191
7598H–AVR–07/09
ATtiny25/45/85
30. Table of Contents
Features ..................................................................................................... 1
1
Pin Configurations ................................................................................... 2
2
Overview ................................................................................................... 2
2.1
Block Diagram ...................................................................................................3
2.2
Automotive Quality Grade .................................................................................4
2.3
Pin Descriptions .................................................................................................5
3
About Code Examples ............................................................................. 5
4
AVR CPU Core .......................................................................................... 5
4.1
Introduction ........................................................................................................5
4.2
Architectural Overview .......................................................................................6
4.3
ALU – Arithmetic Logic Unit ...............................................................................7
4.4
Status Register ..................................................................................................7
4.5
General Purpose Register File ..........................................................................9
4.6
Stack Pointer ...................................................................................................10
4.7
Instruction Execution Timing ...........................................................................11
4.8
Reset and Interrupt Handling ...........................................................................11
5
AVR ATtiny25/45/85 Memories ............................................................. 13
5.1
In-System Re-programmable Flash Program Memory ....................................13
5.2
SRAM Data Memory ........................................................................................14
5.3
EEPROM Data Memory ..................................................................................15
5.4
I/O Memory ......................................................................................................21
6
System Clock and Clock Options ......................................................... 21
6.1
Clock Systems and their Distribution ...............................................................21
6.2
Clock Sources .................................................................................................23
6.3
Default Clock Source .......................................................................................24
6.4
Crystal Oscillator .............................................................................................24
6.5
Low-frequency Crystal Oscillator .....................................................................25
6.6
Calibrated Internal RC Oscillator .....................................................................26
6.7
External Clock .................................................................................................27
6.8
128 kHz Internal Oscillator ..............................................................................28
6.9
Clock Output Buffer .........................................................................................29
6.10
System Clock Prescaler ..................................................................................29