Uart Application developed for RS485 Communication on BeagleBone Black, using termios.

• Modular based interface
• pthread and termios implementation
• stty

• compileUART.sh :

  Simple g++ compiler commands to build app.

• MakeFile :

  This can also be used to build app. ( Preferred )

• multiUART.cpp :

  BBB provides 4 Uart ( 1,2,4,5) . Uart0 is used for boot messages. This app runs them all in parallel using thread having read/write fxns.

• multiUARTApp.cpp :

  2 thread based app for testing the application, as required in the Project. This is similar to above file, and more specific to the Project specs.

• uartconfig.txt :

  Uart configuration used for termios structure

• uartRx.cpp :

  A simple Uart receive module prototype for testing RX case

• uartTx.cpp :

  A simple Uart transmit module prototype for testing TX case

• uartTxLoop.cpp -

  Test a continuous transmission case

• uartPinsConfig.sh -

  Pin configuration for all UARTs , this is specfic to BeagleBone black and may vary.

1. Compile :

You can either use compileuart or makefile , since it is a small project, it doesn't matter much. The variable "Target" has to be changed in MAKEFILE for different App as required.

Run

chmod a+x compileUART.sh
./compileUART.sh

OR

make clean
make

2. Pin Configurtion :

For BeagleBone Black, if the cape-overlay is loaded, config-pin can be directly used to set pins for UART. Else corresponding BB-UART1-00A0.dtbo like devicetree overlays has to be added in uEnv.txt file.

Run

chmod a+x uartPinsConfig.sh
./uartPinsConfig.sh

• Now you can execute the application

• multiUARTApp.cpp
  • Implement mutex-based lock in threads.

The following links provide a very good read about Serial programming and termios structure details.

• HOWTO-Serial-Programming - Also include sample code. Good explanation of canonical and non-canonical modes.
• Serial_Programming-wiki
• termios - good explanation of termios flags
• stty and man page