This is an old project, and probably no one currently at Omega Verksted knows anything more about it than what is provided on this page. You can try to recreate it if you want, but the documentation is provided as-is and it may be outdated.
The master circuit board will hold an Atmel AVR Mega128 as the main processor for the rocket. This will be in charge of all the other electrical components located in the rocket, critical timing, and the selection of when certain tasks are to be performed. Also, there is an Atmel DataFlash(c) which will function as the rockets main memory. As this is easy to interface through SPI, small current consumption and is physically small this was easily chosen over other storage solutions.