Atmel ATmega128 Manual page 381

2467S–AVR–07/09
Timer/Counter3, Timer/Counter2, and Timer/Counter1 Prescalers
143
8-bit Timer/Counter2 with PWM 145
Overview 145
Timer/Counter Clock Sources 146
Counter Unit 146
Output Compare Unit 147
Compare Match Output Unit 148
Modes of Operation 149
Timer/Counter Timing Diagrams 155
8-bit Timer/Counter Register Description 157
Output Compare Modulator (OCM1C2) 161
Overview 161
Description 161
Serial Peripheral Interface – SPI 163
SS Pin Functionality 167
Data Modes 170
USART 171
Overview 171
Clock Generation 173
Frame Formats 176
USART Initialization 177
Data Transmission – The USART Transmitter 178
Data Reception – The USART Receiver 180
Multi-processor Communication Mode 187
USART Register Description 189
Examples of Baud Rate Setting 194
Two-wire Serial Interface 198
Features 198
Two-wire Serial Interface Bus Definition 198
Data Transfer and Frame Format 199
Multi-master Bus Systems, Arbitration and Synchronization 201
Overview of the TWI Module 204
TWI Register Description 206
Using the TWI 208
Transmission Modes 213
Multi-master Systems and Arbitration 225
Analog Comparator 227
Analog Comparator Multiplexed Input 228
ATmega128
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