Note

This discussion of interrupts was originally taken from Rich Neswold's document. See Acknowledgments.

Introduction to avr-libc's interrupt handling

It's nearly impossible to find compilers that agree on how to handle interrupt code. Since the C language tries to stay away from machine dependent details, each compiler writer is forced to design their method of support.

In the AVR-GCC environment, the vector table is predefined to point to interrupt routines with predetermined names. By using the appropriate name, your routine will be called when the corresponding interrupt occurs. The device library provides a set of default interrupt routines, which will get used if you don't define your own.

Patching into the vector table is only one part of the problem. The compiler uses, by convention, a set of registers when it's normally executing compiler-generated code. It's important that these registers, as well as the status register, get saved and restored. The extra code needed to do this is enabled by tagging the interrupt function with __attribute__((signal)).

These details seem to make interrupt routines a little messy, but all these details are handled by the Interrupt API. An interrupt routine is defined with ISR(). This macro register and mark the routine as an interrupt handler for the specified peripheral. The following is an example definition of a handler for the ADC interrupt.

#include <avr/interrupt.h>

ISR(ADC_vect)
{
    // user code here
}

Refer to the chapter explaining assembler programming for an explanation about interrupt routines written solely in assembler language.

Catch-all interrupt vector

If an unexpected interrupt occurs (interrupt is enabled and no handler is installed, which usually indicates a bug), then the default action is to reset the device by jumping to the reset vector. You can override this by supplying a function named BADISR_vect which should be defined with ISR() as such. (The name BADISR_vect is actually an alias for __vector_default. The latter must be used inside assembly code in case <avr/interrupt.h> is not included.)

#include <avr/interrupt.h>

ISR(BADISR_vect)
{
    // user code here
}

Nested interrupts

The AVR hardware clears the global interrupt flag in SREG before entering an interrupt vector. Thus, normally interrupts will remain disabled inside the handler until the handler exits, where the RETI instruction (that is emitted by the compiler as part of the normal function epilogue for an interrupt handler) will eventually re-enable further interrupts. For that reason, interrupt handlers normally do not nest. For most interrupt handlers, this is the desired behaviour, for some it is even required in order to prevent infinitely recursive interrupts (like UART interrupts, or level-triggered external interrupts). In rare circumstances though it might be desired to re-enable the global interrupt flag as early as possible in the interrupt handler, in order to not defer any other interrupt more than absolutely needed. This could be done using an sei() instruction right at the beginning of the interrupt handler, but this still leaves few instructions inside the compiler-generated function prologue to run with global interrupts disabled. The compiler can be instructed to insert an SEI instruction right at the beginning of an interrupt handler by declaring the handler the following way:

ISR(XXX_vect, ISR_NOBLOCK)
{
  ...
}

where XXX_vect is the name of a valid interrupt vector for the MCU type in question, as explained below.

Two vectors sharing the same code

In some circumstances, the actions to be taken upon two different interrupts might be completely identical so a single implementation for the ISR would suffice. For example, pin-change interrupts arriving from two different ports could logically signal an event that is independent from the actual port (and thus interrupt vector) where it happened. Sharing interrupt vector code can be accomplished using the ISR_ALIASOF() attribute to the ISR macro:

ISR(PCINT0_vect)
{
  ...
  // Code to handle the event.
}

ISR(PCINT1_vect, ISR_ALIASOF(PCINT0_vect));

Note that the ISR_ALIASOF() feature requires GCC 4.2 or above (or a patched version of GCC 4.1.x). See the documentation of the ISR_ALIAS() macro for an implementation which is less elegant but could be applied to all compiler versions.

Empty interrupt service routines

In rare circumstances, in interrupt vector does not need any code to be implemented at all. The vector must be declared anyway, so when the interrupt triggers it won't execute the BADISR_vect code (which by default restarts the application).

This could for example be the case for interrupts that are solely enabled for the purpose of getting the controller out of sleep_mode().

A handler for such an interrupt vector can be declared using the EMPTY_INTERRUPT() macro:

EMPTY_INTERRUPT(ADC_vect);

Manually defined ISRs

In some circumstances, the compiler-generated prologue and epilogue of the ISR might not be optimal for the job, and a manually defined ISR could be considered particularly to speedup the interrupt handling.

One solution to this could be to implement the entire ISR as manual assembly code in a separate (assembly) file. See Combining C and assembly source files for an example of how to implement it that way.

