HP HP-65 User guide

HEWILETTT.-PAGCKARID
KRGS
Owner’s Handbook

HEWLETT hp] PAGKARD
&
HP-65
Owner’s Handbook
January 1974
00065-90200
PRINTED IN U.S.A. ©HEWLETT-PACKARD COMPANY 1974

Table of Contents
Introduction 4-17)
Three Ways to Use the HP-65 . ................ 4
1. Calculating Manually ...................... 5
2. Running a Prerecorded Program ............ 11
3. Creating Your OwnProgram ................ 14
1. General Instructions (18-26)
Clear Operations ..........c.c.coviviniiinenn. 18
Display .. ... 19
Keying in Large and Small Numbers ........... 23
Last X ... 24
Stack Lift Enable, Disable .................... 26
2. Registers (27-35)
Addressable Registers .................... ... 27
Additional Stack Operations .................. 30
Recalling « « . voove e 32
A Compound Growth Schedule ................ 33
3. Functions (35-47)
Functions Involving Angles ................... 36
CONVEISIONS ..ottt 43
Functions of x and the Exponential Function (yx) . 44
4. Programming (48-78)
LookingataProgram ........................ 48
Control Operations .................coouan.. 50
Editing Operations ........... ... ... ... . ... 57
Test Operations ............ ... ... .ot 59
A Complete Problem . ........................ 66
Miscellaneous Programming Topics ............ 76
Programming is a Creative Process ............ 78

Appendices (79-96)
Appendix A: Operating Limits ................. 79
Appendix B: Accessories ..................... 83
Appendix C: Service and Maintenance .......... 85
Appendix D: Common Errors ................. 95
List of Illustrations
Figure 1-1. Blinking Display Errors ............ 22
Figure 3-1. Functions Involving Angles ......... 37
Figure 3-2. Conversionsof X .................. 42
Figure 3-3. Functions of x and Exponential
Function (yX) ........ ... ... ... .... 45
Figure 4-1. Memory, Codes, and the
Single StepKey ................... 51
Figure 4-2. Control Operations for
Defining Functions ................ 52
Figure 4-3. Control Operations for
Stopping and Branching ........... 56
Figure 4-4. Editing Operations ................ 60
Figure 4-5. Operations Used for
Programmed Decisions ............ 63
Figure 4-6. CalculationResults ................ 67
Figure 4-7. Graphic Representation of
Program Tasks ................... 68

Introduction
Three Ways to Use the HP-65
Congratulations on purchasing your HP-65 Programmable
Pocket Calculator. In addition to all the computational capa-
bilities that have made the earlier HP-35 and HP-45 models so
popular with professional people, your new HP-65 offers a fea-
ture that no other pocket calculator can provide: true program-
mability.
Simply defined, programmability is the HP-65’s ability to learn,
remember, and automatically execute the keystroke sequence
required to solve a particular type of problem. The value of this
feature becomes clearer when we consider that most of us who
routinely work with numbers spend a great deal of time doing
the same types of calculations over and over again. No matter
whether we're preparing flight plans, surveying construction sites,
calculating returns-on-investment, or designing power supplies,
we can all identify repetitive, time-consuming problems which
diminish our productivity and frustrate our goals.
Although programmable computers and desk-top calculators
have been available for some time, their expense, complexity
and non-portability have made them inappropriate or impractical
for many tasks. The real significance of the HP-65 is that it
overcomes these limitations and lets almost anyone enjoy the
advantages —speed, accuracy, convenience —of a programmable
calculating device.
You can use this powerful device in three ways:
1. To Calculate Manually
You control every step of the calculation by pressing keys in the
actual order of execution: you enter data, perform functions,
store results, control display, etc., by pressing keys.
2. To Run a Prerecorded Program
By using prerecorded magnetic cards (like those supplied in the
Standard Pac shipped with your calculator) you can do highly
complex calculations with minimal effort or study of the calcu-
lator itself. You load a card into the calculator and let the stored
4

