Avr-gcc

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How to setup avr-gcc and get compiling for an Arduino!

<pre> $ yum install avr-gcc avr-libc avr-binutils avrdude </pre>

See: using the Arduino IDE

<h2>avrdude</h2> use avrdude to load files into the arduino

<h2>makefile</h2>

<h3>devices</h3>

• <code>atmega168</code>
• <code>atmega328p</code>

<h3>simple</h3> Just produces the .elf and .hex file. Also optimizes for space (HUGE difference) <pre> all:

       avr-gcc avr.c -mmcu=atmega328p -o example.elf -Wall -Os
       avr-objcopy -j .text -O ihex example.elf example.hex
       avrdude -c buspirate -P /dev/ttyUSB1 -p m328p -U flash:w:example.hex

</pre>

<h3>complex</h3> produces .o, .asm, .map and .lst files too <pre> all:

       avr-gcc -g -mmcu=atmega328p -c avr.c -Wa,-alh,-L -o example.o > example.asm
       avr-gcc -g -mmcu=atmega328p -Wl,-Map,example.map -o example.elf example.o
       avr-objdump -h -S example.elf > example.lst
       avr-objcopy -j .text -j .data -O ihex example.elf example.hex
       avrdude -c buspirate -P /dev/ttyUSB1 -p m328p -U flash:w:example.hex

</pre>

<h2>sample source</h2>

<h3>blink</h3> <source lang="c"> /* 8 Mhz cpu */

1. define F_CPU 8000000UL

/* led pin */

1. define LED 0b00100000

1. include <util/delay.h>
2. include <avr/io.h>

int main(void) {

 /* set port b direction register to output for led pin */
 DDRB = LED;

 while(1) {

   /* turn led off */
   PORTB &= ~LED;
   _delay_ms(450);

   /* turn led on */
   PORTB |= LED;
   _delay_ms(50);
 }

} </source>

<h3>S.O.S.</h3> <source lang="c"> /* 8 Mhz cpu */

1. define F_CPU 8000000UL

/* led pin */

1. define LED 0b00100000

1. include <util/delay.h>
2. include <avr/io.h>

void dot(void) {

 /* turn led on */
 PORTB |= LED;
 _delay_ms(200);

 /* turn led off */
 PORTB &= ~LED;
 _delay_ms(500);

}

void dash(void) {

 /* turn led on */
 PORTB |= LED;
 _delay_ms(700);

 /* turn led off */
 PORTB &= ~LED;
 _delay_ms(500);

}

int main(void) {

 char i;

 /* set port b direction register to output for led pin */
 DDRB = LED;

 while(1) {

   for (i=0;i<3;i++) {
      dot();
   }
   for (i=0;i<3;i++) {
      dash();
   }
   for (i=0;i<3;i++) {
      dot();
   }

   _delay_ms(5000);

 }

} </source>

<h2>other commands</h2>

<pre> avr-size example.elf avr-gcc --help=optimizers </pre>

<h2>resources</h2> https://www.mainframe.cx/~ckuethe/avr-c-tutorial/<br> http://arduino.cc/en/Hacking/PinMapping168<br> http://hintshop.ludvig.co.nz/show/buspirate-avr-programming/<br> http://itp.nyu.edu/physcomp/uploads/6pinAVRproghead.jpg<br> http://dangerousprototypes.com/bus-pirate-manual/<br> http://www.ladyada.net/library/arduino/bootloader.html