An undocumented command, and a new function of the IV-17 SS
- Thanks to Terry Kennedy for the idea of having the last tube in a scrolling array transmit the characters $S , at the completion of a scrolling routine. This removes the need to calculate how long any scrolling will take to complete prior to sending the scroll command itself. Now you can just listen for $S to be sent back to know that it is safe to send the next command.
The undocumented command is MC , which clears the whole array and in most cases will immediately end any scrolling which is taking place.