DM42 Quick Reference Guide

  • Inspired by the HP-42S Quick Reference Guide (c) Copyright 1988 Dex Smith

Navigation

  • Press ÷ to move one page backward

  • Press × to move one page forward

  • Press - to move one line backward

  • Press + to move one line forward

  • Press ▲ to select previous link

  • Press ▼ to select next link

  • Press ENTER to jump to selected link

  • Press EXIT or F1 to exit

  • Press F2 to jump to Contents

  • Press F3 to open help file selection dialog

Numpad-like navigation keys

  • 2/8 - single line down/up

  • 3/9 - page down/up

  • 4/6 - prev/next link (same as arrows)

  • 5 - follow the link (same as ENTER)

  • 7 - go to the Contents (same as F2)

Symbols used in this guide

  • A 123 represents a soft button or anything on the LCD

  • A STO represents a physical button

    +

Contents

Menus

DM42 calculator has far too many functions to assign a key to each one, so most of them are available in menus rather than directly on keys.
Each menu displays a row of labels at the bottom of the screen, one above each key in the top row of the keyboard.
A function within the menu is activated by pressing the key directly below it. If there are more than six functions in the menu then the ▼▲ annunciator is displayed and the ▼ and ▲ keys allow you to scroll through the menu’s pages. There are two kinds of menu:

Application Menu

There are five applications built into the DM42:

Function Menu

  • CATALOG All DM42 Functions

  • CLEAR Functions for clearing programs and variables

  • CONVERT Angle, time, and coordinate conversion functions

  • CUSTOM Displays custom menu

  • DISP Display Formats

  • FLAGS Flags

  • MODES Angles and Coordinates

  • PGM.FCN Functions useful in programs

  • PRINT Enable IR Printing

  • PROB Combinatorics and probability functions

     +
Unlike application menus, a Function menu closes as soon as you have
used one of the functions that it contains, with the exception of the
[.button]#CUSTOM# menu, which remains open. Should you need to use more
than one function from a Function menu, you can instruct the DM42 to
keep the menu open by opening it twice in succession. +
 +

Storage

The Stack

The stack is the scratchpad that you use for performing calculations. It stores and shows you intermediate results as you work through a problem.
The four registers that make up the stack are known as X,Y,Z,T. Auxiliary register LASTx holds contents of X register used in most recent numeric function. Each of these registers can contain data of any type.

Storage Registers

Because of the ephemeral nature of the stack, data in its registers is likely to be lost when a new calculation is started.
More permanent storage can be achieved in the storage registers, of which there are 25 initially, numbered 00 to 24. This number can be altered with the SIZE function in the MODES menu.
STO nn STOres the contents of the X register into the storage register with the given number.
RCL nn ReCaLls the data from storage register nn into the stack.
If SIZE has been used to define more than 100 storage registers then registers numbered 100 and onwards can only be accessed using indirect addressing.
The STATistics application uses some of the storage registers for its internal housekeeping:

  • R11 Σ x

  • R12 Σ x2

  • R13 Σ y

  • R14 Σ y2

  • R15 Σ xy

  • R16 n

If ALLΣ mode is being used (as opposed to LINΣ mode) then the following additional storage registers are used:

  • R17 Σ ln x

  • R18 Σ (ln x)2

  • R19 Σ ln y

  • R20 Σ (ln y)2

  • R21 Σ ln x ln y

  • R22 Σ x ln y

  • R23 Σ y ln x

The storage registers can be all real numbers or all complex numbers. See Variables for how to switch between the two.

Variables

Rather than referring to stored data by a simple number (the number of the storage register containing it), it is possible to create named variables. Variables allow you to associate a meaningful name with the data. Also, named variables can contain any type of data, not just real or complex numbers.
E.g. suppose you have just calculated the volume of a shape. Store the value currently in the X register representing this volume in a variable named VOL:
STO ENTER VOL ENTER
Variables can have names up to seven characters long.
There is one system-reserved variable, REGS. REGS is a matrix containing the storage registers. REGS can be a real matrix, in which case all of the storage registers, i.e. the elements of REGS, are real numbers, or it can be a complex matrix, in which case all of the storage registers are complex numbers.
To convert REGS (or any other real matrix) to a complex matrix:
0 ENTER COMPLEX STO + REGS
To convert REGS from a complex matrix back into a real matrix:
RCL REGS COMPLEX x<>y STO REGS

The Alpha Register

The alpha Register can store up to 44 characters of text, which equate to two lines of text on the original HP-42S.

