Section 14: Flags216
Flag Descriptions
Over the next few pages are descriptions of all HP-41C flags. Several examples and problems are included to help you become more familiar with how the user flags work.
General Purpose Flags (00 through 10)
The HP-41C is equipped with 11 general purpose user flags (numbered 00 through 10). You have complete control of these flags. They can be set, cleared, and tested using any of the HP-41C flag control functions. Once you set or clear one or all of these flags, that status is maintained by the Continuous Memory of the calculator, even when the HP-41C is turned on and off.
Special Purpose User Flags (11 through 20)
There are 10 special purpose flags in your HP-41C. In addition to their use as flags that you can control, flags 11 through 20 have special functions in the HP-41C. You can test, set and clear these flags using any of the flag commands discussed earlier in this section. However, under certain conditions, the calculator also controls the status of these flags.
When you are using peripheral extensions such as the printer or card reader, it is a good idea to keep in mind that the status of these flags may be altered by the calculator. Refer to the owner’s handbook that belongs to the peripheral extension for specific details about flags.
All of these 10 special purpose user flags (11 through 20) are cleared each time the HP-41C is turned on.
Automatic Execution Flag
Flag 11 is one of the special purpose flags described above. Its special purpose in the HP-41C is to control program execution when the HP-41C is turned on.
When flag 11 is set, and you turn the calculator off, the HP-41C automatically begins executing the current program in program memory when you turn the HP-41C back on again. Execution begins at the instruction the calculator was positioned to before the HP-41C was turned off. In addition, the calculator sounds the audible tone before execution begins.
If flag 11 is clear and you turn the calculator off, when you turn the HP-41C back on again, the calculator turns on normally. Program instructions are not executed.
Remember that flag 11 is automatically cleared each time the calculator is turned on.
Printer Enable Flag
This flag (flag 21) is used to control programs that contain printing functions. You can set, clear end test this flag just like any other of the general of special purpose flags described above.