Overview
ModeldescriptionHP equivalentoriginal priceavail. by HP
DM42 the ultimate calculator based on HP-42S
DM41/DM41LThe alphanumeric 'revolution'.HP-41CX$3251979-90
DM16/DM16Lcomputer programmer's calculatorHP-16C$1501982-89
DM15/DM15Ladvanced scientific calculatorHP-15C$1351982-89
DM12/DM12Lbusiness/financial calculatorHP-12C$1501981-present
DM11/DM11Lmid-range scientific calculatorHP-11C$1351981-89
DM10basic scientific calculatorHP-10C$801982-84

Wikipedia HP-10C series
Wikipedia HP-41C

The small and the large models use the exact same electronic components including the LCD module, therefore the same firmware can be used.

Calculator sizes and weights:
Large model   129mm * 79mm * 13mm : 150gr
Small model   88mm * 59mm * 7mm : 75gr
The Differences to the original HP Calculators
  • these calculators are NOT by HP!
  • they do not have all the bugs found in the HP-15C LE, see that bug list!
  • they run on a battery saving LPC1115 ARM processor emulating the NUT processor
  • they use a single CR2032 battery (220mAh) which should last for many years in OFF-mode (~1.8uA), or several weeks with the display turned on (~120uA), or up to 50 hours continuously RUNNING at 12MHZ(~4mA) or about four times shorter at 48MHz
    in a real test with an endless loop the LCD faded and got dull after ~36h, the CPU still continued.
    the battery seems to recover after some minutes
  • the physical dimensions of the DM calculators are 88mm*59mm*7mm
  • they run up to 30 times faster (at 48MHZ) than the original calculator introduced back in 80'
  • matrix display 132*16 pixels
  • miniUSB-RS232 features a command line interface for saving and restoring complete calculator state.
  • en- and decode utility (html with jscript) to save and restore programs.
  • *** new *** en- and decode tool for DM41/DM41L *** new ***
  • reprogrammable through the miniUSB connection using the SwissMicros Firmware Update Tool
  • LCD operating temp. -10°C to +50°C (The response time will be slow below -20°, and the background will become darker at high temperature operating.)
HP Manuals
DM41/DM41L The DM41 is a clone of the HP-41CX including a real-time clock.

The alphanumeric LCD screen of the HP-41C revolutionized the way a calculator could be used, providing user friendliness (for its time) and expandability (keyboard-unassigned functions could be spelled out alphabetically). By using an alphanumeric display, the calculator could tell the user what was going on: it could display meaningful error messages ('ZERO DIVIDE') instead of simply a blinking zero; it could also specifically prompt the user for arguments ('ENTER RADIUS') instead of just displaying a question mark.

DM16/DM16L The DM16 has a sandblasted Grade 1 Titanium housing.

The DM16 is a computer programmer's calculator, designed to assist in debugging. It can display numbers in hexadecimal, decimal, octal and binary, and convert numbers from one base to another. A number of specialized functions are provided to assist the programmer, including left- and right-shifting, masking, and bitwise logical operations.
DM15/DM15L The DM15 has a sandblasted Grade 1 Titanium housing.

The DM15 is a high-end scientific programmable with a root-solver and numerical integration. It is able to handle complex numbers and matrix operations.

The DM15L and DM15 are shipped with maximum extended memory.
There are three versions of firmware for DM15:

  • DM15 firmware
  • DM15 firmware 'M80' with extended memory
  • DM15 firmware 'M1B' with even more memory

The first one is the same as original HP-15C, so it has exactly the same amount of memory.
M80 and M1B firmware versions contain modified ROMs to enable bigger amount of registers.
The hex number after MEM actually means the memory location where the usable area for registers starts (memory location of NUT CPU).
The memory location of the original HP-15C ROM is at 0xC0; M1B and M80 use 0x1B or 0x80 respectively.

The difference can be seen on calc using [g][MEM].
Note that recent M80 and M1B firmware versions have special display for memory configuration including sizes of matrices.
Initial configurations should be:

DM15 19  46  0-0
DM15_M80 30  99  0-0
DM15_M1B 19  211  0-0

This also gives an idea about number of available memory.
If you accidentally don't know what this means, please, look into HP-15C manual Appendix C - Memory allocation.

Known limitations of the extended memory Firmware:
Solving lin.eq and matrix inversions is limited to matrices with sizes up to 8x8, please see the more detailed explanation by J.Fossy Weinzinger.
Unpredictable things may happen when operating with matrices larger than 8x8, it may even completely block the calculator.
DM12/DM12L The DM12 has a sandblasted Grade 1 Titanium housing available.

The DM12's programming mode is very intuitive and works like a macro operation on a computer. Basically, the keys one would press in the calculating mode to arrive at a solution are entered in the programming mode along with logical operators (if, and, etc.) applicable to the solution. After the programming is complete, the macro will run in computation mode to save the user steps and improve accuracy. There are 99 lines of programmable memory on the HP-12C.
DM11/DM11L The DM11 has a sandblasted Grade 1 Titanium housing.

The DM11 is a mid-range scientific programmable calculator.
DM10 The DM10 is not officially available anymore.

The DM10 is the last and lowest-featured calculator in this line, even though its number would suggest an earlier origin. The 10C was a basic scientific programmable. While a useful general purpose RPN calculator, the HP-11C offered twice as much for only a slight increase in price. Designed to be an introductory calculator, it was still costly compared to the competition, and many looking at an HP would just step up to the better HP-11C. Poor sales led to a very short market life, making it one of the most difficult of the series to find today.