# What is ripple in VHDL?

## What is ripple in VHDL?

A Ripple Carry Adder is made of a number of full-adders cascaded together. It is used to add together two binary numbers using only simple logic gates. The figure below shows 4 full-adders connected together to produce a 4-bit ripple carry adder.

**Is called as ripple carry adder *?**

These carry output at each full adder stage is forwarded to its next full adder and there applied as a carry input to it. This process continues up to its last full adder stage. So, each carry output bit is rippled to the next stage of a full adder. By this reason, it is named as “RIPPLE CARRY ADDER”.

**What is a 2 bit ripple carry adder?**

Ripple Carry Adder is a combinational logic circuit. It is used for the purpose of adding two n-bit binary numbers. It requires n full adders in its circuit for adding two n-bit binary numbers. It is also known as n-bit parallel adder.

### What is mean by demarcation line in VLSI?

Explanation: Demarcation line separates n and p transistors. Demarcation line is similar to dotted line in brown.

**What is switch logic in VLSI?**

Explanation: Switch logic is based on pass transistors or transmission gates. Pass transistor describes several logic families used in the design of integrated circuits. This logic reduces the count of transistors used to make different logic gates, by eliminating redundant transistors.

**What is nMOS pass transistor?**

NMOS pass transistor passes Strong ‘0’ but weak ‘1’ An NMOS pass-transistor can pull down to the negative rail, but it can pull-up to a threshold voltage below the positive rail. => It can output a strong zero, but a weak one.

## Is ripple carry adder scalable for all input widths?

The second example uses a generic (in VHDL) or a parameter (in Verilog) that creates a ripple carry adder that accepts as an input parameter the WIDTH of the inputs. Therefore it is scalable for any input widths.

**What are the basic operations of Alu in VHDL?**

It normally executes logic and arithmetic operations such as addition, subtraction, multiplication, division, etc. In this VHDL project, an ALU is designed and implemented in VHDL. VHDL code for the ALU is fully presented. 1. Arithmetic Addition 2. Arithmetic Subtraction 3. Arithmetic Multiplication 4. Arithmetic Division 5. Logical Shift Left 6.

**Why can’t we just do a*B in VHDL?**

VHDL coding vs Software Programming 28. VHDL code for MIPS Processor 29. VHDL code for Moore FSM Sequence Detector 30. VHDL code for Seven-Segment Display on Basys 3 FPGA why cannot we just do A*B? Because the * multiplication operator is not supported for std_logic_vector type in VHDL.