Commodore 64 Keyboard User Manual

KEYBOARD
Now that you've got everything set up and adjusted, please take a
few moments to familiarize yourself with the keyboard which is your
most important means of communication with the Commodore 64.
You will find the keyboard similar to a standard typewriter keyboard
found in most areas. There are, however, a number of new keys which
control specialized functions. What follows is a brief description of the
various keys and how they function. The detailed operation of each key
will be covered in later sections.
--
Ii
The .~j:llll~jl. key signals the computer to look at the information that
you typed and enters that information into memory.
The"
are capable
_
_
key works like that on a standard
of displaying two letters or symbols
acters. In the "upper/lower
case" mode the
dard upper case characters.
In the "upper
typewriter.
Many keys
and two graphic char-
key gives you .stancase/graphic"
mode the
..
key will display the graphic character on the right hand side of
the front part of the key.
In the case of special YELLOWfunction keys, the
key will give
you the function marked on the front of the key.
14
EDITING
No one is perfect, and the Commodore 64 takes that into account. A
number of editing keys let you correct typing mistakes and move information around on the screen.
There are two keys marked
arrows
Em'(CuRSoR), one
11.00:i"I:.~I,the other with left and right arrows
with up and down
r301:~:EI
. You can
use these keys to move the cursor up and down or left and right. In the
unshifted mode, the,Em
keys will let you move the cursor down and to
the right. Using the EmIiI key and ail
keys allows the cursor to be
moved either up or to the left. The cursor keys have a special repeat
feature that keeps the cursor mQving until you release the key.
If you hit the .I/I I'A.I~. key, the cursor will move back a space, erasing (DELeting) the previous character
you typed. If you're in the middle
of a line, the character
to the left is deleted and the characters
to the
right automC?tically
move together
to cI.ose up the space.
A 'EDDed
.1/h"I'A'I~. ,allows you to INSerT information
on a line. For
example,
if you noticed a typing mistake in the beginning
of a lineperhaps you left out part of a name-you
could use the r301:io'l:EI:key to
move back to the error and then hit .1/h'1I'A'I~. to insert a space. Then
just Itype in the missing
letter.
'IOI.:'A:lI],'positions the cursor at the "HOME" position of the screen,
which is:the' upper left-hand corner. A shifted IOI.:'A:I''''''''
will clear the
screen and place the cursor in the home position.
.W"'..lmI8 operates as the name implies. It restores the computer to the
normal state it was in before you changed things with a program or
some command. A lot more will be said on this in later chapters.
15
FUNCTION KEYS
The four function keys on the right side of the keyboard can be "pro_
grammed" to handle a variety of functions. They can be defined in
many ways to handle repetitive tasks.
Thell3key,
which stands for ConTRol, allows you to set colors, and
perform other specialized functions. You hold the I13key
down while
depressing another designated key to get a control function. You had an
_
key when you changed
opportunity to try the
different color bars during the setup procedure.
text colors to create
Normally, depressing the 1:lIIlrj,'tIlI:ll
key will stop the execution of a
BASIC program. It signals the computer to STOP doing something. Using
16
the 1:lIIlrl.'tlllli key in the shifted
load a program
from tape.
[I
mode
will allow
you to automatically
COMMODORE KEY
~
performs a number of functions. First, it
The Commodore key
allows you to move between the text and graphic display modes.
When the computer is first turned on, it is in the Upper Case/Graphic
mode, that is, everything you type is in upper case letters. As was mentioned, using the IDIIiI key in this mode will display the graphic on the
right side of the keys.
If you hold down
to upper and lower
the
case.
~
EmI
key and
key, the display will change
Now, if you hold down the
key and any
~
other key with a graphic symbol, the graphic shown on the left side of
the key will be displayed.
To get back into the upper
and IDIIiI key again.
The second function of the
case/graphic
mode
~
hold down
the
~
key
key is to allow you access to a second
key and any of the
number keys, any text now typed will be in the alternate color available
from the key you depressed. Chapter 5 lists the text colors available
from each key.
set of eight text colors. By holding down the
~
BACK TO NORMAL
Now that you've had a chance to look over the keyboard, let's explore
some of the Commodore 64's many capabilities.
If you still have the color bars on the screen from adjusting your TV
set, hold IDIIiI
and
will be positioned
screen).
11:I1:'Jllm,l... The screen
in the "home"
should
clear
spot (upper left-hand
and
the cursor
corner of the
~
Now, simultaneously hold
and the.
key. This sets the text color
back to light blue. There is one more step needed to get everything back
to normal.
