John's Vademecum

DM41X Info - [Purchase Information]

john@undisclosed.example.com (john) — Mon, 13 Apr 2026 18:35:30 +0000

DM41X Info

Purchase Information

Date : February 2022
From : Swiss Micros (Direct)
Price : £185
Serial : 01266
Battery Swap
- 22/09/22
- 11/02/25
- 19/02/26
- 13/04/26

Firmware

Date	Serial No.	DM41X Version	DMCP Version	Firmware Files
24/05/22	01266	2.1	3.20	dmcp_flash_3.20_dm41x-2.1.zip
27/07/24	01266	2.2	3.25	dmcp_flash_3.25_dm41x-2.2.zip
21/12/25	01266	2.3	3.28	dmcp_flash_3.28_dm41x-2.3.zip

RTC Correction

approx. error +3.5s/d = +40.5ppm
Correction factor C from C = 2^20 P /(10^6 + P)
Approximations :
- C = 1.04858 P
- P = 0.953674 C
Calculated C = -42.47

Put a text file /rtccalib.cfg in root directory of FAT drive with contents:

-42.47

Update 28/5/22

After a period of observation the rate is now over-corrected. Try reducing correction to -37.5 which corresponds to a ppm error of 35.76ppm, or 3.26 s/d.

Date Start	Date Check	Accumulated Error (s)	Rate Error (s/d)	Comments
28/3/22	24/5/22		-0.1	correction applied (C=40). Uncorrected error +3.5
24/5/22				new correction C=-42.47
24/5/22	25/5/22		-0.3	new correction in wrong direction?
28/5/22			-0.3	still over-corrected. New factor: -37.5. DM41X reports this is a correction of -35.3ppm
28/5/22	31/5/22		+0.2	Now under-corrected? Difference across 3 days is only 0.5 seconds, so perhaps needs longer to reduce reaction-time-error
28/5/22	28/6/22		+0.1	Almost 1 month later. Delta 31/5/22 = -15.7s, Delta 28/6/22 = -11.6s. +4.1s in 28 days
28/5/22	8/7/22		+0.1	Delta -10.1s
28/5/22	21/9/22		+ 0.2	Delta +1.2s. Still slightly under-corrected but good enough
28/5/22	15/4/23	-7.6	+0.0	Delta -7.6s in 322 days = 0.02 s/d
15/04/23	22/11/23	+33.3	+0.2	33.3s in 221 days = 0.15 s/d

Update January 2026

Using my python Watchcheck

Date Start	Date Check	Delta	Latest Rate Error	Average Rate Error	Comments
23/01/26		+2.7			New Period: correction-35.3ppm
23/01/26	24/01/26	+2.6	-0.1	-0.1	After 24 hours
23/01/26	26/01/26	+3.0	+0.2	+0.1	After 3 days
23/01/26	27/01/26	+3.2	+0.3	+0.1	After 4 days
23/01/26	04/02/26	+5.0	+0.2	+0.2	After 12 days
23/01/26	11/02/26	+6.1	+0.1	+0.2	After 19 days

Notes

Complex Numbers

For more about the 41Z see the separate page DM41X 41z Module

I'm using the 41Z complex number module by Angel Martin to add a 4-level complex number stack. It's a bit confusing at first to get to grips with, but adds a lot of functionality to the the DM41x.

After a bit of trial and error (this is my first play with a “plug-in module” after all) I discovered the simplest way to make the keyboard function normally, and get easy access when needed to the complex functions, was to assign a USER key (usually the statistics summation key ∑+ to the 41Z module function ∑ZL.

Each press of ∑+ now temporarily modifies all the keys to access specific 41Z functions. The functions available are extensive, through the use of the SHIFT key and by multiple presses of the ∑+ (henceforth referred to as Z) key.

I drew out a diagram to show the various functions available.

Once a selection is made the keyboard switches back to its normal behaviour, so all the usual functionality is available.

Most of these are unlikely to be used often - and it's also possible to make a much narrow selection of 41Z functions and make your own USER assignments, rather than use the ∑ZL keyboard - although this might mean you block access to inbuilt functions you might want - which would mean switching out of USER keyboard mode at times. At the moment the ∑ZL option seems the most versatile.

Many of the 41Z functions available are beyond my pay grade and unlikely to ever find a use, but the Complex Keyboard still makes things much easier to deal with.

For example the two keypresses:

Z 1\x

is much easier than the 7 it would otherwise need to invert a complex number

XEQALPHAZINVALPHA I need to practice finding the right function (the main ones printed on the keyboard as well as the new ones provided by 41Z's ∑ZL keyboard, but my fingers are slowly starting to move in the right direction.

One thing I do notice, though, as that due to the need to press various keys (XEQ, ALPHA, SHIFT etc) it's sometimes possible to make a real mess if you miss a vital key in the middle of entering lots of data & instructions and find your stack totally screwed up, or several lines of program code full of nonsense….

I'm sure it'll all become second nature soon enough.

HP16C Emulator module

This is another interesting module to add the functionality of the HP16C - the Programmer's Calculator designed to handle calculations in various mathematical bases as used in computer programming and networking : Binary, Octal, Hexadecimal and Decimal. I adds much more value than the rather basic functions in the Advantage Pac module.

After much trial and error I found a combination of HP16C module and Library 4 library that worked correctly. The HP16C module needs the Library 4 module, but I found some problems with different versions. Using the versions contained in the Swiss Micros package had a weird bug - the 16* (multiplication) function simply didn't work. I found a post by Angel Martin on the HP Calculator Forum with a ZIP file containing the 2 modules that worked correctly.

Here is the zip file : hp-16c_rev.1a.zip

I'll make a separate guide to using the main features here DM41X HP16C Module

Guides

Hints & Tips

Swiss Micros Info

Firmware : https://technical.swissmicros.com/dm41x/firmware/
Documentation : Online User Manual
Documentation : PDF Manual
Product Page : DM41X

Issues

Arrived new with a speck of dirt behind the glass in front of the LCD.
- Able to remove by carefully prising the glass from its bezel (it's held in with double-sided tape)

41Z Deluxe Module

Weird behaviour with its "common factor" display

Update September 2024

The factorization error in the deluxe version has been fixed by Angel….

Swiss Micros forum discussion about the issue

the fixed version 41z_bs_2x2_2_.zip
My page DM41X 41z Module

DM41X Program Listings

See DM41X Progs

HP-41CX Owner's Manuals

Download from https://literature.hpcalc.org

HP-41CX Owner's Manual Vol. 1 : https://literature.hpcalc.org/community/hp41cx-om-vol1-en.pdf
HP-41CX Owner's Manual Vol. 2 : https://literature.hpcalc.org/community/hp41cx-om-vol2-en.pdf
HP-41CX Quick Reference Guide : https://literature.hpcalc.org/community/hp41cx-qrg-en.pdf

Page Updated : 13/04/26 19:35 BST

calculator, dm41x

LF15C - firmware for the DM15 - [LF15C Firmware Files]

john@undisclosed.example.com (john) — 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

lf15c_260412.hex - created

john@undisclosed.example.com (john) — Mon, 13 Apr 2026 07:38:54 +0000

DM15L Non-linear Curve Fit - [Example Data]

john@undisclosed.example.com (john) — Mon, 06 Apr 2026 12:40:53 +0000

←Hints & Tips

DM15L Non-linear Curve Fit

Using DM15L/HP15C built-in L.R function to fit non-linear curves

Background

The idea is that the 3 different non-linear function forms can be expressed as linear expression y = m.x + c if we manipulate the x or y values before adding them to the statistics accumulator.

The different curves require different treatment of the data to linearize, and the resulting coefficients may require treatment too.

Tl;dr

Method for Exponential

y = b.e^ax

Ln(y) = a.x + Ln(b)

Enter Accumulation data	`y_i gLn x_i ∑+`
Calculate coefficients	`fL.R.e^x`
Estimate ŷ & r for a new `x`	`x fŷ.r e^x`

Method for Logarithmic

y=a.ln(x)+b

y = a.Ln(x) + b

Enter Accumulation data	`y_i Enter x_i gLn∑+`
Calculate coefficients	`fL.R.`
Estimate ŷ & r for a new `x`	`xgLn fŷ.r`

Method for Power

y=b.x^a

Ln(y) = a.Ln(x) + Ln(b)

Enter Accumulation data	`y_i gLn x_i gLn∑+`
Calculate coefficients	`fL.R.e^x`
Estimate ŷ & r for a new `x`	`x gLnfŷ.re^x`

Exponential

y = b.e^ax

This can be expressed as Ln(y) = Ln(b) + a.x

Ln(y) = a.x + ln(b)

compare with a linear expression y = m.x + c

Using Ln(y) and x as data points and running the L.R. function will give coefficients equal to a and ln(b)

You can obtain the actual value of b finding its antilog with e^x.

Once the L.R. has run you can find estimates of ŷ by running the fŷ.r to get the estimate of Ln(y) and then finding its antilog with e^x

Mechanism

To enter the data points you convert the y data to its Ln first, then accumulate as normal

y_i gLn x_i ∑+

Once all the data has been entered you get the Linear Regression coefficients a & b fL.R. and e^x to correct the b LR coefficient.

Example Data

y	2.8	3.6	5.8	8.0
x	0.8	1.1	1.7	2.1

fClear ∑

2.8 gLn 0.8 ∑+

3.6 gLn 1.1 ∑+

5.8 gLn 1.7 ∑+

8.0 gLn 2.1 ∑+

All data is in the accumulator, now do the Linear Regression fL.R.

This gives a and Ln b coefficients

Y: 0.805 = a

X: 0.3897 = ln b

so we need to find b so e^x

Y: 0.805 = a

X: 1.476 = b

Equation estimation is therefore y = 1.476 e ^0.805x

I made the data table by using the equation y = 1.5 e ^0.8x and then used approx. y values for the data table…. so the estimate looks pretty good

To do an estimation of y when x = 0.9

0.9 fŷ.r e^x

Y: 0.999962 = r correlation coefficient

X: 3.047425 = ŷ estimation

Method for Exponential

Enter Accumulation data	`y_i gLn x_i ∑+`
Calculate coefficients	`fL.R.e^x`
Estimate ŷ & r for a new `x`	`x fŷ.r e^x`

Logarithmic

y = a.ln(x) + b

Compare to a linear expression y = m.x + c shows the logarithmic curve is linear if we use Ln(x) as we accumulate data points.

