Atmel ATtiny25

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