Lee

  • 0 in reply to Lee Szymanski
    TI__Genius 15975 points

    Hi Lee,

    Are you unable to read just the Product ID incorrectly or is this the case with Attenuation control as well? On the LMH6881 evaluation board, please make sure that all the DIP switches of "SW1" are in the OFF position while using the device in SPI mode. If any of the DIP switches are ON, they will interfere with the SPI mode of the device which will cause the registers to be read/written incorrectly. Also, please make sure that the SPI pin of the device is connected to logic high = 1 state.

    Best Regards,

    Rohit