What are the minimum and maximum values in HEX we can get as output from FFT?
May biggest concern is how I can understand that there is saturation in any of AFE or Auxiliary channels?
What library are you using ? This should be explained in that context for my understanding and should be clarified with the library supplier..
I am using IAR library, which is with the original AD development kit. What is the relation between FFT values and libraries?
So you may check with IAR how this is implemented in detail.
It is not the problem how it is implemented in IAR.
I want to know how it is implemented in the hardware of the IC itself and what are the min and max value I can get from it.
If the values can be from 0 to 0xFFFF or there is any limit.
If I have for example saturation of the input of the AFE (signal is with an amplitude higher than the limit of AFE(ADC) input), will it give me 0xFFFF as a real part ( amplitude is saturated ) , or no.
Is there any way to understand from FFT Real or Imeginary registers that my signal is outside the limits?
Instead of looking at it from a DFT perspective look at it from the input to the ADC. If you can ensure that the AC signal does not saturate the ADC, with correct RTIA selection etc. http://www.analog.com/media/en/technical-documentation/application-notes/AN-1271.pdf , then you will not saturate DFT measurement.
For monitoring purposes we have AFE_ADCMIN and AFE_ADCMAX registers which are sticky bits and can be used to monitor the ADC inputs to ensure you do not go outside your designed limits.
I shall take care, but it is possible to get saturation because of the specific of my application. Are these registers ADCMIN and ADMAX updating in every FFT cycle ?
What should be their value in case of saturation - 0xFFFF and 0x0000 or something else ?
They monitor all ADC data.
See Figure 154 on ADC transfer function. So scale the RTIA from say 0x3000 to 0xD000 and have ADCMIN at 0x2000 and ADCMAX at 0XE000.
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