At long last my dream of an Arduino-compatible board with built-in Ethernet is about to come true. The EtherTen design is finished, all the parts for the first production batch are queued up at the assembler's production line, and the first PCBs are being produced this weekend. In just a couple of days we'll have photos of the first ever units once they have been assembled, but for now we have to settle for preview images of the PCB:
It's a jam-packed board, so let's take a quick tour of the features.
ATmega328 MCU. For space reasons we had to switch to the tiny TQFP32 version rather than the large DIP-28 version, which means you can't remove it from the board - but it also means you get 2 extra analog inputs. We've brought A6 and A7 out to solder pads so you can use them in your projects.
Built-in Ethernet. The big RJ45 jack on the left means you can plug your EtherTen directly into a LAN without needing an Ethernet shield on top. In fact the EtherTen is basically a Freetronics Eleven and a Freetronics Ethernet Shield stuffed onto a single PCB. We've used the Wiznet W5100 chipset just like the official Arduino Ethernet Shield, which means the EtherTen is fully supported by the official Ethernet library and example sketches. As far as development is concerned, it's functionally identical to having an Arduino Uno and an Arduino Ethernet Shield stacked together.
Power-over-Ethernet. Just like the Ethernet Shield, you can power the EtherTen directly from the LAN cable using either cheap home-brew PoE or full 802.3af standards-compliant PoE. Combine it with a regular Ethernet switch and our 4-Channel PoE Injector for a simple system, or connect a commercial PoE switch to be able to pull more than 12W of power via the network cable.
ATmega8u2 USB-to-Serial Converter. Also just like on the Eleven (and on the Uno) we've used an ATmega8u2 to provide a high-speed USB interface for uploading sketches. It's much faster than the FTDI converter used on older Arduino models and opens the way to using the EtherTen as a custom USB device.
Micro-SD Card Slot. Store sensor data or web content on an SD card. Handy!
Triple Crystals. Rather than scrimp a few cents by using ceramic resonators we used proper crystals for the primary MCU, the USB MCU, and the Wiznet Ethernet chip.
Reset Management Chip. Some combinations of Ethernet shield and Arduino model have trouble resetting cleanly under certain conditions. We've added a dedicated reset controller (with brown-out detection) to ensure that the EtherTen resets and comes up cleanly every time.
There are a host of other improvements compared to typical Arduino models, including a mini USB connector, gold-plated PCB with header labels on both sides, and D13 isolation using a FET.
We're really excited about the EtherTen. I'll be using a lot of them in my home-brew home automation system, and it'll be fascinating to see what ideas people come up with for them. Follow @freetronics on Twitter for up-to-the-minute news about its availability.