The CS pin is an active low input that enables the ADC serial interface for communication and is useful when multiple devices share the same serial bus. CS must be low during the entire data transaction. When CS is high, the serial interface is reset, SCLK input activity is ignored (blocking input commands), and the DOUT/DRDY output enters a high-impedance state. ADC conversions are not affected by the state of CS. In situations where multiple devices are present on the bus, the dedicated DRDY pin can provide an uninterrupted monitor of the conversion status and is not affected by CS. If the serial bus is not shared with another peripheral, CS can be tied to DGND to permanently enable the ADC interface and DOUT/DRDY can be used to indicate conversion status. These changes reduce the serial interface from five I/Os to three I/Os.