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AD7656a-1 NOT Working

Hi All ,

I have purchased AD7656A-1 ADC for my experimental work. I have configured it for SPI interface using zedboard.

Configuration is on Hardware. Using ALL data line A,B,and C. with internal ref selected.

But there is a problem that I am getting All time same value i.e. -32768 on all channels .

When I measured the voltage across open terminal of analog input to AGND , it was -2.25 V.

What is this mean? Is ADC is no more live?

Here the signals captured by DSO for reference,

Legends are as follows for scop_0:





While in scope_1, and _2 :

4th signal is DOUT A , ( when no analog signal is applied)

While in scope_2:  1 volt 500 Hz sine bipolar signal has been applied on V1 analog input using function generator, with OP07 as buffer.

I am unable to find out, what actually happening, why ADC is  not capturing signals!

Thanks in Advance,