Another solution is to still implement the ISR in C language but take over the compiler's job of generating the prologue and epilogue. This can be done using the ISR_NAKED attribute to the ISR() macro. Note that the compiler does not generate anything as prologue or epilogue, so the final reti() must be provided by the actual implementation. SREG must be manually saved if the ISR code modifies it, and the compiler-implied assumption of __zero_reg__ always being 0 could be wrong (e. g. when interrupting right after of a MUL instruction).

ISR(TIMER1_OVF_vect, ISR_NAKED)
{
  PORTB |= _BV(0);  // results in SBI which does not affect SREG
  reti();
}

Choosing the vector: Interrupt vector names

The interrupt is chosen by supplying one of the symbols in following table.

There are currently two different styles present for naming the vectors. One form uses names starting with SIG_, followed by a relatively verbose but arbitrarily chosen name describing the interrupt vector. This has been the only available style in avr-libc up to version 1.2.x.

Starting with avr-libc version 1.4.0, a second style of interrupt vector names has been added, where a short phrase for the vector description is followed by _vect. The short phrase matches the vector name as described in the datasheet of the respective device (and in Atmel's XML files), with spaces replaced by an underscore and other non-alphanumeric characters dropped. Using the suffix _vect is intented to improve portability to other C compilers available for the AVR that use a similar naming convention.

The historical naming style might become deprecated in a future release, so it is not recommended for new projects.

Note

The ISR() macro cannot really spell-check the argument passed to them. Thus, by misspelling one of the names below in a call to ISR(), a function will be created that, while possibly being usable as an interrupt function, is not actually wired into the interrupt vector table. The compiler will generate a warning if it detects a suspiciously looking name of a ISR() function (i.e. one that after macro replacement does not start with "__vector_").

Vector name

Old vector name

Description

Applicable for device

ADC_vect

SIG_ADC

ADC Conversion Complete

AT90S2333, AT90S4433, AT90S4434, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny13, ATtiny15, ATtiny26, ATtiny43U, ATtiny48, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

ANALOG_COMP_0_vect

SIG_COMPARATOR0

Analog Comparator 0

AT90PWM3, AT90PWM2, AT90PWM1

ANALOG_COMP_1_vect

SIG_COMPARATOR1

Analog Comparator 1

AT90PWM3, AT90PWM2, AT90PWM1

ANALOG_COMP_2_vect

SIG_COMPARATOR2

Analog Comparator 2

AT90PWM3, AT90PWM2, AT90PWM1

ANALOG_COMP_vect

SIG_COMPARATOR

Analog Comparator

AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

ANA_COMP_vect

SIG_COMPARATOR

Analog Comparator

AT90S1200, AT90S2313, AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, ATmega16, ATmega161, ATmega162, ATmega163, ATmega32, ATmega323, ATmega8, ATmega8515, ATmega8535, ATtiny11, ATtiny12, ATtiny13, ATtiny15, ATtiny2313, ATtiny26, ATtiny28, ATtiny43U, ATtiny48, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861

CANIT_vect

SIG_CAN_INTERRUPT1

CAN Transfer Complete or Error

AT90CAN128, AT90CAN32, AT90CAN64

EEPROM_READY_vect

SIG_EEPROM_READY, SIG_EE_READY

ATtiny2313

EE_RDY_vect

SIG_EEPROM_READY

EEPROM Ready

AT90S2333, AT90S4433, AT90S4434, AT90S8535, ATmega16, ATmega161, ATmega162, ATmega163, ATmega32, ATmega323, ATmega8, ATmega8515, ATmega8535, ATtiny12, ATtiny13, ATtiny15, ATtiny26, ATtiny43U, ATtiny48, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861

EE_READY_vect

SIG_EEPROM_READY

EEPROM Ready

AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega406, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

EXT_INT0_vect

SIG_INTERRUPT0

External Interrupt Request 0

ATtiny24, ATtiny44, ATtiny84

INT0_vect

SIG_INTERRUPT0

External Interrupt 0

AT90S1200, AT90S2313, AT90S2323, AT90S2333, AT90S2343, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega406, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny11, ATtiny12, ATtiny13, ATtiny15, ATtiny22, ATtiny2313, ATtiny26, ATtiny28, ATtiny43U, ATtiny48, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT1_vect

SIG_INTERRUPT1

External Interrupt Request 1

AT90S2313, AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega168P, ATmega32, ATmega323, ATmega328P, ATmega32HVB, ATmega406, ATmega48P, ATmega64, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny2313, ATtiny28, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT2_vect

