100 Section 8: Program Branching and Controls

Flag 9. An overflow condition (described on page 61) automatically sets flag 9. Flag 9 causes the display to blink or, if a program is running, waits until execution is complete and then starts blinking the display.

Flag 9 may be cleared in three ways:

Press "9 (the common procedure for clearing flags).

Press . This will only clear flag 9 and stop the blinking—it will not clear the display.

Turn the calculator off. (Flag 9 is not cleared if the calculator turns itself off.)

If you set flag 9 manually (F9), it causes the display to blink irrespective of the overflow status of the calculator. As usual, a program will run to completion before the display starts blinking. Therefore, flag 9 can be used as a programming tool to provide a visual signal for a selected condition.