HP48 Shortcut Keys

[Steve Simpkin]

Official HP48 FAQ
https://www.hpcalc.org/hp48/docs/faq/48faq.html

What are all the different ON-KEY combinations?
https://www.hpcalc.org/hp48/docs/faq/48faq-4.html#ss4.6

From: Dave Arnett

ON

In most cases, this will move you to, or toward, the stack environment.

ON+A+F

This is the manual Coldstart. It will break out of almost any hung program, and offer you the dreaded option... "Try to recover memory?" Note that this is your next-to-last resort in a lock-up, so don't give your machine this three-fingered salute unless you really want to possibly clear memory.

ON+B

This is the Oops! key for ON codes. For many ON sequences, this cancels the operation, so long as you press the B before releasing the ON key. Try it sometime, if you must, just so you remember it. It can be a life-saver, in case of an accidental ON+A+F in process, or even accidentally hitting ON during a plotting routine.

ON+C

This will initiate a Warmstart. You'll lose the stack and PICT, but it will often get you out of a locked up program with memory intact.

ON+D

Enters interactive test mode. Back up your own machine and play around. Exit this test mode with Warmstart, ON+C. See the next question for all the various tests available here.

ON+E

Starts a looping self-test mode. Kinda dull after the first five minutes, but it keeps a rather solid tempo. Exit with Warmstart, ON+C.

ON+4

Cancels repeating alarms.

ON+1

Screen dump utility.

ON+'+' and ON+'-'

Adjusts display contrast.

ON+SPC

Initiates Coma Mode and clears Warm Start Log. In Coma mode, all the clocked activity is halted. The battery power drain is basically the few nano-amps [nA] necessary to sustain your RAM contents. The Warm Start Log is a nearly bullet-proof area of memory which keeps track of the last four hazardous events. View it using the command WSLOG. This log is one of the few things not cleared by a Coldstart. But it is cleared by ON+SPC. Enter Coma this way if you want to clear the Warm Start Log, if you are planning to study crystal healing in Tibet for a few years and want to keep your pirated version of Tetris alive, or you just have a low power fetish. Exit Coma mode with the ON key (tough to remember, huh?), and plan to find your stack cleared out.

Two additional notes on this Coma stuff. First, I'm not gonna try to list the log codes in WSLOG. Sorry! Second, if your machine is on, and you drop the batteries out, you will usually end up in a coma mode to preserve power. WSLOG will not be cleared. Instead, you will find a code 1 entry there. Some people are paranoid and want to be in Coma when they change batteries, just in case they have a sudden emergency call from the Prime Minister and don't get back to their battery change for a half hour. If you are one of these... shall I say, weenies? No, that would be unprofessional ...users, then I recommend you use the ON+SPC entry route, rather than the kamikaze method of dropping batteries with the machine running. Myself, I just turn the machine OFF, like the manual says.

Now, a Coma story... sort of. During the G/GX development, I maintained a small number of units on which I changed ROM chips as incremental code releases came out. This was so folks like Bill Wickes and Jim Donnelly could have fully-real hardware to test, instead of just the EPROM handsets some of you may have seen. We always backed up anything of importance in the machine before we did this. But I got into the habit of using ON+SPC before I opened up the calculator. Better than half of the time, I could remove the batteries, open the case, desolder the old surface-mounted ROM chip, solder down a new chip, and reassemble the machine... with all of RAM intact! When I pressed ON, I'd come right back up without a "Try to Recover Memory?" prompt. Pretty good, huh? The folks who put that mode into the machine certainly weren't in a coma.