What is d difference between serial and parallel data transfer?
As an example of serial data transfer using the shift register
approach, a set of four shifts triggered by clock pulses places the
contents of the X-register into the Y-register. Since four clock
cycles are needed, it is much slower than parallel transfer, but is
simpler and cheaper.
The illustration below shows the parallel transfer of 8 bits of
data from the X Register to the Y Register upon application of an
enabling transfer pulse. Clearly, parallel data transfer is faster
than serial data transfer, but serial transfer has the advantages
of requiring less hardware. These registers are made up of D
flip-flops, which can serve as memory locations. The information in
the X Register is intact after the transfer to the Y Register, so
this process shows a possible scenario for accessing digital
information stored in memory.