Unit 3 Sequential Logic Flashcards
Binary Counter
Group of flip-flops connected in a special arrangement in which the states of the flip-flops represent the binary number equivalent to the number of pulses that have occurred at the input of the counter
Asynchronous Counter
Type of counter in which each flip-flop output serves as the clock input signal for the next flip-flop in the chain
Decade Counter
Any counter capable of going through 10 different logic states
Down Counter
Counter that counts from a maximum count downward to 0
Modulus
The number of states through which a counter sequences before repeating
Modulus N Counter
A counter with a modulus of N
Synchronous Counter
Counter in which all of the flip-flops are clocked simultaneously
Up Counter
Counter that counts upward from 0 to a maximum count
Up/Down Counter
Counter that can count up or down depending on how its inputs are activated
Asynchronous Inputs
Flip-Flop inputs that can affect the operation of the flip-flop independent of the synchronous and clock inputs
Clock
Digital signal in the form of a rectangular pulse train or a square wave
Clocked D Flip-Flop
Type of flip-flop in which the D (data) input is the synchronous input
Clocked J-K Flip-Flop
Type of flip-flop in which inputs J and K are the synchronous inputs
D Latch
Circuit that contains a NAND gate latch and two steering NAND gates
Duty Cycle
Fraction of the total period that a digital waveform is in the HIGH state. DC=th/T
Edge-Sensitive
Manner in which a flip-flop is activated by a signal transistion
Falling Edge
The part of a pulse where the logic level is in transition from a HIGH to a LOW
Flip-Flop
A sequential circuit based on a latch whose output changes when it’s clock CLOCK input receives a pulse
Frequency
The number of cycles per unit time of a periodic waveform
Level-Sensitive
Enabled by a logic HIGH or LOW level
Period
The amount of time required for one complete cycle of a periodic event or waveform
PRESET
Asynchronous input used to set Q=1 immediately
Propagation Delays
Delay from the time a signal is applied to the time when the output makes its change
RESET/CLEAR
Asynchronous input used to set Q=0 immediately
Rising Edge
The part of a pulse where the logic level is in transition from a LOW to a HIGH
Sequential Logic
Digital circuitry in which the output state of the circuit depends not only on the states of the inputs, but also on the sequence in which they reached their present states
Shift register
Digital circuit that attempts binary data from some input source and then shifts these data through a chain of flip-flops one bit at a time
State Machines
A sequential circuit that advances through several defined states
Trigger
Input signal to a flip-flop or one-shot that causes the output to change states depending on the conditions of the control signals
