Hardware register

In digital electronics, especially computing, hardware registers are circuits typically composed of flip-flops, often with many characteristics similar to memory, such as:^{[citation needed]}

• The ability to read or write multiple bits at a time, and
• Using an address to select a particular register in a manner similar to a memory address.

Their distinguishing characteristic, however, is that they also have special hardware-related functions beyond those of ordinary memory. So, depending on the point of view, hardware registers are like memory with additional hardware-related functions; or, memory circuits are like hardware registers that just store data.^{[citation needed]}

Hardware registers are used in the interface between software and peripherals. Software writes them to send information to the device, and reads them to get information from the device. Some hardware devices also include registers that are not visible to software, for their internal use.

Depending on their complexity, modern hardware devices can have many registers. Standard integrated circuits typically document their externally-exposed registers as part of their electronic component datasheet.