Datasheet

Table of Contents
Introduction......................................................................................................................1
Features.......................................................................................................................... 1
1. Description.................................................................................................................9
2. Configuration Summary...........................................................................................10
3. Ordering Information................................................................................................ 11
4. Block Diagram......................................................................................................... 12
5. ATmega103 and ATmega64A Compatibility............................................................ 13
5.1. ATmega103 Compatibility Mode.................................................................................................13
6. Pin Configurations................................................................................................... 14
6.1. Pin Descriptions..........................................................................................................................14
7. Resources................................................................................................................18
8. Data Retention.........................................................................................................19
9. About Code Examples.............................................................................................20
10. Capacitive Touch Sensing....................................................................................... 21
11. AVR CPU Core........................................................................................................ 22
11.1. Overview.....................................................................................................................................22
11.2. ALU – Arithmetic Logic Unit........................................................................................................23
11.3. Status Register...........................................................................................................................23
11.4. General Purpose Register File................................................................................................... 25
11.5. Stack Pointer.............................................................................................................................. 26
11.6. Instruction Execution Timing...................................................................................................... 26
11.7. Reset and Interrupt Handling..................................................................................................... 27
12. AVR Memories.........................................................................................................30
12.1. Overview.....................................................................................................................................30
12.2. In-System Reprogrammable Flash Program Memory................................................................30
12.3. SRAM Data Memory...................................................................................................................31
12.4. EEPROM Data Memory............................................................................................................. 33
12.5. I/O Memory.................................................................................................................................34
12.6. External Memory Interface......................................................................................................... 34
12.7. Register Description................................................................................................................... 41
13. System Clock and Clock Options............................................................................ 52
13.1. Clock Systems and their Distribution..........................................................................................52
13.2. Clock Sources............................................................................................................................ 53