RegisterBits.h

Purpose: Register bit positions and field masks.

Namespace: atmega2560::register_bits.

Reserved bit positions are intentionally excluded. Every declared bit is a named constant with its hardware position.

#include <atmega2560/RegisterBits.h>
 
namespace mcu = atmega2560;
 
static_assert(mcu::register_bits::eimsk::int7 == 7, "ATmega2560 RegisterBits definition");
static_assert(mcu::register_bits::smcr::se == 0, "ATmega2560 SMCR definition");
static_assert(mcu::register_bits::xmcrb::xmm2 == 2, "ATmega2560 XMCRB definition");

Register bit identifiers

Bit names are nested under their lowercase register name, for example register_bits::tccr5a::com5a1, register_bits::ucsr3a::rxc3 and register_bits::eimsk::int7.

The ATmega2560-specific definitions also include OCDR, EIND, SPL and SPH. Only EIND0 and the implemented RAMPZ bits are exposed; unimplemented high bits are not defined.

SMCR uses SM2 = 3, SM1 = 2, SM0 = 1, and SE = 0. XMCRB uses XMBK = 7 and XMM2:0 = 2:0.

Numbers are bit positions, not pre-shifted masks. Reserved positions are not exposed as public bit constants.

These are hardware definitions, not runtime register access or initialization.

Source: ATmega2560 datasheet (DS40002211A), Section 33 and register descriptions.