• A register is collection of binary storage
cells capable of holding binary information.
Since flip-flops are memory elements
capable of storing binary information, so a
group of flip-flops working together
constitute a register. To form an n-bit
register, n flip-flops are required. Registers
comprise of flip-flops and may contain
combinational circuits.
,• Registers
• The flip-flops play the prime function of
storing the binary information while the
combinational circuits effect the transition
of the flip-flops and control when and how
new information is transferred into the
register. There are two modes of operation
of registers, the series and parallel
operation. In serial operation the digits are
entered in sequence of one bit per clock
pulse.
, • Registers
• Thus, if the register stores four bits, it will
require four clock pulses to input or output
the four bits. On the other hand, in parallel
operation all data is input or output during
a single clock pulse period. As a result the
parallel operation is faster than serial
operation.