Emacs AVR IDE Template

This repository is a complete template to use Emacs as a lightweight, yet extremely powerful IDE for developing AVR microcontrollers (specifically modern AVR Dx/Ex series, but also fully backwards compatible with older series).

It uses CMake as the build system and relies on the combination of avr-gcc, avrdude (with ELF support), and clangd (Language Server) to enable code completion, fast compilation, and direct flashing from within the editor.

System Prerequisites

avr-gcc (AVR Toolchain Compiler)
avrdude (Version 7.0 or higher highly recommended for native ELF support)
clangd (For code completion, warnings, and error display in Emacs)
cmake (Build System)
ripgrep (Used for extremely fast searching in Emacs)
Device Packs for modern AVRs: Microchip Packs Repository

Emacs Packages

To achieve the perfect IDE feel, this template relies on several proven Emacs packages:

Projectile: For project management (automatically finds the root folder based on CMakeLists.txt).
Eglot: As an integrated C/C++ Language Server Client (communicates with clangd in the background).
Corfu: For the modern auto-completion popup directly at the cursor.
Vertico, Orderless & Consult: For smart, fault-tolerant searching across the entire project (including Ripgrep integration).
Doom Themes: For an eye-friendly, modern dark mode.

Emacs Configuration Installation

If you are setting up Emacs from scratch, you can use the provided example file:

Copy the file init-example.el to your Emacs configuration directory (usually ~/.emacs.d/ or ~/.config/emacs/).
Rename it to init.el.
```
cp init-example.el ~/.emacs.d/init.el
```
Restart Emacs. On the first launch, all missing packages will automatically be downloaded and installed from MELPA.

Changing the Microcontroller (MCU)

This project is configured for the AVR128DB28 by default. If you want to use a different chip:

Open the file CMakeLists.txt.
Change the value of the MCU variable (e.g., to atmega328p or avr128da28).
If necessary, change the DEVICE_PACK_DIR. (For modern AVR Dx/EA series, the Device Pack from Microchip is required. For older models like the ATmega, you can often leave this path empty).
Press F5 in Emacs to do a fresh configure and build. (CMake will regenerate the compile_commands.json file, allowing clangd to immediately know the registers and pins of the new chip for auto-completion!)

Development Workflow & Shortcuts

As soon as you open a .c or .h file in the project, Projectile will automatically detect the project, and Eglot will start the Language Server in the background.

The most important shortcuts for project management (via Projectile & Consult):

C-c p f: Find file in project (Fuzzy Search).
C-r: Search for text across the project (Consult Ripgrep - extremely fast!).
C-c p p: Switch between different, locally stored projects.

The shortcuts for building and flashing (configured via F-keys in init.el):

F5: Clean Build. Radically deletes the cache and completely rebuilds the project (Compiles including linker garbage collection for minimal size).
F6: Flash Code. Flashes only the program code (Flash memory) via Avrdude. (Standard command during development)
Strg + F6: Flash Code & EEPROM. Flashes the code and the EEPROM data.
F7: Read Fuses. Reads the fuses from the microcontroller and displays them in the Emacs Compile window.
Strg + F7: Flash Fuses. Writes the fuses directly defined in the C software (via <avr/fuse.h>) to the chip.

Note: Since we use the modern ELF format, manually generating old .hex files is completely obsolete.

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