Available Memory

The DM42 has about 70KB of system memory that your programs and variables can use. The storage register matrix REGS uses some of this space.
To find out how much memory your DM42 has available, open the CATALOG menu and then press and hold MEM.
If you need more memory then use the CLP (CLear Program) and CLV (CLear Variable) functions from the CLEAR menu to remove unneccesary programs and variables and thus free up additional memory.
DO NOT DELETE THE REGS VARIABLE! Remember, it holds your storage registers! If necessary you can reduce its size with the SIZE command from the MODES menu.

Data Types

Real Numbers

Real numbers cover integer and decimal numbers, positive or negative. The range of numbers that the DM42 can handle is approximately 10-6143 to 106144 with a precision of 34 digits.

Complex Numbers

A complex number consists of two real numbers associated to form its real part and its imaginary part (rectangular coordinate mode).
Complex numbers are always stored internally in rectangular form but can be displayed directly:
0.2343 i1.4456
or in polar coordinate mode with a magnitude and an angle:
1.4645 ∡80.7937
Both of the examples here represent the same complex number.
To enter a complex number in rectangular mode:
real part ENTER imaginary part COMPLEX
To enter a complex number in polar mode:
Magnitude ENTER angle COMPLEX
The COMPLEX function either combines real numbers (or matrices) in the X and Y stack registers to form a complex number (or matrix) in X, or it performs the opposite operation by splitting the complex number (or matrix) in X into two real numbers (or matrices) in X and Y.
The role of the real number (or matrix) taken from X when combining X and Y or left in X when splitting the complex number (or matrix) in X depends on the display mode, rectangular or polar, in force when COMPLEX is executed. If rectangular then X is/was the imaginary part. If polar then X is/was the angle.
Complex numbers are displayed in polar mode normalised such that the magnitude is always positive and the absolute value of the angle does not exceed 180 degrees.

Alpha Strings

The alpha register contains strings of text up to 44 characters (2 lines on the HP-42S) in length.
Real variables and elements of real matrices (including REGS ) can also contain strings of up to 6 characters in length. Basically, you can store snippets of text anywhere you can store real numbers. However, you cannot store two such snippets in a complex variable.

Matrices

Matrices can be one-dimensional or two-dimensional. A matrix can have any number of rows and columns as long as there is enough memory in the DM42 to store all of its individual elements.
See Matrix Operations for more details.

Modes

Angles and Coordinates

Press MODES
The angle specifiers DEG, RAD and GRAD tell the DM42 to use degrees, radians, and gradians respectively when displaying and interpreting angles.
RECT and POLAR tell the DM42 to display and interpret complex numbers in rectangular and polar mode, respectively.

Other Modes

Press MODES ▼
SIZE resizes the REGS matrix variable, thus defining the number of storage registers you can use.
QUIET switches off the internal buzzer and keeps the DM42 nice and…​. quiet!
CPXRES allows the DM42 to return complex results when working on real numbers (e.g. square root of a negative number) while REALRES ensures that only real numbers are returned. In this case, operations that would otherwise return a complex result trigger an Invalid Data error. Operations given a complex number as an argument will return a complex number regardless of the CPXRES/REALRES setting.
KEYASN means that variables and programs assigned to the CUSTOM menu with the ASSIGN command will be shown in the CUSTOM menu. If LCLBL is selected then local alpha labels populate the CUSTOM menu.

Display Formats

Press DISP
FIX, SCI and ENG instruct the DM42 to display real numbers in fixed decimal, scientific and engineering notation, respectively, with a set number of decimals.
When ALL is selected, numbers are displayed with up to 12 digits precision, which was the native precision of the HP-42S.
Depending on where in the world you are, you will be used to using a dot as the decimal separator and a comma for grouping digits three by three before the decimal (e.g. 1,234.56 ) or, as in most of Europe, a comma as the decimal separator and a dot for grouping digits before the decimal (e.g. 1.234,56 ). RDX. selects the dot as the decimal separator and RDX, selects the comma.

Printing

Press PRINT ▲
PRON and PROFF enable and disable printing by setting or clearing respectively flags 21 and 55.
MAN leads to items being printed manually. NORM leads to input and calculation results alone being printed automatically while TRACE sends a trace of all operations to the printer.
Additional modes are described under "Matrix Operations" and "Statistics."