Hold
ami and EJ(Zero
not Oh I). This sets
the
display
mode
back to normal. If you remember, we turned REVERSEtype on with the
to create the color bars (the color bars were actually reversed
spaces). If we were in the normal text mode during the color test, the
cursor would have moved, but just left blank spaces.
EmI.
17
TIP:
Now that you've done things the hard way, there is a simple way to reset the
machine to the normal display. First press the IiI!IIIiD
key and then press
the
IiIiI!IiII
EmI
key.
Ii1!EI!II
must always
be held down
in order
to use the
key function.
This will clear the screen and return everything to normal. If there is a program in
the computer, it will be left untouched. This is a good sequence to remember, especially if you do a lot of programming.
If you wish to reset the machine as if it were turned off and then switched on
EmID.. Be careful
again, type, SYS64759 and press
wipe out any program or information
using this command!
that is currently in the computer.
It will
LOADING AND SAVING PROGRAMS
One of the most important features of the Commodore 64 is the ability
to save and load programs to and from cassette tape or disk.
This capability allows you to save the programs you write for use at a
later time, or purchase prewritten programs to use with the Commodore
64.
Make sure that either the disk drive or datasette unit is attached
properly.
LOADING
PREPACKAGED
PROGRAMS
For those of you interested
in using only prepackaged
programs
available
on cartridges,
cassette,
or disk here's all you have to do:
1. CARTRIDGES: The Commodore 64 computer has a line of programs
and games on cartridge. The programs offer a wide variety of business
and personal applications and the games are just like real arcade
games-not
imitations. To load these games, first turn on your TV set.
Next turn OFF your Commodore 64. YOU MUST TURN OFF YOUR COMMODORE 64 BEFORE INSERTING OR REMOVING CARTRIDGESOR YOU
MAY DAMAGE THE CARTRIDGE AND/OR YOUR COMMODORE 641
Third insert the cartridge. Now turn your Commodore 64 on. Finally type
the appropriate STARTkey as is listed on the instruction sheet that comes
with each game.
2. CASSETTES:US?your DATASSETTErecorder and the ordinary audio cas18
settes that came as part of your prepackaged
program. Make sure
the tape is completely rewound to the beginning of the first side.
Then, just type lOAD. The computer will answer with PRESS PLAYON
TAPE, so you respond by pressing play on your datasette machine. At
this point the computer screen will go blank until the program is
found. The computer will say FOUND (PROGRAM NAME) on the
[I
KEY. This will actually
screen. Now you press down on the
load the program into the computer. If you want to stop the loading
simply press the .:Ullr~"II'I:Ikey.
3. DISK:Using your disk drive, carefully insert the preprogrammed
disk
so that the label on the disk is facing up and is closest to you. look
for a little notch on the disk (it might be covered with a little piece of
tape). If you're inserting the disk properly the notch will be on the left
side. Once the disk is inside close the protective gate by pushing down
on the lever. Now type lOAD "PROGRAM NAME", 8 and hit the
.:~:lIII:U. key. The disk will make noise and your screen will say:
When the READYcomes on and the.
is on, just type RUN, and
your prepackaged
software is ready to use.
LOADING PROGRAMS FROM TAPE
loading a program back from tape or disk is just as simple. For tape,
rewind the tape back to the beginning and type:
LOAD
"Pf;:OGRAfo1
t.jAt'1E"
If you don't remember the program name, just type lOAD and the
first program on the tape will be loaded into memory.
After you press ..:~:lIII:~I- the computer will respond with:
19
PRESS PLAY ON TAPE
After you depress the play key, the screen will blank, turning the
border color of the screen as the computer searches for the program.
When the program is found, the screen will display:
FOUND PROGRAM
NAME
[I
To actually LOAD the program, depress the
key. To abandon the
LOADing procedure, hit .:ml'~"tI8I:.J1.
If you hit the Commodore key, the
screen will again turn the border color while the program is LOADed.
After the LOADing procedure is completed, the screen will return to the
normal state and the READYprompt will reappear.
LOADING PROGRAMS FROM DISK
Loading
a program
from disk follows
the same
format.
Type:
LOAD "PROGRAM NAME",8
The 8 is the code for the disk, so you're just letting the computer know
that you want the program loaded from the disk.
