ATmega644PA datasheet(464/468 Pages) ATMEL

464 / 468 page

8152G–AVR–11/09

ATmega164PA/324PA/644PA/1284P

16.8Timer/Counter Timing Diagrams .........................................................................150

16.9Asynchronous Operation of Timer/Counter2 .......................................................152

16.10Timer/Counter Prescaler ...................................................................................154

16.11Register Description ..........................................................................................154

SPI – Serial Peripheral Interface ......................................................... 163

17.1Features ..............................................................................................................163

17.2Overview .............................................................................................................163

17.3SS Pin Functionality ............................................................................................168

17.4Data Modes .........................................................................................................168

17.5Register Description ............................................................................................170

USART ................................................................................................... 173

18.1Features ..............................................................................................................173

18.2USART1 and USART0 ........................................................................................173

18.3Overview .............................................................................................................173

18.4Clock Generation .................................................................................................174

18.5Frame Formats ....................................................................................................177

18.6USART Initialization ............................................................................................178

18.7Data Transmission – The USART Transmitter ....................................................179

18.8Data Reception – The USART Receiver .............................................................182

18.9Asynchronous Data Reception ............................................................................186

18.10Multi-processor Communication Mode ..............................................................189

18.11Register Description ..........................................................................................191

18.12Examples of Baud Rate Setting ........................................................................196

USART in SPI Mode ............................................................................. 200

19.1Features ..............................................................................................................200

19.2Overview .............................................................................................................200

19.3Clock Generation .................................................................................................200

19.4SPI Data Modes and Timing ...............................................................................201

19.5Frame Formats ....................................................................................................201

19.6Data Transfer ......................................................................................................203

19.7AVR USART MSPIM vs. AVR SPI ......................................................................205

19.8Register Description ............................................................................................206

2-wire Serial Interface .......................................................................... 209

20.1Features ..............................................................................................................209

20.22-wire Serial Interface Bus Definition ..................................................................209

ATmega644PA Datasheet(PDF) 464 Page - ATMEL Corporation