WIZ what? Understanding WizNet W5500 for Your CNC Projects

THere seems to be a lot of confusion (and range of prices) surrounding the WizNet W5500 based Ethernet module we use for the RP23CNC. Hopefully this will help clear some of that up.

When WizNet introduced the W5500 networking chip, they also introduced an evaluation module, the Wiz550io. It was rather large and had an odd arrangement of pins - 6 on one side and 8 on the other. But it was popular because it allowed adding Ethernet to a design via SPI, and the designer didn't have to worry about Ethernet voodoo and high-speed traces on the PCB. Later, they introduced the Wiz850io, which was much more compact and had 2 rows of 6 pins on either side. This is the version that we selected for the PicoCNC and RP23CNC. It has proven to be reliable and useful.

But along the way, there have been a number of knockoffs. And the ones I have gotten my hands on all seem to work. It appears they all use the same design and PCB layout. Some claim to not be 5V compatible, but we don't use 5V to interface with it. And there are a lot of different names for these knockoffs: Wiz820 compatible, USR-ES1, Wiz850io, W5500io, Wiz850-lite. There may be more.

There was also a version that used the W5200 chip, the Wiz820io. It is not compatible with the Wiz850io designs, yet somehow that has also crept into the knockoff descriptions. We see Wiz820io compatible as a description. Yes, confusing, but another clue to Wiz850io compatibility.

Another confusing point is the description of 5V compatibility. The knockoffs are sometimes described as not 5V compatible, unlike the original Wiz850io. However, we have examined all the modules in detail and don't see any real difference. The Wiz850io only runs at 3.3V, but the inputs to the W5500 chip are 5V tolerant. It is possible the knockoffs use lower-rated components, but since the RP23CNC (and PicoCNC) only use 3.3V, it's a moot point. So, you can safely ignore the 5V blather.

So how do you know if one is compatible with our boards? Basically, if it has the W5500 chip on it, 2 rows of 6x1 pin headers, and a 23mm x 25mm size, there is a very good chance it will work. If you want certainty, order an actual WizNet module. DigiKey, Mouser, and most other mainstream distributors carry them. The typical price is around $20 USD. Don't forget to buy 2 6x1 2.54mm sockets - you will need them. Amazon has knockoffs cheaper, but you typically have to buy 2 or more. The modules called USR-ES1 are typically cheaper, as are those called W5500 lite. I've seen some called just W5500. I have been buying as many variations as I can find and have yet to find one that doesn't work.

So, you can save some money by buying the knockoffs and have a good chance of getting something that will work. Our Ethernet kit is $14 USD and contains two 6x1 sockets as well as the W5500 module. While we typically source knockoffs, each batch we buy is validated to work with the RP23CNC. Also, we generally only sell the kits with the board, but if you didn't get one when you bought your board, contact us and we will gladly sell you a kit.

About Me.

I'm Phil Barrett, a long time CNC enthusiast. I run a small company, Brookwood Design, that makes several breakout boards for grblHAL and love to help people get the most out of their CNC machines.