Executing Functions & Programs

  • Quick access to programs and functions

  • Addressing modes

     +
Any function or program can be executed by pressing [.button]#XEQ# and
entering its name. If there is more than one program with the same name
then when you attempt to [.button]#XEQ# that program, the one closest to
the permanent [.lcd]#.END.# marker will be executed. +
Only the current program will be searched if the name that you give is
that of a local label. +
 +

Quick access to programs and functions

There are four ways to get at your programs and at the DM42’s functions quickly:

  • You can ASSIGN up to 18 names of programs or variables to the CUSTOM menu. Pressing an item in the CUSTOM menu is the same as executing it (XEQ ) if it’s a program or built in function or, if it is a variable, recalling it (RCL ).

  • When you press the XEQ button, the program catalog is automatially presented to you. Simply scroll through the catalog with the ▲ and ▼ keys if needed and select the program to run.

  • The Run/Stop Key R/S starts running the current program at the current line or stops a running program once the instruction that it is working on has completed.

  • All of the built in functions of the DM42 are available in the Function Catalog that can be opened by pressing CATALOG FCN

    +

Addressing modes

Some functions require a parameter that tells them on what specific item to operate. These functions accept one or more of the following addressing modes:

  • Numeric: these functions include RCL, SF, GTO, and others. They prompt you to enter a numerical value by displaying an underscore for each digit that they are expecting. For example, if you press SIZE, the DM42 displays
    SIZE __
    prompting you to input four digits. You can always input fewer digits and terminate the input with ENTER and the DM42 will assume that the missing digits are zeroes on the left.

  • Alpha: some functions that accept numeric addressing also accept alpha addressing. An example of one such function is RCL, which allows you to specify the number of a storage register to recall or the (alpha) name of a variable. In many cases, the DM42 will show you a menu of alpha names that are valid for the instruction that you are typing but if not, you can always use the ALPHA menu to type it in yourself.

  • Stack: because the stack registers can hold anything that a storage register can, they can also be used in place of a storage register. For example, to recall the contents of the T register into X (trick to roll the stack upwards instead of downwards), do the following:
    RCL . ST T

  • Indirect Addressing: this is a technique that does not give the DM42 the parameter that it needs. Instead, it tells the DM42 where to find that parameter. For example, to execute the program whose name is stored in storage register 24, you would: XEQ . 24
    Stack registers can also be used with indirect addressing. For example, suppose that the name of the program that you want to execute is not in R24 but in the X register of the stack. In this case you would:
    XEQ . . ST X

    +

Programming

Program-Entry

  • PRGM enters or exits Program-entry mode

  • GTO . . moves to a new program space

  • GTO . nnnn moves to line number nnnn

  • ← deletes the current program line

  • SST moves to the next program line*

  • BST moves to the previous pgm line*

     +
* Use [.button]#▲# or [.button]#▼# if no menu is displayed. +
 +

Labels

A program label is simply a marker used to identify a program or a routine within a program.
Global labels can be accessed from anywhere in memory (and therefore should be unique). Global labels are distinguished from local labels by quotation marks (such as LBL "SAMPLE" ).
Local labels can be accessed only within the current program (and should be unique within the current program). There are two types of local labels:

  • Numeric (LBL 00 - LBL 99)

  • Alpha (LBL A - LBL J and LBL a - LBL e )

    +

The Do-If-True Rule

The do-if-true rule determines how program lines are executed when a conditional function is encountered. If the condition is "true," the line immediately following the conditional is executed. If the condition is "false," the line following the conditional is skipped.

Looping

The ISG and DSE functions control looping. Each accesses a variable or register containing a control number in the form ccccccc.fffii; where ccccccc is the current counter value, and fff is the final counter value, and ii is the increment size (default is 1). Both ISG and DSE follow a variation of the do-if-true rule: if the count is not complete, the line following the instruction is executed (usually a branch to the top of the loop).
For example, this program segment counts from 1 to 52 by threes (executing the loop 18 times) and then beeps.
17 1.05203
18 STO "COUNT"
19 LBL 01
…
23 ISG "COUNT"
24 GTO 01
25 BEEP

Using a Variable Menu

A variable menu may be displayed by the Solver or Integration applications, or by the VARMENU function within a program. Each label in the menu represents a variable. While the menu is displayed, you can:

  • Store a value into a variable:
    Key in the value and then press the menu key.

  • Recall the contents of a variable:
    Press RCL and then the menu key.

  • View the contents of a variable without recalling it:
    Press (shift) and then hold the menu key down.

