I added this informations about the CPU280 after reading a message on 

https://www.retrobrewcomputers.org/forum/index.php?t=msg&th=93&start=0&

where Lamar Owen posted a message I couldn't ignore.

https://www.retrobrewcomputers.org/forum/index.php?t=msg&th=93&goto=1189&#msg_1189

Lamar Owen then made a rebuild of the CPU280 supported by Tilmann Reh.
During the rebuild there where some questions, answers, fixes and enhancement.

Please read about it in the forum and for fixes and enhancement
 
goto https://github.com/wwarthen/CPU280

Wayne Warthen made this github page to share his knowledge with us.

Thanks to Lamar Owen, Wayne Warten, all the answers I got and of course Tilmann 
Reh for his CPU280.