Ventu
I'm afraid I don't have a schematic. It just grew. The circuit is based upon recommended circuits in the AD977 datasheet, specifically fig 13 centre, left, for the analogue side, and fig 29 for the digital side. Note the need for a level shifter (MC14504B) and an invertor (MC14584) on the digital side or you will break the Due. Wire up using the circuits in their respective datasheets. You can leave the parts you don't use unconnected. The input can be improved with a simple impedance matching/low pass filter op amp circuit but works without. The connections to the Due are: pin 10 - inverted R/C, pin 12 - CLK, pin 13 - level shifted data out from AD 977. I don't use pin 11.
I hope this helps
Richard