LM80C 64K firmware R1.18
New keyboard shortcut: when pressing "C=" (ALT) and "CTRL" keys together, the system resets the BASIC environment, clears the variables, clears the system stack, set the screen to graphic mode 1, re-initialize the PSG, close any seq. file still open, reset serial lines, and returns to the BASIC prompt; the program into memory is NOT deleted.