SIG_INTERRUPT2

External Interrupt Request 2

AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega32, ATmega323, ATmega32HVB, ATmega406, ATmega64, ATmega8515, ATmega8535, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT3_vect

SIG_INTERRUPT3

External Interrupt Request 3

AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega32HVB, ATmega406, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT4_vect

SIG_INTERRUPT4

External Interrupt Request 4

AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT5_vect

SIG_INTERRUPT5

External Interrupt Request 5

AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT6_vect

SIG_INTERRUPT6

External Interrupt Request 6

AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

INT7_vect

SIG_INTERRUPT7

External Interrupt Request 7

AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

IO_PINS_vect

SIG_PIN, SIG_PIN_CHANGE

External Interrupt Request 0

ATtiny11, ATtiny12, ATtiny15, ATtiny26

LCD_vect

SIG_LCD

LCD Start of Frame

ATmega169, ATmega169P, ATmega329, ATmega3290, ATmega3290P, ATmega649, ATmega6490

LOWLEVEL_IO_PINS_vect

SIG_PIN

Low-level Input on Port B

ATtiny28

OVRIT_vect

SIG_CAN_OVERFLOW1

CAN Timer Overrun

AT90CAN128, AT90CAN32, AT90CAN64

PCINT0_vect

SIG_PIN_CHANGE0

Pin Change Interrupt Request 0

ATmega162, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega406, ATmega48P, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny13, ATtiny43U, ATtiny48, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

PCINT1_vect

SIG_PIN_CHANGE1

Pin Change Interrupt Request 1

ATmega162, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega406, ATmega48P, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny43U, ATtiny48, ATtiny24, ATtiny44, ATtiny84, AT90USB162, AT90USB82

PCINT2_vect

SIG_PIN_CHANGE2

Pin Change Interrupt Request 2

ATmega3250, ATmega3250P, ATmega328P, ATmega3290, ATmega3290P, ATmega48P, ATmega6450, ATmega6490, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny48

PCINT3_vect

SIG_PIN_CHANGE3

Pin Change Interrupt Request 3

ATmega3250, ATmega3250P, ATmega3290, ATmega3290P, ATmega6450, ATmega6490, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny48

PCINT_vect

SIG_PIN_CHANGE, SIG_PCINT

ATtiny2313, ATtiny261, ATtiny461, ATtiny861

PSC0_CAPT_vect

SIG_PSC0_CAPTURE

PSC0 Capture Event

AT90PWM3, AT90PWM2, AT90PWM1

PSC0_EC_vect

SIG_PSC0_END_CYCLE

PSC0 End Cycle

AT90PWM3, AT90PWM2, AT90PWM1

PSC1_CAPT_vect

SIG_PSC1_CAPTURE

PSC1 Capture Event

AT90PWM3, AT90PWM2, AT90PWM1

PSC1_EC_vect

SIG_PSC1_END_CYCLE

PSC1 End Cycle

AT90PWM3, AT90PWM2, AT90PWM1

PSC2_CAPT_vect

SIG_PSC2_CAPTURE

PSC2 Capture Event

AT90PWM3, AT90PWM2, AT90PWM1

PSC2_EC_vect

SIG_PSC2_END_CYCLE

PSC2 End Cycle

AT90PWM3, AT90PWM2, AT90PWM1

SPI_STC_vect

SIG_SPI

Serial Transfer Complete

AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny48, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

SPM_RDY_vect

SIG_SPM_READY

Store Program Memory Ready

ATmega16, ATmega162, ATmega32, ATmega323, ATmega8, ATmega8515, ATmega8535

SPM_READY_vect

SIG_SPM_READY

Store Program Memory Read

AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega406, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIM0_COMPA_vect

SIG_OUTPUT_COMPARE0A

Timer/Counter Compare Match A

ATtiny13, ATtiny43U, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85

TIM0_COMPB_vect

SIG_OUTPUT_COMPARE0B

Timer/Counter Compare Match B

ATtiny13, ATtiny43U, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85

TIM0_OVF_vect

SIG_OVERFLOW0

Timer/Counter0 Overflow

ATtiny13, ATtiny43U, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85

TIM1_CAPT_vect

SIG_INPUT_CAPTURE1

Timer/Counter1 Capture Event

ATtiny24, ATtiny44, ATtiny84

TIM1_COMPA_vect

SIG_OUTPUT_COMPARE1A

Timer/Counter1 Compare Match A

ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85

TIM1_COMPB_vect

SIG_OUTPUT_COMPARE1B

Timer/Counter1 Compare Match B

ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85

TIM1_OVF_vect

SIG_OVERFLOW1

Timer/Counter1 Overflow

ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85

TIMER0_CAPT_vect

SIG_INPUT_CAPTURE0

ADC Conversion Complete

ATtiny261, ATtiny461, ATtiny861

TIMER0_COMPA_vect

SIG_OUTPUT_COMPARE0A

TimerCounter0 Compare Match A

ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny2313, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER0_COMPB_vect

