Atmel ATmega48PV

i
8025I–AVR–02/09
ATmega48P/88P/168P/328P
Table of Contents
Features ..................................................................................................... 1
1 Pin Configurations ...................................................................................2
1.1Pin Descriptions .........................................................................................................3
2 Overview ................................................................................................... 4
2.1Block Diagram ...........................................................................................................5
2.2Comparison Between ATmega48P, ATmega88P, ATmega168P, and ATmega328P 6
3 About ......................................................................................................... 7
3.1Disclaimer ..................................................................................................................7
3.2Resources .................................................................................................................7
3.3Data Retention ...........................................................................................................7
3.4Code Examples .........................................................................................................7
4 AVR CPU Core .......................................................................................... 8
4.1Overview ....................................................................................................................8
4.2ALU – Arithmetic Logic Unit .......................................................................................9
4.3Status Register ..........................................................................................................9
4.4General Purpose Register File ................................................................................11
4.5Stack Pointer ...........................................................................................................12
4.6Instruction Execution Timing ...................................................................................13
4.7Reset and Interrupt Handling ...................................................................................14
5 AVR Memories ........................................................................................16
5.1Overview ..................................................................................................................16
5.2In-System Reprogrammable Flash Program Memory .............................................16
5.3SRAM Data Memory ................................................................................................18
5.4EEPROM Data Memory ..........................................................................................19
5.5I/O Memory ..............................................................................................................20
5.6Register Description ................................................................................................21
6 System Clock and Clock Options .........................................................26
6.1Clock Systems and their Distribution .......................................................................26
6.2Clock Sources .........................................................................................................27
6.3Low Power Crystal Oscillator ...................................................................................28
6.4Full Swing Crystal Oscillator ....................................................................................30
6.5Low Frequency Crystal Oscillator ............................................................................32