ATmega32(L)
Compare Match Output Unit............................................................................. 117
Modes of Operation .......................................................................................... 118
Timer/Counter Timing Diagrams....................................................................... 123
8-bit Timer/Counter Register Description ......................................................... 125
Asynchronous Operation of the Timer/Counter ................................................ 128
Timer/Counter Prescaler................................................................................... 131
Serial Peripheral Interface – SPI..................................................... 132
SS Pin Functionality.......................................................................................... 136
Data Modes ...................................................................................................... 139
USART .............................................................................................. 140
Overview........................................................................................................... 140
Clock Generation.............................................................................................. 141
Frame Formats ................................................................................................. 144
USART Initialization.......................................................................................... 146
Data Transmission – The USART Transmitter ................................................. 147
Data Reception – The USART Receiver .......................................................... 150
Asynchronous Data Reception ......................................................................... 153
Multi-processor Communication Mode ............................................................. 157
Accessing UBRRH/ UCSRC Registers............................................................. 158
USART Register Description ............................................................................ 159
Examples of Baud Rate Setting........................................................................ 165
Two-wire Serial Interface ................................................................ 169
Features............................................................................................................ 169
Two-wire Serial Interface Bus Definition........................................................... 169
Data Transfer and Frame Format..................................................................... 170
Multi-master Bus Systems, Arbitration and Synchronization............................ 172
Overview of the TWI Module ............................................................................ 175
TWI Register Description.................................................................................. 177
Using the TWI................................................................................................... 180
Transmission Modes......................................................................................... 183
Multi-master Systems and Arbitration............................................................... 196
Analog Comparator ......................................................................... 198
Analog Comparator Multiplexed Input .............................................................. 200
Analog to Digital Converter ............................................................ 201
Features............................................................................................................ 201
Operation.......................................................................................................... 202
Starting a Conversion ....................................................................................... 203
Prescaling and Conversion Timing................................................................... 204
Changing Channel or Reference Selection ...................................................... 207
ADC Noise Canceler......................................................................................... 209
ADC Conversion Result.................................................................................... 213
iii
2503J–AVR–10/06
ATMEL [ ATMEL ]
