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8052B–AVR–09/08
ATmega4HVD/8HVD
8.10System Clock Prescaler ........................................................................................25
8.11ADC Clock Prescaler .............................................................................................26
8.12OSI – Oscillator Sampling Interface ......................................................................27
8.13Register Description ..............................................................................................29
9
Power Management and Sleep Modes ................................................. 32
9.1Sleep Modes ............................................................................................................32
9.2Idle Mode .................................................................................................................34
9.3ADC Noise Reduction ..............................................................................................34
9.4Power-save Mode ....................................................................................................34
9.5Power-off Mode .......................................................................................................35
9.6Power Reduction Register .......................................................................................35
9.7Minimizing Power Consumption ..............................................................................35
9.8Register Description ................................................................................................36
10
System Control and Reset .................................................................... 38
10.1Resetting the AVR .................................................................................................38
10.2Reset Sources .......................................................................................................38
10.3External Reset .......................................................................................................40
10.4Watchdog Reset ....................................................................................................40
10.5Black-out Detection ...............................................................................................40
10.6ATmega4HVD/8HVD Start-up Sequence ..............................................................42
10.7Watchdog Timer ....................................................................................................45
10.8Register Description ..............................................................................................48
11
Interrupts ................................................................................................ 51
11.1Interrupt Vectors in ATmega4HVD/8HVD .............................................................51
12
External Interrupt ................................................................................... 53
12.1Register Description ..............................................................................................53
13
High Voltage I/O Ports ........................................................................... 56
13.1High Voltage Ports as General Digital Outputs .....................................................57
13.2Alternate Port Functions ........................................................................................57
13.3Register Description ..............................................................................................60
14
Low Voltage I/O-Ports ............................................................................ 61
14.1Overview ................................................................................................................61
14.2Low Voltage Ports as General Digital I/O ..............................................................62
14.3Alternate Port Functions ........................................................................................66