The L.R. will provide the actual a and b coefficients.

To estimate ŷ first find the Ln of x then use the fŷ.r

Mechanism

y_i Enter x_i gLn∑+

Calculate LR Coefficients

fL.R.

Calculate estimated ŷ by finding the Ln of your x value first and then using fŷ.r

xgLnfŷ.r

Example Data

y	1.5	1.7	1.8	2.1
x	0.8	1.7	2.6	4.9

fClear ∑

1.5 Enter 0.8 gLn∑+

1.7 Enter 1.7 gLn∑+

1.8 Enter 2.6 gLn∑+

2.1 Enter 4.9 gLn∑+

Linear Regression Coefficients : fL.R.

Y: 0.324 = a

X: 1.544 = b

Equation y = 0.324 . Ln(x) + 1.544

Estimate ŷ for X = 3

3 gLn fŷ.r

Y: 0.985 = r, correlation coefficient

X: 1.900 = ŷ, estimation

Method for Logarithmic

Enter Accumulation data	`y_i Enter x_i gLn∑+`
Calculate coefficients	`fL.R.`
Estimate ŷ & r for a new `x`	`xgLn fŷ.r`

Power

y = b.x^a

This can be rearranged as Ln(y) = Ln(b) + a.Ln(x) or Ln(y) = a.Ln(x) + Ln(b)

Compare to a linear expression y = m.x + c

Our expression will be a straight line if we accumulate Ln(y) and Ln(x)

The coefficients given by the L.R. function will be a and Ln(b) - so to get the real b coefficient we find its antilog e^x

We get the estimate for ŷ we first find the Ln of our chosen x and then use the ŷ.r to get Ln(ŷ) and then e^x to get ŷ

Mechanism

Accumulate using

y_i gLn x_i gLn∑+

Calculate LR Coefficients

fL.R.e^x

Calculate estimated ŷ

xgLnfŷ.re^x

Example Data

y	1.3	2.2	3.3	4.4
x	0.6	1.3	2.4	3.6

fClear ∑

1.3 gLn 0.6 gLn∑+

2.2 gLn 1.3 gLn∑+

3.3 gLn 2.4 gLn∑+

4.4 gLn 3.6 gLn∑+

Linear Regression Coefficients : fL.R.e^x

Y: 0.678 = a

X: 1.837 = b

Equation : y = 1.837x^0.678

Estimate ŷ for X = 3

3 gLnfŷ.re^x

Y: 1.000 = r, correlation coefficient

X: 3.869 = ŷ, estimation

Method for Power

Enter Accumulation data	`y_i gLn x_i gLn∑+`
Calculate coefficients	`fL.R.e^x`
Estimate ŷ & r for a new `x`	`x gLnfŷ.re^x`

— John Pumford-Green 01/02/26 08:42 GMT

Further Information

calculator, dm15l

lf15c_260331.hex - created

john@undisclosed.example.com (john) — Sun, 05 Apr 2026 11:16:49 +0000

lf15c_260404.hex - created

john@undisclosed.example.com (john) — Sun, 05 Apr 2026 11:15:27 +0000

lf15c_260404.txt - created

john@undisclosed.example.com (john) — Sun, 05 Apr 2026 11:13:42 +0000

DM15L Progs - [Integrate Tests]

john@undisclosed.example.com (john) — Sun, 05 Apr 2026 08:46:21 +0000

←Programs

DM15L Progs

Dumps taken from the DM15L using a serial console session in Putty.

DM15L Startup Keys & Serial Console

Stock Swiss Micros Firmware

Dumps are also converted to readable program listings using the Swiss Micros online encode/decode tool at https://technical.swissmicros.com/decoders/nut/

Normal + "Complex Z to....."

LBL E converts Z=R±jX to RL, SWR, |ρ|∠ρ, |Z|∠Z

Data input :

if Z = R + j X, put R in Y-stack and X in X-stack and then run LBL E

R ENTER
X (and CHS as needed)
F
E

Results appear:

Stack X → Return Loss
Stack Y → SWR
Stack Z → (Re) |ρ| (Im) ∠ρ
Stack T → (Re) |Z| (Im) ∠Z

DM15_M1B
04  000000fffff000  00000000000008  0000000000000c  00000996010eae
08  00000000000000  2faf8befbe2280  00000000000000  00000000000000
10  91000000000000  00000000000000  00000000000000  02875000000998
14  f0000000000000  1b2d2d2d2d2d2d  000000000002ef  00000000000000
18  00000000000000  0000000000007f  00000000a00000  01900000000001
1c  02232142865997  01800000000002  02232142865997  01004474273000
20  05302556024001  00000000000000  00000000000000  00000000000000
ec  00000000000000  00000000000000  00000000000000  0000000000b237
f0  36a43433a43231  44db43e1a43433  42db41e1a43231  47c3fcf0f2bc35
f4  46fda5cff185cf  f145b3db44db43  fdfaf0f5a43231  fbf0f5a4323141
f8  c5420eb23344fc  c3f0f2bcfdfaf1  33fbf143fda2cf  f182cff142cafd
fc  0ab2c3fcf0f2bc  fdfaf132fbf142  0bb2fdfbf132fa  f142ccfdf0f20c
A: 000000fffff000  B: 000000fffffeae  C: 00000996010eae
S: 00000000000000
M: 00000000000000  N: 00000000000000  G: 04

Decoded Dump

001  LBL C        | 42,21,13
002  2            |        2
003  0            |        0
004  /            |       10
005  10^x         |       13
006  STO 2        |    44  2
007  1            |        1
008  +            |       40
009  RCL 2        |    45  2
010  1            |        1
011  -            |       30
012  /            |       10
013  RTN          |   43  32
014  LBL B        | 42,21,12
015  STO 2        |    44  2
016  1            |        1
017  -            |       30
018  RCL 2        |    45  2
019  1            |        1
020  +            |       40
021  /            |       10
022  LOG          |   43  13
023  2            |        2
024  0            |        0
025  *            |       20
026  CHS          |       16
027  RTN          |   43  32
028  LBL A        | 42,21,11
029  /            |       10
030  sqrt         |       11
031  STO 2        |    44  2
032  1            |        1
033  RCL+2        | 45,40, 2
034  1            |        1
035  RCL-2        | 45,30, 2
036  /            |       10
037  STO 3        |    44  3
038  1            |        1
039  -            |       30
040  RCL 3        |    45  3
041  1            |        1
042  +            |       40
043  /            |       10
044  LOG          |   43  13
045  2            |        2
046  0            |        0
047  CHS          |       16
048  *            |       20
049  STO 4        |    44  4
050  RCL 3        |    45  3
051  RTN          |   43  32
052  LBL E        | 42,21,15
053  STO 2        |    44  2
054  x<>y         |       34
055  STO 1        |    44  1
056  RCL 1        |    45  1
057  RCL 2        |    45  2
058  I            |   42  25
059  5            |        5
060  0            |        0
061  -            |       30
062  RCL 1        |    45  1
063  RCL 2        |    45  2
064  I            |   42  25
065  5            |        5
066  0            |        0
067  +            |       40
068  /            |       10
069  STO 3        |    44  3
070  Re<>Im       |   42  30
071  STO 4        |    44  4
072  Re<>Im       |   42  30
073  ABS          |   43  16
074  STO 5        |    44  5
075  1            |        1
076  RCL+5        | 45,40, 5
077  1            |        1
078  RCL-5        | 45,30, 5
079  /            |       10
080  STO 6        |    44  6
081  RCL 5        |    45  5
082  LOG          |   43  13
083  2            |        2
084  0            |        0
085  *            |       20
086  CHS          |       16
087  STO 7        |    44  7
088  RCL 1        |    45  1
089  RCL 2        |    45  2
090  I            |   42  25
091  ->P          |     43 1
092  STO 1        |    44  1
093  Re<>Im       |   42  30
094  STO 2        |    44  2
095  RCL 3        |    45  3
096  RCL 4        |    45  4
097  I            |   42  25
098  ->P          |     43 1
099  STO 3        |    44  3
100  Re<>Im       |   42  30
101  STO 4        |    44  4
102  RCL 1        |    45  1
103  RCL 2        |    45  2
104  I            |   42  25
105  RCL 3        |    45  3
106  RCL 4        |    45  4
107  I            |   42  25
108  RCL 6        |    45  6
109  RCL 7        |    45  7
110  RTN          |   43  32

"Normal"

### 27/7/22 ####
# This is the usual set of 3 useful tool progs I have in the DM15L for quick calculation/conversion
# of antenna parameters.
#

Ref Power ENTER Fwd Power fA → SWR x<>y RL
SWR fB → Return Loss
Return Loss fC → SWR

DM15_M1B
00  03400000000001  01000000000001  08000000000000  00000000000000
04  155000000ff000  00000000000008  0000000000000c  00002000010eae
08  00000000000000  2faf0bde7aa28f  000080bcbcaf80  00000000000000
10  00000000000000  01000000000001  00000000000000  03400000000001
14  f7365289440000  1b2d2d2d2d2d2d  000000000004f8  00000000000000
18  00000000000000  0000000000007f  00000000a00000  01387265622000
1c  01387265622000  01579783596001  05000000000001  02500000000003
20  01800000000002  00000000000000  00000000000000  00000000000000
f8  000000b23344fc  c3f0f2bcfdfaf1  33fbf143fda2cf  f182cff142cafd
fc  0ab2c3fcf0f2bc  fdfaf132fbf142  0bb2fdfbf132fa  f142ccfdf0f20c
A: 155000000ff000  B: 155000000ffeae  C: 00002000010eae
S: 00000000000000
M: 00000000000000  N: 05500000000001  G: 06

