SPI.h

Purpose: SPI interface and pin definitions.

Namespace: atmega2560::spi.

ATmega2560 hardware SPI pins: SS PB0, SCK PB1, MOSI PB2, MISO PB3. These are MCU port pins, not Arduino Mega shield pin numbers.

#include <atmega2560/SPI.h>
 
namespace mcu = atmega2560;
 
static_assert(mcu::spi::ss_pin_value == 0x10, "ATmega2560 SPI definition");

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

Source: ATmega2560 datasheet (DS40002211A).