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6 marksComputer Architecture

CAPE Computer Science Unit 1 · 2011 · Paper 2 · Question 1(a)

Truth table with inputs x, y and output z: (0,0)->1, (0,1)->1, (1,0)->0, (1,1)->0.

Using only primary logic gates, design and draw the circuit for the given truth table.

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Other parts of this question

  1. 1(b)Write down the truth table (listing all input bit patterns and corresponding outputs) for the logic circuit shown in Figure 1.[4 marks]
  2. 1(c)(i)Explain what is meant by the term 'Flip-flop'.[2 marks]
  3. 1(c)(ii)Explain what is meant by the term 'Multiplexor'.[2 marks]
  4. 1(d)(i)Draw a clearly labelled block diagram of a 2-to-4 line decoder.[3 marks]
  5. 1(d)(ii)A circuit controls four light bulbs B1, B2, B3, and B4 such that only one is on at any time. State how a 2-to-4 line decoder can be used in this circuit and…[3 marks]
  6. 1(e)Find the 4-bit two's complement of -6.[2 marks]
  7. 1(f)Given a floating point representation of 1-bit sign, 3-bit exponent, and 5-bit mantissa, calculate the decimal representation of 001000101, showing all working.[3 marks]

More practice: the rest of this paper · more Computer Architecture questions · all CAPE Computer Science Unit 1 past papers