Commodore Computer 4023 Manual de usuario descargar pdf (Pagina 4)

QUESTIONS & ANSWERS by W arren D. Swan

Question: "Can you get the heart, spade, diamond & club

graphics in Superscript?

Answer: I will start by getting off onto one small tangent

that will explain everything; I hope. First, the printer can print

very many characters; in feet, nearly 300 different characters

when you consider all the upper & lower case letters and digits

and special characters ($,@,#, etc.) and punctuation and all the

graphics characters ( , etc.). Secondly, our computer is

limited to being able to handle 256 different possible characters

at one time (this is true of all so-called "8 bit" computers). As

a result of these 2 fects, the designers of the computer & printer

had to make them so that they can be in 1 of 2 "modes" at any

given time.

The NORMal mode allows lower case, upper case, digits,

special characters and some graphics. The GRAPHics mode

allows more graphics, but at the penalty of eliminating the lower

case letters. Remember that the computer may be in one mode

while the printer is in another. The NORM or GRAPH mode

is selected by the key on the computer and by commands for the

printer.

So much for that. The reason why SUPERSCRIPT CAN

NOT HANDLE THE HEART, SPADE, DIAMOND & CLUB

GRAPHICS (which answers the question) is that it can only

handle the NORMal mode. There is no known way to make

Superscript switch the printer to graphics mode and back. If we

could, we would be able to get all the graphics characters

available on our machine. Sorry!

(Editor’s note: This article was written in the early stages

of the User’s Group. Warren and Neil Cumfer later discov

ered that it was possible to switch modes within Superscript.

Check the cover article and Cumfer’s articles).

3 PRC<TER: Assumed: That you are using a Commodore

4023 or like Commodore dot-matrix printer. Also, that the

printer’s device number is 4. If not, replace 4 with the appro

priate device number in the following.

3.5 CHANGING THE NUMBER OF LINES PER PAGE

The Commodore printers are strange in that they require special

"open" statements in order to change how the printer works.

Most other printers only require that special characters be sent

to them to change how they work.

If you are using special forms, you will have to be able to

tell the printer to change the number of lines per page. This is

only true if you are going to use the printer’s built-in pagination

mode. Most pre-packaged software simulates pagination, rather

than having the printer do it. However, to get listings of

programs, you still need the printer’s pagination mode.

When the printer is powered up, it assumes that there are 60

printable lines per page in pagination mode. 3 lines are skipped

at the top and bottom, so that the total is 66 (6 lines per inch

times 11 inches). As fer as pagination goes, the printer only

cares about the number of printable lines per page. If we switch

to a 14 inch form, we now have 14 inches times 6 lines/inch (=

84 lines) minus the 6 inch spacing, equals 78 lines per page. To

tell the printer this we execute:

open 3,4,3: print#3,chr$(78): close 3

The printer knows we want 78 lines/page now, but it will not

actually put it into effect until the next page begins. We can

force that by sending the HOME/CLR sequence to the printer.

The 4023 can handle down to 14 lines/page and up to 127

lines/page.

3.6 CHANGING THE NUMBER OF LINES PER INCH

Another nice feature of the Commodore printers is the ability to

change the number of lines per inch. By doing so, you can

actually have your printer print contiguous graphic pictures.

Unfortunately the printer manual is totally inaccurate here.

Some of the Commodore printers had line feed motors that could

handle up to 144 steps per inch. Other Commodore printers

(such as the 4023) could handle up to 216 steps per inch. You

will notice that these mystical numbers actually come from the

idea that we want to be able to choose so many of these little

steps to make up so many lines per inch. In order to figure out

how many steps are needed to achieve LPI lines per inch, we

would divide, as appropriate:

steps = 144 / lpi: rem for some Commodore printers

steps = 216 / lpi: rem for other Commodore printers,

such as the 4023.

The numbers 144 and 216 were chosen because they can be

divided into so many different numbers. The reason for this is

that

144 = 2*2*2*2*3*3 & 216 = 2*2*2*3*3*3.

OK? Unfortunately, Commodore got mixed up about which

printers had which number of steps per inch. Fortunately, all

we have to do is try some examples and get out our ruler and

measure.

When the printer is turned on, it is set to 6 lines per inch.

That is 216/6 or 36 steps (not the 24 that the book states). To

change it to 8 lines per inch, we would first calculate 216/8 =

27, then issue these commands:

open 6,4,6: print#6,chr$(27): close 6

We could have let BASIC do the calculation by simply using

chr$(216/8). Notice that the printer really can’t do exactly 5 or

7 lines per inch because 5 and 7 don’t go into 216 (or 144) evenly.

But it will get pretty close.

Another thing that changed over time is the size of the

characters printed by the printers. With the older Commodore

printers, 8 lines/inch would allow each line of characters to be

contiguous for drawing pictures or making charts or what have

you. The 4023 characters are smaller and require 12 lines/inch

in order to get contiguous lines. So we would have to use:

open 6,4,6: print$6,chr$(216/12): close 6: rem 216/12 =

18 steps.

PRINTER TIPS by Col. J.E . O’Halloran

4023 line spacing commands

3 lines: REV(*)sa6,66

6 lines:REV(*)sa6,33

9 lines:REV(*)sa6,22

8023p line spacing commands

3 lines per inch:REV(*)sa6,24

6 lines per inch:REV(*)sa6,12

9 lines per inch:REV(*)sa6,8

Northwest Computer News

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