Macros

Macros are limited to device selection, feature detection, and preprocessor checks. C++ namespaces and constants are the primary interface.

Defined by the ATmega328P definitions

Config.h identifies the device:

MCU_ATMEGA328P

It also defines generic feature flags:

• MCU_HAS_GPIO
• MCU_HAS_ADC
• MCU_HAS_PWM
• MCU_HAS_TIMER0, MCU_HAS_TIMER1, MCU_HAS_TIMER2
• MCU_HAS_USART
• MCU_HAS_SPI
• MCU_HAS_TWI
• MCU_HAS_ANALOG_COMPARATOR
• MCU_HAS_WATCHDOG
• MCU_HAS_EXTERNAL_INTERRUPTS
• MCU_HAS_PIN_CHANGE_INTERRUPTS
• MCU_HAS_DEBUGWIRE
• MCU_HAS_SELF_PROGRAMMABLE_FLASH

These macros are useful in #if conditions. In C++ code, prefer the matching namespace constants.

Selected by MCUConfig.h

Define at most one package:

• MCU_PACKAGE_PDIP28
• MCU_PACKAGE_MLF28
• MCU_PACKAGE_TQFP32
• MCU_PACKAGE_MLF32

Define at most one operating grade:

• MCU_GRADE_INDUSTRIAL_85C
• MCU_GRADE_INDUSTRIAL_105C
• MCU_GRADE_AUTOMOTIVE_125C

For MLF32, optionally define MCU_MLF32_PUNCH or MCU_MLF32_SAWN.

Optional checks:

• MCU_REQUIRE_PACKAGE
• MCU_REQUIRE_GRADE
• MCU_REQUIRE_MLF32_STYLE

Board configuration values

The example MCUConfig.h also uses:

• MCU_CLOCK_HZ
• MCU_FUSE_LOW
• MCU_FUSE_HIGH
• MCU_FUSE_EXT

These values belong to the consuming board configuration. The definitions library does not calculate fuse bytes or use these macros internally.

C++ constants instead of macros

Use mcu::gpio::port_count, mcu::memory::flash_size_bytes, mcu::pwm::channel_count, and mcu::register_bits::... instead of creating another macro for each hardware value.

There are no public per-register ATMEGA328P_* macros or long *_MAP(X) lists in the module headers.