The DACx0502 come with a pin-selectable SPI or I2C interface. This configuration makes the system design generic. Pull the SPI2C pin low for SPI or high for I2C. The RSTSEL pin provides a known output at the DAC channels at power up, which helps the system achieve a predictable behavior during start up. When using a processor with multiple power-supply domains, make sure the input/output power (IOVDD) never exceeds the VDD voltage of the DAC. Switching on the IOVDD before VDD can violate the absolute maximum ratings. When there is no power-supply sequencing implemented on the system between the processor and the DAC, use a series resistor on the digital lines so that the current flow on the digital lines is limited to ±10 mA on any pin.