Aug 09, 2019 Read about 'serial communication between arduino' on element14.com. I have two arduinos connected serially meaga and uno i have a numbers 0 to 255 in the uno i should be able to read the numbers 0 to 255 from the uno to. Serial communication on pins TX/RX uses TTL logic levels (5V or 3.3V depending on the board). Don’t connect these pins directly to an RS232 serial port; they operate at +/- 12V and can damage your Arduino board.
Software Serial Example
Arduino and Genuino boards have built in support for serial communication on pins 0 and 1, but what if you need more serial ports? The SoftwareSerial Library has been developed to allow serial communication to take place on the other digital pins of your boards, using software to replicate the functionality of the hardwired RX and TX lines. This can be extremely helpful when the need arises to communicate with two serial enabled devices, or to talk with just one device while leaving the main serial port open for debugging purpose.
Arduino Uno To Arduino Uno Serial Communication
In the example below, digital pins 10 and 11 on your Arduino or Genuino boards are used as virtual RX and TX serial lines. The virtual RX pin is set up to listen for anything coming in on via the main serial line, and to then echo that data out the virtual TX line. Conversely, anything received on the virtual RX is sent out over the hardware TX.
Hardware Required
- Arduino or Genuino Board
Circuit
There is no circuit for this example. Make sure that your Arduino or Genuino board is attached to your computer via USB to enable serial communication through the serial monitor window of the Arduino Software (IDE).
image developed using Fritzing. For more circuit examples, see the Fritzing project page
Schematics
image developed using Fritzing. For more circuit examples, see the Fritzing project page
Code
Serial Communication Between Two Arduino
See also
- TwoPortReceive – Two serial ports that receive data switching from one to the other one when a special character is received.
- MultiSerialMega - Use two of the serial ports available on the Arduino and Genuino Mega.
- Serial Call Response - Send multiple vairables using a call-and-response (handshaking) method.
- Serial Call Response ASCII - Send multiple variables using a call-and-response (handshaking) method, and ASCII-encode the values before sending.
Last revision 2018/05/17 by SM
Arduino Software Serial Tutorial
Description
Arduino To Arduino Serial Communication Protocol
Used for communication between the Arduino board and a computer or other devices. All Arduino boards have at least one serial port (also known as a UART or USART), and some have several.
| Board | USB CDC name | Serial pins | Serial1 pins | Serial2 pins | Serial3 pins |
|---|---|---|---|---|---|
Uno, Nano, Mini | 0(RX), 1(TX) | ||||
Mega | 0(RX), 1(TX) | 19(RX), 18(TX) | 17(RX), 16(TX) | 15(RX), 14(TX) | |
Leonardo, Micro, Yún | Serial | 0(RX), 1(TX) | |||
Uno WiFi Rev.2 | Connected to USB | 0(RX), 1(TX) | Connected to NINA | ||
MKR boards | Serial | 13(RX), 14(TX) | |||
Zero | SerialUSB (Native USB Port only) | Connected to Programming Port | 0(RX), 1(TX) | ||
Due | SerialUSB (Native USB Port only) | 0(RX), 1(TX) | 19(RX), 18(TX) | 17(RX), 16(TX) | 15(RX), 14(TX) |
101 | Serial | 0(RX), 1(TX) |
On Uno, Nano, Mini, and Mega, pins 0 and 1 are used for communication with the computer. Connecting anything to these pins can interfere with that communication, including causing failed uploads to the board.
Arduino To Arduino Serial Communication Library
You can use the Arduino environment’s built-in serial monitor to communicate with an Arduino board. Click the serial monitor button in the toolbar and select the same baud rate used in the call to begin().
Serial communication on pins TX/RX uses TTL logic levels (5V or 3.3V depending on the board). Don’t connect these pins directly to an RS232 serial port; they operate at +/- 12V and can damage your Arduino board.
To use these extra serial ports to communicate with your personal computer, you will need an additional USB-to-serial adaptor, as they are not connected to the Mega’s USB-to-serial adaptor. To use them to communicate with an external TTL serial device, connect the TX pin to your device’s RX pin, the RX to your device’s TX pin, and the ground of your Mega to your device’s ground.