Table of Contents
1
2
Pin Configurations ................................................................................... 3
1.1
Disclaimer ............................................................................................................4
Overview ................................................................................................... 4
2.1
2.2
Block Diagram ......................................................................................................5
Pin Descriptions ...................................................................................................6
3
4
About Code Examples ............................................................................. 8
AVR CPU Core .......................................................................................... 9
4.1
4.2
4.3
4.4
4.5
4.6
4.7
4.8
Introduction ..........................................................................................................9
Architectural Overview .........................................................................................9
ALU – Arithmetic Logic Unit ...............................................................................10
Status Register ..................................................................................................11
General Purpose Register File ...........................................................................12
Stack Pointer ......................................................................................................13
Instruction Execution Timing ..............................................................................14
Reset and Interrupt Handling .............................................................................15
5
6
AVR AT90USB64/128 Memories ........................................................... 18
5.1
5.2
5.3
5.4
5.5
In-System Reprogrammable Flash Program Memory .......................................18
SRAM Data Memory ..........................................................................................19
EEPROM Data Memory .....................................................................................22
I/O Memory ........................................................................................................28
External Memory Interface .................................................................................29
System Clock and Clock Options ......................................................... 38
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
6.9
Clock Systems and their Distribution .................................................................38
Clock Sources ....................................................................................................39
Low Power Crystal Oscillator .............................................................................40
Low Frequency Crystal Oscillator ......................................................................43
Calibrated Internal RC Oscillator .......................................................................43
128 kHz Internal Oscillator .................................................................................45
External Clock ....................................................................................................46
Clock Output Buffer ............................................................................................47
Timer/Counter Oscillator ....................................................................................47
6.10 System Clock Prescaler .....................................................................................47
6.11 PLL .....................................................................................................................49
1
AT90USB64/128
7593A–AVR–02/06
ATMEL [ ATMEL ]
