Definitions model

This repository describes the ATmega328P. It does not implement peripheral behavior.

Primary interface

The public C++ interface uses:

• the root namespace atmega328p;
• short module namespaces such as gpio, pin, timer, pwm, adc, and memory;
• lowercase snake_case names for numeric characteristics;
• typed enums for hardware selections such as pins, channels, modes, and clock sources.

The consuming project creates a common alias:

namespace mcu = atmega328p;

Shared peripheral libraries use mcu::gpio, mcu::timer, and other common namespaces. Another MCU repository should expose the same module names and common member names where the hardware supports them.

Macros

Macros are reserved for package/grade selection, feature detection, and preprocessor checks. Ordinary C++ code should use namespace constants.

Package-dependent data

A logical pin such as PB5 identifies the silicon signal. Its terminal number depends on the physical package. Select the package in MCUConfig.h and use mcu::package::selected::PB5 for the terminal number.

The same approach is used for operating grades: mcu::electrical::selected refers to the selected grade profile.

No runtime implementation

Headers contain compile-time values and enums. They do not access hardware registers, initialize peripherals, declare interrupt handlers, or allocate runtime tables.