/media/sandbox/xtools/avr-dev/build/avr/bin/avr-gcc -g -Wall -O2 -mmcu=avr4 -c -o main.o main.c In file included from main.c:3: /media/sandbox/xtools/avr-dev/build/avr/lib/gcc/avr/3.4.4/../../../../avr/include/avr/io.h:306:6: warning: #warning "device type not defined" main.c:12: warning: return type of 'main' is not `int' main.c: In function `main': main.c:16: error: `DDRB' undeclared (first use in this function) main.c:16: error: (Each undeclared identifier is reported only once main.c:16: error: for each function it appears in.) main.c:20: error: `PORTB' undeclared (first use in this function) make: *** [main.o] Error 1