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3355C–USB–4/05
AT43USB325
Table of Contents
Features..................................................................................................... 1
1
Description ............................................................................................... 1
1.1Pin Configuration .......................................................................................................2
1.2Pin Assignment .........................................................................................................3
1.3Signal Description .....................................................................................................4
2
Architectural Overview ............................................................................ 7
3
General-purpose Register File ................................................................ 9
3.1X-, Y- and Z- Registers ............................................................................................10
3.2Arithmetic Logic Unit (ALU) .....................................................................................10
3.3Program Memory .....................................................................................................10
3.4SPI Serial EEPROM Interface (AT43USB325E Only) .............................................11
3.5SRAM Data Memory ...............................................................................................12
3.6I/O Memory ..............................................................................................................17
3.7USB Hub .................................................................................................................18
4
Functional Description .......................................................................... 20
4.1On-chip Power Supply .............................................................................................20
4.2I/O Pin Characteristics .............................................................................................20
4.3Oscillator and PLL ...................................................................................................20
4.4Reset and Interrupt Handling ..................................................................................21
4.5Reset Sources .........................................................................................................23
4.6Power-on Reset .......................................................................................................24
4.7External Reset .........................................................................................................25
4.8Watchdog Timer Reset ............................................................................................25
4.9Non-USB Related Interrupt Handling ......................................................................26
4.10External Interrupts .................................................................................................29
4.11Interrupt Response Time .......................................................................................29
4.12USB Interrupt Sources ..........................................................................................31
4.13USB Endpoint Interrupt Sources ...........................................................................32
5
AVR Register Set ................................................................................... 40
5.1Status Register and Stack Pointer ..........................................................................40
5.2Sleep Modes ...........................................................................................................41