7
电源管理及睡眠模式............................................. .... 42
7.1空闲模式................................................................................................................43
7.2 ADC噪声抑制模式............................................. ...................................... 43
7.3掉电模式............................................. .................................................. ... 43
7.4省电模式...................................................................................................43
7.5待机模式........................................................................................................44
7.6扩展Standby模式.............................................. .......................................... 44
7.7功率降低注册.............................................. ........................................ 44
7.8最小化功耗.............................................. ............................... 46
8
系统控制和复位.............................................. ...................... 48
8.1内部参考电压.............................................. ....................................... 53
8.2看门狗定时器.....................................................................................................54
9
中断................................................. ............................................... 60
9.1中断向量ATmega16U4 / ATmega32U4 ........................................... ........ 60
10个I / O端口............................................ .................................................. .... 64
10.1简介...........................................................................................................64
10.2端口作为通用数字I / O .......................................... ........................................ 65
10.3端口的第二功能.............................................. ......................................... 69
10.4寄存器说明的I / O端口......................................... ................................ 81
11外部中断............................................... .................................. 84
12定时器/计数器，定时器/计数器和定时器/计数器预分频器... 88
12.1内部时钟源.............................................. ............................................. 88
12.2预分频器复位....................................................................................................88
12.3外部时钟源.............................................. ............................................ 88
12.4通用定时器/计数器控制寄存器 - GTCCR ......................................... .... 89
13 8位定时器/计数器与PWM ......................................... ................... 90
13.1概述...............................................................................................................90
13.2定时器/计数器时钟源............................................ .................................. 91
13.3计数器单元.........................................................................................................91
13.4输出比较单元.............................................. .............................................. 92
13.5比较匹配输出单元............................................. .................................... 94
13.6工作模式.............................................. ................................................ 95
13.7定时器/计数器时序图............................................ .............................. 99
13.8 8位定时器/计数器寄存器的说明......................................... .................. 100
402
ATmega16U4/ATmega32U4
7766D–AVR–01/09
