10. Interrupts
This section describes the specifics of the interrupt handling as performed in ATtiny24/44/84. For a general explanation of the AVR interrupt handling, see ”Reset and Interrupt Handling” on page 13.
10.1Interrupt Vectors
Table 10-1. |
Reset and Interrupt Vectors |
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Vector No. |
Program Address |
Source |
Interrupt Definition |
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1 |
0x0000 |
RESET |
External Pin, Power-on Reset, |
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Brown-out Reset, Watchdog Reset |
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2 |
0x0001 |
INT0 |
External Interrupt Request 0 |
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3 |
0x0002 |
PCINT0 |
Pin Change Interrupt Request 0 |
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4 |
0x0003 |
PCINT1 |
Pin Change Interrupt Request 1 |
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5 |
0x0004 |
WDT |
Watchdog Time-out |
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6 |
0x0005 |
TIMER1 CAPT |
Timer/Counter1 Capture Event |
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7 |
0x0006 |
TIMER1 COMPA |
Timer/Counter1 Compare Match A |
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8 |
0x0007 |
TIMER1 COMPB |
Timer/Counter1 Compare Match B |
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9 |
0x0008 |
TIMER1 OVF |
Timer/Counter0 Overflow |
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10 |
0x0009 |
TIMER0 COMPA |
Timer/Counter0 Compare Match A |
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11 |
0x000A |
TIMER0 COMPB |
Timer/Counter0 Compare Match B |
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12 |
0x000B |
TIMER0 OVF |
Timer/Counter0 Overflow |
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13 |
0x000C |
ANA_COMP |
Analog Comparator |
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14 |
0x000D |
ADC |
ADC Conversion Complete |
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15 |
0x000E |
EE_RDY |
EEPROM Ready |
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16 |
0x000F |
USI_START |
USI START |
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17 |
0x0010 |
USI_OVF |
USI Overflow |
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If the program never enables an interrupt source, the Interrupt Vectors are not used, and regular program code can be placed at these locations. The most typical and general program setup for the Reset and Interrupt Vector Addresses in ATtiny24/44/84 is:
50 ATtiny24/44/84 
8006E–AVR–09/06
ATtiny24/44/84
Address |
Labels Code |
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Comments |
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0x0000 |
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rjmp |
RESET |
; |
Reset Handler |
0x0001 |
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rjmp |
EXT_INT0 |
; |
IRQ0 Handler |
0x0002 |
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rjmp |
PCINT0 |
; |
PCINT0 Handler |
0x0003 |
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rjmp |
PCINT1 |
; |
PCINT1 Handler |
0x0004 |
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rjmp |
WATCHDOG |
; |
Watchdog Interrupt Handler |
0x0005 |
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rjmp |
TIM1_CAPT |
; |
Timer1 Capture Handler |
0x0006 |
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rjmp |
TIM1_COMPA |
; |
Timer1 Compare A Handler |
0x0007 |
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rjmp |
TIM1_COMPB |
; |
Timer1 Compare B Handler |
0x0008 |
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rjmp |
TIM1_OVF |
; |
Timer1 Overflow Handler |
0x0009 |
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rjmp |
TIM0_COMPA |
; |
Timer0 Compare A Handler |
0x000A |
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rjmp |
TIM0_COMPB |
; |
Timer0 Compare B Handler |
0x000B |
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rjmp |
TIM0_OVF |
; |
Timer0 Overflow Handler |
0x000C |
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rjmp |
ANA_COMP |
; |
Analog Comparator Handler |
0x000D |
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rjmp |
ADC |
; |
ADC Conversion Handler |
0x000E |
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rjmp |
EE_RDY |
; |
EEPROM Ready Handler |
0x000F |
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rjmp |
USI_STR |
; |
USI STart Handler |
0x0010 |
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rjmp |
USI_OVF |
; |
USI Overflow Handler |
; |
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0x0011 |
RESET: ldi |
r16, high(RAMEND); Main program start |
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0x0012 |
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out |
SPH,r16 |
; |
Set Stack Pointer to top of RAM |
0x0013 |
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ldi |
r16, low(RAMEND) |
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0x0014 |
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out |
SPL,r16 |
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0x0015 |
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sei |
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; |
Enable interrupts |
0x0016 |
<instr> |
xxx |
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... |
... |
... ... |
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51
8006E–AVR–09/06