Looking through new additions to Atmel family I've found SAMD11 family that's available in easy to solder packages like SOIC14/SOIC20. The biggest benefits of these ARM microcontrollers are that they're able to work over USB bus not requiring any additional extra components like crystals. SAMD11C14 used in this project is an ARM Cortex-M0+ MCU that supports I2C/SPI/USART and USB buses. So, I decided to build a test board for this MCU. As a reference I've used an Atmel's SAMD Xplained Pro schematics. As you can see my board has a minimal number of components, basically just ESD protection diode, LDO regulator (MCP1700T), some decoupling capacitors required by MCU and LDO regulator to run, reset button with external SWD reset capability and one LED. I've used 470Ohm resistors instead of 39Ohm ones in reset circuitry as there's no real difference when resetting the CPU, voltage goes down below RESET threshold and I didn't have anything less then 470Ohm in my stock. You may also want to change the LED resistor to something like 220Ohm if you want 15mA current to flow through LED to make it brighter, but I don't see any issues even when using 470Ohm ones, my LEDs are bright enough and current is only about 7mA with that resistor.
I haven't soldered two I2C pull-up resistors on this board as I'm not using I2C bus at the moment and it's quite easy to add external breadboard resistors if required. Also, these two are in 0603 package because I only have these ones in 4.7kOhm resistance in my stock.
Boards were ordered from OshPark and are of a very good quality, I'm quite happy with these. SOIC14 is really easy to solder but because I'm already used to solder QFNs I actually found that probably for my next project I'd go with QFN24 package, much easier to just heat chip up using reflow station rather then position SOIC chip. But anyway - it was a good experience to solder this chip using soldering iron. The only trouble, as I said, is correct positioning. The trick is to add flux, then add solder just to one first pad, position chip while keeping solder melt and then continue to solder all the rest of the legs one by one when the chip is already correctly positioned and kept in place.
Programming this MCU is quite easy for me as I'm using Atmel Studio and J-Link debugger. It picked up an MCU straight away after connecting SWD bus from debugger to the board. There's plenty of examples that are coming with Atmel Studio 7 so I really recommend to start learning this MCU using these examples as well as with the help of datasheet.
Currently there's not too much information about these MCUs programming in the Internet but still, they're not so hard to learn by yourself. As far as I know you can even use Arduino Software to program one of these but I haven't actually tried to do so.
Please feel free to ask any questions or to make changes to this design. Currently I'm quite happy with the performance of this MCU and the board, everything is rock-solid and stable, no issues whatsoever.