Decoded dump

LBL C
20

/
10^x
STO 2
1
+
RCL 2
1
-
/
RTN
LBL B
STO 2
1
-
RCL 2
1
+
/
LOG
20

*
CHS
RTN
LBL A
/
sqrt
STO 2
1
RCL+2
1
RCL-2
/
STO 3
1
-
RCL 3
1
+
/
LOG
20

CHS
*
STO 4
RCL 3
RTN

001  LBL C        | 42,21,13
002  2            |        2
003  0            |        0
004  /            |       10
005  10^x         |       13
006  STO 2        |    44  2
007  1            |        1
008  +            |       40
009  RCL 2        |    45  2
010  1            |        1
011  -            |       30
012  /            |       10
013  RTN          |   43  32
014  LBL B        | 42,21,12
015  STO 2        |    44  2
016  1            |        1
017  -            |       30
018  RCL 2        |    45  2
019  1            |        1
020  +            |       40
021  /            |       10
022  LOG          |   43  13
023  2            |        2
024  0            |        0
025  *            |       20
026  CHS          |       16
027  RTN          |   43  32
028  LBL A        | 42,21,11
029  /            |       10
030  sqrt         |       11
031  STO 2        |    44  2
032  1            |        1
033  RCL+2        | 45,40, 2
034  1            |        1
035  RCL-2        | 45,30, 2
036  /            |       10
037  STO 3        |    44  3
038  1            |        1
039  -            |       30
040  RCL 3        |    45  3
041  1            |        1
042  +            |       40
043  /            |       10
044  LOG          |   43  13
045  2            |        2
046  0            |        0
047  CHS          |       16
048  *            |       20
049  STO 4        |    44  4
050  RCL 3        |    45  3
051  RTN          |   43  32

N-Queens Benchmark 27/7/22

DM15_M1B
00  08000000000000  08000000000000  00000000000000  00000000000000
04  065140fffff000  00000000000008  0000000000000c  00000000999eae
08  00000000000000  22af8d9e7e0080  00000000000000  00000000000000
10  08000000000000  08000000000000  01000000000000  01000000000000
14  f0000000000537  1b2d2d2d2d2d2d  000000000007f7  00000000000000
18  00000000000000  0000000000007f  00000000a00000  04000000000000
1c  01000000000000  03000000000000  06000000000000  02000000000000
20  07000000000000  05000000000000  00000000000000  08000000000000
24  08760000000002  00000000000000  00000000000000  00000000000000
f4  00000000000000  00000000000000  00000000000000  b25104137030a0
f8  dff1117086bddf  f19730031276fb  3930b313ecfb86  c4973986973010
fc  ec39a9dff10249  3091dff1019650  973080dff11475  50300060f8a50a
A: 065140fffff000  B: 065140fffffeae  C: 00000000999eae
S: 00000000000000
M: aaaaaaaaaaaaaa  N: 06514000000000  G: 04

Decoded Dump

LBL A
CLR_REG
8
STO .0
LBL 0
RCL 0
RCL .0
TEST 5
GTO 4
1
STO+0
RCL 0
STO I
RCL .0
STO (i)
LBL 1
1
STO+.1
RCL 0
STO 9
LBL 2
1
STO-9
RCL 9
x=0
GTO 0
RCL 0
STO I
RCL (i)
RCL 9
STO I
R_down
RCL (i)
-
x=0
GTO 3
ABS
RCL 0
RCL 9
-
TEST 6
GTO 2
LBL 3
RCL 0
STO I
1
STO-(i)
RCL (i)
TEST 0
GTO 1
1
STO-0
RCL 0
TEST 0
GTO 3
LBL 4
RCL .1
RTN

001  LBL A        | 42,21,11
002  CLR_REG      |   42  34
003  8            |        8
004  STO .0       |    44 .0
005  LBL 0        | 42,21, 0
006  RCL 0        |    45  0
007  RCL .0       |    45 .0
008  TEST 5       | 43,30, 5
009  GTO 4        |    22  4
010  1            |        1
011  STO+0        | 44,40, 0
012  RCL 0        |    45  0
013  STO I        |   44  25
014  RCL .0       |    45 .0
015  STO (i)      |   44  24
016  LBL 1        | 42,21, 1
017  1            |        1
018  STO+.1       | 44,40,.1
019  RCL 0        |    45  0
020  STO 9        |    44  9
021  LBL 2        | 42,21, 2
022  1            |        1
023  STO-9        | 44,30, 9
024  RCL 9        |    45  9
025  x=0          |   43  20
026  GTO 0        |    22  0
027  RCL 0        |    45  0
028  STO I        |   44  25
029  RCL (i)      |   45  24
030  RCL 9        |    45  9
031  STO I        |   44  25
032  R_down       |       33
033  RCL (i)      |   45  24
034  -            |       30
035  x=0          |   43  20
036  GTO 3        |    22  3
037  ABS          |   43  16
038  RCL 0        |    45  0
039  RCL 9        |    45  9
040  -            |       30
041  TEST 6       | 43,30, 6
042  GTO 2        |    22  2
043  LBL 3        | 42,21, 3
044  RCL 0        |    45  0
045  STO I        |   44  25
046  1            |        1
047  STO-(i)      | 44,30,24
048  RCL (i)      |   45  24
049  TEST 0       | 43,30, 0
050  GTO 1        |    22  1
051  1            |        1
052  STO-0        | 44,30, 0
053  RCL 0        |    45  0
054  TEST 0       | 43,30, 0
055  GTO 3        |    22  3
056  LBL 4        | 42,21, 4
057  RCL .1       |    45 .1
058  RTN          |   43  32

Savage Benchmark 23/01/26

DM15_M1B
00  01000000000000  01000000000000  01000000000000  00000000000000
04  32499970322000  00000000000008  0000000000000c  40997997010eae
08  00000000000000  3ebeefb6e4228f  e79282e8bc2ac0  00000000000000
10  00000000000000  08000000000000  06000000000000  02498970322003
14  f0000000000504  1b2d2d2d2d2d2d  000000000001fc  00000000000000
18  00000000000000  0000000000007f  00000000a00000  06000000000000
1c  04000000000000  07000000000000  05000000000000  03000000000000
20  00000000000000  00000000000000  04000000000000  08000000000000
24  02100000000001  00000000000000  00000000000000  00000000000000
fc  000000000000b2  1b82fac9b9cbbb  caba0bc1c1c1f1  40f9f9f4f2e80a
A: 32499970322000  B: 32499970322eae  C: 40997997010eae
S: 00000000000000
M: 00000000000000  N: 02499970322003  G: 09

UPDATED "Butterworth" program 12/2/22

############################
#
#  Updated 12/2/22 : change to reduce amount of looping/storing 
#  Sub routine "LBL 8" changed
DM15_M1B
00  05108827280994  05000000000999  05000000000999  00000000000000
04  24547fff912000  00000000000008  0000000000000c  00012012012eae
08  00000000000000  b6000a9eda000f  e6220040000000  00000000000000
10  07000000000000  05108827295994  08007000000000  05000000000001
14  f0000000012435  1b2d2d2d2d2d2d  000000000006f1  00000000000000
18  00000000000000  0000000000007f  00000000a00300  07293277408990
1c  01261776142994  04547284088990  01261776142994  07293277408990
20  05108827280994  01103787069994  04026420096990  08509227540993
24  02583151782990  04031222906993  05481145266989  07025940305993
28  09506412356989  00000000000000  00000000000000  00000000000000
2c  03500000000006  00000000000000  00000000000000  00000000000000
f0  00000000000000  00b2fcf2c7fdfc  f230fcf0f8f1fb  f1fcf200171195
f4  96ce50ff20eb87  012640b340ff72  c56930ff83ff0a  17b2139596fdf0
f8  f52805b2139596  fcf0f5280410ff  1950ffa3fdf2eb  87032607b297fa
fc  f1fdf0f0f0f130  06b21514ec00ff  b21415ec09b2fd  fcb6fcf2598608
A: 24547fff912000  B: 24547fff912eae  C: 00012012012eae
S: 00000100000000
M: 05108827280994  N: 04547284088990  G: 23

Dump above decoded at Swiss micros

001  LBL 8        | 42,21, 8
002  RCL (i)      |   45  24
003  RCL .9       |    45 .9
004  2            |        2
005  *            |       20
006  PI           |   43  26
007  *            |       20
008  /            |       10
009  RTN          |   43  32
010  LBL 9        | 42,21, 9
011  x=0          |   43  20
012  GTO 5        |    22  5
013  GTO 4        |    22  4
014  RTN          |   43  32
015  LBL .0       | 42,21,.0
016  x=0          |   43  20
017  GTO 4        |    22  4
018  GTO 5        |    22  5
019  RTN          |   43  32
020  LBL 6        | 42,21, 6
021  RCL 0        |    45  0
022  1            |        1
023  0            |        0
024  0            |        0
025  0            |        0
026  /            |       10
027  1            |        1
028  +            |       40
029  STO I        |   44  25
030  RTN          |   43  32
031  LBL 7        | 42,21, 7
032  GSB 6        |    32  6
033  LBL 3        | 42,21, 3
034  RCL I        |   45  25
035  INT          |   43  44
036  2            |        2
037  /            |       10
038  FRAC         |   42  44
039  F? 0         | 43, 6, 0
040  GTO 9        |    22  9
041  GTO .0       |    22 .0
042  LBL 4        | 42,21, 4
043  GSB 8        |    32  8
044  5            |        5
045  0            |        0
046  *            |       20
047  STO (i)      |   44  24
048  ISG I        | 42, 6,25
049  GTO 3        |    22  3
050  RTN          |   43  32
051  LBL 5        | 42,21, 5
052  GSB 8        |    32  8
053  5            |        5
054  0            |        0
055  /            |       10
056  STO (i)      |   44  24
057  ISG I        | 42, 6,25
058  GTO 3        |    22  3
059  RTN          |   43  32
060  GTO 7        |    22  7
061  LBL A        | 42,21,11
062  ENG 3        | 42, 9, 3
063  SF 0         | 43, 4, 0
064  STO .9       |    44 .9
065  x<>y         |       34
066  TEST 2       | 43,30, 2
067  CF 0         | 43, 5, 0
068  ABS          |   43  16
069  STO 0        |    44  0
070  GSB 6        |    32  6
071  LBL 1        | 42,21, 1
072  RCL I        |   45  25
073  INT          |   43  44
074  GSB 0        |    32  0
075  F? 0         | 43, 6, 0
076  1/x          |       15
077  STO (i)      |   44  24
078  ISG I        | 42, 6,25
079  GTO 1        |    22  1
080  GTO 7        |    22  7
081  LBL 0        | 42,21, 0
082  2            |        2
083  *            |       20
084  1            |        1
085  -            |       30
086  1            |        1
087  8            |        8
088  0            |        0
089  *            |       20
090  RCL 0        |    45  0
091  2            |        2
092  *            |       20
093  /            |       10
094  SIN          |       23
095  2            |        2
096  *            |       20
097  RTN          |   43  32

Dump

################################

DM15_M1B
00  01040000000003  01750000000002  01750000000002  00000000000000
04  08200000910000  00000000000008  0000000000000c  00002000009eae
08  00000000000000  2faf8bf9fe2280  be220040bcaf80  00000000000000
10  00000000000000  00000000000000  00000000000000  06283185308000
14  f7365289446075  1b2d2d2d2d2d2d  000000000007f2  000000000003ff
18  00000000000000  0000000000007f  00000000a00000  01924950591000
1c  01924950591000  01000000000001  05000000000001  02500000000003
20  01800000000002  00000000000000  00000000000000  00000000000000
f0  00000000000000  00000000000000  b23344fcc3f0f2  bcfdfaf133fbf1
f4  43fda2cff182cf  f142cafd0ab2c3  fcf0f2bcfdfaf1  32fbf1420bb2fd
f8  fbf132faf142cc  fdf0f20cb2fcf0  f1bcfdc3f3c6f1  fdf0f5ba0db2ca
fc  fcf0f5fcc3f3c6  f1ccfdf0f10eb2  c3fcf0f2bcfdfa  f1c5fbf1c1c100
A: 08200000910000  B: 08200000910eae  C: 00002000009eae
S: 00000100000000
M: 00000000000990  N: 08200000000990  G: 19

Dump above decoded @ Swiss Micros

# https://technical.swissmicros.com/decoders/nut/
#
001  LBL 0        | 42,21, 0
002  ENTER        |       36
003  ENTER        |       36
004  1            |        1
005  -            |       30
006  x<>y         |       34
007  1            |        1
008  +            |       40
009  /            |       10
010  LOG          |   43  13
011  2            |        2
012  0            |        0
013  *            |       20
014  CHS          |       16
015  RTN          |   43  32
016  LBL E        | 42,21,15
017  1            |        1
018  0            |        0
019  /            |       10
020  10^x         |       13
021  1            |        1
022  EEX          |       26
023  3            |        3
024  CHS          |       16
025  *            |       20
026  5            |        5
027  0            |        0
028  *            |       20
029  sqrt         |       11
030  RTN          |   43  32
031  LBL D        | 42,21,14
032  x^2          |   43  11
033  5            |        5
034  0            |        0
035  /            |       10
036  1            |        1
037  EEX          |       26
038  3            |        3
039  CHS          |       16
040  /            |       10
041  LOG          |   43  13
042  1            |        1
043  0            |        0
044  *            |       20
045  RTN          |   43  32
046  LBL C        | 42,21,13
047  2            |        2
048  0            |        0
049  /            |       10
050  10^x         |       13
051  STO 2        |    44  2
052  1            |        1
053  +            |       40
054  RCL 2        |    45  2
055  1            |        1
056  -            |       30
057  /            |       10
058  RTN          |   43  32
059  LBL B        | 42,21,12
060  STO 2        |    44  2
061  1            |        1
062  -            |       30
063  RCL 2        |    45  2
064  1            |        1
065  +            |       40
066  /            |       10
067  LOG          |   43  13
068  2            |        2
069  0            |        0
070  *            |       20
071  CHS          |       16
072  RTN          |   43  32
073  LBL A        | 42,21,11
074  /            |       10
075  sqrt         |       11
076  STO 2        |    44  2
077  1            |        1
078  RCL+2        | 45,40, 2
079  1            |        1
080  RCL-2        | 45,30, 2
081  /            |       10
082  STO 3        |    44  3
083  1            |        1
084  -            |       30
085  RCL 3        |    45  3
086  1            |        1
087  +            |       40
088  /            |       10
089  LOG          |   43  13
090  2            |        2
091  0            |        0
092  CHS          |       16
093  *            |       20
094  STO 4        |    44  4
095  RCL 3        |    45  3
096  RTN          |   43  32

Dump

######################################################


DM15
00  01544068044001  01544068044001  01544068044001  00000000000000
04  1154407ffff000  00000000000008  0000000000000c  00000000000eae
08  00000000000000  362f0d9e8a808f  00000000002a00  00000000000000
10  00000000000000  00000000000000  00000000000000  02000000000001
14  f0000000000027  c0d2d2d2d2d2d2  000000000004f8  00000000000000
18  00000000000000  0000000000007f  00000000a00000  00000000000000
c0  01406828223000  01406828223000  01544068044001  00000000000000
f8  000000b23344fc  c3f0f2bcfdfaf1  33fbf143fda2cf  f182cff142cafd
fc  0ab2c3fcf0f2bc  fdfaf132fbf142  0bb2fdfbf132fa  f142ccfdf0f20c
A: 1154407ffff000  B: 1154407ffffeae  C: 00000000000eae
S: 00000000000000
M: 15440680436000  N: 01544068044001  G: 04

Decode of Dump above

#
001  LBL C        | 42,21,13
002  2            |        2
003  0            |        0
004  /            |       10
005  10^x         |       13
006  STO 2        |    44  2
007  1            |        1
008  +            |       40
009  RCL 2        |    45  2
010  1            |        1
011  -            |       30
012  /            |       10
013  RTN          |   43  32
014  LBL B        | 42,21,12
015  STO 2        |    44  2
016  1            |        1
017  -            |       30
018  RCL 2        |    45  2
019  1            |        1
020  +            |       40
021  /            |       10
022  LOG          |   43  13
023  2            |        2
024  0            |        0
025  *            |       20
026  CHS          |       16
027  RTN          |   43  32
028  LBL A        | 42,21,11
029  /            |       10
030  sqrt         |       11
031  STO 2        |    44  2
032  1            |        1
033  RCL+2        | 45,40, 2
034  1            |        1
035  RCL-2        | 45,30, 2
036  /            |       10
037  STO 3        |    44  3
038  1            |        1
039  -            |       30
040  RCL 3        |    45  3
041  1            |        1
042  +            |       40
043  /            |       10
044  LOG          |   43  13
045  2            |        2
046  0            |        0
047  CHS          |       16
048  *            |       20
049  STO 4        |    44  4
050  RCL 3        |    45  3
051  RTN          |   43  32
########################################################################

Dump 23/12/21

### 23/12/21
# A = Stack Y -> Ref, Stack X ->Fwd -> [f][A] -> Stack Y = RL, Stack X = SWR
# B = SWR -> RL
# C = RL -> SWR
# D = PiAttn : (y = attn, x = Zo) -> [f][D] -> (y = series R, x = shunt Rs)
# E = Fibonacci Number x = n -> f(n)
# 


DM15_M1B
00  03400000000001  01000000000001  08000000000000  00000000000000
04  155000000ff000  00000000000008  0000000000000c  00002000010eae
08  00000000000000  2faf0bde7aa28f  000080bcbcaf80  00000000000000
10  00000000000000  01000000000001  00000000000000  03400000000001
14  f7365289446057  1b2d2d2d2d2d2d  000000000001f1  00000000000000
18  00000000000000  0000000000007f  00000000a00000  01387265622000
1c  01387265622000  01579783596001  05000000000001  02500000000003
20  01800000000002  00000000000000  00000000000000  00000000000000
f0  00000000000000  000000000000b2  3344fcc3f0f2bc  fdfaf133fbf143
f4  fda2cff182cff1  42cafd0ab2c3fc  f0f2bcfdfaf132  fbf1420bb2fdfb
f8  f132faf142ccfd  f0f20cb2333444  c0cffdc2cff2fb  ba32f143c0cffd
fc  a2cff182cff142  ccfdc3f0f241c5  400db21182c5b1  fa01f0c1f1400e
A: 155000000ff000  B: 155000000ffeae  C: 00002000010eae
S: 00000000000000
M: 00000000000000  N: 05500000000001  G: 06

Decode of dump above

# 
#
001  LBL E        | 42,21,15
002  STO 0        |    44  0
003  1            |        1
004  ENTER        |       36
005  0            |        0
006  LBL 1        | 42,21, 1
007  +            |       40
008  LSTx         |   43  36
009  x<>y         |       34
010  DSE 0        | 42, 5, 0
011  GTO 1        |    22  1
012  RTN          |   43  32
013  LBL D        | 42,21,14
014  STO 0        |    44  0
015  x<>y         |       34
016  STO 1        |    44  1
017  2            |        2
018  0            |        0
019  CHS          |       16
020  /            |       10
021  10^x         |       13
022  STO 2        |    44  2
023  1            |        1
024  RCL+2        | 45,40, 2
025  1            |        1
026  RCL-2        | 45,30, 2
027  /            |       10
028  RCL*0        | 45,20, 0
029  STO 3        |    44  3
030  1            |        1
031  RCL 2        |    45  2
032  x^2          |   43  11
033  -            |       30
034  2            |        2
035  RCL*2        | 45,20, 2
036  /            |       10
037  RCL*0        | 45,20, 0
038  STO 4        |    44  4
039  RCL 4        |    45  4
040  RCL 3        |    45  3
041  RTN          |   43  32
042  LBL C        | 42,21,13
043  2            |        2
044  0            |        0
045  /            |       10
046  10^x         |       13
047  STO 2        |    44  2
048  1            |        1
049  +            |       40
050  RCL 2        |    45  2
051  1            |        1
052  -            |       30
053  /            |       10
054  RTN          |   43  32
055  LBL B        | 42,21,12
056  STO 2        |    44  2
057  1            |        1
058  -            |       30
059  RCL 2        |    45  2
060  1            |        1
061  +            |       40
062  /            |       10
063  LOG          |   43  13
064  2            |        2
065  0            |        0
066  *            |       20
067  CHS          |       16
068  RTN          |   43  32
069  LBL A        | 42,21,11
070  /            |       10
071  sqrt         |       11
072  STO 2        |    44  2
073  1            |        1
074  RCL+2        | 45,40, 2
075  1            |        1
076  RCL-2        | 45,30, 2
077  /            |       10
078  STO 3        |    44  3
079  1            |        1
080  -            |       30
081  RCL 3        |    45  3
082  1            |        1
083  +            |       40
084  /            |       10
085  LOG          |   43  13
086  2            |        2
087  0            |        0
088  CHS          |       16
089  *            |       20
090  STO 4        |    44  4
091  RCL 3        |    45  3
092  RTN          |   43  32
=======================================================================
#

Dump 10/2/22

#
#    10 Feb 2022
#    Butterworth Filter designer
#    enter filter order (n) into Y register (+ = HPF, - = LPF) , 
#    enter Freq into X register
#    execute program with [f] [A]
#    Values for each component are obtained from registers R1 -> Rn 

DM15_M1B
00  02251666050002  03218976343993  03218976343993  00000000000000
04  16640fff000000  00000000000008  0000000000000c  00012012012eae
08  00000000000000  36800bdf7e820f  bef20200000000  00000000000000
10  05000000000000  03218976343993  06005000000000  02000000000000
14  f0000000012377  1b2d2d2d2d2d2d  000000000005f0  00000000000000
18  00000000000000  0000000000007f  00000000a00300  04918158214989
1c  09947183945992  04918158214989  03218976343993  01103787069994
20  04547284088990  01103787069994  04026420096990  08509227540993
24  02583151782990  04031222906993  05481145266989  07025940305993
28  09506412356989  00000000000000  00000000000000  00000000000000
2c  04000000000007  00000000000000  00000000000000  00000000000000
f0  0000b2fcf2c7fd  fcf230fcf0f8f1  fbf1fcf2001811  9596ce50ff20eb
f4  87012640b340ff  72c56930ff83ff  0a17129596fdfc  b6fcf25986eb87
f8  022608b2139596  fdf0f58605b213  9596fcf0f58604  10ff1950ffa3fd
fc  f2eb87032607b2  97faf1fdf0f0f0  f13006b21514ec  00ffb21415ec09
A: 16640fff000000  B: 16640fff000eae  C: 00012012012eae
S: 00000100000000
M: 02000000000001  N: 06639528095001  G: 23

Decode of dump above

=====================================================================
001  LBL 9        | 42,21, 9
002  x=0          |   43  20
003  GTO 5        |    22  5
004  GTO 4        |    22  4
005  RTN          |   43  32
006  LBL .0       | 42,21,.0
007  x=0          |   43  20
008  GTO 4        |    22  4
009  GTO 5        |    22  5
010  RTN          |   43  32
011  LBL 6        | 42,21, 6
012  RCL 0        |    45  0
013  1            |        1
014  0            |        0
015  0            |        0
016  0            |        0
017  /            |       10
018  1            |        1
019  +            |       40
020  STO I        |   44  25
021  RTN          |   43  32
022  LBL 7        | 42,21, 7
023  GSB 6        |    32  6
024  LBL 3        | 42,21, 3
025  RCL I        |   45  25
026  INT          |   43  44
027  2            |        2
028  /            |       10
029  FRAC         |   42  44
030  F? 0         | 43, 6, 0
031  GTO 9        |    22  9
032  GTO .0       |    22 .0
033  LBL 4        | 42,21, 4
034  RCL (i)      |   45  24
035  5            |        5
036  0            |        0
037  *            |       20
038  STO (i)      |   44  24
039  ISG I        | 42, 6,25
040  GTO 3        |    22  3
041  RTN          |   43  32
042  LBL 5        | 42,21, 5
043  RCL (i)      |   45  24
044  5            |        5
045  0            |        0
046  /            |       10
047  STO (i)      |   44  24
048  ISG I        | 42, 6,25
049  GTO 3        |    22  3
050  RTN          |   43  32
051  LBL 8        | 42,21, 8
052  GSB 6        |    32  6
053  LBL 2        | 42,21, 2
054  RCL I        |   45  25
055  INT          |   43  44
056  RCL (i)      |   45  24
057  RCL .9       |    45 .9
058  2            |        2
059  *            |       20
060  PI           |   43  26
061  *            |       20
062  /            |       10
063  STO (i)      |   44  24
064  ISG I        | 42, 6,25
065  GTO 2        |    22  2
066  GTO 7        |    22  7
067  LBL A        | 42,21,11
068  ENG 3        | 42, 9, 3
069  SF 0         | 43, 4, 0
070  STO .9       |    44 .9
071  x<>y         |       34
072  TEST 2       | 43,30, 2
073  CF 0         | 43, 5, 0
074  ABS          |   43  16
075  STO 0        |    44  0
076  GSB 6        |    32  6
077  LBL 1        | 42,21, 1
078  RCL I        |   45  25
079  INT          |   43  44
080  GSB 0        |    32  0
081  F? 0         | 43, 6, 0
082  1/x          |       15
083  STO (i)      |   44  24
084  ISG I        | 42, 6,25
085  GTO 1        |    22  1
086  GTO 8        |    22  8
087  LBL 0        | 42,21, 0
088  2            |        2
089  *            |       20
090  1            |        1
091  -            |       30
092  1            |        1
093  8            |        8
094  0            |        0
095  *            |       20
096  RCL 0        |    45  0
097  2            |        2
098  *            |       20
099  /            |       10
100  SIN          |       23
101  2            |        2
102  *            |       20
103  RTN          |   43  32

Dump 07/02/25

###############
# 7 Feb 2025
# LBL A = y : ref/ x : fwd fA -> y : RL / x : SWR
# LBL B = SWR -> RL
# LBL C = RL -> SWR
# LBL D = Gas calc (tare ENTER gross ENTER cylinder "full gas weight" (i.e. 6/13/19kg) f D -> percentage full
# LBL E = DTT Freq <-> Channel conversion

DM15_M1B
00  09806650000000  02200000000001  03060000000002  00000000000000
04  066261ff934000  00000000000008  0000000000000c  00000991000eae
08  00000000000000  39a287df7e2200  dba00240000000  00000000000000
10  01579783596001  01579783596001  00000000000000  08000000000000
14  f0000000000014  1b2d2d2d2d2d2d  000000000005f0  00000000000000
18  00000000000000  0000000000007f  00000000a00000  01387265619000
1c  01387265622000  01579783596001  00000000000000  00000000000000
f0  0000b2fdfbf1c5  faf1c1c1ccfdf0  f20cb2c3fcf0f2  bcfdfaf1c5fbf1
f4  c1c10bb23344c3  fcf0f2bcfdfaf1  33fbf143fda2cf  f182cff142cafd
f8  0ab2fcf0f0f1fd  32fbc531fcf4f5  f4c0fafdf6f1fc  f0f0f1a3c5ebc1
fc  40c441c4420db2  faf6f0f3fcf809  b2fdf8fbf6f0f3  1978c5f6f0f30e
A: 066261ff934000  B: 066261ff934eae  C: 00000991000eae
S: 00000100000000
M: 03060000000002  N: 06626070150966  G: 04

Work Tools 23/01/26

###################################
#
#   Label A = DTT : Freq / Channel conversion
#   Label B = Gas : Tare/Gross/Size to calculate percentage-full
#   Label C = Return Loss to SWR conversion
#   Label D = SWR to Return Loss conversion
#   Label E = Reflected & Forward power to Return Loss and SWR calculation

DM15_M1B
00  03060000000002  04925000000001  04925000000001  00000000000000
04  2698000000f000  00000000000008  0000000000000c  00002001001eae
08  00000000000000  bfaf0bfe7e228f  02f082bcbcaf80  00000000000000
10  04002000000001  03650000000001  06000000000000  03060000000002
14  f0000000000100  1b2d2d2d2d2d2d  000000000005f0  00000000000000
18  00000000000000  0000000000007f  00000000a00000  01622214211999
1c  01387265622000  01579783596001  05000000000000  03000000000000
20  00000000000000  00000000000000  04000000000000  08000000000000
24  02100000000001  00000000000000  00000000000000  00000000000000
f0  0000b2faf6f0f3  fcf809b2fdf8fb  f6f0f31978c5f6  f0f30ab2fcf0f0
f4  f1fd32fbc531fc  f4f5f4c0fafdf6  f1fcf0f0f1a3c5  ebc140c441c442
f8  0bb2c3fcf0f2bc  fdfaf1c5fbf1c1  c10db2fdfbf1c5  faf1c1c1ccfdf0
fc  f20cb23344c3fc  f0f2bcfdfaf133  fbf143fda2cff1  82cff142cafd0e
A: 2698000000f000  B: 2698000000feae  C: 00002001001eae
S: 00000000000000
M: 06980000000000  N: 06980000000002  G: 06

Decoded Dump

001  LBL E        | 42,21,15
002  /            |       10
003  sqrt         |       11
004  STO 2        |    44  2
005  1            |        1
006  RCL+2        | 45,40, 2
007  1            |        1
008  RCL-2        | 45,30, 2
009  /            |       10
010  STO 3        |    44  3
011  1            |        1
012  -            |       30
013  RCL 3        |    45  3
014  1            |        1
015  +            |       40
016  /            |       10
017  LOG          |   43  13
018  2            |        2
019  0            |        0
020  *            |       20
021  CHS          |       16
022  STO 4        |    44  4
023  RCL 3        |    45  3
024  RTN          |   43  32
025  LBL C        | 42,21,13
026  2            |        2
027  0            |        0
028  /            |       10
029  10^x         |       13
030  ENTER        |       36
031  ENTER        |       36
032  1            |        1
033  +            |       40
034  x<>y         |       34
035  1            |        1
036  -            |       30
037  /            |       10
038  RTN          |   43  32
039  LBL D        | 42,21,14
040  ENTER        |       36
041  ENTER        |       36
042  1            |        1
043  -            |       30
044  x<>y         |       34
045  1            |        1
046  +            |       40
047  /            |       10
048  LOG          |   43  13
049  2            |        2
050  0            |        0
051  *            |       20
052  CHS          |       16
053  RTN          |   43  32
054  LBL B        | 42,21,12
055  STO 2        |    44  2
056  R_down       |       33
057  STO 1        |    44  1
058  R_down       |       33
059  STO 0        |    44  0
060  ENTER        |       36
061  INT          |   43  44
062  x<>y         |       34
063  FRAC         |   42  44
064  1            |        1
065  0            |        0
066  0            |        0
067  *            |       20
068  1            |        1
069  6            |        6
070  /            |       10
071  +            |       40
072  .            |       48
073  4            |        4
074  5            |        5
075  4            |        4
076  *            |       20
077  RCL 1        |    45  1
078  x<>y         |       34
079  -            |       30
080  RCL 2        |    45  2
081  /            |       10
082  1            |        1
083  0            |        0
084  0            |        0
085  *            |       20
086  RTN          |   43  32
087  LBL A        | 42,21,11
088  3            |        3
089  0            |        0
090  6            |        6
091  x<>y         |       34
092  TEST 8       | 43,30, 8
093  GTO 9        |    22  9
094  3            |        3
095  0            |        0
096  6            |        6
097  -            |       30
098  8            |        8
099  /            |       10
100  RTN          |   43  32
101  LBL 9        | 42,21, 9
102  8            |        8
103  *            |       20
104  3            |        3
105  0            |        0
106  6            |        6
107  +            |       40
108  RTN          |   43  32

LBL A = DTT MHz or Channel No f A → Channel No or MHz
LBL B = Gas : tare weight ENTER gross kg ENTER cylinder size kg f B → Fill percentage %
LBL C = Return Loss dBf C → SWR
LBL D = SWR f D → Return Loss dB
LBL E = Reflected Power ENTER Forward Power f E → Return Loss dB (y), SWR (x)

Solve with an Integral

from HP34C manual pp233
Solves Bessel function for Bessel-zero mod. index value

DM15_M1B
00  02404827787000  00000000000000  01570796327996  30001fd33ff996
04  024048fffff000  00000000000008  0000000000000c  40999997000eae
08  00000000000000  2fbf8db6e42080  00000000000040  00000000000000
10  02404827787000  00000000000000  00000000000000  95139629874993
14  00000000000000  1b2d2d2d2d2d2d  000000000006fd  00000000000000
18  00000000000000  0000000000007f  00000000a00000  00000000000000
fc  00000000000000  00b2fdb6c8fc30  c703b2b170a2ed  b333efb6f0400a
A: 024048fffff000  B: 024048fffffeae  C: 40999997000eae
S: 00000000000000
M: 000000000060fd  N: 02404827787000  G: 04


LBL A
STO 0
0
PI
∫ 3
ABS
         // THIS IS A METHOD OF RESTRICTING SOLVE TO A CERTAIN ACCURACY TO REDUCE THE TIME..
x<=y?    // y has the Integration accuracy estimate. We test if our "zero" is <= this. No point in trying further. Limits search time
CLx      // if our current guess for "zero" is better than the integration accuracy estimate we wipe "x" to an "actual" zero so that the SOLVE will complete
x≠0?     // if it wasn't "zero" we replace the last estimate of the integration and the SOLVE continues
LASTx
RTN

LBL 3
SIN
RCL 0
*
COS
PI
/
RTN

be in RAD angle mode
put initial guesses of 0 ENTER 1 and then f SOLVE A
first bessel zero at mod index 2.405

Program dumps for LF15C

Firmware details

LF15C - firmware for the DM15

Start of thread : https://www.hpmuseum.org/forum/thread-20046.html
- 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
To extract a dump from calculator press and hold STO
- the non-zero digits can be copy/pasted into a text file for storage
To upload a previously saved dump
- copy it to clipboard and then
- press and hold RCL until the terminal shows Paste PrgMemory:
- in Putty ShiftFnInsert to paste clipboard text into terminal

Butterworth Filter

43 8 17 255 17 19 30 39 103 39 40 86 43 9 118 12 7 5 7 4 86 43 10 118 12 7 4 7 5 86 43 6 17 0 26 25 25 25 40 26 37 13 254 86 43 7 6 6 43 3 17 254 93 30 40 53 115 0 7 9 7 10 43 4 6 8 31 25 39 13 255 75 254 7 3 86 43 5 6 8 31 25 40 13 255 75 254 7 3 86 7 7 43 100 76 3 107 0 13 19 14 118 3 111 0 104 13 0 6 6 43 1 17 254 93 6 0 115 0 20 13 255 75 254 7 1 7 7 43 0 30 39 26 38 26 32 25 39 17 0 30 39 40 11 30 39 86 0

Order n (+ is HPF, - is LPF) → y
Frequency (Hz) → X
fA
Results are in R01 … R0n

Benchmarks

Savage, 8-queens, HP Maths and HP Trig

43 77 31 35 29 30 35 13 0 25 13 2 43 78 17 0 11 91 15 95 19 99 88 8 26 121 2 7 78 86 43 104 25 13 2 26 29 25 26 30 34 27 23 35 13 0 30 29 34 27 31 13 1 43 2 17 1 17 0 39 17 1 38 17 0 40 17 1 39 34 29 31 40 4 26 121 2 7 2 86 43 88 54 32 13 10 43 80 17 0 17 10 118 6 7 84 26 121 0 17 0 13 254 17 10 13 255 43 81 26 121 11 17 0 13 9 43 82 26 122 9 17 9 118 12 7 80 17 0 13 254 17 255 17 9 13 254 10 17 255 38 118 12 7 83 104 17 0 17 9 38 118 7 7 82 43 83 17 0 13 254 26 122 255 17 255 118 1 7 81 26 122 0 17 0 118 1 7 83 43 84 17 11 58 86 43 100 112 30 27 36 36 13 0 26 22 22 22 43 101 84 4 88 8 99 19 37 71 0 7 101 58 86 0

Savage is prog A : fA
8-Queens is prog 88 : f LBL 88
- Both the above use runTime to measure execution time - returns result in y and time in x
HP Museum Maths Benchmark is prog E : fE.
- Run for 60 seconds, press R/S and find result in reg 02 RCL02
HP Museum Trig Benchmark is prog 77 : fLBL 77.
- Run for 60 seconds, press R/S and find result in reg 02 RCL02

Work Tools

43 104 40 4 13 2 26 125 2 26 126 2 40 13 3 26 38 17 3 26 37 40 92 30 25 39 24 17 3 86 43 103 22 22 26 38 14 26 37 40 92 30 25 39 24 86 43 102 30 25 40 12 22 22 26 37 14 26 38 40 86 43 101 13 2 10 13 1 10 13 0 22 93 14 53 26 25 25 39 26 35 40 37 29 27 31 27 39 17 1 14 38 17 2 40 26 25 25 39 86 43 100 34 25 31 14 118 8 7 1 32 39 34 25 35 37 86 43 1 34 25 35 38 32 40 86 0

LBL A = DTT (Channel ↔ Freq )
LBL B = Gas
LBL C = Return Loss → SWR
LBL D = SWR → Return Loss
LBL E = Reflected Power & Forward Power → Return Loss & SWR

Work Tools & Benchmarks

43 55 31 35 29 30 35 13 0 25 13 2 43 56 17 0 11 91 15 95 19 99 88 8 26 121 2 7 56 86 43 44 25 13 2 26 29 25 26 30 34 27 23 35 13 0 30 29 34 27 31 13 1 43 45 17 1 17 0 39 17 1 38 17 0 40 17 1 39 34 29 31 40 4 26 121 2 7 45 86 43 88 54 32 13 10 43 80 17 0 17 10 118 6 7 84 26 121 0 17 0 13 254 17 10 13 255 43 81 26 121 11 17 0 13 9 43 82 26 122 9 17 9 118 12 7 80 17 0 13 254 17 255 17 9 13 254 10 17 255 38 118 12 7 83 104 17 0 17 9 38 118 7 7 82 43 83 17 0 13 254 26 122 255 17 255 118 1 7 81 26 122 0 17 0 118 1 7 83 43 84 17 11 58 86 43 66 112 30 27 36 36 13 0 26 22 22 22 43 67 84 4 88 8 99 19 37 71 0 7 67 58 86 43 104 40 4 13 2 26 125 2 26 126 2 40 13 3 26 38 17 3 26 37 40 92 30 25 39 24 17 3 86 43 103 22 22 26 38 14 26 37 40 92 30 25 39 24 86 43 102 30 25 40 12 22 22 26 37 14 26 38 40 86 43 101 13 2 10 13 1 10 13 0 22 93 14 53 26 25 25 39 26 35 40 37 29 27 31 27 39 17 1 14 38 17 2 40 26 25 25 39 86 43 100 34 25 31 14 118 8 7 1 32 39 34 25 35 37 86 43 1 34 25 35 38 32 40 86 0 0

LBL A = DTT (Channel ↔ Freq )
LBL B = Gas
LBL C = Return Loss → SWR
LBL D = SWR → Return Loss
LBL E = Reflected Power & Forward Power → Return Loss & SWR

Savage is prog is prog 66 : f LBL 66
8-Queens is prog 88 : f LBL 88
- Both the above use runTime to measure execution time - returns result in y and time in x
HP Museum Maths Benchmark is prog is prog 44 : f LBL 44
- Run for 60 seconds, press R/S and find result in reg 02 RCL02
HP Museum Trig Benchmark is prog 55 : fLBL 55.
- Run for 60 seconds, press R/S and find result in reg 02 RCL02

Dot/Cross/Uvec

43 12 22 104 40 86 43 11 13 99 10 13 98 55 17 99 39 17 98 17 99 55 39 38 30 78 40 86 43 10 13 98 10 13 99 17 98 55 39 17 98 17 99 55 39 37 30 40 86 0 0

* Dot Product of 2 complex numbers in y and x

|Y||X|Cosθ
- Y = Y_re + j Y_im
- X = X_re + j X_im
- Dot Product Y ⋅ X = Y_reX_re + Y_imX_im
Another way without splitting the complex number into its real & imaginary parts
- Dot Product Y ⋅ X = (Y^*.X + Y.X^*) / 2
  - f LBL 10

Cross Product of 2 complex numbers in y and x
- |Y||X|Sinθ
  - Y = Y_re + j Y_im
  - X = X_re + j X_im
  - Cross Product Y ⊗ X = Y_reX_im - Y_imX_re
- Another way without splitting the complex number into its real & imaginary parts
  - Cross Product Y ⊗ X = (Y^*.X - Y.X^*) / 2i
    - f LBL 11

Unit Vector of a complex number in x : f LBL 12

Dot Product

LBL 10
STO 98
R↓
STO 99
RCL 98
f (i)
x
RCL 98
RCL 99
f (i)
x
+
2
/
RTN

Cross Product

LBL 11
STO 99
R↓
STO 98
f (i)
RCL 99
x
RCL 98
RCL 99
f (i)
x
-
2
f Re<>Im
/
RTN

UVEC

LBL 12
ENTER
ABS
/
RTN

Work Tools & Dot/Cross/UVEC

43 104 40 4 13 2 26 125 2 26 126 2 40 13 3 26 38 17 3 26 37 40 92 30 25 39 24 13 4 17 3 86 43 102 30 25 40 12 22 22 26 37 14 26 38 40 86 43 103 22 22 26 38 14 26 37 40 92 30 25 39 24 86 43 101 13 2 10 13 1 10 13 0 22 93 14 53 26 25 25 39 26 35 40 37 29 27 31 27 39 17 1 14 38 17 2 40 26 25 25 39 86 43 100 34 25 35 14 118 9 7 9 34 25 35 38 32 40 86 43 9 32 39 34 25 35 37 86 43 12 22 104 40 86 43 11 13 99 10 13 98 55 17 99 39 17 98 17 99 55 39 38 30 78 40 86 43 10 13 98 10 13 99 17 98 55 39 17 98 17 99 55 39 37 30 40 86 0 0

