Build an 8-bit CPU with a memory

Objective of this lab:

	The purpose of this lab is to learn about CPU Organization 
	by building an 8-bit CPU with a memory 

Preparation

	Read lab lecture notes.

Lab Assignments

1. Create a project Lab3.circ in the Logisim.
2. Add a circuit window to test the 8-bit RAM, replicate the circuit in the lab notes and practice with the steps following the diagram.

   

3. Add a circuit window to implement the 8-bit CPU design (with memory and PC+1) in the lab notes.

   

4. In the 8-bit CPU, the highest 2-bit in the instruction register IR will hold the operation code.
   The 8-bit CPU will do the following operations:
• For instruction 00, do 8-bit XOR, test 00000010 XOR 00000011 = 00000001
• For instruction 01, do 8-bit AND, test 00000010 AND 00000011 = 00000010
• For instruction 10, do 8-bit NOT operation, the Operand will be in the register ACC, test NOT 00000010 = 11111101.
• For instruction 11, do 8-bit OR, test 00000010 OR 00000011 = 00000011

Hand in the following:

1. Submit the file Lab3.circ which includes all the circuits needed.
2. Submit the file Lab3.pdf which contains the following:
   • Screenshot of the circuit testing the 8-bit RAM, replicate the circuit in the lab notes and practice with the steps after the diagram.
   • Screenshot of the 8-bit CPU circuit that you built.
   • The micro instructions (steps necessary) to implement the following operations described above. Remember to pre-load values.
     • Do the XOR operation with the values in register B and C, and store the result in C.
       test 00000010 XOR 00000011 = 00000001
     • Do the AND operation with the values in register B and C, and store the result in B.
       test 00000010 AND 00000011 = 00000010
     • Do the NOT operation with the value in register C and store the result in register B.
       test NOT 00000010 = 11111101
     • Do the OR operation with the values in register B and TMP, and store the result in C.
       test 00000010 OR 00000011 = 00000011
     
     Please Note: For all above four operations, you need to preload values in the registers from the EXTin.
     Use the above testing examples for your lab assignment hand-in micro instructions.
   • Microinstructions to load the following machine code into the memory.

     	Address		Machine code
     	============================
     	00000000 	10000001  
           	----------------------------
           	00000001	00010110  
           	----------------------------
           	00000010 	00000101  
           	----------------------------
           	00000011 	00001000 
     	=============================