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Basic Computer Faults

Directions: Step through the program already prewritten below (First  "Burn Prom" and "Load RAM") . It will  demonstrate how this programmers model of a simple computer works. The program should add the numbers at addresses 64 and 65 and store results at address 66. Next, insert fault 1, 2, or 3. Inserting fault sets one of the prom bits high or low. By observing program operation determine the address (0 thru 63 of the bad bit  and the Data line affected (I/O - 0 thru I/O - 7) .  You must click "Burn Proms Button to correct faults before selecting a new fault or you will accumulate multiple faults. 

See or make copy of Instruction Set and SPECIFICATIONS.

See Schematic 

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Control Processor Unit (CPU)

Register A        Carry       
Register B        A>B       Program Counter
Accumulator    A=B       Instruction Register
                                    A<B
  Data Bus  Address Bus  
--------------------PROM(8X64)----------------RAM(8X16)---------
00      16       32      48      64
01      17       33      49      65
02      18       34      50      66
03      19       35      51      67
04      20       36      52      68
05      21       37      53      69
06      22       38      54      70
07      23       39      55      71
08      24       40      56      72
09      25       41      57      73
10      26       42      58      74
11      27       43      59      75
12      28       44      60      76
13      29       45      61      77
14      30       46      62      78
15      31       47      63      79

      

  

 

Answer Below

 

 

 

Answer Fault 1

 

Fault 1

At Address 6 Bit1(labeled I/0 line 1) is low when it should be high.  

 

 

 

Fault 2

At Address 2 Bit1(labeled I/0 line 1) is low when it should be high.  

 

 

 

Fault 3

At Address 6 Bit3(labeled I/0 line 3) is high when it should be a low.