HP Prime Screen Dimming Hack

[JDW]

While Googling this issue of Screen Dimming, I found Joe Horn's reply, saying it cannot be done without using the USB cable. The problem is that I want to shoot photos of the Prime without the USB cable attached and without having to press a button every 25 seconds or so to keep the screen alive. Simply pressing a button to reset the dimming timer is a problem because the button press shifts the calculator position slightly, and fingerprints can get on the calculator that way too.

With all of the amazing things this calculator can do, especially through programs and apps, surely there must be some hack to keep the screen at full illumination either indefinitely (until the battery drains) or at least keep in on at full brightness for several minutes.

Tim Wessman, any good ideas?

Thank you!

[Tim Wessman]

Use the new TDim variable as of last release.

[JDW]

(09-01-2018 01:47 AM)Tim Wessman Wrote:  Use the new TDim variable as of last release.

How do we use TDim?

When I type TDim and press Enter, the following appears:

#7530:30h

[Carlos295pz]

For example for 60 seconds:
TDim:=60*1000
TDim is defined in milliseconds

[JDW]

Thank you, but I need more hand-holding. I am in RPN mode. I put 3000 on the stack (3 seconds), then I put 'TDim' on the stack. Then I pressed Blue-Shift & EEX (for "Sto") but I get this error:



And when I true to use sto(), I also get an error:



Could you please provide precise steps?

[Carlos295pz]

For now the minimum value is 5000

[JDW]

Thank you for the tip about the 5 second minimum. And thank you, Tim, for initially alerting me to this great new feature.

For those of you who hate guesswork and love PRECISE STEPS like I do, the follow example shows how to use 5000 (5 seconds) for display dimming while in RPN mode:

1. Type 5000 and press Enter
2. Press Blue-Shift and then the ( ) key (to get single quotes ' ')
3. Press Vars
4. Press 7
5. Press 7 again (you should then see 'TDim')
6. Press Enter
7. Press Blue-Shift
8. Press EEX (for Sto)
9. Turn Prime OFF & ON, then wait 5 seconds and see the screen dim.

Now when you press the Vars key and then 7 and 7 and Enter, you should that the content of the TDim variable is this:

#1388:30h

By default the Prime dims after 30 seconds, and the contents of the TDim variable in that case is this:

#7530:30h

I don't know the maximum backlight duration (there obviously is a maximum if there is a minimum), but I can confirm that a setting of 5 minutes (300000) works fine. And note that if you use 5 minutes, the screen will not DIM at that point but instead the Prime will power OFF.

[Joe Horn]

(09-01-2018 03:02 AM)JDW Wrote:  And note that if you use 5 minutes [as your setting for 'TDim'], the screen will not DIM at that point but instead the Prime will power OFF.

That depends on the value of TOff. The default is 5 minutes, but it is user-settable just like TDim.

In case it isn't obvious, highlighting any variable in the Vars/Settings or Vars/System menus, and then pressing Help, displays useful information about that variable.

[JDW]

When we type TDim and press Enter, a number formatted as follows appears:

#7530:30h

The #7530 is a hex number that sets the timer duration, which I fully understand. What is the ":30" at the end?

[Joe Horn]

(09-06-2018 01:36 AM)JDW Wrote:  When we type TDim and press Enter, a number formatted as follows appears:

#7530:30h

The #7530 is a hex number that sets the timer duration, which I fully understand. What is the ":30" at the end?

It means that its wordsize is 30 bits. Operations on it will be limited to 30 bits (try NOT on it) unless you specify otherwise. More info in Chapter 30 ("Basic integer arithmetic") in your HP Prime User Guide.

[JDW]

Joe, the top of page 582 in the HP Prime User Guide says the default wordsize is 32. I just checked my Home "Settings" and confirmed that it is 32. Why then is "30" the wordsize for TDim? (I am just curious.)

[Joe Horn]

(09-06-2018 01:52 AM)JDW Wrote:  Joe, the top of page 582 in the HP Prime User Guide says the default wordsize is 32. I just checked my Home "Settings" and confirmed that it is 32. Why then is "30" the wordsize for TDim? (I am just curious.)

MY GUESS: It's permanently fixed at 30 bits because otherwise it would be at the mercy of the 'Bits' system variable, which would be disastrous if 'Bits' were very small, thereby causing instant dimming. Why they wanted to let the user specify up to (2^30-1)/1000 seconds before dimming, I don't know, but allocating more bits than that would clearly have been silly, so they capped it at 30 bits.