SIG_OUTPUT_COMPARE0B, SIG_OUTPUT_COMPARE0_B

Timer Counter 0 Compare Match B

AT90PWM3, AT90PWM2, AT90PWM1, ATmega1284P, ATmega168P, ATmega328P, ATmega32HVB, ATmega48P, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny2313, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER0_COMP_A_vect

SIG_OUTPUT_COMPARE0A, SIG_OUTPUT_COMPARE0_A

Timer/Counter0 Compare Match A

AT90PWM3, AT90PWM2, AT90PWM1

TIMER0_COMP_vect

SIG_OUTPUT_COMPARE0

Timer/Counter0 Compare Match

AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega16, ATmega161, ATmega162, ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega329, ATmega3290, ATmega3290P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8515, ATmega8535

TIMER0_OVF0_vect

SIG_OVERFLOW0

Timer/Counter0 Overflow

AT90S2313, AT90S2323, AT90S2343, ATtiny22, ATtiny26

TIMER0_OVF_vect

SIG_OVERFLOW0

Timer/Counter0 Overflow

AT90S1200, AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny11, ATtiny12, ATtiny15, ATtiny2313, ATtiny28, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER1_CAPT1_vect

SIG_INPUT_CAPTURE1

Timer/Counter1 Capture Event

AT90S2313

TIMER1_CAPT_vect

SIG_INPUT_CAPTURE1

Timer/Counter Capture Event

AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny2313, ATtiny48, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER1_CMPA_vect

SIG_OUTPUT_COMPARE1A

Timer/Counter1 Compare Match 1A

ATtiny26

TIMER1_CMPB_vect

SIG_OUTPUT_COMPARE1B

Timer/Counter1 Compare Match 1B

ATtiny26

TIMER1_COMP1_vect

SIG_OUTPUT_COMPARE1A

Timer/Counter1 Compare Match

AT90S2313

TIMER1_COMPA_vect

SIG_OUTPUT_COMPARE1A

Timer/Counter1 Compare Match A

AT90S4414, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny2313, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER1_COMPB_vect

SIG_OUTPUT_COMPARE1B

Timer/Counter1 Compare MatchB

AT90S4414, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny2313, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER1_COMPC_vect

SIG_OUTPUT_COMPARE1C

Timer/Counter1 Compare Match C

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER1_COMPD_vect

SIG_OUTPUT_COMPARE0D

Timer/Counter1 Compare Match D

ATtiny261, ATtiny461, ATtiny861

TIMER1_COMP_vect

SIG_OUTPUT_COMPARE1A

Timer/Counter1 Compare Match

AT90S2333, AT90S4433, ATtiny15

TIMER1_OVF1_vect

SIG_OVERFLOW1

Timer/Counter1 Overflow

AT90S2313, ATtiny26

TIMER1_OVF_vect

SIG_OVERFLOW1

Timer/Counter1 Overflow

AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, AT90PWM216, AT90PWM2B, AT90PWM316, AT90PWM3B, AT90PWM3, AT90PWM2, AT90PWM1, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega32HVB, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8515, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny15, ATtiny2313, ATtiny48, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER2_COMPA_vect

SIG_OUTPUT_COMPARE2A

Timer/Counter2 Compare Match A

ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER2_COMPB_vect

SIG_OUTPUT_COMPARE2B

Timer/Counter2 Compare Match A

ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER2_COMP_vect

SIG_OUTPUT_COMPARE2

Timer/Counter2 Compare Match

AT90S4434, AT90S8535, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega329, ATmega3290, ATmega3290P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8535

TIMER2_OVF_vect

SIG_OVERFLOW2

Timer/Counter2 Overflow

AT90S4434, AT90S8535, AT90CAN128, AT90CAN32, AT90CAN64, ATmega103, ATmega128, ATmega1284P, ATmega16, ATmega161, ATmega162, ATmega163, ATmega165, ATmega165P, ATmega168P, ATmega169, ATmega169P, ATmega32, ATmega323, ATmega325, ATmega3250, ATmega3250P, ATmega328P, ATmega329, ATmega3290, ATmega3290P, ATmega48P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega8, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER3_CAPT_vect

