n bit shift register (Serial Out) in VHDL - Electrical Engineering Stack Exchange[^3^]

VHDL Code for shift register can be categorised in serial in serial out shift register, serial in parallel out shift register, parallel in parallel out shift register and parallel in serial out shift register.

Parallel In Serial Out Shift Register Vhdl Code

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Design of Parallel IN - Serial OUT Shift Register using Behavior Modeling Style -Output Waveform : Parallel IN - Serial OUT Shift RegisterVHDL Code------------------------------------------------------------------------------------ Title : parallel_in_serial_out-- Design : vhdl_upload2-- Author : Naresh Singh Dobal-- Company : nsdobal@gmail.com-- VHDL Programs & Exercise with Naresh Singh Dobal.------------------------------------------------------------------------------------- File : Parallel IN - Serial OUT Shift Register.vhdlibrary IEEE;use IEEE.STD_LOGIC_1164.all;entity parallel_in_serial_out is port( clk : in STD_LOGIC; reset : in STD_LOGIC; load : in STD_LOGIC; din : in STD_LOGIC_VECTOR(3 downto 0); dout : out STD_LOGIC );end parallel_in_serial_out;architecture piso_arc of parallel_in_serial_out isbegin piso : process (clk,reset,load,din) is variable temp : std_logic_vector (din'range); begin if (reset='1') then temp := (others=>'0'); elsif (load='1') then temp := din ; elsif (rising_edge (clk)) then dout

Hello Sir, if I want to increase the input of PISO to 8 inputs (0 to 7), where the code that I must modify...?library IEEE;use IEEE.STD_LOGIC_1164.all;entity parallel_in_serial_out is port( clk : in STD_LOGIC; reset : in STD_LOGIC; load : in STD_LOGIC; din : in STD_LOGIC_VECTOR(7 downto 0); dout : out STD_LOGIC );end parallel_in_serial_out;architecture piso_arc of parallel_in_serial_out isbegin piso : process (clk,reset,load,din) is variable temp : std_logic_vector (din'range); begin if (reset='1') then temp := (others=>'0'); elsif (load='1') then temp := din ; elsif (rising_edge (clk)) then dout

I'm creating an n bit shift register. When the enable signal is high, I want the shift register to shift n times, irrespective of whether enable continues to be high or low. I've put a for loop to shift n times inside a process. My code is given below.

Shift Registers are used for data storage or for the movement of data and are therefore commonly used inside calculators or computers to store data such as two binary numbers before they are added together, or to convert the data from either a serial to parallel or parallel to serial format. The individual data latches that make up a single shift register are all driven by a common clock ( Clk ) signal making them synchronous devices.

Also, the directional movement of the data through a shift register can be either to the left, (left shifting) to the right, (right shifting) left-in but right-out, (rotation) or both left and right shifting within the same register thereby making it bidirectional. In this tutorial it is assumed that all the data shifts to the right, (right shifting).

The effect of each clock pulse is to shift the data contents of each stage one place to the right, and this is shown in the following table until the complete data value of 0-0-0-1 is stored in the register. This data value can now be read directly from the outputs of QA to QD.

This shift register is very similar to the SIPO above, except were before the data was read directly in a parallel form from the outputs QA to QD, this time the data is allowed to flow straight through the register and out of the other end. Since there is only one output, the DATA leaves the shift register one bit at a time in a serial pattern, hence the name Serial-in to Serial-Out Shift Register or SISO.

The SISO shift register is one of the simplest of the four configurations as it has only three connections, the serial input (SI) which determines what enters the left hand flip-flop, the serial output (SO) which is taken from the output of the right hand flip-flop and the sequencing clock signal (Clk). The logic circuit diagram below shows a generalized serial-in serial-out shift register.

The Parallel-in to Serial-out shift register acts in the opposite way to the serial-in to parallel-out one above. The data is loaded into the register in a parallel format in which all the data bits enter their inputs simultaneously, to the parallel input pins PA to PD of the register. The data is then read out sequentially in the normal shift-right mode from the register at Q representing the data present at PA to PD.

This data is outputted one bit at a time on each clock cycle in a serial format. It is important to note that with this type of data register a clock pulse is not required to parallel load the register as it is already present, but four clock pulses are required to unload the data.

The final mode of operation is the Parallel-in to Parallel-out Shift Register. This type of shift register also acts as a temporary storage device or as a time delay device similar to the SISO configuration above. The data is presented in a parallel format to the parallel input pins PA to PD and then transferred together directly to their respective output pins QA to QD by the same clock pulse. Then one clock pulse loads and unloads the register. This arrangement for parallel loading and unloading is shown below.

The PIPO shift register is the simplest of the four configurations as it has only three connections, the parallel input (PI) which determines what enters the flip-flop, the parallel output (PO) and the sequencing clock signal (Clk).

Similar to the Serial-in to Serial-out shift register, this type of register also acts as a temporary storage device or as a time delay device, with the amount of time delay being varied by the frequency of the clock pulses. Also, in this type of register there are no interconnections between the individual flip-flops since no serial shifting of the data is required.

These universal shift registers can perform any combination of parallel and serial input to output operations but require additional inputs to specify desired function and to pre-load and reset the device. A commonly used universal shift register is the TTL 74LS194 as shown below.

