I found that using some of the Advantage Pac programs (e.g. MATRX or CFIT) would lead to AVIEW instructions in programs run subsequently to cause a HALT - requiring use of the R/S key.

I was told via a question on the Swiss Micros Forum that this was likely to be due to the Advantage Pac setting FLAG 21 (printer active) to help in its own presentation of information on the display.

FLAG 21 SET while FLAG 55 is CLEAR (since there's no Printer Module active) causes AVIEW instructions to halt awaiting user intervention (R/S key)

To restore things to normal : either CLEAR Flag 21 via CF or simply turn the calculator off and on again.

See APPENDIX D in the HP41CX User Manual Volume 2 for a better explanation of the use of Flag 21 to control AVIEW behaviour.

Copy a program to Extended Memory:

• Put Prog's name in Alpha register
• XEQ storep
• The prog remains in main memory but can be deleted (CLP) if memory needed
• To restore to main memory put name in Alpha and then XEQ GETSUB

To find the number of days between two dates

• enter 1^st date into Y-stack as dd.mmyyyy
• key in 2^nd date into X-stack as dd.mmyyyy
• XEQ ALPHA D D A Y S ALPHA
• result is the difference in days.
• DDAYS can be added to the CST program chooser to make it easier if multiple calculations are required

Days between 27/2/66 and 31/5/22

27.021966 ENTER 31.052022 XEQ ALPHA D D A Y S ALPHA

Result = 20,547

Check :

365 ÷

Result 56.293

I'm 56 and a bit… sounds right…

Various Alarm functions

Put any message for the Alarm into the ALHPA register

Load the stack registers with:

• Z : Repeat Interval HHHH.MMSSs or 0
• Y : Date DD.MMYYYY or 0
• X : Time HH.MMSSs

Execute XYZALM to set the alarm

When alarm goes off it is acknowledged by pressing any key except STO.

• Acknowledging a non-repeating (i.e. Z was 0) alarm cancels it.
• Acknowledging a repeating alarm cancels it and re-arms it, adding the Repeat Interval to create the new alarm time.
• Pressing STO cancels the alarm but makes it a PAST DUE alarm.

Set alarm for 22:20, today, not repeating, called Supper

• ALPHA S U P PER ALPHA
• 0 ENTER (for Z = repeat interval)
• 0 ENTER (for Y = Date = Today)
• 22.20 XEQ ALPHA X Y Z A L M ALPHA

At 22:20 the alarm is activated. ALPHA shows SUPPER.

Alarm is cancelled by pressing any key but STO

Pressing STO creates a PAST DUE alarm which means it gets re-triggered if the calculator is turned off. It can be cancelled and deleted by pressing any key (except STO) and then the calculator will turn off. Pressing STO will create a new Past Due alarm, and allow the calculator to turn off. On turn on the Past Due alarm will still exist and turning off will trigger it again.

A Past Due alarm is useful to remind you that something happened previously and turning the calculator off is a memory-jogger.

CATALOGUE 5 R/S and ⇑ ⇓ steps through all alarms.

To clear an alarm from the Catalogue: SHIFT C ( where C is √ on top row )

— John Pumford-Green 31/05/22 13:13

Page last updated: 04/08/24 21:19 BST