1.25 UART Ring Buffer

This example application shows how to use UART peripheral in ring buffer mode.

Description

This example demonstrates read and write over UART using the ring buffer mode. The UART is configured in non-blocking mode (interrupts enabled). The example asks the user to enter 10 characters. Once received, the characters are echoed back. In the process, the example demonstrates various ring buffer APIs.

Downloading and Building the Application

To clone or download this application from Github, go to the main page of this repository and then click Clone button to clone this repository or download as zip file. This content can also be downloaded using content manager by following these instructions.

Path of the application within the repository is apps/uart/uart_ring_buffer_interrupt/firmware.

To build the application, refer to the following table and open the project using its IDE.

Project NameDescription
pic32cx_mtsh_db.XMPLABX project for PIC32CXMTSH Development Board

Setting Up the Hardware

The following table shows the target hardware for the application projects.

Project NameBoard
pic32cx_mtsh_db.XPIC32CXMTSH Development Board

Setting Up PIC32CXMTSH Development Board

  • Connect the PD1 and PD2 pins of J18 Header to TX and RX pins of USB-UART Click board respectively
  • Connect the 3.3V and GND pins of J18 Header to 3.3V and GND pins of USB-UART Click board respectively
  • Connecting a mini-USB cable from USB UART Click board to Computer
  • Power on the board using a 12V power supply on J3
  • Attach a debugger to the SWD/JTAG port J17

Running the Application

  1. Build the application using its IDE
  2. Open the Terminal application (Ex.: Tera term) on the computer.
  3. Connect to the Virtual COM port and configure the serial settings as follows:
    • Baud : 115200
    • Data : 8 Bits
    • Parity : None
    • Stop : 1 Bit
    • Flow Control : None
  4. Reset the board to run the application
  5. The console displays the following message
    • The console displays the initial transmit and receive buffer sizes
    • It then adds 10 characters - “0123456789” to the transmit buffer and displays the available free space in the transmit buffer after the 10 characters have been added
    • The message asks the user to enter 10 characters
      Note: For this example, the “Free Space in Transmit Buffer = xx”, where xx can be anything between 117 to 127, depending on the USART baud rate and the CPU execution speed.
  6. Enter 10 characters on the terminal
  7. Entered characters are echoed back on the console and message is displayed indicating that the receive notification is turned on
  8. For every 10 characters typed, it will be echoed back on the console