Disclaimer: Tim and Cyrille know the answer. I'm just guessing here.

EDIT: Wild second guess: Maybe the real-time clock's system-interrupt word is 30 bits wide?

[rprosperi]

(09-06-2018 01:52 AM)JDW Wrote:  Joe, the top of page 582 in the HP Prime User Guide says the default wordsize is 32. I just checked my Home "Settings" and confirmed that it is 32. Why then is "30" the wordsize for TDim? (I am just curious.)

32-bits is the default wordsize of user variables you create and manipulate, which does not affect system variables, otherwise if you set something stupid (by mistake) you could kill the whole system.

Also, I think you don't have the latest User guide; Chapter 30 in the latest copy (Jan '18) starts on page 696. You can get the latest from the ftp site Tim lists whenever a new version is released, holler if you can't find it.

[JDW]

(09-06-2018 02:27 AM)rprosperi Wrote:  ...I think you don't have the latest User guide... You can get the latest from the ftp site Tim lists whenever a new version is released, holler if you can't find it.

Here's the official HP Prime User Guide download page. Why are there 2 versions of the guide posted there?

HP Prime Graphing Calculator, 3rd Edition, Dec. 2017, 813269-003

HP Prime Graphing Calculator, 2nd Edition, Sep. 2016, 813269-002

If there is a 4th edition dated 2018, shouldn't it be on that official download page?

[CyberAngel]

(09-06-2018 01:43 AM)Joe Horn Wrote:  

(09-06-2018 01:36 AM)JDW Wrote:  When we type TDim and press Enter, a number formatted as follows appears:

#7530:30h

The #7530 is a hex number that sets the timer duration, which I fully understand. What is the ":30" at the end?

It means that its wordsize is 30 bits. Operations on it will be limited to 30 bits (try NOT on it) unless you specify otherwise. More info in Chapter 30 ("Basic integer arithmetic") in your HP Prime User Guide.

Hey, Joe!
Try entering that in the CAS
You can also use
[Menu] the Copy from Home
select that example and press [Enter]

[rprosperi]

(09-06-2018 02:41 AM)JDW Wrote:  

(09-06-2018 02:27 AM)rprosperi Wrote:  ...I think you don't have the latest User guide... You can get the latest from the ftp site Tim lists whenever a new version is released, holler if you can't find it.

Here's the official HP Prime User Guide download page. Why are there 2 versions of the guide posted there?

HP Prime Graphing Calculator, 3rd Edition, Dec. 2017, 813269-003

HP Prime Graphing Calculator, 2nd Edition, Sep. 2016, 813269-002

If there is a 4th edition dated 2018, shouldn't it be on that official download page?

The "January" edition I mentioned is the 3rd Edition you reference here. It was copyrighted in Dec 2017, but actually released in Jan 2018, hence the informal version name used above.

When new items are released and announced here by Tim, they are available immediately on the ftp site. It takes a while for the 'official' support website pages to be updated, so many folks here have the latest version before it appears there.

The reason no one posts true links to the ftp site here is the mybb s/w mangles the url (converts the ftp:// prefix into an http:// prefix) resulting in links that don't work.

The actual url is "ftp://ftp.hp.com/pub/calculators/Prime/Documentation/Calculator/EN/"

I can't speak for HP, but back versions may be listed here (as well as many sites) as often folks like to have all versions, compare what has changed, etc.

[JDW]

(09-06-2018 01:35 PM)rprosperi Wrote:  

Code:

ftp://ftp.hp.com/pub/calculators/Prime/Documentation/Calculator/EN/

Thank you!


I made a short video on Screen Dimming here, with thanks to Tim, Carlos and Joe in the text Description:

[Geoff]

I find the default dimming a bit short so it's nice that I can increase it to suit, but not sure how I would know this feature is available.

I have the 3rd Edition manual, but can't find TDim documented. I would have guessed it would be on page 694 with TOff.

Where can this info be found?

Geoff

[Didier Lachieze]

TDim is not yet in the manual because it has been added in the latest firmware revision last July as mentionned in the release notes (you can also find on your PC the release notes of the latest firmware loaded on your Prime under: Documents\HP Connectivity Kit\Firmware\PrimeG1 (or Prime G2) ).

You can find more details about TDim with the on-calc help: look into Vars > Home > System > TDim , long press on TDim to select it and press then the Help key.