Serial 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. 作为使用移位寄存器方法的串行数据传输的例子，由时钟脉冲触发的四次移位将X寄存器的内容移入Y寄存器。由于需要四个时钟周期，这种传输方式比并行传输慢很多，但更简单且成本更低。

Parallel Data Transfer

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.

Shift Register

Binary data can be shifted from one flip-flop to the next on each clock pulse. The shift from left to right here is the kind of data transfer that occurs in a serial transfer. 在每个时钟脉冲下，二进制数据可以从一个触发器转移到下一个触发器。这里的向右移动是串行传输中发生的数据传输方式。