Wire

Wire: transmits a one-bit signal

Connected device can write 0 or 1 to the wire

At most 1 device can write to a wire at any given time

Result is undefined if:

More than 1 device attempts to write to the wire

No device is writing to the wire

More than 1 device can read from the wire

Wire has no memory: signal must be continuously asserted to be valid

Example: 4 devices

D1 is writing to the wire

D2, D3, D4 are reading from the wire

Assume each device has 2 connections to the wire (1 to read, 1 to write)

What are the devices?

ALU, registers, gates, flip-flops, etc.