#include <avr/io.h>
#include <avr/interrupt.h>

#define Freq 4000000

ISR(TIMER0_OVF_vect)
{
  TCNT1 = 0x10000 - (Freq / 1024);
  PORTB ^= 0x01;
}

int main (void)
{
  DDRB = 0x01;
  TCCR1A = 0;
  TCCR1B = 5;
  TCNT1 = 0x10000 - (Freq / 1024);
  TIFR = 0;
  TIMSK = 0x80;
  GIMSK = 0;
  sei();
  while(1);
}

-------- begin --------
Cleaning project:
rm -f main.hex
rm -f main.srec
rm -f main.eep
rm -f main.cof
rm -f main.elf
rm -f main.map
rm -f main.sym
rm -f main.lss
rm -rf obj
rm -f main.s
rm -f main.d
rm -rf .dep
-------- end --------
-------- begin --------
avr-gcc (GCC) 3.4.6
Copyright (C) 2006 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
Compiling C: main.c
avr-gcc -c -mmcu=atmega32 -I. -gdwarf-2 -DF_CPU=16000000UL -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Wstrict-prototypes -Wundef -Wa,-adhlns=obj/main.lst  -std=gnu99 -MD -MP -MF .dep/main.o.d main.c -o obj/main.o
Linking: main.elf
avr-gcc -mmcu=atmega32 -I. -gdwarf-2 -DF_CPU=16000000UL -Os -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums -Wall -Wstrict-prototypes -Wundef -Wa,-adhlns=obj/main.o  -std=gnu99 -MD -MP -MF .dep/main.elf.d obj/main.o --output main.elf -Wl,-Map=main.map,--cref --section-start=.text=0x0000,
Creating load file for Flash: main.hex
avr-objcopy -O ihex -R .eeprom main.elf main.hex
srec_cat main.hex -Intel -Output main.srec -Motorola
srec_cat: main.hex: 15: warning: no start address record
Creating load file for EEPROM: main.eep
avr-objcopy -j .eeprom --set-section-flags=.eeprom="alloc,load" \
--change-section-lma .eeprom=0 -O ihex main.elf main.eep
Creating Extended Listing: main.lss
avr-objdump -h -S main.elf > main.lss
Creating Symbol Table: main.sym
avr-nm -n main.elf > main.sym
Size after:
main.elf  :
section           size      addr
.text              224         0
.data                0   8388704
.bss                 0   8388704
.noinit              0   8388704
.eeprom              0   8454144
.stab              876         0
.stabstr           132         0
.debug_aranges      20         0
.debug_pubnames     43         0
.debug_info        138         0
.debug_abbrev       86         0
.debug_line        198         0
.debug_str         128         0
Total             1845
-------- end --------
Process terminated with status 0 (2 minutes, 29 seconds)
0 errors, 1 warnings

#include <avr/io.h>
#include <math.h>

double b=15.485;
double tmpVar;

int main (void)
{
tmpVar = floor(b); //берем целую часть от 15.485, т.е. 15
while (1)
{
char i=1;
}
return (0);
}

#include <avr/io.h>
#include <math.h>

double tmpVar;

int main (void)
{
tmpVar = floor(15.485);
while (1)
{
char i=1;
}
return (0);
}