Practice Problems: Interrupts
- Initialize Interrupt 1 (INT1) pin to generate an Interrupt on a rising edge. Set all unused bits to default values.
_____ R16, 0x____
_____ EICRA, R16 - Initialize Interrupt 0 (INT0) pin to generate an Interrupt on a falling edge. Do not change the other bits (ISC11, ISC10) in the External Interrupt Control Register A (EICRA). You should assume the previous code (problem 1) has been written (i.e., bits 1 and 0 cleared)
_____ R16, EICRA
_____ R16, 0x____
_____ EICRA, R16 - Configure Pin 15 PB1 (OC1A/PCINT1) to generate an Interrupt whenever the pin changes state. Do not change any other bits. To make things more interesting, do not use the SBR instruction.
_____ R16, PCMSK0 ; load
_____ R17, PCICR
_____ R18, SREG
_____ R16, 0x ; do something
_____ R17, 0x____
_____ R18, 0x____
_____ PCMSK0, R16 ; store
_____ PCICR, R17
_____ SREG, R18