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+-- Forum: Not HP Calculators (/forum-7.html)
+--- Forum: Not quite HP Calculators - but related (/forum-8.html)
+--- Thread: DM 42 (/thread-8366.html)
RE: DM 42 - 48GX - 05-30-2017 12:37 AM
(05-29-2017 11:26 PM)matthiaspaul Wrote:(05-26-2017 12:18 AM)matthiaspaul Wrote: Since the calculator's keyboard area is slightly recessed, it appears to be quite well suited for keyboard overlays in general. Does the case also feature small notches in the rails to the left and right of the keyboard to better afix overlays (like on the HP 48)? If not, that might be a useful tweak to further improve usability.Noone?
What about the power supply? What kind of batteries are needed to power the calculator? Does the calculator also support being powered via USB (I assume yes, but I haven't seen this being mentioned anywere so far)?
The calculator appears to have a size similar to the HP-42S. Does someone know the exact case dimensions already?
Greetings,
Matthias
Hi Matthias,
CR2032 is the battery used to power DM42.
tomorrow will share more pictures.
[attachment=4844]
RE: DM 42 - rprosperi - 05-30-2017 02:21 AM
(05-29-2017 11:26 PM)matthiaspaul Wrote: Noone?
What about the power supply? What kind of batteries are needed to power the calculator? Does the calculator also support being powered via USB (I assume yes, but I haven't seen this being mentioned anywere so far)?
The calculator appears to have a size similar to the HP-42S. Does someone know the exact case dimensions already?
There are 3 slots on both sides of the keyboard to retain an overlay, quite similar to the 48 series.
Battery = 1 x 2032
When connected to USB, the clock speed increases, which certainly implies USB-supplied power, but can't prove it yet.
143mm x 76mm x 12mm
RE: DM 42 - grsbanks - 05-30-2017 10:31 AM
(05-30-2017 02:21 AM)rprosperi Wrote: When connected to USB, the clock speed increases, which certainly implies USB-supplied power, but can't prove it yet.
I can confirm that the DM42 does indeed draw power from USB when connected. It only needs the physical connection. The device does not need to be in bootloader mode or in USB storage mode for it to draw power.
If you look at the voltage reading at the top-right of the screen, it goes up by 0.10-0.15V when the unit is connected to a USB port.
RE: DM 42 - matthiaspaul - 05-30-2017 10:45 AM
Thank you all. I've added the info to the WP article.
Speaking of clock frequency, somewhere I read the calculator runs at 27 MHz, however, from your description above it appears to be clocked dynamically depending on battery state. If the processor is actually a STM32L476RG, it would support up to 80 MHz in theory. So, does it run at 80 MHz with USB plugged in?
The processor comes with 128 KB RAM. How much of it is available to users?
Greetings,
Matthias
RE: DM 42 - Massimo Gnerucci - 05-30-2017 11:37 AM
(05-30-2017 10:45 AM)matthiaspaul Wrote: Thank you all. I've added the info to the WP article.
Speaking of clock frequency, somewhere I read the calculator runs at 27 MHz, however, from your description above it appears to be clocked dynamically depending on battery state. If the processor is actually a STM32L476RG, it would support up to 80 MHz in theory. So, does it run at 80 MHz with USB plugged in?
The processor comes with 128 KB RAM. How much of it is available to users?
Greetings,
Matthias
Yes, 80 is the reading shown.
RE: DM 42 - Guenter Schink - 05-30-2017 12:24 PM
(05-30-2017 10:45 AM)matthiaspaul Wrote: Thank you all. I've added the info to the WP article.
Speaking of clock frequency, somewhere I read the calculator runs at 27 MHz, however, from your description above it appears to be clocked dynamically depending on battery state. If the processor is actually a STM32L476RG, it would support up to 80 MHz in theory. So, does it run at 80 MHz with USB plugged in?
The processor comes with 128 KB RAM. How much of it is available to users?
