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Last site update May 1 2013

Embedded TCP/IP Examples
[Demo Projects]

See also:
1 - FreeRTOS+UDP source code and downloadable examples
2 - Low cost TCP/IP libraries in the FreeRTOS+ ecosystem showcase
3 - FreeRTOS featured demo with telnet, web server, command line and file system integration


This page lists the FreeRTOS demo projects that include an embedded web server within a fully preemptive multitasking environment. Some demos use uIP and some lwIP as the underlying embedded TCP/IP stack. The projects vary in age and therefore also vary in the version of the stacks used. More information is provided on the stacks directly below. The demos themselves are listed by microcontroller manufacturer below that.


Open source TCP/IP stacks

uIP (and FreeTCPIP which is heavily based on uIP)

For several reasons uIP is a great piece of software when it is used in an appropriate application. It runs in a single task so there are no re-entrancy related issues, and it allows a lot to be achieved in a very small RAM and ROM footprint.

The biggest drawback of uIP is that without modification (see below) you can only have one packet outstanding on the network at any one time. This means communicating with a desktop machine is very slow because the desktop will use a delayed ACK algorithm, and therefore wait 200ms between receiving a packet and acknowledging the packet. This is standard practice in non real-time TCP/IP stacks to minimise network traffic - after receiving one packet the stack will wait to see if any more packets arrive in the hope that it can send out a single ACK to acknowledges more than one incoming packet at a time.

There are ways that the slow communication speed can be improved without changing the configuration of the desktop TCP/IP stack, but like everything in engineering - there are trade offs to be made. In this case the trade offs are:

  1. Throughput speed.
  2. RAM usage.
  3. CPU usage.
The FreeRTOS download includes a modified version of uIP that is code named FreeTCPIP. This greatly improves throughput performance when compared to the base (unmodified) uIP code. Throughput will still be slower than that achievable by a more fully featured stack, but will be more than adequate for a lot of deeply embedded microcontroller based applications.

Only the later FreeRTOS uIP demos use FreeTCPIP, and FreeTCPIP itself will continue to be developed in the future.


lwIP

lwIP is also a good stack when used in its intended, memory constrained, environment. It has a higher throughput than uIP, but also has a larger ROM and RAM footprint. Although the footprint is larger than uIP it is still smaller than most commercial TCP/IP offerings. In particular, lwIP saves RAM by making large data buffers by chaining smaller buffers together.

Most (if not all) the FreeRTOS demos listed here make use of quite an old lwIP version. There are however contributed demos available in the FreeRTOS Interactive forums that use a more up to date lwIP code base. Further lwIP related uploads would be gratefully received.

On the negative side, lwIP is undeniably quite complex to use at first, but time invested in its use will pay dividends in future projects. lwIP is also a moving target because it is constantly being developed and updated (which is not necessarily a negative thing).


FreeRTOS demos that include TCP/IP functionality

Examples for Atmel microcontrollers

  1. AVR32 AT32UC3A lwIP web and TFTP server:

    This example uses lwIP to create both a simple web and TFTP server on the AVR32 flash microcontroller.

  2. Open source uIP TCP/IP stack on an AT91SAM7X:

    Includes a simple interrupt driven driver for the SAM7X integrated EMAC peripheral.

  3. The open source uIP TCP/IP stack on an AT91SAM7X again - this time using Eclipse:

    A simple mouse driver is provided along with the web server demo.

  4. Open source lwIP TCP/IP stack on an AT91SAM7X:

    Includes a more comprehensive interrupt driven driver for the SAM7X integrated EMAC peripheral.


Examples for Freescale microcontrollers

  1. Freescale Kinetis K60 using IAR and uIP

    An IAR project is provided that is pre-configured to run on the TWR-K60N512 controller module. The TWR-K60N512 does not itself include an Ethernet connector, so a TWR-SER peripheral module is also required to make use of the embedded web server functionality. The two modules can be purchased together in the TWR-K60N512-KIT tower kit.