  • Select a variable:
    Press the menu key without keying in a number first. This action places the variable name in the alpha register and continues execution.
    (For the Solver, this is how you select the unknown variable. For Integration, this is how you select the variable of integration.)

You can select and use any function menu without exiting from the variable menu.

The Solver

The Solver is a root finder that allows you to solve for an unknown variable in an expression, given values for all the other variables. Expressions are written as programs. There are three parts to a Solver program:

  • The program must begin with a global label.

  • Immediately following the global label, menu variables are declared with MVAR instructions.

  • Finally, the body of the program should evaluate the expression. Recall the variables as they are needed and calculate f(x) (where f(x) = 0 for your expression of one or many variables).

     +
After entering the program, these are the steps for using the Solver: +

  • Press SOLVER

  • Select a Solver pgm from the menu.

  • Use the variable menu to store a value into each of the known variables. Optional: store one or two guesses into the unknown variable to direct the Solver to a solution.

  • Solve for the unknown variable by pressing the corresponding menu key.

     +
*A Simple Example:* For the expression _A + B = C_, rewrite the
expression as _A + B - C_ = 0. The Solver program looks like this: +
 +
[.lcd]#01 LBL "SIMPLE"# +
[.lcd]#02 MVAR "A"# +
[.lcd]#03 MVAR "B"# +
[.lcd]#04 MVAR "C"# +
[.lcd]#05 RCL "A"# +
[.lcd]#06 RCL+ "B"# +
[.lcd]#07 RCL- "C"# +
[.lcd]#08 END# +
 +
Hint: create the variables before entering the program. After entering
the program, you can use it to solve for any variable, given a value for
each of the others. For example, find _A_ when _B_ = 12 and _C_ =
log(_B_). +
 +
Select the program: [.button]#SOLVER# [.lcd]#SIMPL# +
Store _B_: 12 [.lcd]#B# +
Store _C_: [.button]#LOG# [.lcd]#C# +
Solve for _A_: [.lcd]#A# +
 +

Numerical Integration

The Numeric Integration application allows you to calculate an approximation of a definite integral. The integrand, f(x), is written as a program similar to a Solver program (see The Solver ). That is, the program must use a global label, declare the menu variables, and evaluate f(x).

After entering the integrand program, here are the steps for using the Integration application:

  1. Press ∫f(x)

  2. Select an integrand program from the menu.

  3. Use the variable menu to store a value into each of the variables that should remain constant.

  4. Select the variable of integration by pressing the corresponding menu key.

  5. Store the lower limit (LLIM ), the upper limit (ULIM ), and the accuracy factor (ACC ).

  6. Press ∫ to calculate the integral. The approximation for the integral is returned to the X-register and the uncertainty of computation is returned to the Y-register.

    +

Matrix Operations

To create a new m × n matrix, enter the dimensions:
m ENTER n (for m rows and n columns) and then press:
MATRIX NEW for a matrix in the X-register.
Or MATRIX ▼ DIM ENTER name ENTER for a matrix in a variable. If the matrix already exists, the DIM function redimensions it.

Edit the matrix in the X-register:
MATRIX EDIT

Edit a named matrix:
MATRIX ▼ EDITN name

When a matrix is being edited it is said to be indexed. (To index a named matrix without editing it, use the INDEX function.) Whenever there’s an indexed matrix, two pointers are used to indicate the row and column of the current element: I and J, respectively.

Wrap and Grow Modes. If the index pointers are positioned to the last (lower-right) element in a matrix and you move to the right one position:

  • The pointers wrap around to the first element of the matrix (Wrap mode).

  • Or, the matrix grows by one complete row and the pointers move to the new row (Grow mode).

Wrap mode is automatically selected whenever you enter or exit the matrix editor. (The WRAP and GROW functions are in the second row of the editor menu.)

Matrix Arithmetic. Most arithmetic and other operations work for matrices just as for individual numbers. Anytime a matrix is used in a mathematical operation with a complex number, the result is a complex matrix. Therefore, you can make any matrix complex by adding 0 + i0 to it:
0 ENTER COMPLEX # + or 0 [.button]#ENTER# [.button]#COMPLEX# [.button]#STOM# [.button]# name

To solve a system of simultaneous linear equations represented by the matrix equation AX = B:

  1. Press MATRIX SIMQ.

  2. Key in the number of unknowns. The calculator automatically creates or redimensions the matrix variables MATA, MATB, and MATX.

  3. Optional: If your equations involve complex numbers, make MATA and/or MATB complex (as shown at the top of this page).

