I am attempting to program an Arduino to interface with a DAC, specifically the AD7390 made by Analog Devices.
I have tried using the SPI library as a means of realising the interface but am confused by the PIN layout of the DAC. It provides me with SCK, SDI, CLR and LD pins.
The LD (Load Strobe) PIN is used to transfer buffers from the chip's on-board shift register to its DAC register.
The CLR PIN is used to forcibly clear the DAC register.
The documentation claims that the device is SPI compatible but, using these PINs with the Arduino Mega2560 as a micro-controller, only partially works and I am concerned that the circuit requirements of the SPI library are not being satisfied. In SPI documentation, a SS (slave select) PIN is universally mentioned but is not present with my device.
As I have managed to get the CLR PIN working, consistently and as expected, I wonder if a manual approach - i.e. using shiftIn() instead of the SPI library - is the way to go.
Any suggestions or advice would be appreciated.