THERE ARE SEVERAL GITHUB BRANCHES OF ONSTEP:
OnStep is a computerized telescope goto controller, based on Teensy or Arduino control of stepper motors.
It supports Equatorial Mounts (GEM, Fork, etc.) as well as Alt-Az mounts (including Dobsonians, and the like.)
OnStep was designed, from the beginning, as a more or less general purpose system and provisions were made in the firmware to allow for use on a variety of mounts.
OnStep supports a wide variety of connection options. Either two or three serial "command channels" can be utilized. One of the these is normally devoted to a USB connection and for the other(s) choose from the following:
Other software in the OnStep ecosystem include:
OnStep is compatible with the LX200 protocol. This means it can be controlled from other planetarium software, like: Sky Safari, CdC (even without ASCOM), Stellarium, etc.
There are also INDI drivers so it can be used from Linux, with CdC or KStars.
Detailed documentation, including the full set of features, detailed designs for PCBs, instructions on how to build a controller, how to configure the firmware for your particular mount, can all be found the OnStep Group Wiki.
All the changes are tracking in git, and a detailed list can be accessed using the following git command:
git log --date=short --pretty=format:"%h %ad %<(20)%an %<(150,trunc)%s"
Questions and discussion should be on the mailing list (also accessible via the web) at the OnStep Group.
OnStep is open source free software, licensed under the GPL.
See LICENSE.txt file.