Atmel ATmega8535L - Page 317

iii
ATmega8535(L)
2502K–AVR–10/06
Overview........................................................................................................... 117
Timer/Counter Clock Sources........................................................................... 118
Counter Unit...................................................................................................... 119
Output Compare Unit........................................................................................ 119
Compare Match Output Unit ............................................................................. 121
Modes of Operation .......................................................................................... 122
Timer/Counter Timing Diagrams....................................................................... 126
8-bit Timer/Counter Register Description ......................................................... 128
Asynchronous Operation of the Timer/Counter ................................................ 131
Timer/Counter Prescaler................................................................................... 134
Serial Peripheral Interface – SPI..................................................... 136
SS Pin Functionality.......................................................................................... 141
Data Modes ...................................................................................................... 144
USART .............................................................................................. 145
Overview........................................................................................................... 145
Clock Generation.............................................................................................. 146
Frame Formats ................................................................................................. 149
USART Initialization.......................................................................................... 150
Data Transmission – The USART Transmitter ................................................. 152
Data Reception – The USART Receiver .......................................................... 155
Asynchronous Data Reception ......................................................................... 158
Multi-processor Communication Mode ............................................................. 162
Accessing UBRRH/UCSRC Registers.............................................................. 163
USART Register Description ............................................................................ 164
Examples of Baud Rate Setting........................................................................ 170
Two-wire Serial Interface ................................................................ 174
Features............................................................................................................ 174
Two-wire Serial Interface Bus Definition........................................................... 174
Data Transfer and Frame Format ..................................................................... 175
Multi-master Bus Systems, Arbitration and Synchronization ............................ 177
Overview of the TWI Module ............................................................................ 179
TWI Register Description.................................................................................. 181
Using the TWI ................................................................................................... 185
Transmission Modes......................................................................................... 188
Multi-master Systems and Arbitration............................................................... 201
Analog Comparator ......................................................................... 203
Analog Comparator Multiplexed Input .............................................................. 205
Analog-to-Digital Converter............................................................ 206
Features............................................................................................................ 206
Operation .......................................................................................................... 207
Starting a Conversion ....................................................................................... 208