  4. Press MATA , fill the matrix and press EXIT

  5. Press MATB , fill the matrix and press EXIT

  6. Press MATX to calculate the solution matrix. Use the matrix editor keys to view the results.

    +

Statistics

Statistical data is accumulated into 6 or 13 sequential storage registers. Initially, the first summation register is R11. Use the ΣREG function to change the location of the first summation register. ΣREG does not move the data in the registers.

Options to set the summation mode:

  • STAT ▼ ALLΣ to use all 13 coefficients

  • STAT ▼ LINΣ to use only the first six coefficients (which allows only linear curve fitting)

Clear the summation registers:
CLEAR CLΣ

Options to accumulate data:

  • For each x-y data pair: y-value ENTER x-value Σ+

  • For each single-point data value: x-value Σ+

  • For x-y data pairs stored in a two-column matrix (x-values in column 1; y-values in column 2): Place the matrix in the X-register and then press Σ+

     +
*To undo mistakes:* +
Put the incorrect data in the stack (try [.button]#LASTx# ). +
Press [.button]#Σ-# and continue accumulating data. +
 +
*To select a curve model for forecasting:* +
Press [.button]#STAT# [.lcd]#CFIT# [.lcd]#MODL# +
and then one of the following: +

  • LINF linear model: y = mx + b

  • LOGF logarithmic model: y = m ln(x) + b

  • EXPF exponential model: ln(y) = mx + ln(b)

  • PWRF power model: ln(y) = m ln(x) + ln(b)

  • BEST selects the model that returns the best correlation coefficient

    +

Base Conversions

Real numbers are displayed according to the current base mode (Hexadecimal, Decimal, Octal, or Binary). You can change the base mode using the BASE menu or by manually executing HEXM, DECM, OCTM, or BINM. Decimal mode is automatically selected when you exit from the BASE menu.
Press and hold SHOW to display:

  • A hexadecimal, decimal, or octal number in full-precision decimal form.

  • Or, all 36 bits of a binary number.

     +
When the BASE menu is displayed, the following keys are temporarily
redefined with these integer functions: +

± BASE±

36-bit 2’s complement.

÷ BASE÷

36-bit integer divide.

× BASE×

36-bit integer multiply.

- BASE-

36-bit integer subtract.

[.button]## BASE

36-bit integer add.

 
 +
Bits are numbered from right to left beginning with 0. Bit 35 (the most
significant bit) is the sign bit. Negative numbers are represented in
2’s complement form. Nondecimal numbers longer than 36 bits are
displayed as [.lcd]#<Too Big># +
 +

DM42 Functions

ABS

Absolute value

ACOS

Arc cosine

ACOSH

Arc hyperbolic cosine

ADV

Advance paper

AGRAPH

Alpha graphics

AIP

Alpha integer part

ALENG

Alpha length

ALL

All display format

ALLΣ

ALLΣ mode (13 sum regs)

AND

Logical AND

AOFF

Alpha off

AON

Alpha on

ARCL

Alpha recall

AROT

Alpha rotate

ASHF

Alpha shift

ASIN

Arc sine

ASINH

Arc hyperbolic sine

ASSIGN

Assign CUSTOM menu key

ASTO

Alpha store

ATAN

Arc tangent

ATANH

Arc hyperbolic tangent

ATOX

Alpha to X

AVIEW

Alpha view

BASE+

Base add

BASE-

Base subtract

BASE×

Base multiply

BASE÷

Base divide

BASE+/-

Base change sign (2’s compl.)

BEEP

Beep

BEST

Best fit model

BINM

Binary mode

BIT?

Bit test (x-th bit of y)

BST

Back step

CF

Clear flag

CLA

Clear alpha register

CLALL

Clear all memory

CLD

Clear display

CLKEYS

Clear CUSTOM menu keys

CLLCD

Clear LCD

CLMENU

Clear programmable menu

CLP

Clear program

CLRG

Clear registers

CLST

Clear stack

CLV

Clear variable

CLX

Clear X-register

CLΣ

Clear summation registers

COMB

Combinations

COMPLEX

Complex

CORR

Correlation

COS

Cosine

COSH

Hyperbolic cosine

CPXRES

Complex-result enable

CPX?

Complex test

CROSS

Cross product

CUSTOM

CUSTOM menu

DECM

Decimal mode

DEG

Degrees mode

DEL

Delete program lines

DELAY

Printer delay time

DELR

Delete matrix row

DET

Determinant

DIM

Dimension matrix

DIM?

