Home
rOm
Quest
Glossary
Random
Page
Search
Site
Lush
Sim
Class
Subject
Images
Help
FAQ
Sign
Up
Log
In
The Shift Register
-
On the rising edge of the clock pulse, each D is copied to the next Q and all the data moves one place to the right.
-
The data moves one place to the right along the shift register like suitcases on a conveyor belt.
-
Pulses can be delayed using this circuit.
-
Shift registers can be used in simple combination locks. The registers have to be clocked in the correct sequence to unlock the door.
SIMULATION

Pseudo-Random Number Generator
SIMULATION
Notice the diagonal pattern in the truth table.
Each row is copied and shifted one place to the right.
All shift registers work like this.

Serial In, Parallel Out, SIPO
The shift register can be used to delay pulses.
It can also be used to collect a serial stream of pulses. Once all the bits (usually eight) have been collected (a byte) the stored data can be copied to an eight bit latch (a parallel device).
The data is clocked in one bit at a time. When all eight bits have been clocked in, the Parallel data is available at the output.

Parallel in, Serial Out, PISO
-
First reset all the flip flops. This clears any old data.
-
Now each input line is used to set each flip flop.
-
An input line carrying a zero will not clear the flip flop. This is why the first reset step is required.
-
Finally clock the shift register. Each bit comes out of the last flip flop.
On the rising edge of each clock pulse, the next bit of data arrives at the output.
Subject Name
Level
Topic Name
Question Heading
First Name
Last Name Class ID
User ID
Question Text
image url
Help Link
Add
Delete
Clone
Edit
Hardness
Help Text
Debug
- You can attempt a question as many times as you like.
- If you are logged in, your first attempt, each day, is logged.
- To improve your scores, come back on future days, log in and re-do the questions that caused you problems.
- If you are logged in, your most recent wrong answers get remembered. This might help you and your teacher to correct your understanding.
- In the grade book, you can delete your answers for a topic before re-doing the questions. Avoid deleting unless you intend re-doing the questions very soon.