ATmega8(L)
Timer/Counter Clock Sources 103
Counter Unit 104
Output Compare Unit 105
Compare Match Output Unit 107
Modes of Operation 108
Timer/Counter Timing Diagrams 112
8-bit Timer/Counter Register Description 114
Asynchronous Operation of the Timer/Counter 117
Timer/Counter Prescaler 120
Serial Peripheral Interface – SPI 121
SS Pin Functionality 125
Data Modes 127
USART 129
Overview 129
Clock Generation 130
Frame Formats 133
USART Initialization 134
Data Transmission – The USART Transmitter 136
Data Reception – The USART Receiver 138
Asynchronous Data Reception 142
Multi-processor Communication Mode 145
Accessing UBRRH/UCSRC Registers 146
USART Register Description 148
Examples of Baud Rate Setting 153
Two-wire Serial Interface 157
Features 157
Two-wire Serial Interface Bus Definition 157
Data Transfer and Frame Format 158
Multi-master Bus Systems, Arbitration and Synchronization 161
Overview of the TWI Module 163
TWI Register Description 165
Using the TWI 168
Transmission Modes 171
Multi-master Systems and Arbitration 184
Analog Comparator 186
Analog Comparator Multiplexed Input 188
Analog-to-Digital Converter 189
Features 189
Starting a Conversion 191
Prescaling and Conversion Timing 191
Changing Channel or Reference Selection 194
3
2486AA–AVR–02/2013
ATMEL [ ATMEL ]
