Developing in C on the AVR ATmega328P

Introduction

While the Arduino tool set, (both the Arduino IDE and Arduino software framework) are outstanding for quickly developing a working prototype, they do so with a combination of a graphical-user-interface (GUI), the C++ language and Arduino-only classes. This in itself, isn’t a problem, one can be quite efficient and productive using this approach.

This approach is an issue if you are at a university or job which expects a standards-based C language proficiency. It is also an issue, if your class or job, requires understanding how to use command-line-interface (CLI)-based tools. The C language, and not C++, is the basis of a significant number of embedded systems development.

This set of entries are written to help you learn how develop embedded ANSI C programs for the AVR family and specifically the ATmega328P (Arduino Uno R3). While doing so, it will also use a set of tools which can serve as the basis of an intermediate-level software programmer.

Important Links

• ATmega328P Datasheet - critical for understanding how to program the ATmega328P
• Definitive UNO pinout - easy to use reference for the ATmega328P pinout
• Arduino in C | Freedom Embedded - another site describing how to program the ATmega32P in Standard C
• Make: AVR Programming - phenomenal book on programming the AVR family, highly recommended
• Commentary: 10 Things I Wish I Knew Before Learning Embedded Systems - if you want to know why learning how to program embedded systems has value

Course Pages of Significant Interest

• Writings - always shows latest entries, very important to review for new content!
• Developing in C on the AVR ATmega328P: Frequently Asked Questions (FAQ) Like all FAQ’s, if you have a question, check here first.
• Developing in C on the AVR ATmega328P: Frequently Found Errors (FFE) Similar to an FAQ, describes errors found while creating code, best place to check when you have an error you do not understand.
• Example Code Example code for all of the functions, if you have a problem with a function, review the example!

Course Material

Developing in C for the ATmega328P

This course uses the AVR_C repository for a detailed approach to learning C for the AVR-family of microcontrollers

All entries below begin with “Developing in C for the ATmega328P: “

• Why This Is Worth It - optional commentary and explanation as to this approach

1. Raspberry Pi and VS Code Remote Setup (Trixie) STRONGLY RECOMMENDED METHOD

2. Raspberry Pi and VS Code Setup: Developing Remotely

3. Raspberry Pi and VS Code Setup Serial Communication

   Other System Setup (If you aren’t able or don’t wish to use the Raspberry Pi approach)

   • Setup Introduction
   • Raspberry Pi and VS Code Setup Bookworm (DEPRECATED)
   • Linux Setup (Advanced)
   • macOS Setup (Advanced)
   • Windows/WSL Setup (Deprecated)
   • Windows 10 Setup (Advanced)

4. Using git

5. Edit

6. Build

7. Upload

8. AVR_C Library Functions

9. Using a Serial Monitor

10. Functions - Serial input/output

11. Function - analogWrite()

12. Functions - Serial input/output

13. Function - digitalWrite()

14. Function - pinMode()

15. Function - digitalRead()

16. Struct - buttons[]

17. Function - analogRead()

18. Hints

19. Mapping Values

20. Using Data Types and Math

21. Marking Time and Measuring Time

22. User Functions

23. Multi-tasking the Arduino - Part 1

24. Function - tone()

25. Using PROGMEM

26. structures

27. Code vs. Cost

28. Pointers

29. Servos

30. I/O Ports

31. Make, Makefile and env.make

32. Better Serial Input

33. Using the GNU Linker to Enhance printf()

34. Serial Applications for Embedded Development

35. Using the GNU Linker to Enhance printf()

36. Better Serial Input

37. A Second Serial Port

38. Buffer Overflow

AVR Datasheet Notes

Technical tutorial using specific capabilities of the ATmega328P chip. This content is intended to help somone understand how to use the datasheet to implement a specific function using the ATmega328P.

1. AVR Datasheet Note: Blink
2. AVR Datasheet Note: PWM
3. AVR Datasheet Note: analogWrite

Programming Examples

Intermediate tutorials focused on using the AVR-gcc library or examples from the library.

1. Comparison of Languages
2. AVR-gcc Note: Simple Project
3. Using the Standard C Framework
4. Writing Multitasking Programs
5. Using Makefiles to Automate Development

Hardware Debugging

Technical tutorials on using Bloom, gdb, debugWIRE, a hardware debugger such as the Microchip SNAP or the one on the ATmega328PB Xplained Mini board to debug programs on the microcontroller.

1. Hardware Debug: Using gdb to debug
2. Hardware Debug: Setup Bloom and gdb to Debug
3. Hardware Debug: Examples of Bloom with gdb to Debug
4. Hardware Debug: Hints on Solving Issues Bloom and gdb
5. Hardware Debug: Exploring the ATmega328PB Xplained Mini
6. Hardware Debug: Command and Configuration Reference for Bloom and gdb

Reference Content on C

Reference books which are important for understanding C

1. The C Programming Language Kernighan and Ritchie - available in PDF and paper copy
2. Barr Group: Embedded C Coding Standard
3. SEI CERT C Coding Standard
4. Arduino Resources page
5. comp.lang.c FAQ