How do I address the 5500io module


I got an 5500io module for the circuit cellar challenge and I got it powered up with 3.3V and connected to my internet hub switch but don’t know how to address it. It does not appear on my network? The yellow and green LEDs flash when I connect to the unmanaged ethernet switch but I don’t know what to do next.?

I am familiar with serial protocols like SPI and I2C but not familiar with TCP/IP and whats next to see my SPI on the internet, isnt that the point?

Please advise if you can… thanks


I managed to get this far by connecting the Wiznet 5500io board directly to my computer. But still do not know what I need to do next to configure the board for a different IP address and receive my SPI input data.


Ok, I think I am starting to get the idea that I have to write a new IP and MAC address to the chip (is that right?).

have used the Microchip Serial Analyzer as a convenient way to write I2C and SPI to configure chips before.

I am assuming I should write to these addresses…

My question is what pins do I have to hold to ground or place high or whatever else I need to do to Write over the current default IP and MAC address?

Is there a data string that some one knows that would be sent to configure these parameters. Like say i wanted an IP address of and a MAC address of 05 A4 67 D8 F5 E9 for example. Of course a similar data string could also be used to configure “PPPoE” or other parameters etc right ?.?.?..

Please advise if you can, help me along thanks!


Whats wrong with this picture?

I sent 0x00,0x09,0x00 to the W5500 and get nothing back. Wiznet Chipselect is “ENABLED” low.


Hi Garbonzo,

The best way to start is to port the W5500 ioLibrary_BSD driver (can be found here to your platform

Then, as a test, implement your own version of the loopback test like this one for the mbed:

After that, i’m sure you know what to do to continue with your project :wink:



Hi Garbonzo,

It seems you get the ping reply from the WIZ550io. The default IP address is and the MAC address 00.08.dc.1d.29.d7.
This information is stored in the microchip on the WIZ550io and initialized when the power is up.
You don’t need to change the default IP address and you can change it by writing the Source IP address register.

  • PHAR(PPP destination MAC address) is not required if you use normal Ethernet.

As sjoerd recommend you’d better port the W5500 library to your MCU.

  • jbkim

W5500io have N_RDY that it notify the complete of default network configruartion by inside Mircochip.
It takes over 500ms to assert N_RDY(low->high).
As you know, the default network configuration are MAC = 00.08.dc.1d.29.d7 and IP = The others are Gateway = and Subnet =

If you doesn’t want to use those, You can configure the network with another information by using W550io SPI interface.
But we recommend you should use the built in MAC address without modifing because the MAC address must be unique.

To modify the network, Refer to the above recommended driver by jbkim & sjoerd.

For example

uint8_t mac[6] = { 00,08,dc,1d,29,d7 }; // Don't modify
uint8_t ip[4] = {};
uint8_t gip[4] = {};
uint8_t sn[4] = {};
// ...
void main(void)
 // wait to N_RDY high or wait 500 ms

  // To do your network app.

Thank you & Good luck.

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