starting with AVR-GCC

1. get the avr-gcc, avr-libs and avr-binutils
   • ebuilds and urls could be found here
2. create a new folder and add these files:
   • Makefile
     

     file: http://darcs.erazor-zone.de/avr/avr-gcc/avrledtest/Makefile

     MCU=atmega8
     CC=avr-gcc
     OBJCOPY=avr-objcopy
     # optimize for size:
     CFLAGS=-g -mmcu=$(MCU) -Wall -Wstrict-prototypes -Os -mcall-prologues
     HEXLOAD=/usr/sbin/hexload
      
      
      
     all: avrledtest.hex
      
     avrledtest.hex : avrledtest.out 
     	$(OBJCOPY) -R .eeprom -O ihex avrledtest.out avrledtest.hex 
     avrledtest.out : avrledtest.o 
     	$(CC) $(CFLAGS) -o avrledtest.out -Wl,-Map,avrledtest.map avrledtest.o 
     avrledtest.o : avrledtest.c 
     	$(CC) $(CFLAGS) -Os -c avrledtest.c
      
     load: avrledtest.hex
     	$(HEXLOAD) -I avrledtest.hex
      
     clean:
     	rm -f *.o *.map *.out
      

   • avrledtest.c
     

     file: http://darcs.erazor-zone.de/avr/avr-gcc/avrledtest/avrledtest.c

     #include <avr/io.h>
      
     int main(void) {
     	unsigned char w;
     	unsigned int w2;
     	/* enable  PD5 as output */
     	DDRD=255;
     	while (1) {
     	    for(w=0;w<8;w++) {
     		PORTD=(1<<w);
     		/* led on, pin=0 */
     		for (w2=0;w2<50000;w2++);
     		for (w2=0;w2<50000;w2++);
      
     	    }
     	}
     }

Well, the Makefile is used to compile your C-source just by typing 'make' as you can see, that will create the avrledtest.hex by executing:

1. $(CC) $(CFLAGS) -Os -c avrledtest.c

2. $(CC) $(CFLAGS) -o avrledtest.out -Wl,-Map,avrledtest.map avrledtest.o

3. $(OBJCOPY) -R .eeprom -O ihex avrledtest.out avrledtest.hex

Additionally you can use 'make load' for uploading your firmware to the device.

• $(CC) means our c- compiler, thats 'avr-gcc'.
• $(MCU) thats the type of our microcontroler.
• $(OBJCOPY) is used to convert the binary .o file to a ascii .hex file

Thats quite an easy AVR program, it uses the 2 loops, the while-loop is a simple infinete loop, the next one (for-loop) is used to shift the PORD and other 2 simply slow down the whole thing.

• avr-gcc ebuilds
• hexload
• examples

2004-2005 © Alexander 'E-Razor' Krause