Solution
Key PointsThe number of multiplexers required to construct the bus is equal to
n,
where n is the number of bits in each register.
The size of each multiplexer must be k : 1
since it multiplexes k data lines, where k is the number of registers.
Therefore
If there are 8 registers of 16 bits each, then we need 16 multiplexers, each of which is an 8: 1 multiplexer to create the 16-bit data bus.
Additional Information
- Since a computer has many registers, paths must be provided to transfer information from one register to another
- An efficient scheme for transferring information between registers in a multiple-register configuration is a common bus system. A bus structure consists of a set of common lines, one for each bit of a register, through which binary information is transferred one at a time.
- Control signals determine which register is selected by the bus during each particular register transfer.
- Bus systems can be designed using multiplexers and tri-state buffers.
Bus System for four 4-bit registers:
