John's Vademecum - public:calculator:3rd

Desk15 - firmware for the DM15

anonymous@undisclosed.example.com (Anonymous) — Tue, 17 Feb 2026 20:45:30 +0000

Desk15 - firmware for the DM15

From HP Forum https://www.hpmuseum.org/forum/thread-23488.html
You Tube https://youtu.be/ktrKZzN3wJw
Github for firmware and brief README guide https://github.com/zooxo/desk15

Firmware Files

Date	Firmware	Comment
17/02/26	desk15-001.hex	Version 01

README

The developer's README (click to read)

This software is protected by the BSD 3 Clause Licence
and copyright (c) 2025 by deetee. All rights reserved.


DESK15 - Calculator suite (including a Spreadsheet) for the DM-15

____________________

PREAMBLE
____________________

The HP-15c was probably the most simple but versatile scientific calculator.
Similar to DESK42 (for the DM42) DESK15 offers an alternative firmware for the
DM15/DM15L replica of Swissmicros with a suite of some applications like a
complex number calculator, a spreadsheet, a symbolic, a tabletop calculator
and even a sliderule and a simple text editor.

Have fun!
deetee


____________________

INSTALLATION
____________________

To install a new firmware to a DM-15 (Voyager) calculator have a look at
chapter Firmware Update of the Swissmicros Voyager Series User Manual at:
  https://technical.swissmicros.com/voyager/firmware/

On linux computers for example install the package lpc21isp and flash the
desired firmware (hex file) to the calculator with:
  sudo lpc21isp <firmware.hex> /dev/ttyUSB0 115200 12000

After starting this command press the reset button on the backside of the
calculator with a paperclip. After the flashing procedure ends you might need to
reset the calculator again. Every Swissmicros-Calculator has a reset button
on the PCB (even if there is no hole to reach it).


____________________

DESK
____________________

When you start DESK15 the first time you see the application launcher DESK. You
can launch the desired application with the keys 7, 8, 9 and 4, 5, 6:

  7 PLEX ... Complex Number Calculator
  8 FLEX ... Symbolic Calculator
  9 RAX  ... Spreadsheet
  4 TTOP ... Table Top Calculator
  5 RULE ... Slide Rule Simulation
  6 TEX  ... Text Editor

On the right side of the screen you see some extra information like the battery
level, date (day) and time (24 hour format).

Please note that the battery level is a momentarily value that varies due to the
momentarily activity of the calculator. But if you see the empty battery symbol
quite often you might consider changing the battery.

____________________

PLEX
____________________

PLEX is a scientific calculator generically designed to work with complex
numbers. Many routines of PLEX are used by other applications (even if they work
with real numbers only). Beside advanced mathematic functions it even offers an
extensive function analysis (function value, slope, solve, integrate and plot).

PLEX supports the following functions:
  Basic
    0-9.      Number input
    ENTER     Enter number (stack lift) or duplicate TOS
    + - * /   Basic operation
    CHS       Negate TOS (ends number input)
    EEX       Push Y*10^X to the stack
    BSP gBSP  Clear number entry or TOS, clear stack and statistics data
    LASTx     Push last ENTERed number to stack
    SWAP      Swap X and Y
    ROT up/dn Rotate 3 stack elements
    STO RCL   Store TOS or push stored number to stack (store 0 to delete)
  Complex number operations
    fTAN      Convert X and Y (real values) to complex number (and vice versa)
    f1 g1     Display number in rectangular or polar view
    f-        Swap real and imaginary part of complex number
    fCHS      Conjugate complex number
  Advanced mathematics
    SQRT, SQR, EXP, LN, 10^X, LOG, Y^X, %, 1/X, delta%,
    FRAC, INT, ABS, PI, Pxy, Cxy, lnGAMMA (f0),
    SIN, COS, TAN, aSIN, aCOS, aTAN, SINH, COSH, TANH, aSINH, aCOSH, aTANH
    fENTER    NAND ~(X & Y) ... useful in HEX mode
    g-        Calculate 2 roots of quadratic equation xx+px+q=0 (enter p q)
    fCOS      PV (present value) of interest rate (%) and duration (periods)
  Statistics
    SUM+ SUM- Add/remove number to/from statistics registers
    g0 g.     Mean value and standard deviation
    fSUM      Parameters a and b of linear regression (y=a*x+b)
    gBSP      Clears statistics registers (and stack)
  Function analysis
    gR/S      Start key recorder to input f(x) (gR/S R/S to delete)
    R/S       Stop key recorder, calculate y=f(x)
    fg/ fg*   Solve, slope, integrate, plot
    GSB 8/9   SAVE/LOAD a recorded function to/from one of 6 slots
  Conversions
    fg7 8 9   cm<>in, km<>mi, km<>nmi
    fg4 5 6   kg<>lbs, °C<>°F, l<>gal
    fg1 2 3   rect/polar view, h<>h.ms, deg<>rad
  Menu
    GSB       QUIT, SAVE/LOAD, Physical Constant, Size of font, HEX mode
    fGSB      BATTERY, set LCD brightness/voltage, set OFFTIME
    gGSB      Get/set DATE, get/set TIME

    Please note:
    When in HEX mode enter numbers >9 with a dot (ie .1=a, .6=f).
    To set the OFFTIME (default is 60s) enter the desired value (5-300) in
    seconds to the stack and press Toff (fGSB6).
    Be careful when setting the lcd brightness (fGSB4, 0-64) or lcd voltage
    (fGSB5, 0-5-7). The default values are 0 and 5.
    Get/set date and time from/to the real time clock (RTC) with the gGSB menu.
    The format for the date on the stack is YY.MMDDw (where w is the number of
    the weekday (0=Monday). The format for the time is HH.MM.

  Physical constants keys (GSB4):
    ENTER     Select (push) constant
    2 8 3 9   Down, Up, PgDown, PgUp
    GSB       Quit (without selecting)

  Physical constants;
    0  c    299792458         Speed of light
    1  g    9.80665           Acceleration of gravity
    2  G    6.67430e-11       Newton constant of gravity
    3  Vm   0.02271095464     Molar volume of ideal gas
    4  NA   6.02214076e23     Avogadro constant
    5  Rinf 10973731.568160   Rydberg constant
    6  h    6.62607015e-34    Planck constant
    7  Phi0 2.067833848e-15   Magnetic flux quantum
    8  a0   5.29177210903e-11 Bohr radius
    9  k    1.380649e-23      Boltzmann constant
    10 R    8.314462618       Molar gas constant
    11 F    96485.33212       Faraday constant
    12 t    273.15            Celsius temperature
    13 atm  101325            Standard atmosphere
    14 e    1.602176634e-19   Elementary charge
    15 eps0 8.8541878128e-12  Vacuum electric permittivity
    16 mu0  1.25663706212e-6  Vacuum magnetic permeability
    17 Z0   376.730313668     Impedance of vacuum
    18 mU   1.6605390666e-27  Atomic mass constant
    19 re   2.8179403262e-15  Electron radius
    20 me   9.1093837015e-31  Electron mass
    21 mp   1.67262192369e-27 Proton mass
    22 mn   1.67492749804e-27 Neutron mass
    23 mmu  1.883531627e-28   Muon mass
    24 muB  9.2740100783e-24  Bohr magneton
    25 muN  5.0507837461e-27  Nuclear magneton
    26 mue  -9.2847647043e-24 Electron magnetic moment
    27 mup  1.41060679736e-26 Proton magnetic moment
    28 mun  -9.6623651e-27    Neutron magnetic moment
    29 mumu -4.4904483e-26    Muon magnetic moment
    30 alph 7.2973525693e-3   Fine structure constant
    31 sigm 5.670374419e-8    Stefan-Boltzmann constant
    32 G0   7.748091729       Conductance quantum
    33 gamp 2.6752218744e8    Proton gyromagnetic ratio
    34 C1   3.741771852e-16   First radiation constant
    35 C2   1.438776877e-2    Second radiation constant


____________________

RAX
____________________

RAX is the spreadsheet application of DESK15. When starting RAX you are in the
navigation mode, where the number keys work as cursor pad (see below). The
navigation mode is also active when you refer in a formula to a specific cell.

Keys in navigation mode:
  2 4 6 8  Navigation (Down/Left/Right/Up)
  ENTER 5  Edit selected cell, edit new formula cell
  R/S      Define and edit a new text cell
  BSP      Delete cell
  STO RCL  Save/load spreadsheet to/from one of 6 slots
           Please note that a text in the last cell (D8) is used as slot name.
  GSB      Menu: Quit RAX, New sheet, Copy&Glue/Paste, Hex mode (see PLEX)

Keys in edit mode (ENTER to select and quit):
  SST GTO        Cursor left/right
  SUM+           Insert a stack enter command to separate numbers
  BSP            Backspace - delete character
  RCL            Reference (Select reference cell and enter)
  ENTER GSB R/S  Quit edit mode to navigation mode

Keys in text edit mode (R/S):
  2 4 6 8    Navigation (Down/Left/Right/Up)
  7 1 5      Pos1, End, Center
  SST GTO    Cursor left/right
  BSP        Delete character (left of cursor)
  R/S ENTER  Exit text editing mode
  Any other key inserts the selected character.


____________________

FLEX
____________________

The symbolic calculator FLEX has the look and feel of PLEX, but actually
calculates in the first cell of a RAX spreadsheet. Hence you can see and edit
(with R/S) the formula that yields to the result.

Quit FLEX (and go back to the DESK menu) with GSB.

____________________

TTOP
____________________

TTOP is a tabletop calculator that enables (simple) calculations with big
numbers (even in HEX format) with up to 17 digits. If desired two digits are
used for decimals (ie for cent amounts). PLease note that entering decimals
(after pressing ".") always "shifts the pressed number key in".

TTOP supports the following functions:
  + - * / Basic operation
  CHS     Negate TOS (ends number input)
  EEX     Push Y*10^X to the stack (Y*16^X in HEX mode)
  ENTER   Enter number (stack lift) or duplicate TOS
  SWAP    Swap X and Y
  ROT     Rotate 3 stack elements
  BSP     Clear last number
  SQRT    Calculate square root
  SUM+    NAND ~(X & Y) ... useful in HEX mode
  STO RCL Store TOS or push stored number to stack (store 0 to delete)
  GSB     Menu: Quit TTOP, 0/2 decimals, HEX mode


____________________

RULE
____________________

RULE is a simulation of a historic slide rule for reasons of education and
reminiscence.

RULE supports the following functions:
  SQRT /   Slide one pixel left/right
  EXP 9    Slide 5 pixel left/right
  POW10 8  Slide 10 pixel left/right
  POW 7    Slide 20 pixel left/right
  GSB      Quit RULE


____________________

TEX
____________________

TEX is a (very) simple line oriented text editor. But as entering a text with
cursor keys is quite a pain TEX is sufficient to manage a ToDo or shopping list
or some important formulae. Please note that TEX can manage a maximum of 255
characters (with not more than 18 characters per line).

TTOP supports the following functions:
  4 8 3 9  Navigation (Down/Up/PdDown/PgUp)
  ENTER    Edit (top) line
  /        Edit line but split line at cursor position after editing
  *        Join two lines
  - BSP    Delete (top) line
  +        Insert line before top line
  STO RCL  Save/load TEX document to/from one of 6 slots
  GSB      Quit TEX

  To enter a new line after the last line edit with split option (/) and
  leave editor immediately (ENTER).
  To edit a text TEX uses the text editing routines of RAX (see above).

Further Information

calculator, dm15l, desk15

Page created : 17/02/26 17:44 GMT

Page updated : 01/01/70 01:00 BST

LF15C - firmware for the DM15

anonymous@undisclosed.example.com (Anonymous) — Mon, 13 Apr 2026 07:39:18 +0000

←3rd Party Firmware

LF15C - firmware for the DM15

A 3rd Party Firmware for the DM15 family of calculators

Overview of LF15C

Full development history in HP Forum thread New firmware for the Swissmicros DM15L

LF15C is written by HP Museum Forum member jebedeo
It is a replacement firmware for the Swiss Micros DM15C & DM15L calculators.
- also runs on the original DM15 credit card version no longer in production
It is not an emulation or an exact simulation of the HP15C
It runs directly on the hardware without an emulation layer.
It is very much faster than the stock firmware
It has full-time complex number support
- including display of the full real & imaginary parts on the LCD together 3.345 +22.356 i
It has a 4-level stack with full-time 2-level display of X and Y
All the main HP15C functions are included with the exception of Matrix support

Installing LF15C

DM15L running V32 or earlier (Linux)

sudo lpc21isp LF15C_250408.hex /dev/ttyUSB0 115200 1200
Press hidden reset button
- firmware is flashed
press hidden reset button to start new firmware

DM15L running V33 or later (Linux)

This behaviour isn't consistent!

I've seen it be possible to flash and run LF15C directly after DM15 V34 with no problems.

I've also seen the problems described below, requiring downgrade to V32.

Just bear it in mind if you have problems starting LF15C after flashing it on top of V33-onwards

The new Swiss Micros firmware V33 changes the behaviour of the bootloader, and it appears to be impossible to flash 3rd party firmware when the calculator is running V33 or later.

The firmware appears to flash correctly, but on reset it will not start

The solution is to downgrade to V32 first, and then install LF15C

sudo lpc21isp DM15_M1B_32.hex /dev/ttyUSB0 115200 1200
press hidden reset button
- firmware is flashed
press hidden reset button to start V32 firmware
sudo lpc21isp LF15C_250408.hex /dev/ttyUSB0 115200 1200
press hidden reset button
- firmware is flashed
press hidden reset button to start new LF15C firmware

For installation using Windows

The Swiss Micros Voyager Update Tool will work to install LF15C
- Do not use the new Web Update tool
The same caveats regarding installation after using the Swiss Micros V33 apply
- First downgrade to V32
- Then flash with LF15C
You need to use the hidden reset button in all cases.

Files

Download from here

Latest LF15C firmware	lf15c_250408.hex
V32 firmware	dm15_m1b_32.hex
Swiss Micros Voyager Windows Update Tool	voyage_firmware_tool.zip

Download from HP Forum & Swiss Micros

The Firmware files are available from the HP Forum Thread for this firmware - at the foot of Post #1
- the version attached to Post #1 is always the latest available.
At present (Jan '26) there is also a beta version which is being used to test various compiler optimizations, and is buggy and best avoided.

Swiss Micros
- V32 Firmware DM15_M1B_32.hex
- Voyager Update Tool Voyager Firmware Update Tool

LF15C General Info

Full time complex stack shows real & imaginary parts together as e.g. Rectangular: 3.45 +4.34 i or Polar: 5.5442 ∠51.5177
maximum number range approx. ±1.797 x 10³⁰⁸
- largest integer factorial 170fx! = 7.2574 E306
smallest positive number approx. 1.00 10^-323 before 0 is returned
Precision 15 decimal places

π displays as 3.14159265358979
e displays as 2.71828182845905

Fingerprinting - see Fingerprinting

9SINCOSTANATANACOSASIN9-

-1.6584 x10 ^-10

User Programs can be saved/loaded via USB Serial port using a terminal emulator such as Putty

LF15C uses binary floating point representation, rather than the more common BCD.
- This improves the speed but introduces occasional small rounding errors

Example (Click to view)

HP15C functions

Fix / Sci / Eng display formats
√x / x²
e^x / Ln
10^x / Log
y^x / %
1/x / Δ%
Sin / ASin
Cos / ACos
Tan / ATan
Hyperbolics of Sin/Cos/Tan
CHS / ABS
EEX / π
Deg / Rad / Grad Angle Mode
→H.ms / →H Conversions
→Rad / →Deg Conversions
X!
- integer, non-integer, negative and complex support
Statistics
- Σ+ two variable accumulation
- mean
- standard deviation
- Linear Regression
  - slope / intercept
  - ŷ estimation / r correlation coefficient
Combinations / Permutations
Usual 4 level stack manipulations
- Last x
- Roll Down ↓
- Roll Up ↑
- Swap x ↔ y
- Swap x ↔ any Storage Register
100 storage registers (numbered 00-99)
- capable of saving Complex Numbers
Indirect Register pair I / (i)
Indirect Program Label / Line number addressing via Register I
Random Number Generator
Rounding
Fractional / Integer
Usual Keystroke Programming features
- SST/BST
- LBL
  - LBL A - E
  - LBL 00 - 99
- DSE / ISG
  - including usual loop control indexing
- Logical tests
- Branching
  - GTO
  - GSB
  - RTN
- PSE
- R/S
SF / CF / FS?
- 10 user flags for program control
Solver
- can be used via a program
Numerical Integration
- variable precision via display digit format
- can be used via a program
quick clear of
- Statistical data
- Individual Program
- All stored Programs
- Storage Registers (0-99, I and (i))
Full digit mantissa preview

HP15C features not supported

Matrix functions
User Mode
Memory management
- partitioning between Storage Registers and Program Space is not required or supported

DM15L features not supported

Real Time clock
Switchable 1-line display option (V33 feature)
CPU speed switching
Display Font options
Adjustable LCD contrast
Various self-tests
Conversions & Constants (V33 feature)

Speed tests

Very much faster than stock DM15L firmware … see Benchmarking

n-Queens

Calculator	Firmware	Time
DM15L	V34	202 seconds
DM42	3.23	7.30 seconds
DM15L*	LF15C 250408	0.992 seconds

Savage

Calculator	Firmware	Time
DM15L	V34	247 seconds
DM42	3.23	14.9 seconds
DM15L*	LF15C 250408	4.008 seconds

Using LF15C

Complex Numbers

The stack is permanently in complex mode and operates slightly differently to the stock HP15C

Making & manipulating a complex number

Press f I in normal mode to create & destroy a complex number from ⇔ to y and x on the stack.

Example (click to view)

Make a pure imaginary number by using fRe<>Im

Example (Click to view)

Rectangular and Polar modes for complex numbers

f →R and g→P do NOT to convert x and y stack levels between Rect and Polar values as in the HP15C
→R and →P are Mode Switching commands for the whole complex stack.
When in Polar mode ALL Complex numbers on the stack are in Magnitude / Angle format.
- The angle format can be Deg or Rad as appropriate

Example (click to view)

Arithmetic can be done in Rectangular or Polar mode.

Mode can be switched at any time - perhaps switching to Rectangular to enter a Rectangular format number, when working in Polar, and then switching back to Polar once it's been entered on the stack..
Intermediate calculations can be done whatever mode is current.
- this is unlike the HP15C, where complex arithmetic has to be done in Rectangular format - and Polar format numbers must be converted → R first.
To confirm the mode in use an annunciator P is always present when in Polar.
- No P means Rectangular mode is active.

Example (click to view)

Other features

Indirect addressing

Similar features to the standard HP15C, with differences due to increased Program Label numbers

Indirect Register pair I & (i)

Indirect Register pair I and (i) work in the usual way

Example (click to view)

Indirect Program Label addressing

As in the HP15C you can also indirectly address Program Labels using the contents of the I register to point to the label required.

The HP15C allowed 20 numerical Program Labels 0 - .9 which meant indirect addressing for Labels A - E was done by reference to 20 - 24 in Register I

LF15C has 100 numerical Program Labels so….

Store 00 - 99 in I to address numerical Program Labels 00 - 99

Store 100 - 104 I to address Program Labels A - E

Using GTO I or GSB I in a program will lead to a jump to the Program Label referred to by contents of Register I.

Changing Register I's contents (e.g. within a program) can then cause the execution of program to branch in different ways - this can be a very powerful mechanism!

Example (click to view)

Store 100 (for LBL A) in the indirect Register I

100STOI

Use the value stored in I as a Label indirectly by calling it from within a program.

LBL A is a small program to do a simple calculation (area of circle from radius held in x)

LBL B, which has the single command GTO I

Running LBL B fB actually runs the program in LBL A : GTO I is interpreted as GTO A.

LBL A
X^2
PI
*
RTN

LBL B
GTO I
RTN

Changing the contents of Register I will change where LBL B points to.

This allows you to make decisions and branches to different code communicated via the indirect register.

Storing 101 in Reg I and then running LBL B has the effect of an endless loop….. LBL B calls itself (indirectly via I=101)

Use R/S to interrupt the endless loop!

Using GTO I in LBL B means execution passes to LBL A and does not return to LBL B on completion.

Using GSB I in LBL B instead of GTO means that after running LBL A (via indirection) execution returns to LBL B and continues….

Indirect Program Line Number Addressing

Similar to the above, if the Indirect Register I contains a NEGATIVE number then a call to GTO I or GSB I will cause a branch to the absoloute Line Number referred to in I.

Example (Click to view)

0 Empty
1 LBL A
2 GTO I
5 RTN
6 LBL 88
8 X^2
9 PI
10 *
11 RTN
12 Empty

Storing 88 in Register I would make Program A branch to the Label 88 (line 6)

Storing -9 in Register I (9 CHS STO I) would make Program A branch to PI (at line 9) and bypass the X² instruction.

Line numbering isn't straightforward, as each instruction may use one or two line numbers depending on the instruction itself, so you have to be careful about which line you need to address.

And the rest

100 Storage Registers 00 - 99 are capable of storing Complex Numbers

Factorial / Gamma x! works on integer (positive), non-integer (positive and negative) and complex numbers

Program Mode shows human-readable text rather than HP15C op-codes
- 2-line display of Program being edited

Selection of logical tests can be done in usual HP15C fashion with TEST 0 - TEST 9
- Test can also be selected from a scrolling list of options after initially pressing gTEST with the choice being made via soft-keys & LCD Prompts

To run a program with a numeric label (i.e. other than LBL A → LBL E) press f LBL ##
- e.g. f LBL 88
- this is different than on the original HP15C where to run a label you used GSB##

In program mode, f CLEAR PREFIX places the runTime opCode in the program. runTime writes to x the program execution time once it's executed.

Deleting User Programs
- Delete a single program : f CLEAR PRGM followed by a label
- Delete ALL programs : f and long press CLEAR PRGM

FIX/SCI/ENG don't round numbers unless gRND is pressed.

fENGnn sets the number of significant digits as requested, UNLIKE the original HP15C where fENGn sets the significant digits to n + 1

There are 10 user flags, from 0 to 9.
- There are no LCD annunciators to show state, but flags can be set, cleared and tested for decision making in program branching

Long press GTO in program mode to access go to label feature (single press in run mode)
Long press GSB in program mode to access go to line number feature (single press in run mode)

When running a program step by step, a long press on SST doesn’t execute the current step.

Unused Keys
- f USER, gMEM, fDIM, fMATRIX and fRESULT are not implemented and don't do anything at the moment.

LF15C Serial Port Info

Serial Port dump info : https://www.hpmuseum.org/forum/thread-20046-post-194697.html#pid194697
Serial Port settings
- Rate : 57600
- Data : 8 bit
- Stop : 1 bit
- Parity : None
- Flow Control : None

ALWAYS INCLUDE AT LEAST ONE TRAILING ZERO FROM THE STRING OF DIGITS REPRESENTING THE MEMORY DUMP

To extract a dump from calculator press and hold STO
- the string of digits can be copy/pasted into a text file for storage
- it is only necessary to keep one final zero - the rest of the zeros can be ignored
To upload a previously saved dump
- copy it to clipboard and then
- press and hold RCL until the terminal shows Paste PrgMemory:
- in Putty ShiftInsert to paste clipboard text into terminal

LF15C Firmware Files

Tabulated List of LF15C firmware versions

Date	Firmware	Version	Firmware File	Comments
12/09/24	LF15C	beta240911	lf15c_beta240911.zip	initial public beta
15/09/24	LF15C	beta240914	lf15c_beta240914.zip
17/09/24	LF15C	beta240916	lf15c_beta240916.zip
17/09/24	LF15C	beta240916_2	lf15c_beta240916_2.zip
21/09/24	LF15C	beta240920	lf15c_beta240920.zip	very fast benchmarking, roots of -ve numbers bug
21/09/24	LF15C	beta240921	lf15c_beta240921.zip	Fix of “powers of negative numbers” bug, new 10^x bug
23/09/24	LF15C	beta240923	lf15c_beta240923.zip	10^x fix, other bug fixes
25/09/24	LF15C	beta240925	lf15c_beta240925.zip	Bug fixes More new bugs
28/09/24	LF15C	beta240928	lf15c_beta240928.zip	bug fixes
30/09/24	LF15C	beta240929	lf15c_beta240929.zip	Bug Fixes etc.
30/09/24	LF15C	beta240929_2	lf15c_beta240929_2.zip	RCL I Bug fix
01/10/24	LF15C	beta240930	lf15c_beta240930.zip	Bug Fixes
02/10/24	LF15C	debug241001	lf15c_debug_for_john241001.zip	version pre-loaded with my B.Fil prog for debug purposes
02/10/24	LF15C	beta241002	lf15c_beta241002.zip	Bug Fix my B.Fil runs correctly. No known showstoppers left?
03/10/24	LF15C	beta241003	lf15c_beta241003.zip	fPREFIX fix. Discovered inverse HYP SIN bug
06/10/24	LF15C	beta241005	lf15c_beta241005.zip	fixes ,HYP ASIN bug still present
07/10/24	LF15C	beta241006	lf15c_beta241006.zip	Bug fix and new runTime function
08/10/24	LF15C	beta241007	lf15c_beta241007.zip	Bug Fixes
10/10/24	LF15C	beta241009	lf15c_beta241009.zip	Bug Fixes
12/10/24	LF15C	beta241011	lf15c_beta241011.zip	RND bug fix
14/10/24	LF15C	beta241014	lf15c_beta241014.zip
20/10/24	LF15C	beta241020	lf15c_beta241020.zip
21/10/24	LF15C	beta241021	lf15c_beta241021.zip
22/10/24	LF15C	beta241022	lf15c_beta241022.zip
24/10/24	LF15C	beta241024	lf15c_beta241024.zip
31/10/24	LF15C	beta241031	lf15c_beta241031.zip
02/11/24	LF15C	beta241102	lf15c_beta241102.zip
10/12/24	LF15C	beta241210_2	lf15c_beta241210_2.zip	Integrate feature
17/12/24	LF15C	beta241217	lf15c_beta241217.zip	Integrate improvements
21/12/24	LF15C	beta241221	lf15c_beta241221.zip	Bug Fixes
22/12/24	LF15C	beta241222	lf15c_beta241222.zip	Sin(180)=0 Fixed
14/02/25	LF15C	beta250123	lf15c_beta250123.zip	Enter Key bug fixes
15/02/25	LF15C	beta250215	lf15c_beta250215.zip	Better integration routine and bug fixes
16/02/25	LF15C	beta250216	lf15c_beta250216.zip	Y↑X and TEST bug fixes
17/02/25	LF15C	beta250217b	lf15c_beta250217b.zip	Integration bug fix
19/02/25	LF15C	beta250218	lf15c_beta250218.zip	Integration programability
20/02/25	LF15C	beta250220	lf15c_beta250220.zip	Linear Regression bug fix
21/02/25	LF15C	beta250221	lf15c_beta250221.zip	Complex/non-integer factorial
25/02/25	LF15C	beta250225	lf15c_beta250225.zip	improved precision in x! function
26/02/25	LF15C	beta250226	lf15c_beta250226.hex	f-PREFIX bug fix
12/01/26	LF15C	250408	lf15c_250408.hex	no longer BETA. Stable version - mature??
31/03/26	LF15C	260331	lf15c_260331.hex	Differences unknown - various changes since last stable version 250408. Has Solver issues?
04/04/26	LF15C	260404	lf15c_260404.hex	Differences unknown… performs well on all tests, solver issues resolved
12/04/26	LF15C	260412	lf15c_260412.hex	SOLVE adjustments

Further Information

LF15C program dumps Program dumps for LF15C

calculator, dm15l, lf15c

Page created : 17/02/26 17:51 GMT

Page updated : 13/04/26 08:39 BST

3rd Party Firmware

anonymous@undisclosed.example.com (Anonymous) — Tue, 17 Feb 2026 17:51:11 +0000

←Calculators

3rd Party Firmware

For Swiss Micros Calculators

Further Information

calculator

Page created : 17/02/26 17:50 GMT

Page updated : 01/01/70 01:00 BST