NetBurner 3.5.7
PDF Version
TCP to Serial

TCP to Serial Bridge

A NetBurner embedded application that creates a bidirectional bridge between TCP network connections and serial communication ports.

Overview

This application enables remote access to serial devices over a network by creating a TCP server that forwards data between network clients and a serial port. It's commonly used for remote device management, debugging, and data acquisition from serial-based equipment.

Note
You can test with on a single PC by using a telnet application and serial terminal like MTTTY

Features

  • Bidirectional Communication: Data flows seamlessly between TCP clients and serial devices
  • Telnet Compatible: Listens on port 23 (standard Telnet port) for easy connection
  • Connection Management: Handles multiple connection attempts with configurable override behavior
  • Timeout Protection: Automatically closes idle connections after 60 seconds
  • Multi-Platform Support: Supports various NetBurner platforms (SOMRT1061, MODRT1171, SB800EX)
  • Status Monitoring: Provides connection status messages to both serial and network interfaces

Configuration

Serial Port Settings

  • Baud Rate: 115,200 bps
  • Data Bits: 8
  • Stop Bits: 1
  • Parity: None

Network Settings

  • TCP Listen Port: 23 (Telnet)
  • Connection Timeout: 60 seconds of inactivity
  • Override Timeout: 20 seconds (configurable)

Connection Override Behavior

The application supports three modes for handling new connections when one is already active:

  1. Ignore New Connections (OVERIDE_TIMEOUT = 0xFFFFFFFF)
    • Maintains current connection, rejects new attempts
  2. Timed Override (OVERIDE_TIMEOUT = 20 seconds)
    • Allows new connection to replace existing one after 20 seconds of current connection activity
  3. Always Override (OVERIDE_TIMEOUT = 0)
    • Immediately replaces existing connection with new one

Platform Support

The application automatically configures pins for different NetBurner platforms where necessary:

  • SOMRT1061: Uses LPUART4 on pins 87 (RX), 88 (TX), with flow control on pins 2 (RTS), 3 (CTS)
  • MODRT1171: Uses LPUART2 on pins 21 (RX), 22 (TX)
  • SB800EX: Uses UART2

Notes for SOMRT1061

  • The console port for status messages is J13 on the development board, which is routed to LPUART3 on the processor.
  • The data port is J14 on the development board, which is routed to LPUART4 on the processor.
  • RX, TX, RTS, CTS pin selection is always required before opening the serial port.
Note
Refer to the OpenAllUARTS example for your particular platform to see all possible pin configurations.

Usage

  1. Compile and Deploy: Build the application for your NetBurner platform and deploy to the device
  2. Connect Serial Device: Attach your serial device to the configured UART pins
  3. Network Connection: Connect via Telnet client to the device's IP address on port 23
    telnet <device-ip-address> 23
  4. Data Exchange: Data typed in the Telnet session is sent to the serial device, and serial responses appear in the Telnet session

Status Messages

The application provides informative status messages:

To Serial Port:**

  • "Waiting for connection"
  • "New Connection Opened"
  • "Connection Closed by Network"
  • "Connection Timed out and Closed"

  • "This Connection is being Overridden"

    To Network Client:**

  • "Connection Opened"
  • "Your Connection was just Overridden"
  • "Your Connection Timed out and will be Closed"

Technical Details

  • Uses NetBurner's RTOS with select() for efficient I/O multiplexing
  • Implements proper socket management with error handling
  • Supports hardware flow control (RTS/CTS) where available
  • Buffer size: 40 bytes for data transfers
  • Non-blocking I/O operations for responsive performance

Use Cases

  • Remote serial device configuration and monitoring
  • Data logging from serial sensors over network
  • Remote debugging of embedded systems
  • Industrial automation equipment access
  • Legacy serial device integration into modern networks

Requirements

  • NetBurner development kit
  • NetBurner development environment
  • Network connectivity (Ethernet)
  • Serial device or equipment to bridge

Notes

  • Ensure proper pin configuration for your specific NetBurner platform
  • Test connection override behavior matches your application requirements