Chip select

Chip select (CS) or slave select (SS) is the name of a control line in digital electronics used to select one (or a set) of integrated circuits (commonly called "chips") out of several connected to the same computer bus, usually utilizing the three-state logic.

[3] When an engineer needs to connect several devices to the same set of input wires (e.g., a computer bus), but retain the ability to send and receive data or commands to each device independently of the others on the bus, they can use a chip select.

The chip select is a command pin on many integrated circuits which connects the I/O pins on the device to the internal circuitry of that device.

[4] When the chip select pin is held in the inactive state, the chip or device is "deaf", and pays no heed to changes in the state of its other input pins; it holds its outputs in the high impedance state, so other chips can drive those signals.

[5] CS may also affect a power consumption or serve as cycle control in certain circuits (such as SRAM or DRAM).