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358
7647F–AVR–04/09
ATmega16/32/64/M1/C1
34. Table of Contents
Features ..................................................................................................... 1
1
Pin Configurations ................................................................................... 3
1.1
Pin Descriptions .................................................................................................5
2
Overview ................................................................................................... 8
2.1
Block Diagram ...................................................................................................8
2.2
Automotive Quality Grade .................................................................................9
2.3
Pin Descriptions ...............................................................................................10
2.4
About Code Examples .....................................................................................11
3
AVR CPU Core
.................................................................................... 12
3.1
Introduction ......................................................................................................12
3.2
Architectural Overview .....................................................................................12
3.3
ALU – Arithmetic Logic Unit .............................................................................13
3.4
Status Register ................................................................................................14
3.5
General Purpose Register File ........................................................................15
3.6
Stack Pointer ...................................................................................................16
3.7
Instruction Execution Timing ...........................................................................17
3.8
Reset and Interrupt Handling ...........................................................................17
4
Memories ................................................................................................ 20
4.1
In-System Reprogrammable Flash Program Memory .....................................20
4.2
SRAM Data Memory ........................................................................................21
4.3
EEPROM Data Memory ..................................................................................22
4.4
I/O Memory ......................................................................................................28
4.5
General Purpose I/O Registers .......................................................................28
5
System Clock ......................................................................................... 29
5.1
Clock Systems and their Distribution ...............................................................29
5.2
Clock Sources .................................................................................................30
5.3
Default Clock Source .......................................................................................31
5.4
Low Power Crystal Oscillator ...........................................................................31
5.5
Calibrated Internal RC Oscillator .....................................................................33
5.6
PLL ..................................................................................................................34
5.7
128 kHz Internal Oscillator ..............................................................................36
5.8
External Clock .................................................................................................36
5.9
Clock Output Buffer .........................................................................................37