This tutorial represents communication between Beaglebone black and Arduino through UART. You don’t need any another peripheral for this tutorial. UART stands for universal asynchronous receiver and transmitter. It transmits and receives data asynchronously with another device which also supports UART protocol.

Required Tools:

Beaglebone Black
Arduino
Female to Female connectors

Setup of Software environment

Install the latest python version in BBB as explained in tutorial How to make first python program with Beaglebone Black. Install the adafruit python-GPIO library.

Working

Beaglebone transmits the message which is entered from command prompt and Arduino receives the data and displays it on Arduino serial terminal. Run the python script from SSH terminal and at the same time open Arduino serial in PC. Write some message from SSH terminal. BBB transfers the data through UART which is then received by Arduino and displayed on serial terminal.

Description

BBB has on chip five UART ports each containing two pins: RX pin and TX pin to receive and transmit respectively. In this tutorial, UART1 is used for communication with Arduino. Here, BBB acts as transmitter and Arduino as receiver. Connect the UART1 transmitting pin (24^th pin of header P9) of BBB to receiving pin (pin number 10^th) of Arduino. I have used software UART in Arduino that’s why I have connected it with pin number 10^th (I declared 10^th and 11^th pin as RX and TX in program respectively). Make the common ground connection between Arduino and BBB which is necessary for communication.

Open the command terminal and access Beaglebone black through SSH as explained in getting started with Beaglebone black. Create a new file using touch command with .py extension (i.e. led.py). Open the file with any text editor (i.e. nano, vim etc.) and write a code in python language.

Connect Arduino with PC through USB cable. Open it and then write a code for receiving data in C language. For help, you may refer to the tutorial how to Install and run Arduino in Linux.

UART setup in BBB

You need to import UART in program to make use of I2C device. You can create your own library but that would consume more time. Hence Ad fruit library can be used that provides all kind of python library of BBB.

import Adafruit_BBIO.UART as UART

Also import the serial from python library. It encapsulates access to serial port.

import serial

Configure UART by following function:

UART.setup(“UART1”)

serial.Serial (port = “/dev/ttyO1”, baudrate=9600)

First function is setup and configuration of UART1. Second function accesses the serial device with defined baud rate. Find the device port attached with UART from the list below and access it.

Now, you can transmit and receive data through UART. You can close the port when you don’t want to use it.

Arduino Setup

Write a receiving source code in Arduino and load it onto Arduino Uno. After the data is received, it will be displayed on the serial terminal.

Run the script from terminal:

Enter the following command with file name from command prompt:

python filename.py

i.e. python uart.py

Project Source Code

###

// UART.C
#include <SoftwareSerial.h>
 
SoftwareSerial uart(10,11);
 
 
void setup()
{
  Serial.begin(9600);
  uart.begin(9600);
  
}
 
void loop()
{
 
  if(uart.available() > 0)
  {
    Serial.write(uart.read());
  }
 
}
 
//
 
import Adafruit_BBIO.UART as UART
 
import serial
 
UART.setup("UART1")
 
disp = serial.Serial (port = "/dev/ttyO1", baudrate=9600)
 
disp.close()
disp.open()
 
while True:
        if disp.isOpen():
 
                print "Serial is Openn"
                message = raw_input("Enter your message:n")
 
                disp.write(message)
                disp.write("n")
 
                exit = raw_input("You want to exit or not YN:")
 
                while ((exit != 'Y') and (exit != 'N') and (exit != 'y') and (exit != 'n')):
 
                        print "Invalid Input!!!n"
 
                        exit = raw_input("You want to exit or not YN:")
 
 
                if (exit == 'Y') or (exit == 'y'):
                        break
 
                else:
                        print "To be continue....n"
 
 
print "Sorry!!! You not able to do communicate with device" 
disp.close()
###