Homework 3

• Using only or and and gates, produce a circuit that produces a 1 if the contents of a register have even parity, and a 0 if the parity is odd. Implement this in T tkgate. Provide the user with a way to store a value in the register.
• Design a digital lock that has a 3 number combination. The lock should operate as follows:
  • The user enters the first number (on a keypad) and throws a switch
  • The user then enters a second number and throws the switch again
  • The user enters the third number and throws the switch
  • If all three numbers are correct, the lock is unlocked, otherwise, the lock remains locked.
  You should implement this in tkgate. Your implementation should have one switch for input and one dipswitch for numeric input. You should have an led to indicate that the lock is locked (light - unlocked, dim - locked).

  You should store the combination within the circuit, perhaps in a switch. I used a register to store the "state" of the lock. Each time a correct number was entered the state was changed, and if an incorrect number was entered, the state was reset.

• Implement figure 3.8 in tkgate. Your implementation should
  • Implement an 2⁸ x 16 memory that is byte and word (16 bit) addressable.
  • Use two 2⁸x8 memory modules
  • Make sure that words are aligned on even addresses, if not, light an error light. and don't perform the memory access.
  • Bytes read and written should be justified (or placed on data lines 0-7)
  • Have a size line, a 0 represents a word operation, a 1 represents a byte operation
  Provide sufficient interface to test your memory.