Dimensions of matrix in X

DOT

Dot product

DSE

Decrement, skip if ≤ zero

EDIT

Edit matrix in X-register

EDITN

Edit named matrix

END

End of a program

ENG

Engineering display format

ENTER

Enter

EXITALL

Exit all menus

EXPF

Curve-fitting model: exp.

E↑X

Natural exponential

E↑X-1

Nat. exp values near zero

FCSTX

Forecast x given y (stat)

FCSTY

Forecast y given x (stat)

FIX

Fixed dec. display format

FRNM

Frobenius norm of X matrix

FP

Return fractional part

GAMMA

Gamma function

GETKEY

Put next key number to X-reg

GETM

Get matrix

GRAD

Grads angular mode

GROW

Grow mode (matrix edition)

GOTO

Go to label

HEXM

Hexadecimal mode

HMS+

Add x and y using H.MMSSss

HMS-

Subtract x from y H.MMSSss

I+

Inc. row pointer (matrix)

I-

Dec. row pointer (matrix)

INDEX

Index matrix

INPUT

User input (prog. only)

INSR

Insert row (matrix edition)

INTEG

Integrate

INVRT

Invert matrix in X-register

IP

Return integer part

ISG

Increment, skip if greater

J+

Inc. column pointer (matrix)

J-

Dec. column pointer (matrix)

KEYASN

Key-assignments mode

KEYG

On key, go to

KEYX

On key, execute

LASTX

Last x

LBL

Label

LCLBL

Local label mode

LINF

Linear fit model

LINE

Linear mode (six sum regs)

LIST

List program lines

LN

Natural logarithm

LN1+X

Nat log for values near zero

LOG

Common logarithm

LOGF

Logarithmic fit

MAN

Manual printing

MAT?

Matrix test

MEAN

Arithmetic mean (average)

MENU

Programmable MENU

MOD

Modulo

MVAR

Menu variable

N!

Factorial

NEWMAT

New matrix

NORM

Normal printing

NOT

Logical NOT

OCTM

Octal mode

OFF

Off

OLD

Old element value

ON

Continuous on

OR

Logical OR

PERM

Permutations

PGMINT

Program to integrate

PGMSLV

Program to solve

PI

pi

PIXEL

Pixel on

POLAR

Polar mode

POSA

Position in alpha

PRA

Print alpha

PRLCD

Print LCD

PROFF

Printing off

PROMPT

Prompt

PRON

Printing on

PR?

Print program

PRSTK

Print stack

PRUSR

Print user vars and labels

PRV

Print variable

PRX

Print X-register

PR2

Print summation registers

PSE

Pause

PUTM

Put matrix

PWRF

Power fit

QUIET

Quiet mode

RAD

Radians mode

RAN

Random number

RCL

Recall

RCL+

Recall add

RCL-

Recall subtract

RCL×

Recall multiply

RCL÷

Recall divide

RCLEL

Recall element

RCLIJ

Recall IJ pointers

RDX,

Radix comma

RDX.

Radix period

REALRES

Real-results only

REAL?

Real test

RECT

Rectangular mode

RND

Round

RNRM

Row norm

ROTXY

Rotate y by x bits

RSUM

Row sum

RTN

Return

R<>R

Row swap row

R↑

Roll up

R↓

Roll down

SCI

Scientific notation

SDEV

Standard deviation

SEED

Seed (for RAN)

SF

Set flag

SIGN

Sign

SIN

Sine

SINH

Hyperbolic sine

SIZE

Size of REGS

SLOPE

Slope

SOLVE

Solve for variable

SQRT

Square root

SST

Single step

STO

Store

STO+

Store add

STO-

Store subtract

STO×

Store multiply

STO÷

Store divide

STOEL

Store element

STOIJ

Store IJ pointers

STOP

Stop program

STR?

String test

SUM

Recall Σx and Σy

TAN

Tangent

TANH

Hyperbolic tangent

TONE

Tone (0-9)

TRACE

Trace printing

TRANS

Transpose matrix

UVEC

Unit vector

VARMENU

Variable menu

VIEW

View

WMEAN

Weighted mean

WRAP

Wrap mode

X<>

x exchange

X<>Y

x exchange y

XEQ

Execute

XOR

Exclusive OR

XTOA

X to alpha

X2

Square, x2

YINT

Y-intercept

YX

Power, yx

1/X

Reciprocal

10X

Common exponential, 10x

+

Add

-

Subtract

×

Multiply

÷

Divide

+/-

Change sign

Σ+

Summation plus

Σ-

Summation minus

ΣREG

Set loc. of 1. sum reg

ΣREG?

