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AD7763 Filter Download Question

Hi,

 

I am having problems downloading filters to the AD7763. I have tried the example in the datasheet (in Table 16) so that I know the checksum is correct but I am not getting the FILTER_OK or DL_OK bits set in the Status read (the other bits of the Status read are fine - and UFILTER is set).

 

I am convinced that I have no problems with the data timing and I have a good clean clock, frame sync and data. I am clocking at 12.8 MHz.

 

I would be grateful for answers to the following questions:

 

1. Are there are any errors or omissions in the datasheet with respect to the download?

2. Is there any difference between the effects of applying a hardware SYNC (via the SYNC pin) or writing to the SYNC bit in Control Register 1?

3. In Table 16 it is not clear whether the delay for the checksum should be before or after writing the checksum, could you clarify this please?

 

Many thanks,

 

Gary Moore

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  • Hi Francois,

     

    Sorry for the delayed reply. Unfortunately I haven’t solved the problem, I got around it by implementing the filter in software – probably not a lot of help to you, sorry.

     

    I suspect that my problems may have been because my SYNC pulse wasn’t long enough but I’m not sure. I may have another look at it later but it’s a low priority for me now as I have the software work-around and I have other aspects of the system that I need to sort out.

     

    Very sorry that I can’t be more helpful. If you do find the answer I would be interested to hear.

     

    Regards,

    Gary

Reply
  • Hi Francois,

     

    Sorry for the delayed reply. Unfortunately I haven’t solved the problem, I got around it by implementing the filter in software – probably not a lot of help to you, sorry.

     

    I suspect that my problems may have been because my SYNC pulse wasn’t long enough but I’m not sure. I may have another look at it later but it’s a low priority for me now as I have the software work-around and I have other aspects of the system that I need to sort out.

     

    Very sorry that I can’t be more helpful. If you do find the answer I would be interested to hear.

     

    Regards,

    Gary

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