HP 48g Graphing Calculator - Manual (Page 74)

5 Special Memory Operations
Occasionally the HP 48 may seem to freeze while executing something,
and won’t respond to the (CANCEL) key. This can happen if the
memory becomes corrupted, or if the system becomes “confused”
during execution.
If this happens, you have two ways to try to correct it: a system, halt
and a memory reset.
Caution If you must reset your calculator, always attempt a
system halt first. Consider a memory reset only if
the system halt fails.
System Halt
A system halt does the following:
■ Interrupts and cancels all executing programs and system
operations.
■ Clears the stack, all local variables, the three LAST variables, the
PICTURE display, and the temporary system storage section of
memory.
■ Turns off the user keyboard (clears flag -62).
■ Detaches all libraries from the HOME directory, and reconfigures all
libraries in all available ports (see “Using Libraries” in chapter 28
for details).
■ Makes the HOME directory the current directory.
B Activates the main MTH menu.
Note that a system halt does not affect the stored objects in HOME
and Port 0.
To halt the system from the keyboard:
1. Press and hold (ON).
2. Press the menu key.
3. Release both keys.
A system halt is also performed automatically when you turn on the
calculator tf you have added, removed, or changed the write-protect
switch position of any plug-in card since you last turned the calculator
5-16 Memory