Chip Search: I2C to Ethernet PHY + mini-hub

[Richard Crowley]

I am working on a design that requires Ethernet interface (control panels for BlackMagic Design ATEM videoswitchers). Arduino (or equivalent)-based. But trying to make it rather low-profile, so that huge hulking Ethernet shield for Arduino is way too big. And the Arduino Ethernet model is apparently obsolete here in the era of WiFi.

There are smaller products with the MagJack and W5500 or ENC28J60 or similar chips, but they have only the one Ethernet port. I would like to make something with a PAIR of Ethernet ports so that it can be used as a "mini-hub" or even "daisy-chained" as is commonly found in the broadcast equipment environment.

I could have sworn I saw a specialty chip (from NXP?) that combined an Ethernet interface plus at least two Ethernet ports. But I didn't book-mark it and now I can't find it again.  And maybe it isn't even the best solution here in 2016?  Thanks for any help or suggestions.

[Yansi]

What about something like this and a proper ETH MAC equipped micro? (Like STM32F207 or such), instead of the kiddies toy?

http://www.mouser.com/ds/2/268/9303-320903.pdf

I'm still tempted to try that out, however I have no real use for that :-(

//EDIT: Wurth does some interesting low profile ETH connectors: http://katalog.we-online.de/pbs/datasheet/7498011122R.pdf

[nctnico]

IC+ (http://www.icplus.com.tw ) has a bunch of switch chips with an integrated switch/PHY and RMI/MII ports. A long time ago I used one in a design and bit-banged a RMI/MII master interface (yes, you can do that) to get data from and to the network. MOQ may apply.

[hans]

Just throwing it out there, I haven't used it personally so I don't know what data routing possibilities this chip has. Or maybe this is the chip you meant:

http://ww1.microchip.com/downloads/en/DeviceDoc/KSZ8863MLL_FLL_RLL_DS.pdf


Tho, there are lot of more "managed" switches: http://www.microchip.com/ParamChartSearch/chart.aspx?branchID=1633

[rstofer]

I would think you would want to use SPI rather than I2C.  SPI can be fairly fast (multiple MHz) compared to I2C at perhaps 400 kHz.

[dannyf]

there are ethernet-capable mcus - nxp and luminary for example;

there are also spi/ethernet bridges - microchip for example.

you just need to loosen some constraints.

[nctnico]

Still having the ethernet stack inside the microcontroller may be daunting. Another solution would be to use a switch chip and connect one of the ports directly (with capacitors) to a W5500 chip which also handles all the network related stuff.

[mrpackethead]

Lan9304 from Microchip. 3 ports.. 2 Phys + 1 RMII

[Yansi]

I have already suggested the LAN9303 from Microchip.  So two votes for LAN9303 :-)

[westfw]

I would like to make something with a PAIR of Ethernet ports so that it can be used as a "mini-hub" or even "daisy-chained"

You're going to have to do a lot more definition than that.   The ubiquitous multi-port RJ45 ethernet "thing" is a lot more complicated internally than you might think, and they're only cheap because someone threw all the complexity into a single chip.  (For example, your chances of being able to implement anything meaningfully similar given an Arduino with two of the traditional ethernet interfaces is essentially zero, even assuming that that you count interface two of them to the AVR.)