18 Questions
What is the purpose of a tri-state buffer?
To control when an output signal reaches the data bus
What is the function of a D-flip flop in output interfacing?
To store and transfer data from the data bus to external devices
What is the primary function of a flip-flop in digital electronics?
To store a single bit of binary data
How does a tri-state buffer prevent conflicts on the data bus?
By ensuring only one device can write to the bus at a time
What is the significance of the control inputs in a flip-flop?
They determine the state of the flip-flop and when it changes
How many stable states can a basic flip-flop have?
Two
What is the purpose of a tri-state buffer?
To prevent more than one device from writing to a bus at the same time
In the example given, how many wires are connected to the input of the tri-state buffer?
32
What is the behavior of a tri-state buffer when the control input c = 1?
The output is in a high impedance state (no current)
How does a tri-state buffer differ from a regular buffer?
A tri-state buffer has an additional control input
In the example with three devices outputting 32 bits each, what would happen if no tri-state buffers were used?
The bus would not function correctly due to conflicting outputs
What is the purpose of the control input in a tri-state buffer?
To enable or disable the output of the buffer
What is the primary function of a D flip-flop in a digital system?
To store a single bit of data based on the clock signal
Which component is typically used to interface between a controller and external devices for input/output operations?
Latch
What is the primary difference between a buffer and a latch?
A buffer has a constant output, while a latch can store data
Which type of buffer is typically used for bidirectional data transfer between a controller and external devices?
74LS245 (bidirectional)
What is the purpose of using a tri-state buffer in digital systems?
To allow multiple devices to share a common data bus
In a digital system, what component is responsible for generating control signals to latch data from the data bus into a D flip-flop?
The control unit or controller
Study Notes
Tri-State Buffers
- A tri-state buffer is a device that allows control over when an output signal reaches the bus.
- When the control bit is active, the input signal passes through to the output; when inactive, the output is high-impedance or Z (nothing).
- Multi-bit tri-state buffers can be implemented using multiple single-bit tri-state buffers.
- Tri-state buffers are necessary to prevent multiple devices from writing to a bus simultaneously.
Bus Communication
- Multiple devices can read from a bus, but only one device should write to it at a time.
- Tri-state buffers enable control over what gets on the bus and what doesn't.
Flip-Flops
- A flip-flop is a circuit with two stable states, used to store state information.
- Flip-flops have control inputs and one or two outputs.
- They are fundamental building blocks of digital electronics systems.
- Flip-flops can be divided into types: SR, D, T, and JK.
- A D flip-flop captures the value of the D-input at a specific clock cycle and stores it as the Q output.
Output Interfacing
- Output interfacing involves outputting data from the data bus to external devices.
- Components used in output interfacing include D-flip flops and latches.
Latches and Buffers
- Latches, such as 74LS374, are used to latch and hold data for input to the controller and output to external devices.
- Latches protect the controller from external device shorts.
- Buffers, such as 74LS244 and 74LS245, are used in interfacing circuitry to input and output data between the CPU and external devices.
- A buffer's output always follows its input.
- A latch stores data and holds it until instructed to change.
- A flip-flop is a type of latch that captures data at a specific clock cycle.
Explore the concept of tri-state buffers in bus systems and how control bits prevent multiple devices from writing simultaneously. Learn how to control output signals using tri-state buffers and the concept of high-impedance state (Z).
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
