Wireless FreeRTOS IP stack

Libraries
1

Hi

I would like to know if there is an implementation of the FreeRTOS IP stack running on a Wireless interface.
I am looking for an alternative to the ESP32 running lwIP stack on its wireless interface.

Can you tell in which demo board this has been implemented?

thanks,
Eduardo

2

Hi @EduardoGoncalves1966
Thanks for reaching out to the FreeRTOS Forum community!

FreeRTOS, by design, uses the vendor specific WiFi APIs directly with a TCP/IP and network transport layer in between.
FreeRTOS+TCP has a network interface implemented for ESP32 board here
You can use it to replace the default Lwip , ESP IDF currently implements.
The best place to look at for these will be the ESP IDF at GitHub - espressif/esp-aws-iot: AWS IoT SDK for ESP32 based chipsets. This has some good examples which can be referred in the folder “examples”.
Apart from ESP32, FreeRTOS+TCP has also been implemented on the wireless interface in the Pic32 board
FreeRTOS-Plus-TCP/NetworkInterface_wifi.c at main · FreeRTOS/FreeRTOS-Plus-TCP · GitHub

3

Hi
Thanks for the fast answer and the links.

I am more interested in implementing an Application that will communicate using UDP broadcasts (without Access Points. Just like if it was running on Ethernet). And also creating a TCP connection to communicate between 2 systems.

Is there a simple project for this? I inspected the directory and it seems there are implementations for complex protocols like MQTT, HTTP, etc.

I am looking for something as simple as possible that allows to use TCP connections and UDP broadcasts.

thanks

4

Did you look at this one - FreeRTOS/FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_Minimal_Windows_Simulator/DemoTasks at main · FreeRTOS/FreeRTOS · GitHub

5

Hi

Does that example run on a WiFi interface?

One thing that I don’t understand is on hopw to choose the interface that the TCP/IP stack should use:

xListeningSocket = FreeRTOS_socket( FREERTOS_AF_INET, FREERTOS_SOCK_STREAM, FREERTOS_IPPROTO_TCP );

When a socket is created how does one associate this stream with Ethernet or WiFi?

thanks

6

Hi @EduardoGoncalves1966,
It depends on what port you’re using for the platform.
Take esp32 as example, the xNetworkInterfaceOutput is the interface for FreeRTOS-Plus-TCP to transmit output packet through the network interface. And esp_wifi_internal_tx() is esp32’s wifi API!
You can also try this Networking Demo Project. It uses libpcap as network interface on top of Linux, support on any available network interfaces on your machine.

Thanks.

7

Thanks for the answers.

Although I am looking for an example project where a TCP connection is being made between two ESP32 boards, ideally ESP32-WROOM.
Also a UDP broadcast example would be nice but I think when I have a the TCP project I can make this one.

Any help? Thanks.

9

You can refer to the demo FreeRTOS/FreeRTOS-Plus/Demo/FreeRTOS_Plus_TCP_IPv6_Demo/IPv6_Multi_WinSim_demo at devIPv6 · FreeRTOS/FreeRTOS · GitHub. This creates multiple endpoints. For ESP32, you will will have to use the ESP32 portable layer(FreeRTOS-Plus-TCP/source/portable/NetworkInterface/esp32 at main · FreeRTOS/FreeRTOS-Plus-TCP · GitHub) instead of the libpcap portable layer.

10

Can someone help setting up an example?
i am struggling with idf and cmake. So it is maybe more a esp-idf question,…

I started a normal idf project and freertos-plus-tcpip is a submodule

set(FREERTOS_PLUS_TCP_NETWORK_IF "ESP32")
add_subdirectory(../submodules/FreeRTOS-Plus-TCP freertos_plus_tcp)

lines in the main/CMakeLists.txt

dependencies needed:

freertos_plus_tcp need

target_link_libraries( freertos_plus_tcp
  PUBLIC
    freertos_config
    freertos_plus_tcp_port # for pack_struct_start.h
  PRIVATE
    freertos_kernel
    freertos_plus_tcp_network_if
    freertos_plus_tcp_utilities
)

and ESP32 networkdriver

target_link_libraries( freertos_plus_tcp_network_if
  PRIVATE
    esp32_lib
)

At idf idf BuildSystem there are some info how to achieve what i need but i cannot set up a working example.

Do i have to follow the idf component way or go the plain cmake way with idf as library?

11

I think using the IDF component way would be easier but I’d suggest to reach out to Espressif and confirm with them.