ATmega48/88/168
Table of Contents
Features................................................................................................ 1
Pin Configurations............................................................................... 2
Disclaimer............................................................................................................. 2
Overview............................................................................................... 3
Block Diagram ...................................................................................................... 3
Comparison Between ATmega48, ATmega88, and ATmega168......................... 4
Pin Descriptions.................................................................................................... 5
About Code Examples......................................................................... 6
AVR CPU Core ..................................................................................... 7
Introduction........................................................................................................... 7
Architectural Overview.......................................................................................... 7
ALU – Arithmetic Logic Unit.................................................................................. 8
Status Register ..................................................................................................... 9
General Purpose Register File ........................................................................... 10
Stack Pointer ...................................................................................................... 11
Instruction Execution Timing............................................................................... 12
Reset and Interrupt Handling.............................................................................. 12
AVR ATmega48/88/168 Memories .................................................... 15
In-System Reprogrammable Flash Program Memory ........................................ 15
SRAM Data Memory........................................................................................... 16
EEPROM Data Memory...................................................................................... 17
I/O Memory......................................................................................................... 23
System Clock and Clock Options .................................................... 24
Clock Systems and their Distribution.................................................................. 24
Clock Sources..................................................................................................... 25
Low Power Crystal Oscillator.............................................................................. 26
Full Swing Crystal Oscillator............................................................................... 28
Low Frequency Crystal Oscillator....................................................................... 29
Calibrated Internal RC Oscillator ........................................................................ 30
128 kHz Internal Oscillator.................................................................................. 31
External Clock..................................................................................................... 31
Clock Output Buffer ............................................................................................ 32
Timer/Counter Oscillator..................................................................................... 32
System Clock Prescaler...................................................................................... 33
Power Management and Sleep Modes............................................. 35
Idle Mode............................................................................................................ 36
ADC Noise Reduction Mode............................................................................... 36
Power-down Mode.............................................................................................. 36
Power-save Mode............................................................................................... 36
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2545D–AVR–07/04
ATMEL [ ATMEL ]
