For quite long time Raspberry Pi was the only platform that was using BCM2835 processor. But recently it started selling it to anyone that opened gate for Rpi clones. So it seems that one of the first ones is ODROID-W miniature board. It is compatible with Raspberry Pi in several ways. Forst of all it carry same GPIO layout for connecting existing modules. Of course it doesn’t have pinheaders soldered to keep it’s initial profile low. It features same processor and memory as Raspberry Pi, so it can run any Rpi OS. Being small size allows it to be used as wearable electronics.
To make things more easy, there are several additions made. First of all it has Li Polymer battery connector. Also board includes RTC chip with backup battery connector as well. To keep low profile there is no Ethernet connector, the HDMI port was replaced with Micro HDMI. It still has camera interface, but no display interface which still doesn’t have its module. The list continues with built in DC/DC step-down converter also with DC/DC step-up converter for 5V rails. There is also couple ADC inputs included that were so needed in Raspberry Pi (Actually comes with RTC RC5T619 IC which also is a Li-ion charger).
And the size of board is also very attractive – 60mm x 36mm x 7mm. It’s price is $30 plus shipping is practically same as Raspberry Pi. So if you’re looking for Linux based small board – it can be great choice.