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Arduino

Arduino is an open-source electronic prototyping platform made using an ATMega microcontroller. The most popular version is the Arduino Uno that mount an ATMega328p. The difference between Arduino and a standalone AVR is the bootloader that allow us to easy develop using the Arduino IDE. Is possible to burn the bootloader into a standalone ATMega328p (and others devices ) using an AVR programmer (ISP).

## Arduino on breadboard (ATMega328p)

By default, the ATMega328p use the internal 8MHz oscillator; Arduino, instead, use a 16MHz external oscillator. The 16MHz cristall is connected to the XTAL1 and XTAL2 pins with 2 capacitors of 22pF connected to GND. Is a good idea to add a pull-up resistor on the reset pin.

Connect an ISP programmer

In order to configure the fuse bits and burn the bootloader an ISP is required.

ISP

Wire Function
Gray Reset
Brown SCK
White MISO
Orange MOSI

Arduino as ISP

Is possible to use an Arduino as ISP using a specific sketch; open this sketch by File -> Examples -> 11.ArduinoISP -> ArduinoISP and burn it to the original board.

UART

BusPirate as ISP

In order to use a BusPirate as ISP only a simple connection is required:

BusPirate ATMega328p
GND GND
CS RESET
MOSI MOSI
MISO MISO
SCLK/CLK SCK

Burn bootloader

The easy way to upload the bootload on e empty ATMega is to use the Arduino IDE, but also the malually way is possible.

Using Arduino IDE

In the Tools menu, select the right programmer and the right port. After this, it's enough to go on Tools -> Burn Bootloader. This operation also change the fuse bits.

Manually (with avrdude)

Is possible to manually burn the bootloader on the ATMega328p with avrdude; before this, is required to change the fuse bits.

BusPirate as ISP:

avrdude -P PORT -c buspirate -p m328p -v -e -U efuse:w:0x05:m -U hfuse:w:0xD6:m -U lfuse:w:0xFF:m

Arduino as ISP:

avrdude -P PORT -b 19200 -c avrisp -p m328p -v -e -U efuse:w:0x05:m -U hfuse:w:0xD6:m -U lfuse:w:0xFF:m

Now, is possible to burn the bootloader; the compiled files are available on the Arduino repositori.

BusPirate as ISP:

avrdude -P PORT -c buspirate -p m328p -v -e -U flash:w:BOOTLOADER.hex -U lock:w:0x0F:m

Arduino as ISP:

avrdude -P PORT -b 19200 -c avrisp -p m328p -v -e -U flash:w:BOOTLOADER.hex -U lock:w:0x0F:m

## Links