;;;;blinky.S, assemble with avr-as blinky.S to get a.out .set DDRB, 0x04 .set PORTB, 0x05 .org 0x0000 rjmp RESET RESET: ldi R16,0x20 out DDRB,R16 ldi R18,0x00 ldi R17,0x00 ldi R20,0x20 Loop: ldi R19,0xE8 aloop: inc R17 cpi R17,0x00 brne aloop inc R18 cpi R18,0x00 brne aloop inc R19 cpi R19,0x00 brne aloop eor R16,R20 out PORTB, R16 rjmp Loop