I'm trying to interface an AD9910 DDS evaluation board with an external micro-controller through SPI in 3-wire mode. I have a few questions related to this:
1) What are the minimum and maximum voltages that can be applied to CS, SCLK, SDIO and SDO (1.8V or 3.3V?)?
2) What is the role of MASTER_RESET (pin14) , IO_UPDATE (pin 59) and EXT_PWR_DWN(pin 18) (and the min and max voltages that can be applied to these pins) in SPI operation?
3) Does the AD9910 operate in slave or master mode (i.e. SCLK is an input or output [i checked the voltage level on SCLK, it was 1.8v high])?
4) The sequence of operation (i.e. application of voltages on pins, initialization of registers) before any meaningful command can be sent to the AD9910?