1. IT Systems Flip - Flops EN230-1 Justin Champion C208 – 3273 www.staffs.ac.uk/personel/engineering_and_technology/jjc1

2. IT Systems Contents What are they Types of Flip flops SR D Program design

3. IT Systems What are they ? A circuit which will store a value A certain switch will allow the value to change from one value to another and return This is referred to as sequential logic Output is based upon the current input and previous outputs These give us high speed Memory Because they remember there state each flip-flop can store one bit Put together in a sequence and you have memory!

4. IT Systems Simply memory device Value at start will be the value after the loop 1 1 0

5. IT Systems NOR Gate Not OR gate ABQ 001 010 100 110 Q A B

6. IT Systems Types of Flip-Flop S-R (Set – Reset) S R SRQQ 00Remembers 0101 1010 11Illegal Q Q

7. IT Systems Types of Flip-Flop The condition of 0 and 0 needs to be checked for If S = 1 and R = 1 then the previous values are remembered and returned S R Q

8. IT Systems Types of Flip-Flop D Type allows the value of D to be stored as the clock changes states Only when the clock changes state can the value of D be updated

9. IT Systems Types of Flip-Flop

10. IT Systems Program Design Designing your program before you start is essential in any language Although you may start with a good idea of how to do things, this soon becomes confused Someone else can see how your program works Once you have drawn how your program works you can then start the ‘programming’! Not the other way round

11. IT Systems Program Design Flow chart design This allows the reader to quickly see how the program should work The following are the symbols you will use TerminalProcess Decision Yes No Input Output Sub-Routine

12. IT Systems Start Load 1 into A A > 10 Yes No Add 1 to A End

13. IT Systems Program Design Flow chart design The programmer can see what needs doing The design of the program can be written to this diagram Potential problems with the design can be sorted at this stage Alternative method is Pseudo Code This can end up messy and difficult to understand especially with larger programs Time Although designing these diagrams takes time Ultimately YOU will get the work done quicker Also part of the marking criteria !

14. IT Systems Summary of what we have discussed What is a Flip-Flop? SR Type D Type Program Designing