After you hit .:~IIIII~I. the disk will start whirring and the display
shows:
20
NOTE:
When you load a new program into the computer's memory, any instructions that were in the computer previously will be erased. Make
sure you save a program you're working on before loading a new one.
Once a program has been loaded, you can RUN it, LIST it, or make
changes and re-save the new version.
SAVING PROGRAMS ON TAPE
After entering a program,
:::;A'.iE
if you wish to save it on tape,
"PF.:OOF.:AN
t.jAt'1E"
"PROGRAM NAME" can be up to 16 characters
.:I:lIII:j/. the computer will respond with:
PRESS
type:
PLAY AND
F.:ECOF.:O
long. After you hit
ON TAPE
Press both the record and play keys on the datasette. The screen will
blank, turning the color of the border.
After the program is saved on tape, the READYprompt will reappear,
indicating that you can start working on another program, or just turn
off the computer for a while.
SAVING PROGRAMS ON DISK
Saving a program
:::;A E
on disk is even simpler. Type:
"PPOGF.:At'1
t.jAt'1E"., ::::
21
The 8 is the code for the disk, so you're just letting the computer know
you want the program saved to disk.
After you press 8:j:llll:j/8 the disk will start to turn and the computer
will respond with:
PRINT AND CALCULATIONS
Now that you've gotten through a couple of the more difficult operations you need in order to keep the programs you like, lets start making
some programs for you to save.
Try typing the following exactly as shown:
If you make a typing mistake, use the .1/1.'1f'.t'I~.key to erase the character immediately to the left of the cursor. You can delete as many
characters as necessary.
let's see what went on in the example above. First, you instructed
(commanded) the computer to PRINT whatever was inside the quote
marks. By hitting 8:j:llll:j/8 you told the computer to do what you instructed and COMMODORE 64 was printed on the screen.
When you use the PRINT statement in this form, whatever is enclosed
in quotes is printed exactly as you typed it.
If the computer responded with:
?SYNTAX ERROR
ask yourself if you made a mistake in typing, or forgot the quote marks.
22
The computer is precise and expects instructions to be given in a specific
form.
But don't get worried; just remember to enter things as we present
them in the examples and you'll get along great with the Commodore 64.
Remember, you can't hurt the computer by typing on it, and the best
way to learn BASIC is to try different things and see what happens.
PRINTis one of the most useful and powerful commands in the BASIC
language. With it, you can display just about anything you wish, including graphics and results of computations.
For example, try the following. Clear the screen by holding down the
Emil key
and
[11.:''':lt!l'''' key and
type
(be sure to use the '1' key for
one, not a letter 'I'):
What you've discovered is that the Commodore 64 is a calculator i.nits
basic form. The result of "24" was calculated and printed automatically.
In fact, you can also perform subtraction, multiplication, division, exponentiation, and advanced math functions such as calculating square
roots, etc. And you're not limited to a single calculation on a line, but
more on that later.
Note that in the above form, PRINT behaved differently from the first
example. In this case, a value or result of a calculation is printed, rather than
the exact message you entered because the quote marks were omitted.
ADDITION
The plus sign (+ rsignals addition: we instructed the computer to print
the result of 12 added to 12. Other arithmetic operations take a similar
form to addition. Remember to always hit .:~"III:~I. after typing PRINT
and the calculation.
23
SUBTRACTION
To subtract,
use the conventional
minus (-) sign. Type:
MULTIPLICATION
If you wanted to multiply 12 times 12, use the asterisk (*) to represent
multiplication. You would type:
DIVISION
Division uses the familiar "I". For example, to divide 144 by 12, type:
24
EXPONENTIATION
In a like fashion, you can easily raise a number to a power (this is the
same as multiplying a number by itself a specified number of times).
The 'j' (Up arrow) signifies exponentiation.
PRINT
2488:32
12
t
This is the same
PRINT
5
as typing:
12 .. 12 .. 12 .. 12 .. 12
248:3:32
TIP:
BASIC has a number of shortcut ways of doing things. One such way is abbreviating BASIC commands (or keywords). A ? can be used in place of PRINT,for example. As we go on you'll be presented with many commands; Appendix D shows the
abbreviations for each and what will be displayed on the screen when you type the
abbreviated
form.
The last example brings up another important point: many calculations may be performed
on the same line, and they can be of mixed
types.
You could calculate this problem:
25
Up to this point we've just used small numbers and simple examples.
However, the .Commodore 64 is capable of more complex calculations.
