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PC-SCHEMATIC DOCUMENTATION VERSION 3.2
TABLE OF CONTENTS
page
REGISTRATION FORM ----------------------------------- 1
BACKGROUND ------------------------------------------ 2
REQUIRED EQUIPMENT ---------------------------------- 3
APPLICATIONS ---------------------------------------- 3
GENERAL INFORMATION --------------------------------- 4
VERSION 3.0 ADDITIONS AND IMPROVEMENTS -------------- 4
VERSION 3.1 ADDITIONS AND IMPROVEMENTS -------------- 4
PC-SCHEMATIC FILES ---------------------------------- 4
SCREEN DESIGN --------------------------------------- 5
Welcome screen ------------------------------------ 5
Working screen ------------------------------------ 5
Help screen --------------------------------------- 6
Directory ----------------------------------------- 6
GETTING STARTED ------------------------------------- 6
Character mode ------------------------------------ 7
Bitmap mode --------------------------------------- 8
Bitmap circle ------------------------------------- 9
Bitmap rectangle ---------------------------------- 9
Bitmap line --------------------------------------- 9
Editing ------------------------------------------- 10
FONT EDITOR ----------------------------------------- 11
KEYBOARD ASSIGNMENTS -------------------------------- 12
Character graphics mode ---------------------------- 12
Bitmap mode ---------------------------------------- 13
CHARACTER GRAPHICS MODE ----------------------------- 13
The writing cursor --------------------------------- 13
The menu cursor ------------------------------------ 13
Dedicated keystrokes --------------------------------13
EDITING CHARACTER GRAPHICS -------------------------- 14
Selecting an area ---------------------------------- 14
Erasing a selected area ---------------------------- 14
Duplicating a selected area ------------------------ 14
Duplicating and erasing a selected area ------------ 14
Zoom out ------------------------------------------- 14
BITMAP MODE ----------------------------------------- 15
Drawing a circle ----------------------------------- 15
Drawing a rectangle -------------------------------- 15
Drawing some lines --------------------------------- 15
Drawing any line ----------------------------------- 16
Rotating a selected area --------------------------- 16
Creating characters -------------------------------- 16
Zoom in -------------------------------------------- 17
Enlarge selected area ------------------------------ 17
EDITING IN BITMAP MODE ------------------------------ 17
LOADING DRAWINGS ------------------------------------ 17
Single drawings ------------------------------------ 17
Multiple drawings ---------------------------------- 18
SAVING A DRAWING ------------------------------------ 18
PRINTING THE DRAWING -------------------------------- 18
Control codes and performance ---------------------- 18
Table of line spacing codes ------------------------ 19
Printing circuit board artwork --------------------- 19
PRECAUTIONS AND TIPS -------------------------------- 19
CONCLUSION ------------------------------------------ 20
REFERENCES ------------------------------------------ 20
PAGE 0
REGISTRATION
PC SCHEMATIC is a Shareware product. You may copy this
software and pass it along to friends for their evaluation.
If you use this software after a trial period you are
expected to pay a registration fee of $25. To register
complete the form below and enclose it with your remittance.
Registration will entitle you to telephone or mail support
and an update to the most current software.
-----------------------------------------------------------------
PC SCHEMATIC REGISTRATION FORM
NAME _______________________________________ DATE ________
STREET ADDRESS _____________________________
CITY ADDRESS _______________________________
PHONE ______________________________________
ENCLOSED _____ FOR _____ COPIES
PAYMENT BY:
CHECK ____
VISA # _____________________________________ EXP _________
MASTERCHARGE # _____________________________ EXP _________
DISK SIZE 5 1/4 ____ 3 1/2 ____
Note that this product has been received and accepted by the
customer. Upon receipt of this registration , a current disk and
data extensions will be sent.
-----------------------------------------------------------------
PAGE 1
BACKGROUND
Early versions of this drawing program were written for my
own use on a TI99/A computer. It allowed me to draw and print
electrical schematics and circuit board artwork. Because of the
limited memory of this computer, the program was broken down into
several parts which were loaded and run consecutively. None of
the parts were particularly sophisticated but they did allow me to
draw schematics and to produce simple circuit board artwork which
was used to etch small single sided circuit boards.
The first version of PC SCHEMATIC combined various pieces of
the early programs, enhanced them, and combined them into one
drawing program without the capability for printed circuit
artwork. The artwork was omitted primarily because of scaling
inaccuracy in the printed output when using a 9 pin dot matrix
printer. To conform to component dimensions the board wiring must
lie on tenth inch centers exactly. In fact, it would be desirable
to use half that spacing but this is out of the question on a 9
pin printer.
When means for achieving accuracy was worked out it was only
at the expense of reduced printing speed. Therefore, PC-SCHEMATIC
V3.0 offers a choice of two printing modes. One mode, the same as
that used in version 2.0, is for use when exact dimensions are not
important and the other, slower mode, for use where accuracy is
needed.
The version 2.0 software has a second limitation that was
would bother some users. While there was a way combine the
elementary characters into new configurations there was no way to
create new elementary characters to suit unusual needs. Also,
there was no way to display additional characters and no available
ASCII code to which additional characters could be assigned. A
major revision was needed to overcome this limitation.
The use of ASCII code in the drawing array as a pointer would
need to be retained because of it's efficiency. Accordingly, the
array and it's associated code was redesigned so that the previous
limit of 255 characters was raised to 4095 in version 3.0. Now,
there are far more characters than could reasonably be displayed
in a screen menu. These extra characters are used to produce
library drawings containing symbols, circuits, and mechanical
details. Some of the library is drawn using characters from the
screen menu; but much of the library requires unique characters
not found in the screen menu.
The method selected for creating new characters is the bitmap
mode. In the version 3.0 bitmap mode the user can create sketches
containing both menu characters and bitmap drawings comprised of
rectangles, circles, lines, and pixels that are converted to
characters when the sketch is complete. The non menu characters
are then assigned ASCII numbers as if they had been created using
the font editor and the circuits are saved on library drawings for
later use. This is easier and far more flexible than using a font
editor to do the job. Note, that each character file will be
unique and generally drawings must be used with the same character
file used during their creation.
Page 2
Version 3.0 has provided reasonable trade offs for these
conflicting aspects and combines into one program the ability to
draw electrical schematics, to mechanically layout the circuit,
and finally to transfer key dimensions from the layout to the
artwork drawings. The artwork drawings may be for single or
double sided printed circuit boards and are used to expose a
photo-sensitive printed circuit board.
Version 3.0 has been used to create drawings for a home
addition with window, door and furniture placement, etc. The
program has also been used to create the graph paper on which
ASCII characters 1 through 464 were designed and recorded. This
has led to the Version 3.0 provision for loading an alternate
character set that will be used for completely unrelated purposes.
This alternate set has not been written yet but, when done will be
completely compatible with the Version 3.0 program. Note that
Version 3.0 program is not downward compatible with version 2.0
drawings.
REQUIRED EQUIPMENT
The program will run on most IBM PCS and compatibles using
the 8088, V20, 8086, 80286, or 80386 microprocessors. It will
also run on the PCJR and the TANDY 1000. 512k of ram memory
is required due to the large number of simultaneous drawings that
can be loaded and the large number of graphic characters allowed.
The printer must be a 9 pin dot matrix type or be able to
emulate a 9 pin printer. The printer also must have a line feed
mode that allows the line spacing to be set in 1/216 of an inch
increments and a high resolution graphics mode supporting 960 dots
per line. IBM compatible printers have these necessary
characteristics.
DOS version 3.0 or later is required and a CGA display or one
that emulates the CGA is a requirement. Neither a a mouse nor a
hard disk are needed.
APPLICATIONS
The PC-SCHEMATIC version 3.0 has been used for a number of
purposes:
* To draw electrical schematics
* To create printed circuit artwork
* To create parts layouts
* To create graph paper
* To draw unusual scales
* To layout a house addition and locate furniture
* To draw electronic timing or clock diagrams
* To draw block diagrams
In addition VERSION 3.2 has the potential for drawing:
* Flow charts
* Scheduling charts
* Parts lists
* Landscape design
Page 3
GENERAL INFORMATION
PC- SCHEMATIC allows the user to create drawings, to save
them to disk, and to print them using an inexpensive 9 pin IBM
compatible printer. Two size drawings are allowed: a small one
that is 8.5 by 11 or a larger one that is 8.5 by 14 inches. Both
sizes are printed sideways.
The program was written in Microsoft Quick Basic version 4.0
and was compiled using the Microsoft Quick Basic Compiler into a
stand alone EXE file. This work was done on a Tandy 1000SX with
640k RAM using Tandy MS-DOS 3.2. An Express accelerator card
(80286) was installed in the Tandy and used while writing PC
SCHEMATICS. The drawings were printed on a reliable old EPSON
MX80 with Graphtrax Plus.
