clocked vs unclocked circuits
Sequential circuits are categorized into two main types: synchronous (clocked) and asynchronous (unclocked).
The main difference between the two is the timing of their signals:
Digital circuits that use clock signals to determine the timing of their operations. They are commonly used in digital systems to implement timers, counters, and memory elements.
D flip flop
A D flip-flop stores one bit of data. It captures the input (D) at the rising or falling edge of the clock signal (CLK), synchronizing data with the clock. Widely used in digital systems for storage, synchronization, and sequential logic operations.
Timing diagram:
Asynchronous circuits, also known as unclocked circuits, are digital circuits that do not depend on a clock signal to coordinate or synchronize the timing of their operations.
SR latch:
One of the simplest examples of an asynchronous circuit is the SR latch. An SR latch is a fundamental building block in digital electronics, often used for memory storage or basic control applications. It consists of two cross-coupled NAND gates or NOR gates, forming a feedback loop that allows the circuit to latch into one of two stable states: SET (S = 1, R = 0) or RESET (S = 0, R = 1). When both inputs are set to 0 (S = 0, R = 0), the circuit maintains its current state. Asynchronous here implies that the transition between states can occur at any time, depending solely on the input signals, without the need for a clock signal to coordinate the timing of operations.
Timing diagram:
