C Programming Lab

BME554L - Fall 2025 - Palmeri

Prelab

• Complete Nordic DevAcademy: Lesson 3 – Elements of an nRF Connect SDK application
• Complete Nordic DevAcademy: Lesson 4 – Printing messages to console and logging
• Review Debugging resource.

Objectives

• Introduction to C Programming
• Building Zephyr application
• Flashing Zephyr application
• Viewing serial output from Zephyr application running on your nrf52833DK
• Debugging Zephyr applications in VS Code

Zephyr Application Git Repository Overview

• src/main.c - main application code
• .gitingore - ignore files that are not needed in the git repository
• CMakeLists.txt - build system configuration file
• prj.conf - Zephyr configuration file
• README.md - this file
• CMakePresets.json - CMake presets file (build configuration)
• .gitlab-ci.yml - GitLab CI configuration file

Things To Do

Git Best Practices

• Use best practices for version control (branching, commit messages, etc.).
• Do all development on a dedicated branch that is merged into main once it is functional.
• Commits should be very specific to the changes/additions you are making to your code. This will help you and others understand what you did and why you did it.
  
• On a given development branch, try to implement one small piece of functionality at a time, commit it, and then move on to the next piece of functionality.

Important

You do not want one, monolithic git commit right before you submit your project.

Fork / Clone / Build / Flash / View Serial Output

• Fork the C Programing lab repository on Duke’s GitLab server: https://gitlab.oit.duke.edu/kits/BME-554L-001-F25/c-programming-lab
• Add Dr. Palmeri (mlp6) as a Maintainer in your forked repository.
• Clone your forked repository to your local machine.
• Build the Zephyr application “as is” (review DevAcademy: Lesson 1).
• Flash the Zephyr application to your development kit.
  • Connect the VCOM port on the nrf52833DK to your computer (using Connected Devices and the plug icon)
  • Look at the serial output in the VS Code Terminal

Modify the Zephyr Application (DataTypes / Typecasting / Formatted Printing)

• Inspect the code to see how variables a, b and c are declared and initialized.
• Flash the existing code and note the terminal output:

• On a development branch called fix_division, without changing the declared datatypes of a, b, or c, correct the code so that c is output in the terminal:

• Push the fix_division branch to your GitLab repository.
• Create a Merge Request to merge the fix_division branch into your main branch.
• Make sure the GitLab CI pipeline is successful before merging the fix_division branch into main. If it isn’t passing, fix the problem locally on the same branch and push the changes to GitLab.
• Pull your updated main branch to your local machine.
• Create an annotated tag for the merged commit on main with the fixed division named v1.0.0.
• Push this annotated tag to your GitLab repository.

Tip

Note that the CI pipelines running on the GitLab server can take a while to complete. Do not rely on them for immediate development feedback, but rather as a final check before merging code into main.

Library Refactor

• On another development branch on your local machine called refactor_library, refactor the code to put the divide_numbers() function into a library called my_math_functions.h.
• Once you have your code working with this library, locally merge the refactor_library branch into main.
• Create an annotated tag for the merged commit on main with the refactored library named v1.1.0.
• Push the new commit(s) and annotated tag to your GitLab repository. Remember, this will need to be done with two commands, git push and git push --tags.

Push Everything to GitLab & Create an Issue to Notify Dr. Palmeri

• Make sure all of your commits are pushed to your main branch, along with both annotated tags.
• Confirm that the GitLab CI pipeline is successful.
• Create an Issue titled C Programming Lab Complete and assign it to Dr. Palmeri (mlp6).

Gradescope

Complete the Gradescope assignment for this lab that is a few simple tasks:

1. Confirm that you created the Issue above
2. Confirm that you completed both of the Nordic DevAcademy lessons
3. Upload a screenshot of your CI pipeline jobs passing

How to Ask for Help

1. If you have a general / non-coding question, you should ask your TAs / Dr. Palmeri on Ed to allow any of them to respond in a timely manner.
2. Push you code to your GitLab repository, ideally with your active development on a non-main branch.
3. Create an Issue in your repository.
   • Add as much detail as possible as to your problem, and add links to specific lines / section of code when possible.
   • Assign the label “Bug” or “Question”, as appropriate.
   • Be sure to specify what branch you are working on.
   • Assign the Issue to one of the TAs.
   • If your TA cannot solve your Issue, they can escalate the Issue to Dr. Palmeri.
4. You will get a response to your Issue, and maybe a new branch of code will be pushed to help you with some example syntax that you can use git diff to visualize.