VERSION 3.0 ADDITIONS and IMPROVEMENTS
* Increased the number of simultaneous drawings to 8.
* Increased the graphics character file size to 2x4096
* Increased the scale resolution to 1 pixel.
* Added tracking markers to all scales.
* Increased no. of characters per drawing by 30%.
* Added a second print driver with high scale accuracy.
* Added BITMAP mode for drawing and creating characters.
* Added circle, arc, rectangle, and line routines in bitmap.
* Added a rotate routine for window sized patterns.
* Added fill routine for closed objects.
* Added OOPS keystroke to restore last bitmap image.
* Windowing is now activated by cursor.
* Added multiple strike printing for darker artwork.
* Produces both positive and negative artwork.
* Transfers pads from layout to artwork drawing.
Note that in Version 3.0 all high order images, consisting of
two or more graphic characters, are stored on library drawings.
This greatly increases the variety and number of possible images
that can be used in the drawings.
VERSION 3.2 ADDITIONS AND IMPROVEMENTS
* Added character mode Zoom out to show whole drawing.
* Added bitmap Zoom in to facititate drawing.
* Added multiple drawing load for selected drawings.
PC-SCHEMATIC V3.2 FILES
SCH-PRG.EXE Compiled version of the QUICK BASIC program.
SCH-CHR.DAE File containing character specifications.
SCH-CHRU.DAE File to contain user defined characters.
SCH-PRN.CDE Holds printer codes (see setting printer codes).
SCH-ART.FLS Holds 4 files to be simultaneously loaded.
SCH-ART.LYO Library drawing of mechanical outlines.
SCH-ART.SCL Library drawing of electrical representations.
SCH-ART.TMP Drawing template with border and title box.
SCH-ART.DEM Demonstration drawing.
README.DOC The documentation.
Page 4
PC-SCHEMATIC offers two drawing sizes 8.5 by 11 inches and
8.5 by 14 inches. All ART files listed above are done in the small
8.5 by 11 inch format. If you wish to use the larger format you
may choose the larger format at start up and load in the smaller
drawings for transfer of data to the current larger size drawings.
It is not possible to change the size of a drawing only to
transfer data from the small drawing to the larger drawing. The
larger drawings will require different file names when they are
saved.
SCREEN DESIGN
Welcome screen
There are several screens that you will become familiar with.
At startup the welcome screen calls your attention to the author
and his place of business with a reminder that PC SCHEMATIC is
offered as shareware. This screen also requests setup data, You
are asked to provide the following:
* The disk drive where the ART files are located.
* The graphics control codes for your printer.
* The drawing size you wish to use.
* The character set that you wish to use.
The defaults for the requested inputs are the current disk
drive and the first choices. Once the printer control code is
entered correctly, the default N is used at startup. The
alternate character set G is reserved for future use.
Working screen
The next screen is the working screen where the drawing is
done. Unfortunately, the CGA screen is not nearly large enough to
hold an entire drawing even in the high resolution graphics mode.
Since windowing is needed to overcome the screen limitation
anyway, the medium resolution mode was favored as it eliminates
the severe aspect ratio distortion that results in the high
resolution mode. The screen displays the complete drawing as a
series of connected windows. A scale at the top and one on the
left side allows the exact position of the cursor to be read. A
menu identifying the purpose of each function key is spread across
the bottom.
A column of graphic characters that can be selected by means
of the menu cursor is located on the right. The TAB key toggles
between four different sets of characters. In each case, there are
three similar hidden characters under each visible one. The
hidden characters are accessed using the ATL-R combination that
prints the characters sequentially. Many of the characters are
arranged so they appear to rotate when displayed sequentially. A
total of 336 characters are available from this menu.
Page 5
The keyboard functions much like a typewriter keyboard
producing the alpha numeric characters shown on the keys. A
character is written in the location of the writing cursor which
moves to the right as the keys are pressed.
The graphics characters are placed on the screen three ways.
* The ENTER key writes the graphics character selected by
the menu cursor.
* The ALT-R keystroke will write the selected character
and the three hidden characters to the screen.
* Four dedicated keystrokes that write to the screen
independent of the menu cursor.
The cursor which is controlled by the direction arrow keys
moves across the screen without affecting the existing characters
in any way. The cursor when controlled by the keypad direction
arrow keys (right shift key pressed) autorepeats the initial
character whatever it is and overwrites existing characters. When
the graphics characters are written to the screen the writing
cursor will not advance. The space bar erases whatever is located
under the writing cursor. At least this is what happens in the
character graphics mode.
What happens in the bit map mode is quite different. Here
screen size images are computed and drawn simultaneously.
Later, after returning to the character graphics mode, predefined
characters may be added to the result from the bitmap mode.
The placement of a marking cursor and a bitmap submode cursor
provides the computer with the dimensional information it needs to
draw your figure. It is really quite convenient. The position of
the marker and bitmap submode cursor are read directly from the
scales so you always know exactly what the result will be.
Help screen
The help screen which is accessed with the function key F1
lists all expert mode key strokes that are used in the character
graphics mode. You will learn these keystrokes, not defined on
the working screen, in time but until you do the help screen will
get you started. There is a a second help screen (any key) that
lists the keystrokes used in the bitmap mode. In both cases the
choices are mnemonic so that they are easier to learn and
remember.
Directory screen
The directory screen, which is accessed with the function key
F2, lists all the ART files or drawings that can be loaded into
the running program. The directory screen also allows multiple
files to be loaded after once being specified. The choices are by
a self explanatory menu. This is an improvement over version 3.1.
GETTING STARTED
The program may be started with any current disk drive, but
welcome screen will ask you to enter the disk drive where ALL
other data files are located. In most cases it will be the
Page 6
current drive. Responding to the other queries with an ENTER
selects the default or first item in the parenthesis.
Later, when you are ready to use the printer you will need to
consult the section on printing and also your printer manual so
that the proper printer control codes can be entered.
Character mode
The working screen will appear after the setup on the welcome
screen is completed. You will see the scales, the function key
menu, and a column of characters or menu with a menu cursor at the
top of the column. The remaining screen area is blank except for a
second writing cursor near the center. The writing cursor will
respond to the direction arrow keys. Type in a short word on the
keyboard and then move the cursor through it. Note that the word
is unaffected.
The cursor is also controlled by the keypad direction keys
when used with the right shift key. Type in a any letter. Now set
the cursor on the letter and use the keypad direction keys with
the right shift key to move the cursor. It now forms a line of
characters, all a repetition of the original character. This is
the autorepeat mode. If you had started with a blank, the cursor
would erase every thing in it's path. To erase a single character
under the cursor press the space bar.
The visible graphics characters selected by the menu cursor
are displayed by the ENTER key. Three other characters that are
closely related to the one displayed are hidden under each
displayed character. All four characters in each group are
accessed by the ALT-R keystroke that toggles through the four and
then repeats. In some cases the character appears to rotate. The
menu cursor itself is controlled by the PG-UP and PG-DN keys and
toggles the next column of characters when pushed off the end.
The TAB key toggles through four different character sets in the
menu space. Enter a few graphics characters for practice.
Move the menu cursor down 2 spaces to the elbow and then
repeatedly press the ALT-R combination. You see the elbow turning
to the right a quarter turn on each keystroke. Not all of the
characters will turn but in every case the hidden characters will
be closely related to the displayed one. Use the TAB key to move
to the next character set and repeat. A different elbow turns to
the right a quarter turn each time ALT-R is pressed.
Press F1 and observe the help screen. This help screen
information applies to the character graphics mode that you were
just in. Press F1 or any key and a second screen appears. This
help screen applies to the bitmap mode that offers a way to create
additional characters. Press F1 again and your are back in the
character graphics mode.
Press F2 and after a pause a list of drawing files names is
displayed. The one with the extension LYO contains electronic
component outlines. Press any key to return to the character
graphics screen. Press F3 and type "lyo" in the window that
appears and then press ENTER. Note, that the file names are not
case sensitive.
Page 7
The library drawing "lyo" is loaded and displayed. These
electronic component outlines are displayed using the character
mode characters augmented by characters drawn in the bitmap mode.
You will want to preserve the library as is represents the only
way to utilize the characters not in the menu.
You will have noticed that only part of the drawing is
displayed. Pressing F4 shifts the drawing to the left displaying
another part of the drawing. Note, that the Horizontal scale
corresponds to the part being displayed. Pressing F6 causes the
drawing to move upward displaying still another part of the
complete drawing. In this case the vertical scale moves up with
the drawing.
Now move the cursor off the screen to the right. The drawing
moves to the left and the scale and cursor go with it. Check that
F5 moves the drawing back down and F7 moves the drawing back to
the right. A complete small drawing (s) is three windows wide and
four windows high. The large drawing (l) is four windows wide and
four windows high.
