My recommendation is to code to the project at hand but do that in a modular way. Make a single source file for each specific hardware function and have each one also have a parallel include (header) file. Do a nice bit of documentation in each of these files as to how it is configured and intended to work.

Once you finish this current project and move on to the next one start your new project by bringing together the set of source files that you intend to try to "re apply". Then go through each one and custom taylor each one to the new setup. You will find this MUCH MUCH faster than trying to re-write the whole thing from the ground up each time. Also keep in mind that this project by project customization of each function is a good review for getting back up to speed about the functonality so when you come to debugging it is all fresh in your mind.

Michael Karas