A bug of the HP-15C Collector's Edition running in HP-16C mode?

[fvogel]

Just discovered what seems to be a bug of the HP-15C Collector's Edition running in HP-16C NOMAS mode. Steps:

1. Enter the 16C hidden mode (From the OFF state, push g and ENTER and then ON ; hit 4 and then 7)

2. Hit a key to erase the "Pr Error" message. Then hit, say, 8

3. Hit f and SHOW BIN (for instance, or OCT, or ...) to display the current value in BIN temporarily.

4. Before the end of the temporary display, hit a key, say 2

-> The calculator is totally frozen

Only the reset button (or battery removal) brings it back in a working state.

Anyone else seeing this? Any fix available perhaps?

Thanks!

[rprosperi]

Thanks for reporting this.

It is known that the 15c CE's NOMAS 16C mode [f]+[BASE] display modes are not correct (the display should stay on as long as you hold down the [BASE] key) and this behavior you're reporting is really a side-effect of that core problem, but detailing it this way is useful to let folks know to not press another key so quickly and thus avoid having to reset. So, thanks!

[Valentin Albillo]

.
Hi,

This post (#3 in the thread) by brouhaha mentions the probable cause of most (if not all) display problems.

Seems to be a hardware problem so perhaps not fixable by firmware updates ?

V.

[Voldemar]

Let's try this:
Default mode (or 15.2 mode)
Press [f]
Press and hold [<-] PREFIX
Press any digit key

[brouhaha]

(03-09-2024 04:00 PM)Valentin Albillo Wrote:  Seems to be a hardware problem so perhaps not fixable by firmware updates ?

Hi V.!

I'm reasonably sure that it's a problem with the SIMULATED hardware, not the physical hardware, so it should be correctable in the simulation code that's running on the ARM core. Alas, since I don't have access to the source code of the simulator running on the ARM, and don't want to spend a lot of time reverse-engineering it, I don't know exactly how it's going off the rails nor how to fix it.

In the past Cyrille has solved similar problems in the 12C and and 15C, and I've occasionally been able to offer him a little advice, but it remains unclear as to whether there will ever be a firmware update for the 15C CE that might include fixes to the undocumented and unsupported 16C mode.

[fvogel]

(03-09-2024 09:57 PM)Voldemar Wrote:  Let's try this:
Default mode (or 15.2 mode)
Press [f]
Press and hold [<-] PREFIX
Press any digit key

--> The display showing the digit that got hit during the last step flashes. This looks indeed like another display bug.

At least it has no adverse impact because hitting another key restores normal working.

[rjwalker]

Just tried out HP-16C mode on my new HP-15C and immediately, accidentally encountered the "f SHOW BIN" issue. (It was "f SHOW HEX" in my case.) Thank you to fvogel for reporting so that I know what I did and what to avoid in future; I confirm that the problem persists with firmware 2024-06-03. Any more news?

Richard.

[AnnoyedOne]

I just tried this in my original (1985) HP-16C and no problem.

So the bug is probably a "race condition" in the emulator code and therefore fixable. In the meantime "don't do that".

A1

[rjwalker]

(Continuing with the HP-15C CE in HP-16C mode ...)

I'm working through the HP-16C manual and trying everything out. On page 20 there are instructions for "Resetting Continuous Memory" using a combination of the "ON" and "-" keys:

1. Turn the calculator off.
2. Press and hold "ON", then press and hold "-".
3. Release "ON", then "-".
   

This doesn't seem to work for me; it's equivalent just to pressing "ON" then "-" in sequence. It doesn't reset the base to HEX, or clear the stack or the program memory.

Not a problem per se, as there are other ways to do a reset (e.g., switch to HP-15C mode and back again).

I then tried the key sequence in reverse: with the calculator off, press and hold "-", then press "ON". Uh-oh. The calculator stays off, and won't come on despite repeated presses of the "ON" key. I had to open the back and press the RESET button.

[ThomasF]

(09-09-2024 12:02 AM)rjwalker Wrote:  (Continuing with the HP-15C CE in HP-16C mode ...)

I'm working through the HP-16C manual and trying everything out. On page 20 there are instructions for "Resetting Continuous Memory" using a combination of the "ON" and "-" keys:

Hi,

It has been mentioned several times here on the forum before regarding the hidden calculator modes of the 15CE, that none of the [ON]/[x] commands work in the other calculator modes.

Cheers,
Thomas

[RPNerd]

(09-09-2024 04:53 AM)ThomasF Wrote:  It has been mentioned several times here on the forum before regarding the hidden calculator modes of the 15CE, that none of the [ON]/[x] commands work in the other calculator modes.

Furthermore, HP-16C mode is provided NOMAS (NO MAnufacturer Support) so don't expect this to be "fixed". This is made clear here: https://www.hpmuseum.org/forum/thread-20262.html