Documentation here: Media:AtomCNC_MANUAL.pdf (new version has the drivers attached w/in the .pdf)
Driver link: https://atomsoft.wordpress.com/2013/01/14/atomcnc/ or on the Forums: http://www.shapeoko.com/forum/download/file.php?id=4606 
Forum discussion: http://www.shapeoko.com/forum/viewtopic.php?f=7&t=375
A custom control board, shown w/ power supply and wiring block:
More information was at: AtomWiki but site is off-line.