Raspberry Pi has been very popular small computer board. It’s initial layout is quite flexible that allows it to use as standalone computer or embedded device with controllable I/Os. Probably standard Raspberry Pi is more oriented to be small single board computer, where you can connect peripherals like keyboard, mouse, display, Ethernet. The I/O part seemed to be left on a side. Eventually extension boards started to appear to fill the need of functionality like ADC, DAC, more digital I/Os. Eventually you end up stacking stuff on top like Arduino. But we like elegant things don’t we? So Raspberry Pi team has been working on different Raspberry Pi concept – Compute module. This is smaller module which have same BCM2835 processor, same RAM. Instead of SD flash there is a 4Gbyte flash memory. Practically this is it. Module is traced on DDR2 SODIMM sized PCB which actually fits this connector.
It has no external connectors like Ethernet, USB or audio but there are way more GPIOs. Module can be snapped in to any custom made I/O board that can have more controllable I/Os or interfaces like found on standard Raspberry Pi. So definitely module will have to go along with custom I/O board. It will give even more freedom to community. They’ve also taken care of example I/O board to get started.