How to use avr-gcc and avrdude with Arduino Pro-Mini on FreeBSD

howto.md

How to use AVR-GCC and avrdude with Arduino pro-mini on FreeBSD

Required packages / ports

devel/avr-gcc
devel/avr-binutils
devel/avrdude

They can be installed via binary package management

pkg install devel/avr-gcc
pkg install devel/avr-binutils
pkg install devel/avrdude

or from ports

cd /usr/ports/devel/avr-gcc
make install clean
cd /usr/ports/devel/avr-binutils
make install clean
cd /usr/ports/devel/avrdude
make install clean

Compiling and flashing

This works pretty straight forward. First compile and link as usual, then use objcopy to extract the eeprom section into an Intel HEX file and after that flash using avrdude. If one wants to compile - for example - blink.c and upload it to an ATMega328P (i.e. for example an Arduino pro mini) using the Arduino bootloader on Port /dev/ttyU0 (check permissions if something doesn't work and possibly set them in /etc/devfs.conf):

avr-gcc -Wall -mmcu=atmega328p -Os blink.c -Wl,-gc-sections -Wl,-relax -o blink.o
avr-objcopy -R .eeprom -O ihex blink.o blink.hex
avrdude -v -p atmega328p -c arduino -P /dev/ttyU0 -b 57600 -D -U flash:w:blink.hex:i

This can of crouse be done parameterized with a Makefile:

MCU=atmega328p
CFLAGS=-Wall -mmcu=$(MCU) -Os
LDFLAGS=-Wl,-gc-sections -Wl,-relax
CC=avr-gcc

all: blink.hex

clean:

        rm -f *.o *.hex *.obj *.hex

%.hex: %.obj

        avr-objcopy -R .eeprom -O ihex $< $@

%obj: blink.c

        $(CC) $(CFLAGS) blink.c $(LDFLAGS) -o $@

flash: blink.hex

        avrdude -v -p $(MCU) -c arduino -P /dev/ttyU0 -b 57600 -D -U flash:w:blink.hex:i


.PHONY: flash clean

Note that different boards use different chips and different BAUD rates:

Board	Chip	Baud
Arduino Pro Mini	atmega328p	57600

A simple test program

This is a simple "blink" test program that blinks with a requency of 1 Hz and a duty cycle of 50%

#define F_CPU 16000000
#include <avr/io.h>
#include <util/delay.h>

int main() {
        DDRB = DDRB | 0x20;
        for(;;) {
                PORTB = PORTB | 0x20;
                _delay_ms(500);
                PORTB = PORTB & ~0x20;
                _delay_ms(500);
        }
}