I'm testing a board with a AD7609 interfaced with a cyclone II fpga. I managed to start the conversion process and read the data however the output is shifted to the right by 1 bit. The values on the bits<17:2> of the 18 bit value are exactly half the value you would expect and I cannot get negative values as bit 17 is always zero.
The DB15 line (pin 33) is always in high impedance state.
I have tested all the connections and they are ok.
Has anyone come across this? Would appreciate any pointers at this stage. Thanks.