I have yet to see ANY separate document that match the software, thus, my attitude is that no text should exist outside the code.

When I start a project I typically decide which modules I will have and equip these modules with functions with no actual code.

an example

/////////////////////////////////////////////////////////////////////////////////
//
//  U8 FetchKbdChar(void)
//
// return character from keyboard if any or zero if none
//

U8 FetchKbdChar(void)
{
U8 dummy;
  
  dummy = 0;
  return(dummy); // patch dummy in the ICE to test calling func
}

The next step, then is to make the main() function with the skeleton functions.

Then start filling out the skeletons.

This way you get most decisions made before too much code is written AND the documentation is done BEFORE the code.

Some will like this approach, some will not. I am not saying this is the right or the only way, but it works for me.

Erik