Recall loc. of 1. sum reg

→DEC

To decimal

→DEG

To degrees

→HMS

To hours-minutes-seconds

→HR

To decimal hours

→OCT

To octal

→POL

To polar

→RAD

To radians

→REC

To rectangular

←

Index pointers left

↑

Index pointers up

↓

Index pointers down

→

Index pointers right

%

Percent

%CH

Percent change

ADATE

Append date from X to alpha

ATIME

Append time from X to alpha

AT24

Append 24h time from X to a.

CL12

Set 12h time format AM/PM

CL24

Set 24h time format

DATE

Put date to X register

DATE+

Add dates in X and Y regs

DDAYS

Delta days of X and Y regs

DMY

Set date format to DMY

DOW

Day of Week of date in X reg

MDY

Set date format to MDY

TIME

Put time to X register

 
 +
 +
Note: If you execute an link:#HP-41_Functions[HP-41 Function], it is
automatically converted into the corresponding DM42 function. +
 +

Test Functions

If true, execute the next program line. If false, skip the next program line.

X<0?

less than zero

X<Y?

less than y

X≤0?

less than or equal to zero

X≤Y?

less than or equal to y

X=0?

equal to zero

X=Y?

equal to y

X≠0?

not equal to zero

X≠Y?

not equal to y

X>0?

greater than zero

X>Y?

greater than y

X≥0?

greater than or equal to zero

X≥Y?

greater than or equal to y

 
+
+

HP41 Functions

CHS

+/-

DEG

→DEG

D-R

→RAD

ENTER↑

ENTER

FACT

N!

FRC

FP

HMS

→HMS

HR

→HR

INT

IP

OCT

→OCT

P-R

→REC

RDN

R↓

R-D

→DEG

R-P

→POL

ST+

STO+

ST-

STO-

ST*

STO×

ST/

STO÷

X⇐0?

X≤0?

X⇐Y?

X≤Y?

*

×

/

÷

 
+

Using the ALPHA Menu

To type an alpha string into the alpha register:

  1. Press ALPHA to select the ALPHA menu.

  2. Optional: press ENTER to turn on the cursor (in Program-entry mode, inserts the I- symbol).

  3. Type the string using the characters shown below. Use shift to type lowercase letters.

  4. Press EXIT or ENTER

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Flags

  • 00-10 User Flags

  • 11 Auto Execute

  • 12 Print Double-wide

  • 13 Print Lowercase

  • 15-16 Print Mode

  • 19-20 General Use

  • 21 Printer Enable

  • 22 Numeric Input

  • 23 Alpha Input

  • 24 Ignore Range Errors

  • 25 Ignore Next Error

  • 26 Beeper Enable

  • 27 CUSTOM Menu

  • 28 Radix Mark Period

  • 29 Digit Separators

  • 30 Stack Lift Disable

  • 31 DMY Date Format

  • 34-35 AGRAPH Control

  • 36-39 Number of Digits

  • 40-41 Display Format

  • 42 Grads Mode

  • 43 Radians Mode

  • 44 Continuous On

  • 45 Solving

  • 46 Integrating

  • 47 Variable Menu

  • 48 Alpha Mode

  • 49 Low Battery Power

  • 50 Message

  • 51 Two-Line Message

  • 52 Program-Entry Mode

  • 53 INPUT

  • 55 Printer Existence

  • 56 Linear Model

  • 57 Logarithmic Model

  • 58 Exponential Model

  • 59 Power Model

  • 60 AllΣ Mode

  • 61 Log Model Invalid

  • 62 Exp Model Invalid

  • 63 Pwr Model Invalid

  • 64 Shift State

  • 65 Matrix Editor In Use

  • 66 Grow Mode

  • 67 YMD Date Format

  • 68-71 Base Mode

  • 72 Local-Label Mode

  • 73 Polar Mode

  • 74 Real-Result Only

  • 75 MENU

  • 76 Edge Wrap

  • 77 End Wrap

  • 78 Base Signed

  • 79 Base Wrap

  • 81-99 User Flags

Flags 0-10 are indicated by annunciators at the top of the display.
Flags 36-80 are read-only and cannot be altered with SF, CF, FS?C, or FC?C.

