What is the multi clock domain design?

The difference between the single clock domain and multiple clock domain designs is the phase difference between arrivals of the clock signals. The clock sources CLK1 and CLK2 are different for both the domains and regardless of the same or different frequencies the design is treated as multiple clock domain design.

How do you sync two clock domains?

Common methods for synchronizing data between clock domains are:

1. Using m-FF based synchronizers.
2. Using MUX based synchronizers.
3. Using Handshake signals.
4. Using FIFOs (First In First Out memories).
5. Using Toggle synchronizers.
6. Using Xilinx specific clock domain crossing (CDC) tools.

What is clock domain in VLSI?

A clock domain is defined as part of the design that is driven by either one clock or more clocks that have related to each other. For example, a clock with frequency 10MHz and a divide by 2 clock driven from 10MHz clock are treated as a single clock domain design.

What is meant by clock domain crossing?

In digital electronic design a clock domain crossing (CDC), or simply clock crossing, is the traversal of a signal in a synchronous digital circuit from one clock domain into another. If a signal does not assert long enough and is not registered, it may appear asynchronous on the incoming clock boundary.

Why is it necessary to gating a clock?

Clock gating is a popular technique used in many synchronous circuits for reducing dynamic power dissipation, by removing the clock signal when the circuit is not in use. Clock gating saves power by pruning the clock tree, at the cost of adding more logic to a circuit.

What is asynchronous clock?

Clocks are asynchronous when not in-phase or their frequencies are not multiple of the other.

How does a 2 clock FIFO work?

This dual clock FIFO is designed as a way for two circuits operating in different clock frequencies to communicate with each other. There is a read side and write side where data is stored into the internal memory of the FIFO using the write side clock and then read from the internal memory using the read side clock.

What is asynchronous clock domain?

Asynchronous Clock Domain Crossings Clocks which do not have a known phase or frequency relationship between them are known as asynchronous clocks. Whenever there is a clock crossing between two asynchronous clocks, their active edges can arrive very close together leading to metastability.

What is clock domain crossing in FPGA?

CDC occurs whenever data is transferred from a flip-flop driven by one clock to a flip-flop driven by another clock. CDC issues could cause significant amount of failures in both ASIC and FPGA devices.

Why is gating the clock bad?

Among other things, it is very sensitive to timing and can have glitches on the actual clock input. In practice, what is actually done is a mux is inserted in between the data input and the D input of the flip-flop. When the gating signal is active, the mux selects the data input.

What’s the difference between power gating and clock gating?

While clock gating focuses on the dynamic power of the circuit by reducing the switching frequency, the power gating focuses on the static/leakage power of the circuit by reducing the flow of current through the circuit.

What is the difference between synchronous and asynchronous clock?

For synchronous data transfer, both the sender and receiver access the data according to the same clock. Therefore, a special line for the clock signal is required. For asynchronous data transfer, there is no common clock signal between the sender and receivers.

How to transfer a single-bit control signal between two clock domains?

Since the clock signals of different clock domains are independent in general, transferring data between the different clock domains can be a challenging task. This article will discuss a well-known technique called “double flopping” to transfer a single-bit control signal between two clock domains.

What is a clock domain?

A section of the design in which all the synchronous elements, such as flip-flops and RAMs, use the same clock signal is referred to as a clock domain. Having different clock domains can be beneficial but is not as easy as it seems to be. The next section discusses some of the problems that we may face when using a multiple-clock system.

Is it common to employ several clock signals in a system?

It is common to employ several clock signals in a digital system. Since the clock signals of different clock domains are independent in general, transferring data between the different clock domains can be a challenging task.

Why am I getting timing errors when I Cross clock domains?

Commonly when you cross clock domains you will experience timing errors. This is normal! This is the tools telling you that you will have a situation where your setup and hold times are not going to hold, and that you will have a metastable condition.