Step 1 – Creating a Project

The first thing you will see is the Embedded Workbench Startup screen. This screen will be a good shortcut to open existing workspaces and create new projects in the future, but for now, click the Cancel button. Note that a workspace can hold one or more projects, each which can hold groups of source files (the files that contain your assembly code).

Click on File -> New -> Workspace. This opens a new workspace in which to place your projects. You must always open a workspace before you can create a new project. To create a new project, click Project -> Create New Project… The Create New Project box will appear. IAR lets you choose whether you want to create an assembly (asm), C, or C++ project. Expand the asm tab and click OK once you have selected the asm option.

Figure 1

New Project Window

IAR will ask you to specify where you would like to save your .ewp project file. It is recommended you create a folder for your workspaces on your u: drive such as u:\ee251\Labs\ in which you can store all your future labs. Create a folder called Lab 3, name your project Lab 3, and click Save. At this point, you should also download the add_primes.s43 file provided on the class webpage into the same folder.

Look at the left of your screen. You will see the workspace window where your projects and source files are organized.

Figure 2

Workspace Window

On the right is the project window. The project window shows the assembly file template discussed in Introduction To Assembly Programming from the pre-lab material. You will not be using this file for this tutorial. Before anything else, click on File -> Save Workspace and save your workspace in the same folder as the project.

Now add the file we are going to examine in the tutorial. In your workspace window, right click on the project name and select Add -> Add Files… At the bottom of the page, change the Files of type tab to the Assembler Files option. If you downloaded the file from the class webpage, go ahead and select the add_primes.s43 file and click Open. You should see the file added to your workspace window. Right click on the asm.s43 template and remove it from the project then take a look at the add_primes.s43 code. This assembly program has stored the first six prime numbers in an array in memory and adds them up into register six. See if you understand what is going on by referencing the pre-lab material.

Step 2 – Setting the Project Options

Before we can compile our code into an executable object file, we need to set the project options. Using the Project pull-down menu select Options or simply right click on the project and select Options… This will bring you to the Options for node “<project_name>” screen.

Figure 3

Project Options Screen

Step 3 – Running the Program

Before we compile the project, make sure to save your project to preserve its settings. Select the add_primes.s43 file in the workspace window and click Project -> Compile. Alternatively, you can right click on the source file and select Compile. When the workbench is finished compiling your source code, you will see a new window at the bottom of the screen called your Build Messages Window. It should say that there are 0 errors and 0 warnings.

Figure 4

The "build message" window

To see what happens when your code contains an error, erase one of the semicolons preceding a comment in the add_primes.s43 code and re-compile. The build message window displays:

Double click the line that says “Error[0]: Invalid syntax.” In the file, your cursor will be placed close to the location of the error. Fix the error, and then re-compile.

Now make sure that your EZ430 is plugged in and click Project -> Debug. This will run your code on the EZ430 and put you in debugging mode.

Step 4 – Debugging A Project

A new window has been added to the screen in debugging mode. It is called the Disassembly Window. After the assembler compiles your code into machine code, a disassembler program does the opposite and creates the contents of the disassembly window. You can apply the debugging commands to either the coded assembly file or the disassembly window. Generally, this tool is more useful when the developer has written his/her application using the C programming language and wants to see how the machine interpreted his/her code in assembly.

The workbench allows users to move and dock windows as they wish. To see this, click View -> Memory and View -> Registers. Click on the window labels to drag and dock them in the same tab group as the Debug Log and Build windows. These windows are updated as the program executes, giving the user extremely useful insight to the inner workings of his/her program.

NOTE: If the contents of the window selected in each tab group ever change, the changed contents will be highlighted red to show the change.

The Memory Window

The memory window allows the user to navigate the entire memory map of the MSP430. Since we used assembler directives to load the array of prime numbers starting at memory location 0200h, type 0x0200 into the Go to box. You will see the array stored in consecutive words in memory.

Figure 5

Memory Window

Instead of Memory, IAR also gives you the option to looking at:

• SFR: The special function and peripheral registers
• RAM: Memory
• INFO: Information FLASH memory (ROM)
• FLASH: Main FLASH memory (ROM)

NOTE_01: You can use the information and main memories just the same. The only difference is how the memory is physically segmented and the address.

NOTE_02: If you look at the FLASH memory, notice that this is where the main program is stored. The numbers you see are the instructions of the program that have been stored for program execution.

Inspecting Source Statements

Run your mouse over these buttons in the top left corner of your debugging session and read their function in the bottom left corner of the IAR workbench frame.

Figure 6

The Debug Buttons

Subfigure 6.1 Subfigure 6.2: Program Reset Resets the execution of your program. Takes you back to the instruction address located in the reset interrupt vector. Subfigure 6.3: Step Over - Steps over the current step point. Subfigure 6.4: Step Into - When you debug a program with subroutines in assembly, you can choose to “Step Over” the subroutines, meaning that the subroutine is executed but you don’t step through it in the debugger, or you can choose to “Step Into” the subroutine. Stepping into a subroutine will allow the user to see the individual op-codes executed. Subfigure 6.5: Step Out Of - If you have stepped into a subroutine, steps out of the subroutine and to the next instruction after the subroutine call. Subfigure 6.6: Step to Next - Steps to the next statement, regardless of the circumstances. Subfigure 6.7: Execute to Current Cursor Position - Executes the program to the line at which the cursor is currently located. Subfigure 6.8: Run - Runs the program straight through or until a breakpoint. Subfigure 6.9: Stop Debugging - Stops the debugging session returns the user to programming mode. At the top right-hand side of the page, note this button as well: Subfigure 6.10: Make and Reset - Press when code has been modified so that it needs to be re-compiled and the debugger needs to be reset.