UDP sends garbage when concurrent TCP socket is active

Question

Hi, I have an application using a STM32 olimexino board and a W5100 shield. It uses FreeRTOS and runs 4 tasks, of which one task handles a NTP client and another task handles a Web server. The Ethernet library has been modified by myself by adding mutexes around all SPI accesses to guarantee the complete, undisturbed transmission of the read, write and write command operations, in this multitasking environment. The NTP client and the web server work perfectly, when used separately. However, if I use them concurrently, the UDP transmission is corrupted by the Web server activity, and not the contrary (the web server works unaffected by the concurrent operation). What happens is this. Normally the NTP client sends every 20 seconds a UDP datagram of 48 bytes according to the NTP format, and expects a UDP datagram in response. After some time of concurrent operation, the UDP datagram I record using Wireshark has a length of 96 and contains 48 bytes of garbage, followed by the correct 48 bytes of the NTP structure. Of course this datagram receives no response from the server. At the next attempt to send a request, the datagram lengh is 144 and contains 96 bytes of garbage, followed by the correct 48 bytes of the NTP structure. I cannot imagine how garbage data could be inserted BEFORE the data I want to send, nor why this occurs only when the Web server is processing its own traffic.

irina · Answer

Are you using the iolibrary we provide? If no, first you need to use the iolibrary for test.

irina · Answer

This GitHub site is currently adding projects. Among them, there is a project for HTTP Server. https://github.com/WIZnet-ioLibrary/W5x00-HTTPServer You have to modify from W5100S to W5500 in wizchip_conf.h and you can use HTTP Server Project for W5500 image762×337 11.4 KB

Eng.kourosh · Answer

Thank you very much i work with blue pill header board (stm32f103c8t6) and using keil compiler , can you give me source file or training for this ? can i give your skype or whatsapp for asking my questions about w5500 chip and runing web server? i working on smart home company and if i success to runing web server and make web relay we need to many of w5500 Chips for our product

irina · Answer

Please check the link below GitHub GitHub - irinakim12/W5500_STM32F103RB_CUBEMX_keil Contribute to irinakim12/W5500_STM32F103RB_CUBEMX_keil development by creating an account on GitHub.

Eng.kourosh · Answer

thank you very muck dear irina its work very good can i change my ip in web page and storage it on microcontroller? without flash ic or sd card i mean user can change ip and dns or something via web page and when reset microcontroller this configuration does not change

Eng.kourosh · Answer

And next question is how can i compare end of url For example: This is my url:https://192.168.100.45 And i wtite the html code like this : <a href=‘Relay’ Relay1ON < / button > When i click the button the gpio activated but i need code that when i enter this url (Https://192.168.100.45/Relay) its worked too Can you help me?

irina · Answer

The HTTP server we provide finds the corresponding phrase in the message and makes it work. It seems that you want to use Restful. I think you can’t use that mode with the link we provided so you have to implement it yourself.

Eng.kourosh · Answer

It means i can’t use your httpserver.h or its work and i need to change webpage.h and userhanlder.h? Could i use some function in io libraty like ( http_get_uri_name) or something to get value of URL?

Eng.kourosh · Answer

Hello @irina_kim how are you is it work on stm32f101?or i need to port this library for f101 series?

Eng.kourosh · Answer

and which header file should be change for that?