Datasheet

iii
ATmega8535(L)
2502G–AVR–04/05
Counter Unit...................................................................................................... 118
Output Compare Unit........................................................................................ 118
Compare Match Output Unit ............................................................................. 120
Modes of Operation .......................................................................................... 121
Timer/Counter Timing Diagrams....................................................................... 125
8-bit Timer/Counter Register Description ......................................................... 127
Asynchronous Operation of the Timer/Counter ................................................ 130
Timer/Counter Prescaler................................................................................... 133
Serial Peripheral Interface – SPI..................................................... 135
SS Pin Functionality.......................................................................................... 139
Data Modes ...................................................................................................... 142
USART .............................................................................................. 143
Overview........................................................................................................... 143
Clock Generation.............................................................................................. 144
Frame Formats ................................................................................................. 147
USART Initialization.......................................................................................... 148
Data Transmission – The USART Transmitter ................................................. 150
Data Reception – The USART Receiver .......................................................... 153
Asynchronous Data Reception ......................................................................... 156
Multi-processor Communication Mode ............................................................. 160
Accessing UBRRH/UCSRC Registers.............................................................. 161
USART Register Description ............................................................................ 162
Examples of Baud Rate Setting........................................................................ 168
Two-wire Serial Interface ................................................................ 172
Features............................................................................................................ 172
Two-wire Serial Interface Bus Definition........................................................... 172
Data Transfer and Frame Format ..................................................................... 173
Multi-master Bus Systems, Arbitration and Synchronization ............................ 175
Overview of the TWI Module ............................................................................ 177
TWI Register Description.................................................................................. 179
Using the TWI ................................................................................................... 183
Transmission Modes......................................................................................... 186
Multi-master Systems and Arbitration............................................................... 199
Analog Comparator ......................................................................... 201
Analog Comparator Multiplexed Input .............................................................. 203
Analog-to-Digital Converter............................................................ 204
Features............................................................................................................ 204
Operation .......................................................................................................... 205
Starting a Conversion ....................................................................................... 206
Prescaling and Conversion Timing ................................................................... 207
Changing Channel or Reference Selection ...................................................... 210