Setup a C/C++ Environment in Windows

Unix operating systems have been around for a long time, and one great feature they have had for years, was the ease of setting up a programming environment. However, Windows has pretty much caught up with the recent addition of Eclipse C/C++ IDE. All it takes now is the installation of 2 or 3 programs.

How to setup a C/C++ programming environment in Windows

First download and install the latest version of MinGW

I suggest taking the easy route and download the "Automated MinGW Installer" it is just a .exe that does everything for you. This link should bring you to the correct place, you just need to search in the long list of downloads for "Automated MinGW Installer" and get the latest version (i.e. MinGW-5.1.4.exe).

https://sourceforge.net/projects/mingw/files/

By installing this package you will now have the essential compiling commands that most Unix developers/programmers know and love (i.e. gcc and g++). MinGW will also provide their implementation of "make" called mingw32-make.exe. Also MinGW will provide you with essential library/header files and others that you probably have never heard of.


The Second and last step to setting up your environment is to download and install Eclipse C/C++ IDE and/or MSYS.

MSYS can be found in the same link above. Look for "MSYS Base System" and download the most recent version (there should be an exe that you can download). After specifying the install location and finishing the primary installation, the installer will bring up a cmd prompt window and will ask you some questions. It will want to know if you have MinGW installed and what path it was installed at (by default it should be in c:/MinGW, but just double check that is where the folder resides). The installer will update some path variables and will link the evironment to your MinGW install. After it has finished you will have a perfectly healthy MSYS install that works just like a basic unix environment.

Some notes about MSYS unix environment. You will notice that if you issue the command "pwd" after launch the program, it will output /home/, where is your username in windows. The root path "/" is really a folder in the MSYS install directory. For example if my user is "Administrator", pwd would output /home/Administrator which in the windows environment means C:\msys\1.0\home\Administrator. As a result you cannot access your windows filesystem by ordinary means. If you want to access code that is somewhere else on your windows partition you will need to place it in this folder.

Another note, all commands in MSYS will show up as .exe files however you can omit the .exe file extention in the command and MSYS will automatically translate it.

If you prefer a more graphic programming environment you can install Eclipse IDE. Just head over to:

http://www.eclipse.org/downloads/

And download an install the "Eclipse IDE for C/C++ Developers". There isn't really an installation to this program, just run the .jar in the folder and start your project. If everything was installed properly Eclipse should automatically select MinGW in your project options, giving your complete C/C++ programming environment.

Enjoy.

Topic #2 (Part1): Matlab GUI

Taking a little detour from HDL, I would like to discuss the second topic, which concerns the engineering programming/scripting language called Matlab. Practically all electrical/computer engineers have encountered Matlab at some point of their studies. For those less familiar with it, Matlab is a Matrix laboratory that serves as an excellent tool for visualization of engineering problems. Having a strong background can be a huge benefit when it comes to applying for a job concerning research/developement in an electrical/computer engineering field. In this topic, I would like to discuss the methods of creating a GUI without the aid of Matlab's GUI creator GUIDE.

The most fundamental component to creating a GUI in Matlab is the "handle". It is critcal to GUI creation that you fully understand what a handle is, so I will take this very slow. As the name suggests, a handle is a component of an object that you "can grab onto", basically meaning it serves as a unique identifier in the environment that you can call, set, and get different properties. Each time a handle is created Matlab generates a new value that is not in use. In the simplest case you might create a figure by issuing the command:

figure(1);

By dowing this, Matlab creates a handle value of 1 that is used to control the newly created figure window. If two other windows are created after this, where the handle value is not set, matlab will auto-increment to the next unused value. Thus, issueing the command figure twice after figure(1) would yeild two new figure windows one which has a value of 2 and the other a value of 3. If however, before calling that third figure window I were to close/delete the first figure (which has a handle value of 1), that third figure command would recreate the handle value of 1 instead of continuing with the incrementing scheme. Note: these integer handle values are generally reserved for figure windows, other object will generally use floating point but you can manually assign a handle of either integer or double depending on your needs/preference. Whenever an object is being created, such as a figure, an axes, a uicontrol, etc the programmer can choose to store the handle value into a variable to easily reference that object at a later time. For instance:

a=figure;

b=axes;

The commands above would create a figure of some handle value that gets stored into the variable 'a' and an axes figure inside that figure with a handle value storing in b. This makes referenceing each individual object much more simple than finding parent/daughter objects.

Now that we have a good idea of how handles can be used lets introduce some of the most usefull commands that can be used with these handle values.

The "get" command: used to grab all object properties from a handle, or a specific property value.

The "set" command: used to set a property value of a handle.

The "findobj" command: used to find all handles that have a property set to a specific value.

The "uicontrol" command: used to create I/O objects such as radio buttons, pushbuttons, textboxes, etc.

Use the "help" command to learn more about these functions. This is all for now. Next time, I will discuss callback functions and how to create an event based GUI.

Topic #1 (Part 2): HDL - Verilog

When someone is introduced to HDL the common question of "which variant should I choose?" comes up. Verilog and VHDL have a lot of similarities and differences, these differences may make this question simple to answer. Verilog is a variant of HDL that was designed to cater towards people with a background in C, the syntax and keywords are very familiar with only slight differences. If a person was tasked with creating a D register (flip flop) in Verilog, this would be the corresponding code:

module dff(clk,d,q,qn);
 input clk, d;
 output q, qn; 
   reg q=0;
 reg qn=1;
   always @(posedge clk)
 begin
   q<=d;     qn<=~d;   end  endmodule   

The resulting simulation:

When analyzing this code line by line we first see the "module" statement. A module is similar to a function in C where once the function has been properly defined it can later be using in other projects to perform a specific task. After the name of the module (dff was used as the name since this is a D flip flop module) we list the inputs and outputs. These I/Os can be listed in any order. Notice also that statements, just like in C, are terminated with semicolons.

The following two statements, define whether each port is an input port, an output port, or an inout port ("inout" is rarely used).

The next two statements define q and qn (the data output and the inverted data output port) as registers. There are two primary variable types that can be used, reg and wire. A variable of type register, can be updated at specific events. A register can also be defined as an array of values. For instance:

reg [7:0] counter;

This statement would define a register called counter with an 8-bit depth thus giving it 256 unique values. Uses of arrays will be discussed later. A "wire" by definition can only be a single bit as it attempts to replicate the function of a physical wire (meaning at any point in time a wire can only contain one physical value). Unlike the reg the wire does not make use of the assignment operator "<=", a wire uses the keyword "assign" and the "=" operator. The difference between these two are very important when considering timing. HDL has two methods of statement execution: sequential and concurrency. Sequential statements just as the name describes executes statement sequential in the order they appear in the code. Although you can write a lot of code sequentially, it is actually not synthesize-able. Concurrent statements are statements that occur at the end of a clock cycle. The interesting and painful part of concurrency is that you don't necessarily know which register was updated first. Because of this, it is impossible to physically realize a module that updates a register more than once at any point in time. This may sound obvious to most, but from the standpoint of someone with C programming, where sequential statements are the only option. Looking back at the snippet of code, the next statement shows one possible way to control when a register is updated. The "always" keyword says to always perform the following statement(s) "at" (denoted as @) some event. The "begin" and "end" keywords are Verilog's way to encapsulate multiple statements that are to follow the event rule.

Well, this is it for now. I will give an identical example using VHDL