2545M–AVR–09/07

ATmega48/88/168

21.22-wire Serial Interface Bus Definition ..................................................................210

21.3Data Transfer and Frame Format ........................................................................211

21.4Multi-master Bus Systems, Arbitration and Synchronization ...............................214

21.5Overview of the TWI Module ...............................................................................217

21.6Using the TWI ......................................................................................................219

21.7Transmission Modes ...........................................................................................223

21.8Multi-master Systems and Arbitration ..................................................................236

21.9Register Description ............................................................................................237

22 Analog Comparator .............................................................................. 242

22.1Overview ..............................................................................................................242

22.2Analog Comparator Multiplexed Input .................................................................242

22.3Register Description ............................................................................................243

23 Analog-to-Digital Converter ................................................................ 245

23.1Features ..............................................................................................................245

23.2Overview ..............................................................................................................245

23.3Starting a Conversion ..........................................................................................247

23.4Prescaling and Conversion Timing ......................................................................248

23.5Changing Channel or Reference Selection .........................................................250

23.6ADC Noise Canceler ...........................................................................................251

23.7ADC Conversion Result .......................................................................................256

23.8Register Description ............................................................................................256

24 debugWIRE On-chip Debug System .................................................. 261

24.1Features ..............................................................................................................261

24.2Overview ..............................................................................................................261

24.3Physical Interface ................................................................................................261

24.4Software Break Points .........................................................................................262

24.5Limitations of debugWIRE ...................................................................................262

24.6Register Description ............................................................................................262

25 Self-Programming the Flash, ATmega48 ........................................... 263

25.1Overview ..............................................................................................................263

25.2Addressing the Flash During Self-Programming .................................................264

25.3Register Description ............................................................................................268

26 Boot Loader Support – Read-While-Write Self-Programming, ATmega88 and ATmega168

270

26.1Features ..............................................................................................................270

2545M–AVR–09/07

ATmega48/88/168

26.2Overview ..............................................................................................................270

26.3Application and Boot Loader Flash Sections .......................................................270

26.4Read-While-Write and No Read-While-Write Flash Sections ..............................271

26.5Boot Loader Lock Bits .........................................................................................273

26.6Entering the Boot Loader Program ......................................................................274

26.7Addressing the Flash During Self-Programming .................................................275

26.8Self-Programming the Flash ................................................................................276

26.9Register Description ............................................................................................284

27 Memory Programming ......................................................................... 286

27.1Program And Data Memory Lock Bits .................................................................286

27.2Fuse Bits ..............................................................................................................287

27.3Signature Bytes ...................................................................................................289

27.4Calibration Byte ...................................................................................................289

27.5Page Size ............................................................................................................290

27.6Parallel Programming Parameters, Pin Mapping, and Commands .....................290

27.7Parallel Programming ..........................................................................................292

27.8Serial Downloading ..............................................................................................299

28 Electrical Characteristics ....................................................................304

28.1Absolute Maximum Ratings* ...............................................................................304

28.2DC Characteristics ...............................................................................................304

28.3Speed Grades .....................................................................................................306

28.4Clock Characteristics ...........................................................................................307

28.5System and Reset Characteristics ......................................................................308

28.62-wire Serial Interface Characteristics .................................................................309

28.7SPI Timing Characteristics ..................................................................................310

28.8ADC Characteristics ............................................................................................312

28.9Parallel Programming Characteristics .................................................................313

29 Typical Characteristics ........................................................................ 316

29.1Active Supply Current ..........................................................................................316

29.2Idle Supply Current ..............................................................................................319

29.3Supply Current of I/O modules ............................................................................322

29.4Power-Down Supply Current ...............................................................................324

29.5Power-Save Supply Current ................................................................................325

29.6Standby Supply Current ......................................................................................325

29.7Pin Pull-up ...........................................................................................................326

vii

2545M–AVR–09/07

ATmega48/88/168

29.8Pin Driver Strength ..............................................................................................328

29.9Pin Thresholds and Hysteresis ............................................................................331

29.10BOD Thresholds and Analog Comparator Offset ..............................................334

29.11Internal Oscillator Speed ...................................................................................337

29.12Current Consumption of Peripheral Units ..........................................................339

29.13Current Consumption in Reset and Reset Pulse width .....................................341

30 Register Summary ...............................................................................343

31 Instruction Set Summary ..................................................................... 347

32 Ordering Information ........................................................................... 350

32.1ATmega48 ...........................................................................................................350

32.2ATmega88 ...........................................................................................................351

32.3ATmega168 .........................................................................................................352

33 Packaging Information ........................................................................353

33.132A ......................................................................................................................353

33.228M1 ....................................................................................................................354

33.332M1-A ................................................................................................................355

33.428P3 ....................................................................................................................356

34 Errata ..................................................................................................... 357

34.1Errata ATmega48 ................................................................................................357

34.2Errata ATmega88 ................................................................................................360

34.3Errata ATmega168 ..............................................................................................361

35 Datasheet Revision History .................................................................364

35.1Rev. 2545M-09/07 ...............................................................................................364

35.2Rev. 2545L-08/07 ................................................................................................364

35.3Rev. 2545K-04/07 ................................................................................................364

35.4Rev. 2545J-12/06 ................................................................................................364

35.5Rev. 2545I-11/06 .................................................................................................364

35.6Rev. 2545H-10/06 ...............................................................................................364

35.7Rev. 2545G-06/06 ...............................................................................................365

35.8Rev. 2545F-05/05 ................................................................................................365

35.9Rev. 2545E-02/05 ................................................................................................366

35.10Rev. 2545D-07/04 .............................................................................................366

35.11Rev. 2545C-04/04 .............................................................................................366

35.12Rev. 2545B-01/04 ..............................................................................................367

Part #	ATMEGA48-20AU
Description	MCU 8BIT ATMEGA RISC 4KB FLASH 3.3V/5V 32TQFP - Trays
Category	IC
Availability	Out of Stock
Qty	0

ATMEGA48-20AU

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