3 ports switch with W5100


I’m using the W5100 in my project and all works well.
By now I want to implement in my boards a 3 way switch to have the possibility to configure the lan in line instead star.
I see some chips like micrel or Asix to do it, but before starting the project, I ask wich is the best way to follow in order to implement this feature.
Is possible to use the MII or the RGMII with the W5100?
There is any schematic to do it?


It is not possible to use the MII or the RGMII with the W5100.

Thank you for your reply,

so, in your opinion, which is the best way to implement a 3 way switch on my board?



the right answer was: Change the W5100 with W3150A+ and then use the Microchip LAN9303 ethernet switch.
The W3150+ is fully software compatible with W5100, so hardware change is the only work to do.

Thank you.

Hello miaooaim, i have your same need to connect several devices in daisy chain.
I’d like to know if you’ve reached your goal using W3150A+ and LAN9303.
Thank you very much!
Best regards

Hi Ioreno,
yes, it works very well.
Our devices are using this solution since 2014 and we don’t have any problem by now.

Very good! Thank you so much for the reply

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Here an example of the connection beetwen 9303 and 3150+

Dear Giuseppe
I am trying to implement what you have done with 3150 and 9303. I have working 5100 unit, so I am going to follow your reference design and replace 5100 with 3150 and 9303. I cannot seem to read the picture well. Would you mind sending me the readable file of the schematics?

Hope these are useful.
Page_1-2.pdf (1.5 MB) Page_2-2.pdf (2.1 MB)

hi i have many cuestions about you shematic can you help me with your mail please


Ask, if I can I’ll help you

XA is the board microprocessor address bus.
XB is the board microprocessor data bus.
Signal from/to microprocessor are also: /CS, /RD, /WE and /IRQ_EXP.
The addressing of 3150 is with 2 address line only.
SJ13-19-20-21 are solder joint pad on printed circuit. You have to select the LAN9303 functional mode. In my case “Chiuso” means “Closed” and “Aperto” means “Open”.
SJ7-8-9-10-11-12 are also soder joint pad, but with the possibility to switch the pins 2 and 4 in 2 way. “Chiudere” means “Close” the couple of pad indicate after.
I suggest you to study the LAN9303 datasheet to understand why I’ve done this circuit solution.

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