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Showing posts from February, 2011

VHDL–3 to 8 Decoder

Decoder is a combinational logic circuit which has ‘n’ inputs and one output out of 2n outputs. for example if there are 3 inputs the decoder asserts one of the 8 inputs to the output. the following diagram shows the 3 to 8 decoder.here is the truth tableABCQ0Q1Q2Q3Q4Q5Q6Q70001000000000101000000010001000000110001000010000001000101000001001100000001011100000001Whenever the inputs are 000 then the Q0 will be ON and so on.VHDL Code for 3 to 8 decoderTool used: Active HDL Student Edition 7.2library ieee;
use ieee.std_logic_1164.all;

entity dec3to8 is
  port (sel: in std_logic_vector (2 downto 0);
        res: out std_logic_vector (7 downto 0));
end dec3to8;
architecture archi of dec3to8 is
  begin
    res <=  "00000001" when sel = "000" else
            "00000010" when sel = "001" else
            "00000100" when sel = "010" else
            "00001000" when sel = "011&qu…

Photo 53–A shop at T. Nagar

Selling Christmas items ….

VHDL–4 to 1 Multiplexer

Multiplexer is a digital system that outputs only one from the input based on the select lines. The following diagram shows the multiplexer. In short a multiplexer is called as a MUX. Please look at the truth table also. There are 4 inputs D0, D1, D2, and D3 and two Select lines S1 and S2. Depending upon the select line input the Dataout will have either D0 or D1 or D2 or D3.S1S2Dataout00D001D110D211D3The following code shows the VHDL Program for a 4 to 1 Mux and have a look at the waveform for the MUX.library ieee;
use ieee.std_logic_1164.all;entity MUX is
    port (s: in std_logic_vector(1 downto 0) ;
    datain: in std_logic_vector(3 downto 0);
    dataout: out std_logic
    );
end MUX;architecture muxarch of mux is
begin
    process(s,datain)
    begin
        case s is
            when "00" => dataout <= datain(0);
            when "01" => dataout <= datain(1);
            when "10…

Photo 48–A shop

Photo 46–a typical tamilnadu street

It’s a place “Dakshina chitra” near ECR Road, Chennai. It has more than 15 types of houses of southern India and showcase the art and culture of southern India like Pottery making, puppet show, pencil sketch, etc…..

Photo 44–Pathway in a university

A pathway at College of Engineering, Guindy. During my education we spend our time In this place… such a cool and ecstatic place.

Photo 41–Costly Pic

Yes, it’s a diamond stud….

Screen Capture Software for Fedora Linux

There are two screen Capture software for Fedora which takes less space and faster to run.1. tk-record my Desktop or qt-record my desktop2. istanbulto Install the above software, login as super user (root) and then give the commandyum install istanbulyum install gtk-recordmydesktopyum install qt-recordmydesktopThe output file what you will get will be ogv (OGG VORBIS) format which you can convert to avi or mp4 using any video converters

Photo 37–a cool pathway

During a hot sun, here is the cool path near tiruvanmiyur, Chennai

How to install Omnet++ in Windows 7

Installing Omnet++ in windows is a very easy taskStep 1:Click the following link and download Omnet++ along with MinGW (Minimalist GNU for Windows – this gives the look and feel of Linux inside windows, it is similar like cygwin)http://www.omnetpp.org/omnetpp/doc_download/2218-omnet-41-win32-source--ide--mingw-zipStep 2:Unzip the file to C:/(Now your folder looks like this C:\omnetpp-4.1)Step 3:Open Command prompt and go to C:\omnetpp-4.1 (The command is cd \ and cd omnetpp-4.1)Now type the command mingwenv.cmd and press enter (Please type the commands as given in the following pic)Step 4 :A new window will be opening which looks like a Linux Shell (as shown in the following pic)Step 5 :Type the command configure (this command will check all the modules and set the path)Type the command make (This will run for at least 10 minutes, but may vary machine to machine)Once everything is done, you will get a successful message and type omnetpp to open the IDE(Please Install JDK before all th…