LBL A = DTT MHz or Channel No f A → Channel No or MHz
LBL B = Gas : tare weight ENTER gross kg ENTER cylinder size kg f B → Fill percentage %
LBL C = Return Loss dBf C → SWR
LBL D = SWR f D → Return Loss dB
LBL E = Reflected Power ENTER Forward Power f E → Return Loss dB (y), SWR (x)

LBL 10 = Dot Product
LBL 11 = Cross Product
LBL 12 = Unit Vector

Solve with an Integral

from HP34C manual pp233
Solves Bessel function for Bessel-zero mod. index value

differs from the DM15L (HP15C) version because the Integration Accuracy estimate is very small so the test of x < = y? will never be true
instead we store a required ACC value (much like in the HP42S/DM42) in R001 and test against this instead

Memory Dump

43 100 13 0 25 103 79 3 104 17 1 118 8 98 118 1 102 86 43 3 11 17 0 39 15 103 40 86 0 0

Code


LBL A
STO 0
0
PI
∫ 3
ABS
RCL 1
x>y? // test if current guess (y) is better (lower) than our required accuracy (x)
CLx   // if it is, we're near enough, put a real zero in x
x≠0   // if it isn't zero we need to continue
LASTx // put back the last guess into x and the SOLVE goes on
RTN


LBL 3
SIN
RCL 0
*
COS
PI
/
RTN

be in RAD angle mode
put your ACC value in R001 (e.g. 0.0001 or 0.00001)
put initial guesses of 1 ENTER 2 and then f SOLVE A
first bessel zero at mod index 2.4048

Integrate Tests

The 12 Integration examples from the PPC ROM handbook section IG

43 12 84 24 26 37 14 24 30 37 39 4 86 43 11 28 16 14 84 24 26 37 4 39 14 24 30 37 26 34 22 30 40 16 40 86 43 10 84 24 26 37 4 86 43 9 30 20 24 16 86 43 8 88 15 86 43 7 35 25 25 103 39 37 4 14 4 37 14 11 84 35 25 25 39 14 40 86 43 6 24 27 37 14 39 4 86 43 5 4 14 26 38 40 14 88 20 38 86 43 4 88 86 43 3 103 39 11 86 43 2 4 86 43 1 27 14 84 26 37 40 86 0 0

SCI04 display mode

12 programs. Set limits and then execute f ∫ prog number

For example for program 1

0 ENTER 1 f ∫ 0 1 gives answer 3.1416

Limits 0 → 1 answer 3.1416
Limits 0 → 1 answer 6.6667 E-1
Limits 0 → 1 answer 6.3662 E-1 (rads mode)
Limits 0 → 1 answer -1.000
Limits 0 → 1 answer 3.6490 E-2
Limits 0 → 2 answer 3.1416
Limits 0 → π answer 2.1102 E1
Limits 0 → 1 answer 5.0000 E-1 (rads mode)
Limits 0 → 1 answer 2.0000
Limits 0 → 1 answer 7.8540 E-1
Limits -1 → 1 answer 2.3857 E-2
Limits -1 → 1 answer 2.2033

Using FIX10 still allows the integrations to complete almost instantly except for Program 8 which takes around 8 seconds!

Dropping to FIX08 and program 8 integration completes almost instantaneously too. Strangely Program 8 has some odd behaviour regarding display precision.

FIX04 → FIX07 → instantaneous answer 0.5000….
FIX08 → instantaneous answer 0.50000….
FIX09 → 8 seconds answer 0.499964689
FIX10 → 8 seconds answer 0.4999747623
FIX11 → 10 seconds answer 0.49999489949
FIX12 → 10 seconds answer 0.499999962001
FIX13 → instantaneous answer 0.5000……
FIX14 → instantaneous answer 0.500000……
FIX15 → instantaneous answer 0.5000000……

Page Info

Page created Thu May 26 17:35:39 2022 by John Pumford-Green

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

Further Information

calculator, dm15l, lf15c

DM15L Info - [Update January 2026]

john@undisclosed.example.com (john) — Sat, 04 Apr 2026 10:40:50 +0000

←Calculator Hardware

DM15L Info

Purchase Information

Date : September 2021
From : Swiss Micros (direct)
Price : £95
Serial : 21350
New Battery
- July 27^th 2022
- July 26^th 2024

Firmware

Upgrade firmware on Linux

sudo lpc21isp <firmware_file> /dev/ttyUSB0 115200 12000

bash scripts

just to reduce the typing…. still need to press the hidden reset button to start the flashing and to start the new firmware.

You can have separate scripts for ease of loading different firmware

./lf_flash.sh

#!/bin/bash
#
 
FWARE=LF15C_250408.hex
 
lpc21isp $FWARE /dev/ttyUSB0 115200 1200

./dm32_flash.sh

#!/bin/bash
#
 
FWARE=DM15_M1B_32.hex
 
lpc21isp $FWARE /dev/ttyUSB0 115200 1200

./dm34_flash.sh

#!/bin/bash
#
 
FWARE=DM15_M1B_34.hex
 
lpc21isp $FWARE /dev/ttyUSB0 115200 1200

Upgrade firware on Windows

Serial USB Driver for Windows

cp210x_universal_windows_driver.zip

Windows Firmware Upload Tool

voyage_firmware_tool.zip

Swiss Micros Official

Swiss Micros Firmware files

Date	Serial No.	Firmware	Version	Firmware Files	Comments
24/05/22	21350	DM15_M1B	32	dm15_m1b_32.zip	Extended User Registers
22/11/23	21350	DM15	32	dm15_32.zip	Standard User Registers
21/12/24	21350	DM15_M1B	33	dm15_m1b_33.zip	New 2-line stack and other mods
23/01/26	21350	DM15_M1B	34	dm15_m1b_34.hex	Bug fixes to new version

ROM	Allocatable registers	RAM base addr.	Initial Memory Status
DM15 (Original ROM)	64	0xc0	19 46 0-0
DM15_M80	128	0x80	19 110 0-0
DM15_M1B	229	0x1b	19 211 0-0

LF15C - 3rd Party Firmware

From HP Forum https://www.hpmuseum.org/forum/thread-20046.html

For more details see LF15C - firmware for the DM15

DESK-15 - 3rd Party Firmware

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

I'll try it out and write up some details…..

Desk15 - firmware for the DM15

RTC Error

RTC is not capable of calibration/correction
RTC appears to continue running even when switching firmware
- LF15C has no ability to display RTC but it the rate appears unaffected by the firmware changes
- Requires that Swiss Micros firmware is loaded in order to check current RTC time

Update January 2026

Using my python Watchcheck

Date Start	Date Check	Delta	Latest Rate Error	Average Rate Error	Comments
23/01/26		-49.0			Delta -49.0. New firmware DM15 V34 loaded. New Period
23/01/26	24/01/26	-47.0	+2.1	+2.1	After 24 hours
23/01/26	26/01/26	-43.4	+1.9	+2.0	After 3 days
23/01/26	27/01/26	-41.9	+1.8	+1.9	After 4 days. LF15C loaded after time check
23/01/26	11/02/26	-11.2	+2.0	+2.0	After 19 days. DM15_M1B_34 reloaded to check time
23/01/26	04/04/26	+88.3	+1.9	+1.9	After 71 days

Swiss Micros Info

Firmware : https://technical.swissmicros.com/voyager/firmware/
Documentation : Online HTML User Manual
Documentation : PDF Manual
Product Page : DM15L

HP-15C Owner's Handbooks

Download from https://literature.hpcalc.org/

HP-15C Owner's Handbook : https://literature.hpcalc.org/community/hp15c-oh-en.pdf
HP-15C Advanced Functions Handbook : https://literature.hpcalc.org/community/hp15c-afh-en.pdf

DM15L Memory Dumps and Program Listings

See DM15L Progs

calculator, dm15l

DM41L Info - [Purchase Information]

john@undisclosed.example.com (john) — Sat, 04 Apr 2026 10:33:16 +0000

←Calculator Hardware

DM41L Info

Purchase Information

Date : 26 Aug 2024
From : Swiss Micros (Direct)
Price : approx £200
Serial : 05121
Battery Change
- 26/08/24
- 04/04/26

Firmware

cp210x_universal_windows_driver.zip

Date	Serial No.	Firmware	Version	Firmware Files	Firmware Tool
26/08/24	05121	DM41	V32	dm41_32.zip	voyage_firmware_tool.zip
01/02/25	05121	DM41	V33	dm41_33.zip
21/12/25	05121	DM41	V34	dm41_34.zip	Linux, using lpc21isp

RTC

RTC is not capable of calibration/correction?
- Perhaps the HP41CX Time corr. feature works?
- Gather data on inherent time error for a period and then try to change the values via HP41CX functionality

Update January 2026

Using my python Watchcheck

Date Start	Date Check	Delta	Latest Rate Error	Average Rate Error	Comments
23/01/26		+49.6			New Period Start
23/01/26	24/01/26	+50.6	+1.0	+1.0	After 24 hours
23/01/26	26/01/26	+52.8	+1.2	+1.1	After 3 days
23/01/26	27/01/26	+53.6	+1.0	+1.1	After 4 days

Swiss Micros Info

Firmware : https://technical.swissmicros.com/voyager/firmware/
Documentation : Online HTML User Manual
Documentation : PDF Manual
Product Page : DM41L

HP-41CX Owner's Manuals

Download from https://literature.hpcalc.org

HP-41CX Owner's Manual Vol. 1 : https://literature.hpcalc.org/community/hp41cx-om-vol1-en.pdf
HP-41CX Owner's Manual Vol. 2 : https://literature.hpcalc.org/community/hp41cx-om-vol2-en.pdf
HP-41CX Quick Reference Guide : https://literature.hpcalc.org/community/hp41cx-qrg-en.pdf

Further Information

calculator, dm41l

brq_com_6_txa2_exa_p2_21_r_.tmp - created

john@undisclosed.example.com (john) — Thu, 19 Mar 2026 11:59:33 +0000

brq_com_6_txa2_exa_p1_21_m_.tmp - created

john@undisclosed.example.com (john) — Thu, 19 Mar 2026 11:59:06 +0000

Pure Blog - [Installation & Configuration]

john@undisclosed.example.com (john) — Tue, 03 Mar 2026 07:32:20 +0000

←Computers

Pure Blog

I've installed Pure Blog

After trying the Blog Plugin in dokuwiki and Chyrp-Lite PHP/SQLite blogging platform I switched to Pure Blog.

