Digital Logic & Microprocessors Flashcards
7 cards from real CET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Digital Logic & Microprocessors flashcards as text
A euthanasia chamber's microprocessor checks a door-sensor pin and reads logic level 0 (LOW). The system is designed with active-LOW logic for safety. What does this reading indicate?
Answer: The door is closed and the safety condition is met
In active-LOW logic, a LOW (0) signal represents the active or asserted condition, so a LOW door sensor means the door is closed and the safety interlock is satisfied.
A euthanasia system uses a watchdog timer. If the microprocessor program freezes or enters an infinite loop, what does the watchdog timer do?
Answer: Resets the microprocessor to restore normal operation
A watchdog timer resets the microprocessor if the software fails to periodically 'kick' or reset the timer, recovering the system from software hangs.
Which logic family is most commonly used in modern euthanasia equipment microcontrollers due to its low power consumption and wide noise immunity?
Answer: CMOS (Complementary Metal-Oxide-Semiconductor)
CMOS logic dominates modern microcontrollers because it draws minimal current in static states, provides excellent noise immunity, and operates over a wide voltage range.
In a euthanasia equipment control program stored in memory, machine code instructions are executed by the CPU in a repeating sequence. What is the correct order of this sequence?
Answer: Fetch → Decode → Execute
The instruction cycle always follows Fetch (retrieve instruction from memory), Decode (interpret the instruction), Execute (perform the operation).
A euthanasia system's ADC reads a pressure sensor outputting 0–5V and converts it to a 10-bit digital value. What is the voltage resolution of each digital step?
Answer: ~4.88 mV
A 10-bit ADC over a 5V range has 2^10 = 1024 steps; 5V ÷ 1024 ≈ 4.88 mV per step.
A euthanasia controller uses a multiplexer (MUX) to route signals from 8 different sensors to a single ADC input. How many selection (address) lines are needed to select any one of the 8 sensor channels?
Answer: 3
To select among 8 channels, 3 binary select lines are needed because 2^3 = 8 unique combinations.
In a microprocessor's ALU (Arithmetic Logic Unit) used in euthanasia equipment control, which operation would be used to check whether a gas concentration value has reached a specific threshold by subtracting the threshold and testing for zero?
Answer: Subtraction (SUB) with zero flag check
Subtraction followed by checking the zero flag in the status register is a standard microprocessor technique for comparing two values for equality.