DESIGN OF A COMPUTER BUS SYSTEM FOR FOUR BIT RESIGSTERS USING MULTIPLEXERS Registers Definition: A register is a small amount of fast storage in a CPU or other digital circuit. Used to store binary data temporarily. Made of flip - flops ( 1 flip - flop stores 1 bit). Can be parallel load or serial load. Examples: Instruction Register, Data Register, Address Register. Types of Registers • Shift Registers (Serial In/Serial Out, Serial In/Parallel Out, etc.) • Parallel Registers (load all bits at once) • Counters (special registers that increment/decrement automatically) • Status Registers (hold flags like zero, carry, overflow) Buses Definition: A bus is a communication system that transfers data between components inside a computer or between computers. Consists of multiple parallel lines (wires) for bits. Types: Data bus, Address bus, Control bus. Bus width = number of bits transferred simultaneously. Shared resource; only one device transmits at a time. Types of Computer Buses • Data Bus – transfers actual data. • Address Bus – specifies memory or I/O locations. • Control Bus – carries control signals (Read/Write, Clock, etc.) Multiplexers Definition: A multiplexer (MUX) selects one of several input signals and forwards the selected input into a single line. Acts as a digital switch. Controlled by select lines. n select lines can choose from 2 ^n inputs. Used to share a single resource among multiple data sources. Four - Bit Multiplexer A four - bit multiplexer has 4 parallel MUXes, one for each bit of the bus. Each MUX selects one bit from multiple input sources. Controlled by the same select lines to ensure bits come from the same source. Example: 4:1 four - bit MUX selects from 4 registers (A,B,C,D) onto a 4 - bit bus. BLOCK DIAGRAM Summary • Registers store data temporarily. • Buses transfer data between components. • Multiplexers allow multiple sources to share a bus. • A four - bit MUX handles 4 parallel bits with synchronized selection.