Greetings,
Matthias
Some specs:
Dimension (mm). 144x77x6.5-13
Weight: 170gr
Processor speed 24MHz on battery, 80 MHz on USB power
RAM available on clean machine with only "REGS" allocated 78748 Bytes
Key features beyond HP42S achieved so far:
- Flash memory available to store and retrieve programs (total flash is 9MByte, about 1.5 MByte used by math library. How much available for the user is unknown for now)
- Save state to flash and retrieve
- Show stack registers on screen
- Alpha characters on faceplate
- enable access to numbers in alpha mode also functions like AStO ARCL
- enable infrared printing or printing to screen (or both?)
- include recent update of Free42 (handling of pseudo complex numbers corrected)
Edit: Corrected 27MHz to 24MHz
RE: DM 42 - Thomas Okken - 05-30-2017 12:50 PM
(05-30-2017 12:24 PM)Guenter Schink Wrote: include recent update of Free42 (handling of pseudo complex numbers corrected)
By "pseudo complex," I assume you meant "complex with zero real and/or imaginary part"?
I don't think "pseudo complex" is a commonly used mathematical term.
RE: DM 42 - Ángel Martin - 05-30-2017 04:44 PM
(05-30-2017 12:50 PM)Thomas Okken Wrote:(05-30-2017 12:24 PM)Guenter Schink Wrote: include recent update of Free42 (handling of pseudo complex numbers corrected)
By "pseudo complex," I assume you meant "complex with zero real and/or imaginary part"?
I don't think "pseudo complex" is a commonly used mathematical term.
Can't resist: there's nothing pseudo in complex numbers with zero in one of their real parts. For what is worth, all real numbers are also complex ;-)
Çheers,
ÁM
RE: DM 42 - Guenter Schink - 05-30-2017 06:48 PM
(05-30-2017 04:44 PM)Ángel Martin Wrote:Yes you and Thomas are right, as plain real numbers are just a subset of complex numbers. But for good, and practical, reasons the calculator distinguishes between real and complex numbers. And here I had the impression that you see a difference between "1" and "1+0*i". Both are identical complex numbers, only with different notation, having only a real part, but no imaginary. Therefore I used, wrongly I admit, the term "pseudo complex" to emphasize that the latter notation is a real number in complex notation.(05-30-2017 12:50 PM)Thomas Okken Wrote: By "pseudo complex," I assume you meant "complex with zero real and/or imaginary part"?
I don't think "pseudo complex" is a commonly used mathematical term.
Can't resist: there's nothing pseudo in complex numbers with zero in one of their real parts. For what is worth, all real numbers are also complex ;-)
Çheers,
ÁM
Günter
RE: DM 42 - Ángel Martin - 05-30-2017 07:47 PM
(05-30-2017 06:48 PM)Guenter Schink Wrote:(05-30-2017 04:44 PM)Ángel Martin Wrote: Can't resist: there's nothing pseudo in complex numbers with zero in one of their real parts. For what is worth, all real numbers are also complex ;-)Yes you and Thomas are right, as plain real numbers are just a subset of complex numbers. But for good, and practical, reasons the calculator distinguishes between real and complex numbers. And here I had the impression that you see a difference between "1" and "1+0*i". Both are identical complex numbers, only with different notation, having only a real part, but no imaginary. Therefore I used, wrongly I admit, the term "pseudo complex" to emphasize that the latter notation is a real number in complex notation.
Çheers,
ÁM
Günter
You're completely right about the practical purposes, and a calculator is meant to be very practical ;-)
RE: DM 42 - David Hayden - 02-10-2018 08:51 PM
This may be an embarrassing question but how do you change the battery in the DM42? I didn't see anything about it in the manual and there is no battery door. I found a picture that shows the CR2032 on the inside. So do you have to remove the screws and separate the case to change the battery?
RE: DM 42 - Logan - 02-10-2018 09:47 PM
That's correct. The four screws come out easily and you'll see the battery, which can slide out from its slot. You might need something non-conductive to push it out of its holder.
Battery seems to last for a good long while though.
RE: DM 42 - Guenter Schink - 02-10-2018 11:18 PM
(02-10-2018 09:47 PM)Logan Wrote: That's correct. The four screws come out easily and you'll see the battery, which can slide out from its slot. You might need something non-conductive to push it out of its holder.
Battery seems to last for a good long while though.
Two screws only
Günter