Flags used by HP-82182A Time Module

[Joe Horn]

Sorry, the state of CLK12/CLK24 and CLKT/CLKTD are not stored in user-accessible flags. The CLK12/CLK24 status can be determined in a program if you have a CX (or an X Function module) in many ways, including this:

CLA CLX ATIME ANUM
--> 12 = CLK12
--> 0 = CLK24

Determining the CLKT/CLKTD status is left as an exercise for the student, because I can't think of any way of doing it.

Including the 3 flags you already mentioned, flags 12-20 are allocated for "External device control". All are cleared each time the HP-41 is turned on. "The precise meaning of these flags depends on the particular devices that are present; refer to the appropriate manuals for details." [HP-41CX Owner's Manual Volume 2, pages 289-293]

For example, flags 15-16 control the IL printer's print mode (00=MAN, 01=NORM, 10=TRACE, 11=TR/STACK) [gleaned from Jeremy Smith's "HP-41 Synthetic Quick Reference Guide"].

Flag 11 is normally used for auto-execution at turn-on, but it can also be used by the card reader. If a program is recorded while flag 11 is set, then it will be automatically run (starting at line 1) when read by the card reader. [Card Reader Owner's Handbook, page 20-21]

Flag 17 is labeled as "(CR) record incomplete" in Jeremy's QRG. I assume CR means Card Reader, but I am not sure what "record incomplete" means.

Flag 18 is labeled as "enable TINTR" in Jeremy's QRG. I have no idea what that means. Timer Interrupt maybe?

If flags 19 and/or 20 are used by any other peripherals, you'll have to see their respective manuals for details (or read the postings below by other inveterate HP calculator enthusiasts).

Flag 53 is labeled as "I/O" in Jeremy's QRG. So I guess that has something to do with peripherals too?

Flag 55 of course is the "Printer existence" flag, which is mentioned in every flag list. There's also an entire appendix in the 41-CX manual (page 368-369) that discusses how to use fags 21 and 55 to control program execution and display.