The first step in making your Arduino projects functional is to install an Arduino bootloader. This piece of software enables you to easily and regularly upload Arduino sketches to the board without the need for any special programming tools.
Although this may sound like rocket science, it’s simpler than you think—even for novices. We'll show you how to quickly install a bootloader on your Arduino board in just a few simple steps.
But first, what is a bootloader on an Arduino board?
What Is a Bootloader?
An Arduino bootloader is a small program that is stored in the board's non-volatile memory and is executed every time the board is switched on, uploaded with new code, or reset. The main sketch or program that is stored in the board's flash memory is loaded whenever the bootloader program is executed after initializing the hardware of the board.
It's worth noting that all Arduino boards ship with a bootloader already loaded by the manufacturer. Some boards may have defective bootloaders right out of the box. This rarely occurs, however.
Why Use a Bootloader?
An Arduino bootloader may be helpful in several different situations. For example, if you are new to the Arduino platform, using a bootloader may make uploading new programs to your board easier and faster. This is because you do not need to upload your code using any additional programming tools, such as a programmer or a USB-to-serial converter.
If you are working on a project that requires regular updates to the code, you’ll find it incredibly beneficial. In this scenario, employing a bootloader may save you time and effort, as you can simply upload the new code to the board without having to use additional programming devices.
Moreover, if you are working on a project that requires the Arduino to be in a specific state when it is powered on, such as running a particular program, then employing a bootloader might be handy. The bootloader enables you to set the initial state of the board so that it will automatically execute the chosen program when it is powered on.
Finally, it provides a way to recover the Arduino if the main sketch gets corrupted or otherwise fails to operate.
Why Is My Bootloader Missing?
There are four possible reasons why your board could need a new bootloader:
- No pre-installed bootloader: There are a lot of ATMEGA328P stand-alone projects where you solder your chip onto a board and unavoidably fry the chip, which is pretty frequent. So, it is possible that you replaced the board with a chip without first installing the chip bootloader.
- Replaced bootloader: You could have replaced your bootloader with a corrupted, modified third-party bootloader.
- Corrupted bootloader: This is the least likely possibility. Unfortunately, in rare instances, the Arduino's flash memory might become corrupted.
- Extended memory: Your bootloader is missing if you replaced (flashed) the entire bootloader with your application to enjoy the remaining 2K of program memory.
Here's what you need to do.
Installing/Re-Installing the Arduino Bootloader
Typically, microcontrollers are programmed before being soldered onto a Board. In-system serial programming (ISP), such as in-circuit serial programming (ICSP), which enables the microcontroller to be programmed by an external programmer, is typically used for this. For this reason, several microcontroller makers, like Atmel and Microchip, include an ISP header on their boards.
Using Another Arduino Board
To install the bootloader on an ATmega328 microcontroller, you must use the ICSP header on the board before you can flash the bootloader using the other board as an ISP programmer.
Open the Arduino IDE, navigate to ArduinoISP as shown below, and upload the sample code to the board you intend to use as a programmer. (Follow the video tutorial for hardware connectivity.)
Just so you know you're on the right track, the code should look like this.
On the Tools menu, go to Programmer, then click on Arduino as an ISP, as seen below.
To finish, click on Burn Bootloader as indicated in the Tools tab once again.
The target board is now ready to be programmed once the process is finished.
Read More: The best way to Make an Arduino clone board
Using a Dedicated Programmer
For this kind of installation, a variety of AVR programming devices are available. The AVR Pocket Programmer (Windows only), which is based on Dick Streefland's USBtiny and Limor Fried's USBtinyISP, is a worthwhile option to consider. It provides a simpler way to program AVR microcontrollers, such as those used in Arduino boards. It's the greatest option since, in addition to being powered by a USB connection, it's compatible with a variety of programming languages and tools, making it a versatile tool for every Arduino user.
Especially if you are not using Windows, you might try alternative options like the official Atmel-ICE programmer for ARM microcontrollers.
Connect the Arduino board to the programmer and flash the bootloader. Refer to the video tutorial below.
The process shouldn't take more than 20 seconds and should be simple.
Note: Before attempting this method, the target board must be properly powered on. If not, you won't be able to flash the .hex file to your target.
There is a more involved way to install the bootloader via the command line for power users. It's not required to get to this point, but it gives you the power to modify or recompile the code for a more personalized experience.
The first step in the process is to set up the fuse bits, which are a part of the AVR chip, and regulate settings like the usage of an external crystal. To set your fuse bits, use the following command:
avrdude -b 19200 -c usbtiny -p m328p -v -e -U efuse:w:0x05:m -U hfuse:w:0xD6:m -U lfuse:w:0xFF:m
The next step is to transfer a compiled.hex file to the target board and set the lock bits once the fuse bits have been set. You will be able to run the program on the board as a result. Before using this command, make sure you are in the same directory as the optiboot-atmega328.hex file:
avrdude -b 19200 -c usbtiny -p m328p -v -e -U flash:w:hexfilename.hex -U lock:w:0x0F:m
Note: For the Arduino Uno, use these instructions. To make them function, you'll need to tweak the AVRDUDE's part number parameters as well as refactor the fuse bits for your board contained in the board.txt file.
What Will You Do With Arduino Next?
The Arduino bootloader is what makes programming so simple, even for novices. You may now upload your own unique sketches to the Arduino and hopefully restore the bootloader for future Arduino do-it-yourself projects.