Homework Problem Set: Combinational Devices & ASM Charts. Answer all questions on this sheet. You may attach additional pages if necessary.

Transcription

1 Student Name:.. Student Number:.. Session I (1 or 2):. Table I (1-11):... Group I (,, ): Homework Problem Set: ombinational evices & SM harts We will collect these sheets from students at the start of class. Please write clearly and legibly. nswer all questions on this sheet. You may attach additional pages if necessary. Page 1 of 10

2 Question 1: (8 marks - 2 per each waveform) etermine the output waveform X for the logic circuit shown below by first finding the intermediate waveform at each of the points Y1, Y2, Y3, and Y4. Use the input waveforms provided in the timing diagram below. Y 1 Y 3 X Y 2 Y 4 Y 1 Y 2 Y 3 Y 4 Page 2 of 10

3 Question 2: (3 marks) ssuming a propagation delay through each gate os 10 ns, determine if the desired output waveform X in the figure below (a pulse with a minimum tw = 25 ns positioned as shown) will be generated properly with the given inputs. (The grid on the timing diagram is on a 10 ns spacing.) Show your working clearly on the timing diagram below. E X E X Page 3 of 10

4 Question 3: ( 2 marks - 1 for the faulty gate + 1 for the type of failure) The circuit below is a logic circuit under test. The observed waveforms are shown. The output waveform is incorrect for the inputs that are applied to the circuit. ssuming that one gate in the circuit has failed, with its output either an apparent constant HIGH or a constant LOW, determine the faulty gate and the type of failure. G1 G2 G4 X E F G3 E F X Page 4 of 10

5 Question 4: ( 4 marks - 2 for each waveform) The input waveforms below are applied to a 2-bit adder. etermine the waveforms for the sum and the output carry in relation to the inputs by constructing a timing diagram in Page 5 of 10

6 Question 5: ( 2 marks) numbers are applied sequentially to the -to-decimal decoder shown below. raw a timing diagram, showing each output in the proper relationship with the others and with the inputs Page 6 of 10

7 Page 7 of 10

8 Question 6: (2 marks) If the data-select lines of the multiplexer shown below are sequenced by the given waveform, determine the output waveform with 0 = 0, 1 = 1, 2 = 1, 3 = 0. S0 S Y S0 S1 Page 8 of 10

9 Question 7: (5 marks - 2 for block diagram and 3 for SM chart) clock mode digital system called a start signal generator is to be designed having two inputs REY and GO, and an output Z. The output is to remain 0 until the following sequence of events takes place: REY must go to 1 Following that, Z will go to 1 for a clock period as soon as GO is 1. REY and GO will never be 1 simultaneously. fter completion of one entire cycle the REY input must go to 1 to repeat the sequence. evelop a block diagram and an SM chart. Page 9 of 10

10 Question 8: (5 marks - 2 for block diagram and 3 for SM chart) raw a block diagram and an SM chart having the following description. The circuit has control input, a clock, and outputs x, y and z. If = 1, on every rising edge of the clock the outputs x, y and z change through the sequence 000 -> 010 -> > 110 -> 000, and so repeats. If = 0, the circuit holds the present state. Page 10 of 10