Pressing F8 starts up the printing window sequence but do not
try this until you have checked on the printer control codes for
your printer.
Pressing F9 saves the current drawing or drawing on display.
You probably do not have any additions to "lyo" so you may skip
this now. F10 initiates the exit sequence where you are given an
opportunity to save additions to the character file. Later, when
you exit simply chose not to save the characters.
A very important feature of this software is the ability to
load multiple drawings. In fact, version 3.0 will hold eight (8)
simultaneous drawings. Now use the key stroke ALT-2. The screen
becomes blank. Press F3 and enter the file name SCL. This time a
library drawing of electrical symbols is loaded and displayed.
Press ALT-1 to return to the original drawing. The remaining
drawings are selected by ALT-3 through ALT-8. You can verify any
one of these by loading the template drawing TMP. Note that the
name of the current drawing appears in the lower left hand corner
of the screen.
Bitmap mode
In the bitmap mode a sketch cannot exceed the size of one
window. Please note that a sketch drawn in bitmap mode cannot be
manipulated in the character graphics mode as it exists only in
screen memory until it has been installed. If you switch to
character graphics and then return to bitmap your bitmap sketches
will not be displayed but may be restored with the CTRL-O
keystroke.
The bitmap mode is accessed by the key combination CTRL-B and
the mode is designated in the lower right-hand corner of the
screen. The function keys are now inoperative, the keyboard will
not print to the screen, and the cursor is now a cross. This mode
has several submodes, one for circles, one for rectangles, and one
for lines.
Page 8
Bitmap-circle
Try he circle first. Press CTRL-C and note that the mode
shown is circle and that the cursor is a single pixel. This pixel
will be the center of your circle. Using the direction arrow keys
move it to a location of your choice. Then press CTRL-M And note
that a second pixel appears two pixels to the right. The left
hand pixel fixes the center of your circle and the second pixel
now moves with the direction keys. The second pixel marks the
start of the circle or arc. Move the second pixel so that distance
from the first one equals the radius you want. The second pixel
may be anywhere on the screen and if you are drawing a full circle
the result depends only on the direct distance between the two
pixels. The scale is useful in setting the radius to a specific
distance. Now press CTRL-D and the circle will be computed and
plotted and you will then return to bitmap. Repeat the steps above
and strike any key while the circle is being drawn. An incomplete
circle or arc starting at the position of the second pixel is the
result.
Bitmap-rectangle
Drawing a rectangle is quite similar to drawing a circle.
CTRL-R puts you in the rectangle submode and the first or initial
pixel locates one corner of your rectangle. When you mark this
corner with CTRL-M a second pixel appears to fix the opposite
corner of the rectangle. Move it with the direction keys to locate
the opposite corner. It doesn't matter which corner is which, they
will be opposite no matter what you do. Now press CTRL-D and the
rectangle is computed and drawn and you are returned to the bitmap
mode.
Bitmap-line
Drawing a line is also quite similar to drawing a circle.
CTRL-L enters the line mode and CTRL-M again marks the start of
the line. The first pixel fixes the start of the line and the
second pixel the end of the line. Move the second pixel to locate
the end of the line and press CTRL-D. The line is computed and
drawn but in this case you will remain in the line mode afterward.
This facilitates drawing a series of connected lines. The second
pixel remains in place at the end of the line, to become the first
pixel for the next line.
The line mode has several other features that should be
mentioned. As in the character mode the numeric keypad direction
keys produce a result that differs from the regular keys. Try
using these direction keys with the right shift key. The pixel now
writes as it moves. The pixel when controlled by the regular
direction keys neither writes or disturbs existing patterns.
Verify this by moving the pixels through the circle or rectangle
you have drawn. The ESCAPE keystroke will return you to the bitmap
mode and a second press will return you to character graphics
mode.
Page 9
While in character graphics run the cursor through any of
your drawings and notice that this cursor now erases the bitmap
drawing. The drawing is erased as the circle and rectangle only
exist in the screen memory and have not yet been added to the
complete drawing. This requires the installation procedure that
is explained in an other section.
Editing
Most editing features are available in the character graphics
mode. Write a word on the screen and place the cursor on the first
letter of the word. Use the keystroke CTRL-M to mark the start of
the word to be saved to the clipboard. Never mind that the first
character has been replaced with the strange arrow. Move the
cursor to the last letter of the word and press CTRL-C. This
copies the word to the clipboard and restores the first letter of
the word. You now can duplicate the word on any window of any of
the eight drawings as many times as you wish ! In fact you can
duplicate the word even if it straddles two screens. The only
requirement is that it fits on the last screen. If not, the word
will be partially written on the screen but will not be added to
the complete drawing. Use CTRL-P to paste the word in the
location of your choice. If you had used CTRL-S instead of CTRL-C
to copy the word to the clipboard then the original word would
have been erased.
