Datasheet

Table of Contents
Introduction......................................................................................................................1
Feature............................................................................................................................ 1
1. Description.................................................................................................................9
2. Configuration Summary...........................................................................................10
3. Ordering Information ............................................................................................... 11
4. Block Diagram......................................................................................................... 12
5. Pin Configurations................................................................................................... 13
5.1. Pinout......................................................................................................................................... 13
5.2. Pin Descriptions..........................................................................................................................14
6. I/O Multiplexing........................................................................................................16
7. General Information.................................................................................................18
7.1. Resources.................................................................................................................................. 18
7.2. Data Retention............................................................................................................................18
7.3. About Code Examples................................................................................................................18
7.4. Capacitive Touch Sensing.......................................................................................................... 18
8. AVR CPU Core........................................................................................................ 19
8.1. Overview.....................................................................................................................................19
8.2. ALU – Arithmetic Logic Unit........................................................................................................20
8.3. Status Register...........................................................................................................................20
8.4. General Purpose Register File................................................................................................... 22
8.5. Stack Pointer.............................................................................................................................. 23
8.6. Accessing 16-bit Registers.........................................................................................................25
8.7. Instruction Execution Timing...................................................................................................... 26
8.8. Reset and Interrupt Handling..................................................................................................... 26
9. AVR Memories.........................................................................................................29
9.1. Overview.....................................................................................................................................29
9.2. In-System Reprogrammable Flash Program Memory................................................................29
9.3. SRAM Data Memory...................................................................................................................30
9.4. EEPROM Data Memory............................................................................................................. 31
9.5. I/O Memory.................................................................................................................................32
9.6. Register Description................................................................................................................... 32
10. System Clock and Clock Options............................................................................ 42
10.1. Clock Systems and Their Distribution.........................................................................................42
10.2. Clock Sources............................................................................................................................ 43
10.3. Low Power Crystal Oscillator......................................................................................................45