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Important Digital Logic and Design Short Questions

Chapter: 37
Question 1:
What does the DIR variable indicate in the elevator control system?
Answer: DIR indicates the current floor of the elevator: DIR=0 means the elevator is on the first floor, and DIR=1 means it is on the second floor.
Chapter: 37
Question 2:
In the simplified state table for SR1, what is the next state when SR1=1 and REQ1=1?
Answer: When SR1=1 and REQ1=1, the next state depends on the values of other inputs but will be either C1 or DO based on the simplified state table for SR1.
Chapter: 37
Question 3:
What is the purpose of the ARRIVAL input in the elevator state machine?
Answer: The ARRIVAL input is used to determine state transitions in the elevator state machine, affecting the transition between states like W1, C1, and UP based on the current states of SR1, SR2, and ARRIVAL.
Chapter: 37
Question 4:
How does the Traffic Signal Controller handle the NSG state during the day?
Answer: During the day, if LTIME is active, the Traffic Signal Controller transitions from NSG to NSY; otherwise, it remains in the NSG state.
Chapter: 37
Question 5:
What are the inputs to the Traffic Signal Controller?
Answer: Inputs include NSSR (North-South section sensor), EWSR (East-West section sensor), LTIME (5-minute timer), and STIME (1-minute timer).
Chapter: 37
Question 6:
What does the STIME signal do in the Traffic Signal Controller?
Answer: The STIME signal is activated if 1 minute has elapsed; it prompts the state machine to switch states during the night when traffic is light.
Chapter: 37
Question 7:
In the Traffic Signal Controller, what is the next state from NSY?
Answer: The next state from NSY is NSY2.
Chapter: 37
Question 8:
How does the state machine in the Traffic Signal Controller respond to both EWSR and NSSR being active?
Answer: If both EWSR and NSSR are active, the state machine transitions to NSY.
Chapter: 37
Question 9:
What is the purpose of the TMRST signal in the Traffic Signal Controller?
Answer: The TMRST signal resets the timer after the LTIME or STIME signals indicate that the 5-minute or 1-minute intervals have elapsed.
Chapter: 37
Question 10:
What are the outputs of the Traffic Signal Controller?
Answer: The outputs are NSGrn (North-South Green), NSYel (North-South Yellow), NSRed (North-South Red), EWGrn (East-West Green), EWYel (East-West Yellow), EWRed (East-West Red), and TMRST (Timer Reset).