I am seeking a method for using the Custom Solutions header GPIO pins as contol outputs to another circuit board. Is there documentation for accessing these pins through software control?
Tedh_1, I would recommend you to post your question on The Intel Developer Zone. There is an online community and discussion forums.
Here is the link Forums | Intel® Developer Zone
You can also check this link for more information Intel® NUC Boards and Kits — Custom Solutions Header for Home Theatre PCs (HTPC)