It's just what I need, and nothing extra to make it big and bloated.

Installation & Configuration

See https://g4slv.info/installing-pure-blog for some info.

Webfonts used

CSS

.tag-cloud a {
   margin: 0 0.5rem;
   line-height: 2rem;
 
}
 
.archive li {
  line-height: 1.5rem;
  font-size: 1.1rem;
  list-style-type: none;
}
 
body {
  font-size: 1rem;
  line-height: 1.25rem;
}
 
main {
  max-width: 50rem;
}
 
article {
  margin-bottom: 0;
}
 
p.post-archive-view {
  font-size : 1.1rem;
  line-height: 1.1rem;
}
main h1 {
  font-size: 2.8rem;
}
 
header, footer{
  font-family: "atkinson_next", sans-serif;
  font-size: 1.1rem;
}
 
footer {
  margin-top: 3rem;
}
 
main h1, main h2, main h3, main h4, main h5, main h6 {
  margin-left: -1rem;
  font-family: "atkinson_next", sans-serif;
}
 
.tag-list {
    border-top: 1px solid var(--border-color);
    padding-top: 2rem;
}
 
.post-nav {
  margin-top : 0;
  margin-bottom: 3rem;
}
@font-face {
  font-family: 'atkinson_next';
  src: url('/content/fonts/AtkinsonHyperlegibleNext-Regular.woff2') format('woff2');
       font-weight: normal;
       font-display: swap;
       font-style: normal;
}
@font-face {
  font-family: 'atkinson_next';
  src: url('/content/fonts/AtkinsonHyperlegibleNext-Bold.woff2') format('woff2');
       font-weight: bold;
       font-display: swap;
       font-style: normal;
}
@font-face {
  font-family: 'atkinson_next';
  src: url('/content/fonts/AtkinsonHyperlegibleNext-RegularItalic.woff2') format('woff2');
       font-weight: normal;
       font-display: swap;
       font-style: italic;
}
@font-face {
  font-family: 'atkinson_next';
  src: url('/content/fonts/AtkinsonHyperlegibleNext-BoldItalic.woff2') format('woff2');
       font-weight: bold;
       font-display: swap;
       font-style: italic;
}
@font-face {
  font-family: 'atkinson_mono';
  src: url('/content/fonts/AtkinsonHyperlegibleMono-Regular.woff2') format('woff2');
       font-weight: normal;
       font-display: swap;
       font-style: normal;
}
@font-face {
  font-family: 'atkinson_mono';
  src: url('/content/fonts/AtkinsonHyperlegibleMono-RegularItalic.woff2') format('woff2');
       font-weight: normal;
       font-display: swap;
       font-style: italic;
}
@font-face {
  font-family: 'atkinson_mono';
  src: url('/content/fonts/AtkinsonHyperlegibleMono-Bold.woff2') format('woff2');
       font-weight: bold;
       font-display: swap;
       font-style: normal;
}
@font-face {
  font-family: 'atkinson_mono';
  src: url('/content/fonts/AtkinsonHyperlegibleMono-BoldItalic.woff2') format('woff2');
       font-weight: bold;
       font-display: swap;
       font-style: italic;
}
 
:root {
  --font-stack: "atkinson_mono", system-ui, monospace;
}
 
pre {
  font-family: "atkinson_mono", monospace;
}
 
code {
  font-family: "atkinson_mono", monospace;
}

Addons

Kev sent me 2 PHP scripts to provide a Tag-Cloud and a full site Archive page.

I tweaked them a bit, and here are my current versions.

tag-cloud.php

<?php
 
 
 
declare(strict_types=1);
 
 
 
$pageTitle = 'Tag Cloud';
 
$metaDescription = 'All tags, sized by how often they appear.';
 
 
 
$tagIndex = load_tag_index();
 
$tagCounts = [];
 
if ($tagIndex) {
 
    foreach ($tagIndex as $slug => $slugs) {
 
        $tagCounts[$slug] = count($slugs);
 
    }
 
}
 
 
 
// Collect original display names from posts (slugs alone lose capitalisation/spaces)
 
$originalNames = [];
 
foreach (get_all_posts(false) as $post) {
 
    foreach (($post['tags'] ?? []) as $tag) {
 
        $slug = normalize_tag($tag);
 
        if (!isset($originalNames[$slug])) {
 
            $originalNames[$slug] = $tag;
 
        }
 
    }
 
}
 
 
 
// Sort alphabetically by display name
 
uksort($tagCounts, function (string $a, string $b) use ($originalNames): int {
 
    return strcasecmp($originalNames[$a] ?? $a, $originalNames[$b] ?? $b);
 
});
 
 
 
$maxCount = $tagCounts ? max($tagCounts) : 1;
 
$minCount = $tagCounts ? min($tagCounts) : 1;
 
$range    = $maxCount > $minCount ? $maxCount - $minCount : 1;
 
 
 
require PUREBLOG_BASE_PATH . '/includes/header.php';
 
render_masthead_layout($config, ['page' => null]);
 
?>
 
<main>
 
    <h1>Tag Cloud</h1>
 
 
 
    <?php if (empty($tagCounts)): ?>
 
        <p>No tags found.</p>
 
    <?php else: ?>
 
        <p class="tag-cloud">
 
            <?php foreach ($tagCounts as $slug => $count):
 
                $name     = $originalNames[$slug] ?? $slug;
 
                $ratio    = ($count - $minCount) / $range;
 
                $fontSize = round(0.85 + $ratio * 1.4, 2);
 
                $postWord = $count === 1 ? 'post' : 'posts';
 
                echo '<a href="/tag/' . e(rawurlencode($slug)) . '"'
 
                   . ' style="font-size: ' . $fontSize . 'em"'
 
                   . ' title="' . e((string) $count) . ' ' . $postWord . '">'
 
                   . e($name) .  '(' .  e((string) $count) . ')' .  '</a>' . '&emsp;&emsp;';
 
            endforeach; ?>
 
        </p>
 
    <?php endif; ?>
 
</main>
 
<?php render_footer_layout($config, ['page' => null]); ?>
 
</body>
 
</html>

archive.php

<?php
declare(strict_types=1);
 
$allPosts = get_all_posts(false);
$postsByYear = [];
 
foreach ($allPosts as $entry) {
    $year = !empty($entry['date']) ? date('Y', strtotime((string) $entry['date'])) : 'Unknown';
    $postsByYear[$year][] = $entry;
}
 
krsort($postsByYear, SORT_NATURAL);
 
$pageTitle = 'Archive';
$metaDescription = 'Browse all published posts by year.';
?>
<?php require PUREBLOG_BASE_PATH . '/includes/header.php'; ?>
<?php render_masthead_layout($config); ?>
<main class=archive>
    <article>
        <h1>Archive</h1>
        <p><?= e((string) count($allPosts)) ?> published posts.</p>
 
        <?php if (!$allPosts): ?>
            <p>No published posts yet.</p>
        <?php else: ?>
            <?php foreach ($postsByYear as $year => $yearPosts): ?>
                <h3><?= e((string) $year) ?> (<?= e((string) count($yearPosts)) ?>)</h3>
                <ul>
                    <?php foreach ($yearPosts as $postItem): ?>
                        <li>
                            <?php if (!empty($postItem['date'])): ?>
                              <!--  <small> -->
                                    <time datetime="<?= e((string) $postItem['date']) ?>">
                                        <?= e(date('D Y-m-d H:i', strtotime((string) $postItem['date']))) ?>
                                    </time>
			   <!--     </small> -->
				&emsp;
                            <?php endif; ?>
                            <a href="/<?= e((string) ($postItem['slug'] ?? '')) ?>">
                                <?= e((string) ($postItem['title'] ?? 'Untitled')) ?>
                            </a>
                        </li>
                    <?php endforeach; ?>
                </ul>
            <?php endforeach; ?>
        <?php endif; ?>
    </article>
</main>
<?php render_footer_layout($config); ?>
</body>
</html>

Further Information

pure, blog

Page created : 02/03/26 08:50 GMT

Page updated : 03/03/26 07:32 GMT

atkinson_next_woff2.zip - created

john@undisclosed.example.com (john) — Tue, 03 Mar 2026 07:29:44 +0000

atkinson_hyperlegible_mono_woff2.zip - created

john@undisclosed.example.com (john) — Tue, 03 Mar 2026 07:29:14 +0000

John's Vademecum

DM41X Info - [Purchase Information]

DM41X Info

Purchase Information

Firmware

RTC Correction

Update 28/5/22

Update January 2026

Notes

Complex Numbers

HP16C Emulator module

Guides

Swiss Micros Info

Issues

41Z Deluxe Module

Module files that work (for me)

Update September 2024

DM41X Program Listings

HP-41CX Owner's Manuals

LF15C - firmware for the DM15 - [LF15C Firmware Files]

LF15C - firmware for the DM15

Overview of LF15C

Installing LF15C

DM15L running V32 or earlier (Linux)

DM15L running V33 or later (Linux)

For installation using Windows

Files

Download from here

Download from HP Forum & Swiss Micros

LF15C General Info

HP15C functions

HP15C features not supported

DM15L features not supported

Speed tests

n-Queens

Savage

Using LF15C

Complex Numbers

Making & manipulating a complex number

Rectangular and Polar modes for complex numbers

Arithmetic can be done in Rectangular or Polar mode.

Other features

Indirect addressing

Indirect Register pair I & (i)

Indirect Program Label addressing

Indirect Program Line Number Addressing

And the rest

LF15C Serial Port Info

LF15C Firmware Files

Further Information

lf15c_260412.hex - created

DM15L Non-linear Curve Fit - [Example Data]

DM15L Non-linear Curve Fit

Background

Tl;dr

Method for Exponential

Method for Logarithmic

Method for Power

Exponential

Mechanism

Example Data

Method for Exponential

Logarithmic

Mechanism

Example Data

Method for Logarithmic

Power

Mechanism

Example Data

Method for Power

Further Information

lf15c_260331.hex - created

lf15c_260404.hex - created

lf15c_260404.txt - created

DM15L Progs - [Integrate Tests]

DM15L Progs

Stock Swiss Micros Firmware

Normal + "Complex Z to....."

"Normal"

N-Queens Benchmark 27/7/22