You could, for example, add a number of large figures together. Try
this, but don't use any commas, or you'll get an error:
..
? 123.45 + 345.78 + 7895.687
8364.917
That looks fine, but now try this:
? 12123123.45 + :345.78 + 7895.687
121:~:1:364. 9
If you took the time to add this up by hand, you would get a different
result.
What's going on here? Even though the computer has a lot of power,
there's a limit to the numbers it can handle. The Commodore 64 can
work with numbers containing 10 digits. However when a number is
printed, only nine digits are displayed.
So in our example, the result was "rounded" to fit in the proper
range. The Commodore 64 rounds up when the next digit is five or more;
it rounds down when the next digit is four or less.
Numbers between 0.01 and 999,999,999 are printed using standard
notation. Numbers outside this range are printed using scientific notation.
Scientific notation is just a process of expressing a very large or small
number as a power of 1o.
If you type:
? 123000000000000000
1.23E+17
26
This is the same as 1.23 * loi17 and is used just to keep things tidy.
There is a limit to the numbers the computer can handle, even in
scientific notation. These limits are:
Largest::t: 1.70141183E+38
Smallest (different from zero): :t 2.93873588-39
PRECEDENCE
If you tried to perform some mixed calculations different from the
examples we showed earlier, you might not have gotten the results that
you expected. The reason is that the computer performs calculations in a
certain order.
In this calculation:
20 + 8 / 2
you can't tell whether the answer should be 24 or 14 until you know in
which order to perform the calculations. If you add 20 to 8 divided by 2
(or 4), then the result is 24. But, if you add 20 plus 8 and then divide by
2 the answer is 14. Try the example and see what result you get.
The reason you got 24 is because the Commodore 64 performs calculations left to right according to the following:
First:
-
Second: i
Third:
*/
Fourth: + -
minus sign indicating negative numbers
expon~ntiation, left to right
multiplication and divisions, left to right
addition and subtraction, left to right
Follow along according to the order of precedence, and you will see
that in the above example the division was performed first and then the
addition to get a result of 24.
Make up some problems of your own and see if you can follow along
and predict the results according to the rules set down above.
There's also an easy way to alter the precedence process by using
parentheses to set off which operations you want performed first.
For example, if you want to divide 35 by 5-plus-2 you type:
? ::::5 ("' 5 + 2
9
27
you will get 35 divided by 5 with 2 added to the answer, which is not
what you intended at all. To get what you really wanted, try this:
?
~
.,
35
/
(5
+ 2)
What happens now is that the computer evaluates what is contained
in the parentheses flrst. If there are parentheses within parentheses, the
innermost parentheses are evaluated flrst.
Where there are a number of parentheses on a line, such as:
? (i2
147
+ 9)
.
(6 + 1)
the computer evaluates them left to right. Here 21 would be multiplied
by 7 for the result of 147.
COMBINING THINGS
Even though we've spent a lot of time in areas that might not seem
very important, the details presented here will make more sense once
you start to program, and will prove invaluable.
To give you an idea how things flt in place, consider the following:
how could you combine the two types of print statements we've examined so far to print something more meaningful on the screen?
We know that by enclosing something within quote marks prints that
information on the screen exactly as it was entered, and by using math
operators, calculations can be performed. So why not combine the two
types of PRINT statements like this:
SEMICOLON MEANS NO SPACE.
?
5
115 :+: 9 :;::; II::
;t :3 = 45
5
:« 9
28
Even though this might seem a bit redundant, what we've done is
simply use both types of print statements together. The first part prints
"5 * 9 =" exactly as it was typed. The second part does the actual work
and prints the result, with the semicolon separating the message part of
the statement from the actual calculation.
You can separate the parts of a mixed print statement with punctuation for various formats. Try a comma in place of the semicolon and see
what happens.
For the curious, the semicolon causes the next part of the statement to
be printed immediately after the previous part, without any spaces. The
comma does something different. Even though it is an acceptable
separator, it spaces things out more. If you type:
the numbers will be printed across the screen and down on to the next
line.
The Commodore 64's display is organized into 4 areas of 10 columns
each. The comma tabs each result into the next available area. Since
we asked for more information to be printed than would fit on one line,
(we tried to fit five 10-column areas on one line) the last item was moved
down to the next line.
The basic difference between the comma and semicolon in formatting
PRINT statements can be used to our advantage when creating more
complex displays: it will allow us to create some sophisticated results
very easily.
29
">