program handle the busy part of the calculation. Typically, you
just key in the data and start the program running. The program
stops when it needs more data or when it displays a result.
3. To Create, Record, and Execute Your Own Programs
No prior programming experience is necessary to program the
HP-65. You can easily define the five zop row keys to calculate
functions of your own creation for use alone or with other pro-
grams. You plan your problem in terms of the keystrokes needed
for calculation and the additional keystrokes needed to control
your program. You set the mode switch to W/PRGM position
and key the keystroke sequence into memory. You may then re-
cord your program for future re-entry by merely passing a mag-
netic card through the calculator. Upon switching back to RUN
mode, you can execute your stored program.
In this introduction, we will briefly demonstrate these three
methods. We suggest that you do the examples to confirm that
your calculator works properly and to become familiar with it.
1. Calculating Manually
Getting Started
Your HP-65 Pocket Calculator is shipped fully assembled includ-
ing a battery. Before using the calculator for portable use, charge
it for 14 hours as described in Appendix C. You may run the
calculator on battery power alone or you may connect the battery
charger and run while the battery is charging. To get started:
= Set W/PRGM —RUN switch to RUN position.
®= Turn OFF—ON switch to ON position.
You should now see displayed [lili}; if not, please turn to Ap-
pendix C.
Keying In Numbers
Key in the number and include the decimal point if it is a part
of the number. For example, try keying in 314.32 which would
be done by merely pressing:
BoEEEE

| Display
— W/PRGM-RUN Switch
OFF-ON Switch —]
Window
User Definable Function Keys
opgEEa
Blue Downshift Key
Gold Upshift Keys =
Arithmetic Keys
+
%
@ HEWLETT-PACKA

If you make a mistake when keying in a number, clear the entire
number by pressing ‘€LX (clear X); then key in the number cor-
rectly.
Negative Numbers. To key in a negative number, press
(change sign) after keying in the positive value. For example, to
key in —12:
Press: 12 |CHS
To change the sign of a negative or positive number, press CHS .
For example, to change the previous number back to a positive
12:
Press: CHS
Performing Simple Arithmetic
In the HP-65 arithmetic answers are calculated by pressing + ,
- ,/x , or/+ . For any problem having two numbers and one
arithmetic operator, you key in the first number and save it by
pressing |ENTER4 ; then you key in the second number and follow
it by the arithmetic operator. For example, add 12 and 3 by
pressing:
12 (ENTER® 3 +
The calculator uses the last number saved and the last number
keyed in: it adds the latter to the number saved; it subtracts the
latter from the number saved; it multiplies the latter by the num-
ber saved; or it divides the latter into the number saved. For
example, you can subtract 3 from 12 by pressing:
12 ENTER4 3 -
To divide 12 by 3, press:
12 ENTER¢ 3 +
Nonarithmetic Functions
A blue symbol on the inclined lower key surface denotes the
function of the key when preceded by the downshift [@ key. A
gold symbol above the key denotes the function of the key when

preceded by the upshift [ key; the same gold symbol above a
key denotes the inverse (or complement) of the function of the
key when preceded by the [ key. To use a blue or gold function,
press the appropriate shift key (|81, [, or ) immediately be-
fore pressing the selected key. For example, you
Compute
sin (90°)=1
arc sin (.5)=30°
1/5=.2
By Pressing See Displayed
90 [l (510 1.00
5 W N 30.00]
5 @ A XN
The Operational Stack
There are four working registers in the HP-65 called X, Y, Z, and
T. They are arranged in a ‘stack’ with X on the bottom (see below).
To avoid confusion between
the name of a register and its
contents, the register is desig-
nated in this handbook by a
capital letter and the contents
Contents Location
t T
z z
y Y
X X
by a small letter. Thus x, y, z,
and t are the contents of the
X, Y, Z, and T registers.
When you key in a number, it goes into X, the displayed register.
When you press [ENTER®| , this number is also reproduced in Y.
At the same time Y is transferred to Z, z is transferred to T, and
tis lost (see below):
Press
Contents l Location
ENTER#
_/(Iost)
—
e

Introduction
The HP-65 can save a number in each of the four registers.
Most problems can be solved by keying in the numbers in the
same order as they appear in the original expression, that is, from
left-to-right. To work a problem, key in the first number. If there
is an operation you can perform at this point, do it. If there is
not, press [ENTER®| . Now key in the next number. Perform any
operation that can be done (+,—,X,—, etc.). If there is no
operation you can perform, [ENTER®] this number and repeat the
procedure, keying in the next number. The following examples
illustrate this procedure.
Arithmetic and the Stack. When you press the addition key the
contents of X and Y are added together. The stack then drops,
with t reproduced in T and Z, z transferred to Y, (y+x) trans-
ferred to X, and x transferred to Last X. (Last X is described in
Section 1.)
Press Contents [ Location
*
+ y \ Y
Last X
The same dropping action takes place with any arithmetic oper-
ator (+,—, X, or=); the result is placed in X.