SIG_INPUT_CAPTURE3

Timer/Counter3 Capture Event

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega162, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER3_COMPA_vect

SIG_OUTPUT_COMPARE3A

Timer/Counter3 Compare Match A

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega162, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER3_COMPB_vect

SIG_OUTPUT_COMPARE3B

Timer/Counter3 Compare Match B

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega162, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER3_COMPC_vect

SIG_OUTPUT_COMPARE3C

Timer/Counter3 Compare Match C

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER3_OVF_vect

SIG_OVERFLOW3

Timer/Counter3 Overflow

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega162, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TIMER4_CAPT_vect

SIG_INPUT_CAPTURE4

Timer/Counter4 Capture Event

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER4_COMPA_vect

SIG_OUTPUT_COMPARE4A

Timer/Counter4 Compare Match A

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER4_COMPB_vect

SIG_OUTPUT_COMPARE4B

Timer/Counter4 Compare Match B

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER4_COMPC_vect

SIG_OUTPUT_COMPARE4C

Timer/Counter4 Compare Match C

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER4_OVF_vect

SIG_OVERFLOW4

Timer/Counter4 Overflow

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER5_CAPT_vect

SIG_INPUT_CAPTURE5

Timer/Counter5 Capture Event

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER5_COMPA_vect

SIG_OUTPUT_COMPARE5A

Timer/Counter5 Compare Match A

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER5_COMPB_vect

SIG_OUTPUT_COMPARE5B

Timer/Counter5 Compare Match B

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER5_COMPC_vect

SIG_OUTPUT_COMPARE5C

Timer/Counter5 Compare Match C

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TIMER5_OVF_vect

SIG_OVERFLOW5

Timer/Counter5 Overflow

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

TWI_vect

SIG_2WIRE_SERIAL

2-wire Serial Interface

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega16, ATmega163, ATmega168P, ATmega32, ATmega323, ATmega328P, ATmega32HVB, ATmega406, ATmega48P, ATmega64, ATmega8, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATtiny48, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

TXDONE_vect

SIG_TXDONE

Transmission Done, Bit Timer Flag 2 Interrupt

AT86RF401

TXEMPTY_vect

SIG_TXBE

Transmit Buffer Empty, Bit Itmer Flag 0 Interrupt

AT86RF401

UART0_RX_vect

SIG_UART0_RECV

UART0, Rx Complete

ATmega161

UART0_TX_vect

SIG_UART0_TRANS

UART0, Tx Complete

ATmega161

UART0_UDRE_vect

SIG_UART0_DATA

UART0 Data Register Empty

ATmega161

UART1_RX_vect

SIG_UART1_RECV

UART1, Rx Complete

ATmega161

UART1_TX_vect

SIG_UART1_TRANS

UART1, Tx Complete

ATmega161

UART1_UDRE_vect

SIG_UART1_DATA

UART1 Data Register Empty

ATmega161

UART_RX_vect

SIG_UART_RECV

UART, Rx Complete

AT90S2313, AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, ATmega103, ATmega163, ATmega8515

UART_TX_vect

SIG_UART_TRANS

UART, Tx Complete

AT90S2313, AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, ATmega103, ATmega163, ATmega8515

UART_UDRE_vect

SIG_UART_DATA

UART Data Register Empty

AT90S2313, AT90S2333, AT90S4414, AT90S4433, AT90S4434, AT90S8515, AT90S8535, ATmega103, ATmega163, ATmega8515

USART0_RXC_vect

SIG_USART0_RECV

USART0, Rx Complete

ATmega162

USART0_RX_vect

SIG_UART0_RECV

USART0, Rx Complete

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega325, ATmega329, ATmega64, ATmega645, ATmega649, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644

USART0_TXC_vect

SIG_USART0_TRANS

USART0, Tx Complete

ATmega162

USART0_TX_vect

SIG_UART0_TRANS

USART0, Tx Complete

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega329, ATmega3290, ATmega3290P, ATmega64, ATmega645, ATmega6450, ATmega649, ATmega6490, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644

USART0_UDRE_vect

SIG_UART0_DATA

USART0 Data Register Empty

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega162, ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega325, ATmega329, ATmega64, ATmega645, ATmega649, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644

