how to implement a certain comparator using PROM..

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transgalactic

Joined Apr 29, 2008
74
the circuit compares two numbers each number has 3 bits
where Y >=3 and X <=5
it has one output if X>Y then g=1 if X<Y then G=0
if X=Y then G= dont care

i need to implement using 2^2X1 and 2^2X4 PROM's

i cant think of a way to combine them
????
 

beenthere

Joined Apr 20, 2004
15,819
Make a table using the numbers. In each case, the output will be less than, equal, or greater than. Program the PROM using the numbers as the address. Each address should output the correct comparison.

Please stay with one thread instead of opening a new one on the same subject.
 

beenthere

Joined Apr 20, 2004
15,819
Truth table was not a good term. More like a state table. Call one value X and the other Y.

For all X = Y, the EQUAL output is true.
For all X < Y, the LESS THAN output is true
For all X > Y, the GREATER THAN output is true.

Choose some value for the PROM to output for the three conditions, Using the values as addresses, program the PROM so the output expresses the comparison of the X bits to the Y bits.
 
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