Topic: fmc112 configuration  (Read 2213 times)

karen March 10, 2015, 09:49 AM

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Dear Arnaud


I noticed a weird problem on FMC112.
I'm using chipscope to verify the signals in my design. I apply a pulse signal (with 800mV-pp, for example) to one of the channels, and verify the chipscope data, I notice that sometime the internal signal (output of fmc stellar) is getting saturated and tolerates between 8191 to -8192.


I'm using fmc112 stellar IP as you provided without any change. Do you have any idea, what might be the problem?

arnaudNL March 11, 2015, 10:40 AM (#1)

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Dear Karen,


We have seen many times customers reporting strange issues after adding chipscope in their design. I am not saying this is the reason but could you please try to reproduce that on our default reference design (non modified firmware and software). The software will create ASCII data buffer one can visualize in Visual Analog, a tool you can obtain free of charge from ADI from their website.


Do you have a DC coupled board? If I understand your report, you are using a square signal ranging between 0V and 800mV and you see that the ADC input seems to randomly "vibrate" across full scale (0-1-0-1-0)? How wide is your pulse?


Best Regards,
Arnaud

karen March 16, 2015, 04:44 AM (#2)

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Thanks for your reply and sorry for the belated response on my end.




Yes the board is DC coupled. I'm using a square signal with pulse width of 1 us and pulse period of say 11 us (I believe it is not really matter since I can reproduce the phenomenon with other pulses as well). input voltage between 0 to 800 mv.


the output is correct and showing the pulses and sometimes I see output fluctuates between max positive and min negative (since the 14 bit is interpreted as signed two's complement)




I'm suspicious whether it is because of my signal generator or ADC. and it's not my primary focus of work at this moment. let me catch up with my design and gain more knowledge on the behavior, and I come back to give update, meanwhile you can close the topic ...


thanks again.

arnaudNL March 17, 2015, 07:48 AM (#3)

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Dear Karen,


Thanks for the feedback!


As a side note, you wont be able to create new topic on the technical support forum as we are moving to a ticket system. On your next question, please register on support.4dsp.com and post over there.


Best Regards,
Arnaud

arnaudNL March 17, 2015, 07:48 AM (#4)

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This topic is being closed because the issue is considered as resolved by 4DSP. Feel free to create a new topic for any further inquiries.