Thank you Estibaliz
Just to be sure that I have found what there is:
https://github.com/analogdevicesinc/no-OS/tree/master/device_drivers/AD5791
https://github.com/analogdevicesinc/no-OS/tree/master/device_commands/AD5791
On a lower level there is also the SPI interface code, but I will use another processor and will take them from elsewhere. On the top level there is the code for the FPGA (I know nothing about such devices). But that is not C code?
Anything more? Like noise plot, histogram or GUI interface?
Thanks.
Roy