Virtual variables

The concept of "Virtual Variables" is used to manage some of the new features specific to the DM42 calculator. These are variables that do not (and cannot, for that matter) exist in the DM42’s variable table, but are used to read or change state variables specific to DM42.

DevID

(read-only) Hardware device ID

GrMod

(read-write) Graphic Modes

  • 0 = HP-42S resolution 131x16

  • 1 = reserved for future use

  • 2 = DM42 half resolution 200x120

  • 3 = DM42 full resolution 400x240

ResX

(read-only) X-resolution for current graphics mode set in GrMod

ResY

(read-only) Y-resolution for current graphics mode set in GrMod

Vbat

(read-only) battery voltage

 
+
+

F-Buttons

The top row consists of six unprinted buttons referenced as F-Buttons (F1-F6) or soft-menu buttons.

  • F1 Displays this Help

  • F2 Toggle the system soft menu visibility

  • F3 (not assigned)

  • F4 Increase buzzer volume

  • Shift-F4 Decrease buzzer volume

  • F5 Toggle stack alignment (Left, Right, Right Underlined)

  • Shift-F5 Toggle between sans and HP font

  • F6 Increase font size

  • Shift-F6 Decrease font size

     +
Note that font changes using F5/F6 affect displaying of calculator stack
and font in program mode and are stored independently for both stack and
program mode. +
 +

Screenshot

Pressing SHIFT and DISP simultaneously makes a screenshot and saves a BMP graphics file in the folder /SCREENS.
The file name is made up by the current date and time.

Setup Menu

Setup Menu → File

Save and Load DM42 Programs to FAT Disk as *.raw files.

  • Load Program
    Select RAW file and load in DM42 memory

  • Save Program
    Select one or more DM42 programs from memory and save as one RAW file

  • Activate USB Disk
    Prepare DM42 for connection with computer for file exchange

  • Show Disk Info
    Display FAT Disk information

    +

Setup Menu → Calculator State

The complete calculator state can be saved and loaded as one file (*.f42).

  • Load State
    Load previously saved calculator state

  • Save State
    Save current calculator state as a file

  • Load Clean State
    Load default settings

    +

  • Graphics Print
    Selecting this menu item enables printing to graphics file.

  • Text Print
    Selecting this menu item enables printing to text file.

  • Graphics in Text
    Selecting this menu item enables to see graphics in text file.

  • Don’t print to IR
    Selecting this menu item disables default printing to IR printer.

Setup Menu → Settings

  • Set Time
    Set time and select 12h/24h format

  • Set Date
    Set date and select MDY/DMY format

  • Status Bar
    Display State Filename
    Display Day of Week
    Display Date
    Select a Date Separator of . - /
    Display Month Shortcut as 3 letter abrv.
    Display Time
    Display Power Voltage in Header

  • Stack Font Sizes
    Allows to set font size ofsets for registers X, Y, Z, T, L and A

  • Beep Mute
    Mute beep in all cases.

  • Slow Auto-repeat
    This option makes auto-repeat of pressed and holded buttons slower.

  • Stack Layout
    These are the options:
    XYZTL
    XYZTA
    XYZL
    XYZA
    XY
    LXYZT

  • Dynamic Stack Extension
    This option enables or disables the 'Big Stack' extension of Free42

    +

Setup Menu → System

Warning: Certain actions in this menu can destroy all stored data of the calculator.
Please run 'Save Calculator State' in 'File' menu first to preserve data over potential RESET.

  • Flashing firmware from FAT
    Starts flashing of new firmware if firmware file is copied to root of FAT filesystem.

  • Bootloader
    Connect USB to enter bootloader mode. Note that reset is the only way to exit bootloader mode.

  • Program Info
    Displays info about currently loaded program

  • Reset to DMCP menu
    Resets calculator and enters DMCP menu

  • Format FAT Disk
    This will format FAT filesystem. All data will be erased!

  • FAT Disk Media Test
    All data stored in the FAT disk will be destroyed by this low-level media test!

  • Power OFF mode
    Allows to set power OFF mode. Only for diagnostics.

  • Self Test
    Set of tests for KBD, LCD, IR, BEEP and Diagnostics

    +
+

About

  • DM Calculator Platform
    © 2014-2021, SwissMicros GmbH

  • Free42
    © 2004-2021, Thomas Okken

  • Intel Decimal Floating-Point Lib
    © 2007-2018, Intel Corp.

  • DM42 Quick Reference Guide
    based on HP-42S Quick Reference Guide (c) Copyright 1988 Dex Smith

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