Combined Arithmetic Operations. Anytime a new number is
entered after an operation, the HP-65 performs an automatic
ENTER4 on the result of that operation. This feature allows you
to work serial calculations as well as chain and mixed chain cal-
culations. Notice that we implicitly used this in the following:
Sample Case:
[(4X5) / 2+3)] —6=—2
Press
4 ENTER#
5%
2 |[ENTER4
3+
6 —
See Displayed
Notice that the numbers are entered in the same order as they
appear in the problem. Now consider the stack contents as we
do the same example.
Stack Register
T
P4 20 20
Y 4 4 20 2 2 20 4
X 445 20 2 2 3 5 4 6 -2
Keys (2] [+ [5] x [2] '+ [3] + = [6] [-
Note: ENTER4 is here abbreviated as ¢+ .

Sample Case: (12 X 5) + (11 X 4) + (10 X 3) =?
Press See Displayed
12 ENTER4 5 X
11 ENTER® 4 X +
10/ENTER% 3 X +
More Computing Power
The calculator also has nine addressable registers so that the
calculator can hold intermediate results or frequently used con-
stants. This means that calculations of considerable complexity
can be performed without reentering data or intermediate re-
sults. You now have some practice in calculating manually. We
will consider these registers and further capabilities for manual
calculation in the body of this handbook. In the meantime, let
us move on to the question of running a prerecorded program.
2. Running a Prerecorded Program
A built-in magnetic card reader/writer allows a program to be
permanently preserved on magnetic cards for future use. By
reading such a card, your general purpose calculator gains a
highly specific capability in a matter of seconds. Some users may
wish to use professionally programmed cards without themselves
doing any programming.
Irrespective of your major interests, we think that you may find
a use for the Personal Investment Program, the first program in
the Standard Pac shipped with your calculator. You will find the
prerecorded magnetic card for this program in the card case,
along with 18 additional programs, a head cleaning card, and
20 blank cards for recording your own programs.
The programs vary from general to specialized. Some programs
were selected from other pacs available through HP. For ex-
ample, the Pi Network Matching Program is from the EE Pac I,
the Mean and Standard Deviation program is from the Stat Pac,
etc. As leisure permits, you may wish to familiarize yourself with
them all and work the numerical examples. The Personal In-
vestment Program, however, is from no other pac. It was created
for you, to allow you to calculate the growth of a regular monthly

savings plan. Information about this as well as any of the pac’s
prerecorded programs is in the Standard Pac Instruction Book:
what a program does, how to use it, etc. For our present pur-
poses, we merely load the program and execute it, using sample
data.
Loading the Program
1. Select the Personal Investment Card from the card case.
2. Set the W/PRGM-RUN switch to RUN,
3. Imsert the card in the right lower slot as shown. When the
card is part way in, the motor engages and passes the card
through the calculator and out the left side. Let it move
freely.

4. If the card does not read properly, the display will blink
and program memory will be cleared; press and re-
insert the card.
5. Upon completion insert the card in the upper “window”
slot to identify the top row keys.
You are now ready to use the program:
Sample Case: Growth of a Savings Plan
Starting on January 1, 1974, you add $100 per month to your
savings of $1000 invested at 12% per annum, compounded
monthly. How much will you have saved on September 1, 1975?
To solve the problem, just follow the instructions given in
standard format in Figure 0-1. You read the “instructions,” line
by line, keying in the required “input,” pressing the indicated
“key(s),” and observing the displayed “output.” The amount
saved is displayed after the future date is entered via the [ key.
Step INSTRUCTIONS DATA/UNITS KEYS DATA/UNITS
1 Enter program (Personal :":]
Investment Program) as :I:I
shown above [:[:
2| Key in start date (Jan., 1974) tae7a oAl 0.00
3 Key in present savings ($1000) 1000 : 1000.00
4 Key in monthly savings (100) 100 [: 1000.00
5 Key in annual interest rate (12) 12 I: 1000.00
6 Key in future date (Sept., 1975) 91975 E [ 3a4am
[T answer
NOTE: [ENTER# here is ’:”:
abbreviated as '+ :][:
Figure 0-1. Instructions for Running Personal Investment Program
A pad of program worksheet in this format is included with your
HP-65 for use with the blank cards when you write your own
programs.

3. Creating Your Own Program
Programmability and Definable Keys
Highly sophisticated calculations can be achieved by sequences
of keystrokes. Since the calculator is truly programmable, in-
cluding both branching and testing capability, it is quite possible
to set a program to iterate all night. Programs can consist of up
to 100 memory locations.
We have seen how the top row key functions can be defined to a
particular use by loading an appropriately prerecorded magnetic
card. Using a very simple example, we will now define the £}
key. We first plan the function, key it into memory, and then
test it. If it tests satisfactorily, we will record it on a magnetic
card for future use.
Planning the Function
The following key sequence computes x* (the cube of whatever
value k is in the X register).
T
z
k
Y k| k k
k
X k k? k8
Key ¢+ ¢+ X x
Note: ENTER4 is here
abbreviated as ¢ .
To adapt the sequence to be a function that is callable by the
key, we precede the sequence by B (c0 identify the func-
tion) and conclude the sequence by (to return control to
the keyboard).

