Datasheet

Note: If interrupt vectors are placed in the boot loader section and Boot Lock bit BLB02 is programmed,
interrupts are disabled while executing from the application section. If interrupt vectors are placed in the
application section and Boot Lock bit BLB12 is programmed, interrupts are disabled while executing from
the boot loader section.
Bit 0 – IVCE Interrupt Vector Change Enable
The IVCE bit must be written to logic one to enable change of the IVSEL bit. IVCE is cleared by hardware
four cycles after it is written or when IVSEL is written. Setting the IVCE bit will disable interrupts, as
explained in the IVSEL description above. See the code example below.
Assembly Code Example
Move_interrupts:
; Get MCUCR
in r16, MCUCR
mov r17, r16
; Enable change of Interrupt Vectors
ori r16, (1<<IVCE)
out MCUCR, r16
; Move interrupts to Boot Flash section
ori r17, (1<<IVSEL)
out MCUCR, r17
ret
C Code Example
void Move_interrupts(void)
{
uchar temp;
/* GET MCUCR*/
temp = MCUCR;
/* Enable change of Interrupt Vectors */
MCUCR = temp|(1<<IVCE);
/* Move interrupts to Boot Flash section */
MCUCR = temp|(1<<IVSEL);
}
ATmega48PA/88PA/168PA
Interrupts
© 2018 Microchip Technology Inc.
Datasheet Complete
DS40002011A-page 97