Arduino Internals

AVR Core

Refer back to Figure 1-4 in Chapter 1 for a simplified block diagram of the ATmega328. At its center is the AVR Core, containing the arithmetic logic unit (ALU) that performs mathematical and logic calculations, a set of 32 general-purpose 8-bit registers, a status register (SREG), the program counter (PC), an instruction decoder, and interfaces to the built-in memory arrays and the on-board peripherals. See Figure 3-3.

Figure 3-3. The AVR Core contains the essential components of the AVR central processing unit (CPU). It’s tightly integrated into the rest of the microcontroller.

Note The ATmega2560 also has an external memory (XMEM) ...