192
7598H–AVR–07/09
ATtiny25/45/85
7
Power Management and Sleep Modes ................................................. 31
7.1
MCU Control Register – MCUCR ....................................................................31
7.2
Idle Mode .........................................................................................................32
7.3
ADC Noise Reduction Mode ............................................................................32
7.4
Power-down Mode ...........................................................................................32
7.5
Limitations .......................................................................................................33
7.6
Power Reduction Register ...............................................................................33
7.7
Minimizing Power Consumption ......................................................................34
8
System Control and Reset .................................................................... 35
8.1
Resetting the AVR ...........................................................................................35
8.2
Reset Sources .................................................................................................35
8.3
Power-on Reset ...............................................................................................36
8.4
External Reset .................................................................................................37
8.5
Brown-out Detection ........................................................................................38
8.6
Watchdog Reset ..............................................................................................39
8.7
MCU Status Register – MCUSR ......................................................................40
8.8
Internal Voltage Reference ..............................................................................40
8.9
Watchdog Timer ..............................................................................................41
8.10
Timed Sequences for Changing the Configuration of the Watchdog Timer ....44
9
Interrupts ................................................................................................ 45
9.1
Interrupt Vectors in ATtiny25/45/85 .................................................................45
10
I/O Ports .................................................................................................. 46
10.1
Introduction ......................................................................................................46
10.2
Ports as General Digital I/O .............................................................................47
10.3
Alternate Port Functions ..................................................................................52
10.4
Register Description for I/O-Ports ....................................................................58
11
External Interrupts ................................................................................. 58
11.1
MCU Control Register – MCUCR ....................................................................59
11.2
General Interrupt Mask Register – GIMSK ......................................................59
11.3
General Interrupt Flag Register – GIFR ..........................................................60
11.4
Pin Change Mask Register – PCMSK .............................................................60
12
8-bit Timer/Counter0 with PWM ............................................................ 61
12.1
Overview ..........................................................................................................61
12.2
Timer/Counter Clock Sources .........................................................................62