Wellys Dev

Updated: Where I describe the optional steps to setup the Standard C toolchain for the ATmega328P on Windows, Linux, or macOS using a command line-based approach.

Update

In my efforts to continue to refine how to develop Standard C code for the AVR family of microcontrollers, I’ve determined using a Raspberry Pi along with VS Code can provide the optimal experience.

The Raspberry Pi OS is a reliable and steady operating system on which one can build the latest GCC tools for developing code for any microcontrollers in the AVR family. This includes the latest in the DA, Tiny or DD families.

Where I use an example project from avr-gcc to better understand how to program the ATmega328.

Sources

• Microchip AVR ATmega328 Go to this page for the datasheet, you will need it.
• Definitive UNO pinout
• avr-libc Standard AVR C Library
• avr-libc: simple project The project which this entry will cover.

Introduction

In the previous entry, I wrote a C equivilent to the Arduino analogWrite(). The entry demonstrates the fundamental method of getting the ATmega328 to perform, is to program the registers. From here on, we’ll continue to expand on this approach.

Where I take the next step in developing PWM code in C for the ATmega328. This time, I create a new analogWrite() in C.

Sources

• Microchip AVR ATmega328 Go to this page for the datasheet, you will need it.
• Definitive UNO pinout, see below
• avr-libc Standard AVR C Library
• Secrets of Arduino PWM Great tutorial as to how to write code for PWM on the ATmega328
• DIYODE: PWM Classroom Great educational article on PWM and DC Motors

Introduction

In the previous entry, I demonstrated how you could program the ATmega328 to provide a fast PWM signal on pins 5 and 6. In this entry, I’ll take the example a bit further by adjusting for all 6 pins which can provide a PWM signal. (Those marked by a “~” on the Arduino UNO.) I’ll also continue to refine the table which documents how to program the 6 pins.

Where I take the next step in developing code in C for the ATmega328. This time, I review the PWM functionality of the ATmega328.

Sources

• Microchip AVR ATmega328 Go to this page for the datasheet, you will need it.
• Definitive UNO pinout, see below
• avr-libc Standard AVR C Library
• Secrets of Arduino PWM Great tutorial as to how to write code for PWM on the ATmega328
• DIYODE: PWM Classroom Great educational article on PWM and DC Motors

Introduction

Pulse-width modulation (PWM) is a useful technique for controlling DC motor speeds, LED intensity and creating analog waveforms. The idea is to modulate (or change) the width of a digital signal (a pulse) to deliver a varying amount of voltage. The change is called the “duty cycle”, it will range from 0-100%, and the high the number, the greater the voltage delivered. PWM is valuable as it allows you to use less power to keep motors running or make LEDs bright. If the concept remains foreign to you, I recommend you read the noted sources above before going forward.

Where I use a detailed analysis of the ATmega328P datasheet to develop C code using the C toolchain. Yes, another look at the blink program!

Sources

• Microchip AVR ATmega328P Go to this page for the datasheet, you will need it.
• Definitive UNO pinout, see below
• avr-libc Standard AVR C Library.

Introduction

You’ve installed the tool chain, you’ve tested it and added automation. This means you are now ready to begin the process of learning how to program an embedded microcontroller! You might have thought, that was what you were doing with the Arduino. Not quite, you were programming a specific embedded microcontroller board with a specific programming framework.

Where I begin the process of developing in Standard C (and only C) on the Arduino Uno (also known as the ATmega328P).

Sources

• ATmega328P Datasheet
• Definitive UNO pinout
• Arduino in C | Freedom Embedded
• Make: AVR Programming
• Commentary on Microcontroller Development
• AVR Dudes Development tool software for AVR family (avrdude and avarice) as well as source to avr-libc.

Introduction

This series is designed to help someone who has been using the Arduino framework, however, desires to use only the C Language. It covers adding the toolchain to your system of choice, executing the toolchain on examples and (possibly) advancing the ability to debug using a hardware debugging tool. Or stated more formally:

As I got back into Forth after about 35 years of other languages, programs and technical stuff, I’ve been asked, Why Forth?

The most personal reason is that I’ve had a life-long passion for the language and kept a bookshelf full of Forth books for over 40 years. However, once I began to use it again, I realized its perfect for embedded processors. I’m surprised how well it works with today’s microcontrollers. And how relatively easy it is to find a port of Forth for many popular microcontrollers. I still think its a good question to ask, so I start this blog with the question:

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.