In this design, you are going to use a chain of flip-flop to implement a shifter register. The shifter register will be clocked using the clock divider you build in previous projects.
When reset button is pressed, LED0 is on while LED1 to LED 7 are off. When reset button is released, the light keeps shifting from LED0 all the way to LED7 and back to LED0 at a frequency of 0.74Hz
There are different ways to design the system. Two block diagrams of the system that fulfills the requirement are shown as follows. You are always welcome to come up with your own design.
1) Simple Shift Register:
See picture: http://learn.digilentinc.com/Digital/WSU/DC05_ShiftRegister/ShiftRegister.svg
2) Fill-Flop with Round Shifter
See picture: http://learn.digilentinc.com/Digital/WSU/DC05_ShiftRegister/FF_Shifter.svg
Now that you've completed this project, try these modifications:
1) Can you add two switches to control how fast the LED shfits: Say, if switch[1:0] is 0, LED shift frequency is 0.745Hz; if switch[1:0] is 1, LED shift frequency is 1.49Hz; if switch[1:0] is 2, LED shift frequency is 2.98Hz; if switch[1:0] is 3, LED shift frequency is 5.96Hz.
2) Instead of shifting the light on LEDs, can you create some fancy LED pattern using LEDs and/or seven segment display?