  2. Open source uIP TCP/IP stack on a Coldfire MCF52233 ColdFire V2:

    Demonstrates dynamic content generation and control over the target hardware IO from the served web pages.

  3. Open source uIP TCP/IP stack on a Coldfire MCF51CN128 ColdFire V1:

    Demonstrates dynamic content generation and control over the target hardware IO from the served web pages, this time on a V1 core.


Examples for Luminary Micro/Texas Instruments microcontrollers

  1. Open source uIP TCP/IP stack on an LM3S6965 and LM3S8962 ARM Cortex-M3:

    Permits commands to be sent to the target from a web browser. Also permits the display of dynamically generated run time data. A version for use with Eclipse is also available


Examples for Microsemi (formally Actel) FPGAs with ARM Cortex-M3 microcontroller subsystems

  1. Open source uIP TCP/IP stack on a SmartFusion A2F200M3 using IAR and Keil:

    Permits commands to be sent to the target from a web browser. Also permits the display of dynamically generated run time data.

  2. Open source uIP TCP/IP stack on a SmartFusion A2F200M3 using GCC and SoftConsole:

    Permits commands to be sent to the target from a web browser. Also permits the display of dynamically generated run time data.


Examples for NXP microcontrollers

  1. RedSuite uIP TCP/IP stack on the NXP LPC17xx ARM Cortex-M3 microcontroller:

    The demo presented on this page was developed on an LPC1768 mounted on an CRB1768 development board from Code Red. It displays dynamically generated run time information and permits commands to be sent to the target from the web browser.

  2. Rowley CrossWorks uIP TCP/IP stack on the NXP LPC17xx ARM Cortex-M3 microcontroller:

    Similar to the RedSuite LPC1768 demo but this time using Rowley CrossWorks and targeted at the Keil MCB1700 development board.

  3. IAR Embedded Workbench uIP TCP/IP stack on the NXP LPC17xx ARM Cortex-M3 microcontroller:

    Similar to the RedSuite LPC1768 demo but this time using the IAR Embedded Workbench and targeted at the IAR Kickstart evaluation board.

  4. Open source uIP TCP/IP stack on an LPC2368:

    Demonstrates control over the target hardware IO from the served web pages.

  5. LPC2368 project again - this time using Eclipse:

    The LPC2368 embedded web server example created using completely open source development tools.

  6. Open source uIP TCP/IP stack on an LPC2124:

    Includes a polled mode Crystal LAN CS8900 driver (thanks to Paul Curtis).


Examples for Renesas processors

  1. Open source FreeTCPIP (based heavily on uIP) examples for the RX62N microcontroller:

    There are six FreeRTOS demo applications for the RX62N microcontroller. One for the Renesas compiler, one for the GCC compiler, and one for the IAR compiler. Two projects are provided for each compiler, one for the Renesas Starter Kit (RSK), and the other for the Renesas Demonstration Kit (RDK). The web server example includes the use of CGI scripting to show task and run time statistics.

  2. Open source uIP TCP/IP stack on an SH7216 (SuperH SH-2A FPU):

    The web server example includes basic CGI scripting functionality. This is used to generate pages to display both TCP/IP and task run time statistics.


Examples for ST microcontrollers

  1. Open source uIP TCP/IP stack and lwIP TCP/IP stack on an STR912 (ARM9):

    This demo includes options to use either the uIP or the lwIP stack, this time targeted at an ARM9 processor.

  2. Open source uIP TCP/IP stack on an STM32 (ARM Cortex-M3):

    Rowley CrossWorks demo that includes an embedded web server.


Examples using WizNET interfaces

  1. WizNET hardware TCP/IP stack - I2C interface:

    This example uses a TCP/IP coprocessor to produce an embedded web server through the I2C port!

  2. WizNET hardware TCP/IP stack - memory mapped interface:

    This example uses the same TCP/IP coprocessor, but with a memory mapped interface on a Tern E-Engine controller.








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