Putting the Function in Memory
1. Set W/PRGM-RUN switch to W/PRGM and press
to clear the program memory.
2. Press the keys in the order shown:
Key(s) Comment
LBL .. .
Defines beginning of function [[§.
O
ENTER4
ENTER4
Calculates x2.
X
x
0] Defines the end of function [[§.
If (for now) you make a mistake, clear the program and start
over. In section 1 you will learn how to correct mistakes and the
meaning of the numbers in the display. The calculator has now
“learned” to calculate x* when you press [[§ in RUN mode.
Testing the Function
= Switch W/PRGM-RUN switch to RUN.
® Key in a number and press [[§. You should see the cube
of the nymber.
Press See Displayed Comment
2@ X 2
3@ [ 27.00 | 3
+0 64.00 #
5 cns @ BN (—5)

Recording the Function
To record the program
1. Select an unprotected (unclipped) magnetic card.
C
unprotected protected
2. Switch to W/PRGM. (A reminder: W/PRGM stands for
Write.)
3. Pass the card through the right lower slot exactly as in
loading a program (above). Providing the card is unpro-
tected, it now contains your program.
In the above example, we left keys [ . . . [@ undefined.
We could have keyed in definitions for them, also.
We have just shown how you can write a program for a simple
function and identify it with one of the five user-definable keys.
Your HP-65 can also be programmed without any reference to
the top keys. You will see an example of this when you turn again
to the subject of programming later in this handbook. It is easy
to create simple functions. With very little additional effort, you
can create functions or other programs of considerable com-
plexity.
Onward
We hope that you have enjoyed your introduction to the HP-65
Pocket Calculator. The rest of the handbook presents the aspects
of the calculator not covered thus far. In regard to the reference
information (enclosed in blocks, to distinguish it from the narra-
tive), it is probably sufficient to study this material casually on
first reading, postponing a more thorough reading until comple-
tion of the entire book. You can quickly become familiar with
the keyboard and gain assurance by merely keying in the nu-
merous sample cases and making sure that you understand each
of them.

Sections 1 through 3 elaborate on the subject of calculating man-
ually. Section 1 tells how to set the display and how to enter
data in scientific format. Section 2 tells how to use the address-
able registers and to manipulate the stack, while Section 3 tells
how to use the built-in functions.
Section 4 covers the subject of programming, telling how to re-
vise (edit) your programs, how to have them repeat themselves,
to stop themselves, to make decisions, etc. The programming
section also illustrates the use of the program worksheets shipped
with you calculator.
The HP-65 Quick Reference Guide
The guide summarizes the more important procedures given in
this handbook and explains the key functions, arranged in order
of keyboard symbol for ease of reference. Use the guide to check
details. It can be carried in the soft case.
If we have not answered all of your questions, contact your near-
est HP office, or, if you are in the U.S., dial [phone],
collect, and ask for Customer Service. We want you to be com-
pletely satisfied with your HP-65.

Section 1
General Operations
In this section we will describe how to = perform the clear op-
erations ® control the display ® enter numbers in scientific no-
tation ® recover from wrong keystrokes using the Last X feature.
In addition, a reference block is devoted to the operation of the
Stack Lift (automatic enter).
Clear Operations
Four separate clearing operations are possible with the HP-65,
using the [l functions of the fourth row of keys.
Clearing Unwanted Prefix
E cancels the effect of a prefix so that a non-prefix
operation can be done. Let’s say you accidentally press | N B
or [@], before keying in a number. If you then press the number
key, you will get an alternate function of that key instead of the
desired number-entry operation. To prevent this from happening,
press [ to cancel the effect of the unwanted prefix
key, then key in a number. If a wrong prefix key is pressed when
another prefix is wanted, the error can be corrected by simply
pressing the correct prefix and proceeding from there.
The following keys (not yet explained) are also prefix keys:
sto ReL [ER
Clearing Stack Registers
B clears all four registers (X, Y, Z, and T) of the operational
stack. To clear only the X-register, press CLX .
Clearing Addressable Registers
] clears all nine addressable registers. (These will be de-
scribed in a later section.)
18