Overview

Arduino UNO is an Arduino development board based on ATmega328P. It has 14 digital input/output pins (6 of which can be used for PWM output), 6 analog input pins, a 16 MHz crystal oscillator, a USB interface, a DC interface, an ICSP interface, and a reset button . It contains everything a microcontroller needs, and you can drive it by simply connecting it to a computer's USB port, or using an AC-DC adapter, or a battery.

\"Uno\" means "one" in Italian. Arduino UNO is the first development board of the Arduino series. Arduino IDE 1.0 is the first official version of Arduino IDE. Arduino UNO hardware and Arduino IDE software have established a set of Arduino development standards. established on this standard.

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programming

The Arduino UNO can be programmed through the Arduino IDE.

On the ATmega328 chip used by Arduino UNO, the bootloader program is stored, so that the user can upload the program to the development board without using an additional programmer. This process of uploading the program is done using the STK500 protocol.

You can also upload the program to the Arduino UNO by connecting the programmer through the ICSP interface without using the bootloader.

Precautions

There is a resettable fuse on the Arduino Uno, when the current exceeds 500mA when a short circuit or overcurrent occurs, it can automatically disconnect the power supply, thereby protecting the USB port of the computer and the Arduino. While most computer USB ports provide internal protection, this fuse provides additional protection.

power supply

The Arduino Uno can be powered through a USB port or a DC power socket. Arduino UNO comes with automatic power switching function.

The power pins are as follows:

Vin

Power input pin. This pin can output the power supply voltage when using an external power supply through the DC power socket.

5V

5V power supply pin. When using the USB power supply, the 5V voltage provided by the USB is directly output; when using the external power supply, the regulated 5V voltage is output.

3V3

3.3V power supply pin. The maximum output capability is 50 mA.

GND

ground pin

IOREF

I/O reference voltage. Other devices can identify the development board I/O reference voltage through this pin.

storage

ATmega328 has 32KB Flash storage space (0.5KB is used to store bootloader), 2KB SRAM and 1KB EEPROM.

The EEPROM space can be read and written using the officially provided EEPROM library.

input Output

The Arduino Uno has 14 digital input and output pins that can be controlled using pinMode(), digitalWrite() and digitalRead().

Some of them come with special functions, these pins are as follows:

Serial:

0 (RX), 1 (TX), are used to receive and transmit serial data. These two pins are connected to the ATmega16u2 for serial communication with the computer.

External Interrupt:

2, 3, can input external interrupt signal. There are four trigger modes for interrupts: low-level trigger, level-change trigger, rising edge trigger, and falling edge trigger.