Registers, from the gate up

• Section C.8
• A flip-flop is one of the basic tools for memory.
• The RS latch has two inputs,
  • It is called a latch because it does not need a clock to function.
    • S for set
    • R for reset
    • Both on is not defined.
  • It has two outputs
    • Q the state of the device
    • -Q, the opposite of the state.
  • When S is pressed, the device is set to 1
  • When R is presssed, the device is set to 0
• A D Flip Flop is a more common element.
  • Two inputs
    • A data line (D)
    • A clock line
  • Two outputs
    • Q, and -Q (as above)
  • When the clock changes from low to high, the data on D is stored in the flip-flop
• We can build registers out of these.
• an example