[Verified] Arduino development board (ATMEGA328P-MU)

The role of bootloader

Arduino boots the burning program through a pre-written bootloader. Every time a program is downloaded to the Arduino board through the serial port, the Arduino board will be reset first, so that the bootloader is entered first, and then specific download instructions are sent to the Arduino board. After the bootloader recognizes these instructions, it will start to receive the remaining program. The new program code is written into the internal flash. If the bootloader does not recognize the download instruction, it will jump to the program area and work normally.

There is no bootloader in the newly shipped microcontroller, so you need to burn it in yourself.

Two methods to burn bootloader

Two ways:

1. Burn Bootloader through AVR downloader
2. Using another Arduino as ISP to flash the Bootloader

It is recommended to buy this kind. The other one I bought cannot be used.

Open the PROGISP software, select the chip model, and connect the USBISP downloader to the Arduino development board:

ISP Downloader--Target Board

MISO-----MISO

VCC------5V

SCK------SCK

MOSI-----MOSI

RST-------RST

GND------GND

Click to load Flash and select the D:Program FilesArduinohardwarearduinoavr ootloadersatmega folder under the arduino installation directory

If the crystal oscillator used by your development board is 8MHz , then choose ATmegaBOOT_168_atmega328 _pro_8MHz .hex

If the crystal oscillator used by your development board is 16MHz , then choose ATmegaBOOT_168_atmega328.hex

The author uses 16MHz, so I chose ATmegaBOOT_168_atmega328.hex

The bootloader file must match the crystal oscillator, otherwise you will not be able to use the serial port to download the program!

Open the Tools -> Programmer of the arduino IDE and a list of all supported programmers is displayed. It is recommended to use the Arduino as ISP method, which is relatively simple and has a high success rate.

Arduino as ISP is simply to use another Arduino board, download a special program to it in the normal way , turn it into an ISP downloader, and then connect its corresponding pins to the board to be programmed with the bootloader , and then through Arduino IDE is used to control bootloader programming . Here italics show the three steps.

• To make an ISP board,
  open the IDE, Files -> Examples -> ArduinoISP -> ArduinoISP, and use this program to download it to an Arduino board. Let's call this board the ISP board.

• The connection between the ISP board and the target board
  can be seen from the previous introduction. Here, the pins of the ISP board should be connected to the ICSP interface on the target board. The connection correspondence table is as follows (taking UNO as an ISP board as an example)