USART1_RXC_vect

SIG_USART1_RECV

USART1, Rx Complete

ATmega162

USART1_RX_vect

SIG_UART1_RECV

USART1, Rx Complete

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

USART1_TXC_vect

SIG_USART1_TRANS

USART1, Tx Complete

ATmega162

USART1_TX_vect

SIG_UART1_TRANS

USART1, Tx Complete

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

USART1_UDRE_vect

SIG_UART1_DATA

USART1, Data Register Empty

AT90CAN128, AT90CAN32, AT90CAN64, ATmega128, ATmega1284P, ATmega162, ATmega64, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646

USART2_RX_vect

SIG_USART2_RECV

USART2, Rx Complete

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

USART2_TX_vect

SIG_USART2_TRANS

USART2, Tx Complete

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

USART2_UDRE_vect

SIG_USART2_DATA

USART2 Data register Empty

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

USART3_RX_vect

SIG_USART3_RECV

USART3, Rx Complete

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

USART3_TX_vect

SIG_USART3_TRANS

USART3, Tx Complete

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

USART3_UDRE_vect

SIG_USART3_DATA

USART3 Data register Empty

ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561

USART_RXC_vect

SIG_USART_RECV, SIG_UART_RECV

USART, Rx Complete

ATmega16, ATmega32, ATmega323, ATmega8

USART_RX_vect

SIG_USART_RECV, SIG_UART_RECV

USART, Rx Complete

AT90PWM3, AT90PWM2, AT90PWM1, ATmega168P, ATmega3250, ATmega3250P, ATmega328P, ATmega3290, ATmega3290P, ATmega48P, ATmega6450, ATmega6490, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATtiny2313

USART_TXC_vect

SIG_USART_TRANS, SIG_UART_TRANS

USART, Tx Complete

ATmega16, ATmega32, ATmega323, ATmega8

USART_TX_vect

SIG_USART_TRANS, SIG_UART_TRANS

USART, Tx Complete

AT90PWM3, AT90PWM2, AT90PWM1, ATmega168P, ATmega328P, ATmega48P, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATtiny2313

USART_UDRE_vect

SIG_USART_DATA, SIG_UART_DATA

USART Data Register Empty

AT90PWM3, AT90PWM2, AT90PWM1, ATmega16, ATmega168P, ATmega32, ATmega323, ATmega3250, ATmega3250P, ATmega328P, ATmega3290, ATmega3290P, ATmega48P, ATmega6450, ATmega6490, ATmega8, ATmega8535, ATmega88P, ATmega168, ATmega48, ATmega88, ATtiny2313

USI_OVERFLOW_vect

SIG_USI_OVERFLOW

USI Overflow

ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega329, ATmega3290, ATmega3290P, ATmega645, ATmega6450, ATmega649, ATmega6490, ATtiny2313

USI_OVF_vect

SIG_USI_OVERFLOW

USI Overflow

ATtiny26, ATtiny43U, ATtiny24, ATtiny44, ATtiny84, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861

USI_START_vect

SIG_USI_START

USI Start Condition

ATmega165, ATmega165P, ATmega169, ATmega169P, ATmega325, ATmega3250, ATmega3250P, ATmega329, ATmega3290, ATmega3290P, ATmega645, ATmega6450, ATmega649, ATmega6490, ATtiny2313, ATtiny43U, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861

USI_STRT_vect

SIG_USI_START

USI Start

ATtiny26

USI_STR_vect

SIG_USI_START

USI START

ATtiny24, ATtiny44, ATtiny84

WATCHDOG_vect

SIG_WATCHDOG_TIMEOUT

Watchdog Time-out

ATtiny24, ATtiny44, ATtiny84

WDT_OVERFLOW_vect

SIG_WATCHDOG_TIMEOUT, SIG_WDT_OVERFLOW

Watchdog Timer Overflow

ATtiny2313

WDT_vect

SIG_WDT, SIG_WATCHDOG_TIMEOUT

Watchdog Timeout Interrupt

AT90PWM3, AT90PWM2, AT90PWM1, ATmega1284P, ATmega168P, ATmega328P, ATmega32HVB, ATmega406, ATmega48P, ATmega88P, ATmega168, ATmega48, ATmega88, ATmega640, ATmega1280, ATmega1281, ATmega2560, ATmega2561, ATmega324P, ATmega164P, ATmega644P, ATmega644, ATmega16HVA, ATtiny13, ATtiny43U, ATtiny48, ATtiny45, ATtiny25, ATtiny85, ATtiny261, ATtiny461, ATtiny861, AT90USB162, AT90USB82, AT90USB1287, AT90USB1286, AT90USB647, AT90USB646