Links:
http:https://www.oreganosystems.at/download/mc8051_ug.pdf
http:https://www.oreganosystems.at/?page_id=363
http:https://www.cs.ucr.edu/~dalton/i8051/i8051syn/
http:https://www.eecs.ucf.edu/~jinyier/courses/EEE4932/lab3_8051/source/8051_Guide.pdf
http:https://www.eecs.ucf.edu/~jinyier/courses/EEE4932/lab3_8051/