Datasheet

i
4317K–AVR–03/2013
AT90PWM2/3/2B/3B
Table of Contents
1 History 2
2 Disclaimer 2
3 Pin Configurations 3
3.1 Pin Descriptions 5
4 Overview 7
4.1 Block Diagram 8
4.2 Pin Descriptions 9
4.3 About Code Examples 10
5 AVR CPU Core 11
5.1 Introduction 11
5.2 Architectural Overview 11
5.3 ALU – Arithmetic Logic Unit 12
5.4 Status Register 13
5.5 General Purpose Register File 14
5.6 Stack Pointer 15
5.7 Instruction Execution Timing 15
5.8 Reset and Interrupt Handling 16
6 Memories 19
6.1 In-System Reprogrammable Flash Program Memory 19
6.2 SRAM Data Memory 19
6.3 EEPROM Data Memory 21
6.4 I/O Memory 27
6.5 General Purpose I/O Registers 27
7 System Clock 29
7.1 Clock Systems and their Distribution 29
7.2 Clock Sources 31
7.3 Default Clock Source 32
7.4 Low Power Crystal Oscillator 32
7.5 Calibrated Internal RC Oscillator 33
7.6 PLL 35
7.7 128 kHz Internal Oscillator 37
7.8 External Clock 37