1. ITEC 352 Lecture 9 Flip Flops

2. Flip flops Review Questions? HW #2 posted, due next Friday at 10PM Floating point numbers

3. Flip flops Outline Rationale SR D T JK

4. Flip flops Gates So far what have we seen circuitry wise? What can we do with what we have learned? What can’t we do?

5. Flip flops Idea Have the output tied to the input

6. Flip flops Why? State –Why is the state of a machine important? –How does this relate to programming? –What does hooking up the output to the input do to our idea of timing? Not a new idea –Back in 1918

7. Flip flops SR Set and reset latch –Can be implemented with NAND gates What is the truth table for this set of gates? What input set should we stay away from?

8. Flip flops Gating the gates What does this image bring to mind?

9. Flip flops Issue Changes in the input immediately change the output Sometimes keeping the state the same even though the input changes is required What is the truth table? What do you think E does

10. Flip flops D Latch Adding the 1/1 combination –Just like an SR latch except it handles the 1 1 input condition gracefully

11. Flip flops Clock cycles Some sort of order needed –Conductor in an orchestra Need to preserve values through each “beat” Behavior –Designed to delay the output by 1 cycle –Allows access to previous cycles result Clock pulse

12. Flip flops T Flip/flop Toggles value when T is 1 Clock pulse changes values

13. Flip flops JK Flip/Flop Universal flip/flop J=set, K=reset 0 0 is hold 1 1 is toggle

14. Flip flops Next steps Have the capability to store information Have the capability to manipulate binary bits for mathematical and boolean tasks How does it all fit together to form a computer?

15. Flip flops Summary Flip flops Latches Storing bits