Universal shift registers are very useful digital devices. They can be configured to respond to operations that require some form of temporary memory storage or for the delay of information such as the SISO or PIPO configuration modes or transfer data from one point to another in either a serial or parallel format. Universal shift registers are frequently used in arithmetic operations to shift data to the left or right for multiplication or division.

In the next tutorial about Sequential Logic Circuits, we will look at what happens when the output of the last flip-flop in a shift register is connected directly back to the input of the first flip-flop producing a closed loop circuit that constantly recirculates the data around the loop. This then produces another type of sequential logic circuit called a Ring Counter that are used as decade counters and dividers.

Design of Parallel In - Serial OUT Shift Register using Behavior Modeling Style -Output Waveform : Parallel IN - Serial OUT Shift RegisterVerilog CODE -//-----------------------------------------------------------------------------//// Title : parallel_in_serial_out// Design : vhdl_upload2// Author : Naresh Singh Dobal// Company : nsdobal@gmail.com// Verilog HDL Programs & Exercise with Naresh Singh Dobal.////-----------------------------------------------------------------------------//// File : Parallel IN - Serial OUT Shift Register.vmodule parallel_in_serial_out ( din ,clk ,reset ,load ,dout );output dout ;reg dout ;input [3:0] din ;wire [3:0] din ;input clk ;wire clk ;input reset ;wire reset ;input load ;wire load ;reg [3:0]temp;always @ (posedge (clk)) begin if (reset) temp

The Parallel-in to Serial-out shift register acts in the opposite way to the serial-in to parallel-out one above. The data is loaded into the register in a parallel format in which all the data bits enter their inputs simultaneously, to the parallel input pins PA to PD of the register. The data is then read out sequentially in the normal shift-right mode from the register at Q representing the data present at PA to PD. This data is outputted one bit at a time on each clock cycle in a serial format. It is important to note that with this type of data register a clock pulse is not required to parallel load the register as it is already present, but four clock pulses are required to unload the data.

CHAPTER 1: INTRODUCTION TO DIGITAL ELECTRONICS * Basics. - Digital and analog signals. Definition and characteristics. - Digital electronics. Applications. CHAPTER 2: DIGITAL REPRESENTATION OF THE INFORMATION * Digital representation of the information. - Information concept and unit of information. - Information codification. * Numeral systems. - Binary numeral system. - Octal numeral system. - Hexadecimal numeral system. - System conversion. * Binary codes. - Natural binary code. - Decimal codes expressed in binary code: BCD, Excess-3 BCD. - Cyclic and continuous binary codes: Gray and Johnson. - Representation of signed numbers. - Representation of fixed point and floating point numbers. - Alphanumeric codes: ASCII. - Applications. CHAPTER 3: BOOLEAN ALGEBRA. LOGIC FUNCTIONS * Boolean algebra. - Boolean algebra postulates. - Boolean algebra theorems. * Logic functions. - Definition of logic variable. - Definition of logic function. - Representation of logic functions. Truth table. - Basic logic functions and their symbols (logic gates). - Complete sets of logic gates. - Function generation with logic gates. * Simplification with logic functions. - Simplification by application of theorems. - Canonical forms for a logic function. Synthesis by minterms and maxterms. - Simplification with Karnaugh maps. Examples. - Simplification of incomplete functions. - Simplification of multifunctions. CHAPTER 4: DIGITAL ARITHMETIC SYSTEMS * Binary arithmetic. - Introduction. - Arithmetic operations in binary natural code. Binary addition. Binary substraction. Substraction as an addition: Representation of negative numbers in ones complement and in twos complement. Binary multiplication. - Arithmetic operations in BCD: addition and substraction. * Arithmetic circuit. - Basic half-adder. - Complete adder. - Parallel adder with serial carry. - Parallel adder with parallel carry. - Serial adder. - Basic half-substracter. - Complete substracter. - Adder-substracter. - Binary multiplier. - Arithmetic Logic Unit (ALU). CHAPTER 5: OTHER COMBINATIONAL SYSTEMS * Combinational circuits and subsystems. - Combinational circuit concept. - Digital multiplexer. Multiplexer extension. Applications of multiplexers: parallel-serial conversion. Generation of functions. - Encoders. Standard encoders. Priority encoders. - Decoders. Mutual exclusive output decoders. Driver decoders. Decoder extension. Decoder applications: serial-parallel conversion (demultiplexers). Generation of logical functions. - Code coverters. - Parity generator and checker. Parity generator and checker extension. - Binary comparator. Comparator extension. CHAPTER 6: SEQUENTIAL SYSTEMS * Flip-flop circuits. - Sequential system definition. - Types and characteristics: asynchronous and synchronous. - R S flip-flop. - J K flip-flop. - T flip-flop. - D flip-flop. - Flip-flop timing parameters. * Shift registers. - Register concept. - Shift registers. Serial input, serial output. Serial input, parallel output. Parallel input, serial output. Parallel input, parallel output. - Bidirectional register. - Applications of registers. Sequence generator. * Counters. - Digital counters. - Asynchronous counters. Decade counter. - Synchronous counters. Serial and parallel carry. - Reversible counter. - Counters based on shift registers. Ring counter. Johnson counter. Anti-lockout counter. - Applications. * Analysis and design of synchronous sequential circuits. - Analysis of synchronous sequential circuits. - Transition tables and state diagrams: Mealy and Moore machine state. - Synthesis of synchronous sequential systems. 2ff7e9595c