ATmega8U2/16U2/32U2
Table of Contents
Features..................................................................................................... 1
1
Pin Configurations ................................................................................... 2
1.1Disclaimer ..................................................................................................................2
2
Overview ................................................................................................... 3
2.1Block Diagram ...........................................................................................................3
2.2Pin Descriptions .........................................................................................................4
3
4
5
6
Resources ................................................................................................. 6
Code Examples ........................................................................................ 6
Data Retention .......................................................................................... 6
AVR CPU Core .......................................................................................... 7
6.1Introduction ................................................................................................................7
6.2Architectural Overview ...............................................................................................7
6.3ALU – Arithmetic Logic Unit .......................................................................................8
6.4Status Register ..........................................................................................................8
6.5General Purpose Register File ................................................................................10
6.6Stack Pointer ...........................................................................................................11
6.7Instruction Execution Timing ...................................................................................12
6.8Reset and Interrupt Handling ...................................................................................13
7
8
AVR Memories ........................................................................................ 16
7.1In-System Reprogrammable Flash Program Memory .............................................16
7.2SRAM Data Memory ................................................................................................17
7.3EEPROM Data Memory ..........................................................................................18
7.4I/O Memory ..............................................................................................................19
7.5Register Description ................................................................................................20
System Clock and Clock Options ......................................................... 26
8.1Clock Systems and their Distribution .......................................................................26
8.2Clock Switch ............................................................................................................27
8.3Clock Sources .........................................................................................................29
8.4Low Power Crystal Oscillator ...................................................................................30
8.5Full Swing Crystal Oscillator ....................................................................................32
8.6Calibrated Internal RC Oscillator .............................................................................33
8.7External Clock .........................................................................................................35
i
7799D–AVR–11/10
ATMEL [ ATMEL ]
