WIZnet Developer Forum

Wiz550io , Arduino due , Mysql_connector (arduino ide)

About this library , UDP , si not so stable , after some message sometimes crash , do you have some tips , or trick to receive udp , also 24 UDP packet , is bad few limit

It’s seems not all working perfect , also connection of database and udp has some problems. UDP seems blocked after some messages or after database loading and putting . I think is bad thing use ethernet 2 adafruit , it’s not update , we can not a simple conversion of Arduino ethernet library ? We are safe driver is correctly done of w5500 ? about buffer etc

it seems for example , after loading or putting of mysql connector , udp port not working , after cut power yes , can be wiz not reset ?

i’ve test many times , seems board not reset correctly after … udp not work after a software reboot with wdt. If driver not reset correctly board ?

Some DUE correction on Arduino main library w5100 seems not improved on ethernet2 w5500 , why ?

First, I checked UDP with UDPSendReceiveString Example.
It works fine. I think there is a problem in your code.

Second, Ethernet2 library through Arduino IDE isn’t made by WIZnet. If you have any inquiry about that, you must to contact to Arduino.
I just used Arduino Ethernet2 library for your convenience.

Please refer to the official WIZnet site below.


Hi , one problem is resolved , I see this issue after softReset , after yesterday I see wizen note on wiki about HW and SW reset and issues can be generated … we implemented a hw reset and all work.

About your wiznet library , I used at first but mysql connector not work 2 month ago , also this library seems not upgraded as Arduino standard library Ethernet , can be expose library to many issues . It’s work in your test ? it can be managed and fuse with actual standard library ?

We need as stable safe driver , I can’t jump to other every time , If we can do a good work we can use it . We are waiting to order wiznet board , to complete test , thanks for your help !

Dear Jim, could you explain, what are the changes for Arduino Mega adk with Wiz550io?

Dear connaissant

Think of it as similar to Arduino.
Please refer to the W5500 library fix at the top.


Find w5500.h, w5500.cpp in Ethernet2 library.
Windows OS
C:\Users\your username\Documents\Adruino\libraries\Ethernet2\utility
/home/your username/Arduino/libraries/Ethernet2/src/utility/

Insert the following code in w5500.h


Insert the following code in w5500.cpp

#if !defined(WIZ550io_WITH_MACADDRESS)

Thanks for the answer.
Should I change the lines in ethernet2.h? (for mega)
EthernetClass() { _dhcp = NULL; w5500_cspin = 53; }
void init(uint8_t _cspin = 53) { w5500_cspin = _cspin; }

in w5500h:
void init(uint8_t ss_pin = 53);
uint8_t readVersion(void);

or I must explicitly specify in the sketch
void setup()
{ pinMode(53, OUTPUT);
digitalWrite(53, HIGH);


Jim, help me please. The server runs for about 10 seconds and then stops working. I did everything according to the instructions. What could have been the cause? Look at the my previous post please. Kind regards, connaissant.

If you upload whole source code, I will check.

When I download a sketch for the first time, everything is fine, in the subsequent times putty writes “server is at or”
Thank you.
for Jim.zip (67.0 KB)

I used your WebServer application and ArduinoMega+WIZ550io+ioShield-A.
I didn’t find any problem.
I upload my Ethernet2 library.
If the problem persists, please check the connection of H/W.


Ethernet2.zip (62.3 KB)

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