
340
7810C–AVR–10/12
Atmel ATmega328P [Preliminary]
17.3
Timer/Counter Clock Sources .......................................................................137
17.4
Counter Unit ..................................................................................................137
17.5
Output Compare Unit .....................................................................................138
17.6
Compare Match Output Unit ..........................................................................140
17.7
Modes of Operation .......................................................................................141
17.8
Timer/Counter Timing Diagrams ...................................................................146
17.9
Asynchronous Operation of Timer/Counter2 .................................................147
17.10
Timer/Counter Prescaler ...............................................................................149
17.11
Register Description ......................................................................................150
18
SPI – Serial Peripheral Interface ......................................................... 158
18.1
Features ........................................................................................................158
18.2
Overview ........................................................................................................158
18.3
SS Pin Functionality 163
18.4
Data Modes ...................................................................................................163
18.5
Register Description ......................................................................................164
19
USART0 167
19.1
Features ........................................................................................................167
19.2
Overview ........................................................................................................167
19.3
Clock Generation ...........................................................................................168
19.4
Frame Formats ..............................................................................................171
19.5
USART Initialization .......................................................................................173
19.6
Data Transmission – The USART Transmitter ..............................................175
19.7
Data Reception – The USART Receiver .......................................................177
19.8
Asynchronous Data Reception ......................................................................182
19.9
Multi-processor Communication Mode ..........................................................185
19.10
Register Description ......................................................................................187
19.11
Examples of Baud Rate Setting .....................................................................192
20
USART in SPI Mode ............................................................................. 196
20.1
Features ........................................................................................................196
20.2
Overview ........................................................................................................196
20.3
Clock Generation ...........................................................................................196
20.4
SPI Data Modes and Timing ..........................................................................197
20.5
Frame Formats ..............................................................................................198
20.6
Data Transfer .................................................................................................200
20.7
AVR USART MSPIM vs. AVR SPI ................................................................202