Datasheet

i
7593L–AVR–09/12
AT90USB64X/128X
Table of contents
Features ..................................................................................................... 1
1 Pin configurations ................................................................................... 3
2 Overview ................................................................................................... 5
2.1 Block diagram ..........................................................................................................6
2.2 Pin descriptions .......................................................................................................8
3 Resources ............................................................................................... 10
4 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 ...................................................................................16
5.8 Reset and interrupt handling .................................................................................17
6 Atmel AVR AT90USB64/128 memories ................................................ 20
6.1 In-system re-programmable flash program memory .............................................20
6.2 SRAM data memory ..............................................................................................21
6.3 EEPROM data memory .........................................................................................24
6.4 I/O memory ............................................................................................................30
6.5 External memory interface ....................................................................................31
7 System clock and clock options .......................................................... 40
7.1 Clock systems and their distribution ......................................................................40
7.2 Clock sources ........................................................................................................41
7.3 Low power crystal oscillator ..................................................................................42
7.4 Low frequency crystal oscillator ............................................................................44
7.5 Calibrated internal RC oscillator ............................................................................45
7.6 External clock ........................................................................................................46
7.7 Clock output buffer ................................................................................................47
7.8 Timer/counter oscillator .........................................................................................47
7.9 System clock prescaler .........................................................................................47