I am using a Cyclone 2 FPGA to interface with an AD7314. The sensor is used in 3 wire mode, with the SDI pin tied to ground. I am sending a 300kHz serial clock (maximum is 10MHz), as well as a periodic CE signal that goes high every 28us and lasts for 16 clock pulses. What I do not understand is that the sensor output does not change, eventhough I heat it up with the a hair dryer for around 10-20 seconds. Neither did it change when I reduce the temperature as well.
I've attached an image that shows the signals waveforms. The yellow signal is sensor data output. The green signal is the serial clock and the blue signal is the CE.
Am i missing something?
Thanks for your help