AD9265 - Cannot access SPI when analog input ON.

Hi all,

I faced a strange issue about SPI of AD9265. I need to change some ADC register dynamically, but I can't when analog input signal is ON.

AD9265 analog input port is connected to signal generator, and SPI port is connected to Zynq - Xilinx's SOC.

When RF of signal generator was OFF, there was no problem on SPI communication between Zynq and AD9265.

However, RF of signal generator was ON, none of SPI access was successful.

It looked that AD9265 did not support SPI function at all.

When I tried to read Chip ID, no response from ADC.

When I tried to output mode from binary offset to two's complement, the output mode was not changed.(I saw the AD data shape via Vivado's ILA )

In any case, DCO and D[15:0] signals looked good. I was able to capture analog signal.