Erasing blocks is done much like copying an image. The upper
left-hand corner of the image is marked with the keystroke CTRL-M
and the cursor is moved to the lower right hand corner of the
image. Pressing the DELETE key erases the image on the screen,
erases the image from the drawing, but does not affect the
contents of the clipboard.
Any single character that is present on the complete drawing
can be copied to any window of any of the eight drawings. The
character under the cursor is copied with ALT-C and pasted under
the cursor in a new location with ALT-P. This is useful for
storing a character that you will need repeatedly and you wish to
minimize the use of the menu cursor. There is a small group of
dedicated keystrokes also used for this purpose. ALT-W draws line
segments, ALT-E draws corners, ALT-T draws a TEE , and ALT-G draws
electrical ground symbols.
The dedicated keystrokes toggle through the hidden characters
under the four most used character groups. The dedicated keys are
unaffected by the select cursor but are affected by the menu
selection. In some cases the dedicated keys are modified to be
compatible with the other characters in the menu being displayed.
A special editing feature erases user defined graphics.
Place the cursor over an image character in your circle or
rectangle and press CTRL-E. A number appears in the lower right
hand corner of the screen. This number is the extended ASCII code
of that character. A window asks if you wish to erase. In this
case, the character has not been installed and neither choice will
make a difference. If it had been installed though, a Yes answer
Page 10
would have caused the character to be erased from the screen, from
the drawing , from the character definitions, and from the
character definition file on disk when it is saved. A No answer
allows you to note the ASCII number of the character without
making any changes. Erasing a character that is used in drawings
other that the current one is, obviously, not desirable. Note
that the ASCII number of the predefined characters will be
displayed but that the characters themselves will not erase. This
precaution is needed as these characters are not easily renewed.
A special editing feature rotates selected areas in quarter
turns. Again type in a word and switch to bitmap mode with CTRL-
B. Then move the cursor to upper left of the word so
that the CTRL-M character arrow points toward the word and move
the cursor to the lower right of the word. You must be careful
that the word is completely within the selected area originally
and also when it has turned. The mark or the cursor must never
overlap an image being rotated. This in contrast to the select
process for copying where the marking character and the cursor may
overlap the word or sketch. Now press CTRL-R to initiate the
rotation. The word will disappear and in time will reappear
vertically. Press CTRL-R again and the word will be written
upside down. Note, that the rotated image will exist only in the
screen memory and must be installed for permanence. All images
displayed in bitmap mode can be rotated.
FONT EDITOR
The character menu contains 464 predefined characters. These
predefined characters have been drawn by a Font Editor which has
evolved from the original Wait and Morgan editor. The editor now
is so drastically changed that few lines of the original code
remain. The latest editor supports and displays 4096 characters
in a single file. 464 of these characters are predefined and
cannot be altered except by the Font Editor. All characters
including the predefined ones are formatted for use by the PUT
statement.
The characters between ASCII=32 and ASCII=127 inclusive are
standard ASCII and are available at the keyboard. The predefined
characters between ASCII=128 and ASCII=464 are graphic characters
chosen for their usefulness to the programs' mission and are
accessed with the menu cursor. The character file also contains
group of characters above ASCII=464 AND below 4096 that are used
to support the Authors library drawings. These were created from
the running program in the bitmap mode. The exact contents of
this section of file will vary depending on the version but will
be compatible with the library drawings of the same version.
A character file from ASCII=4096 to 8192 will contain
characters created by the user and will be unique to the user's
library drawing or drawings. No compatibility problems will result
if corresponding drawings and character files are used together.
Both the author's and user character files will load together if
available on the disk at startup. A backup of these the user's
library drawings should always be kept.
Page 11
KEYBOARD ASSIGNMENTS - NUMLOCK AND CAPLOCK KEYS OFF !
Character graphics mode - alphanumeric keys active
F1 Gets help screens.
F2 Shows directory.
F3 Loads drawing after file name is given.
F4 Shifts window to the right.
F5 Shifts window up.
F6 Shifts window down.
F7 Shifts window to the left.
F8 Prints current drawing- provides options.
F9 Saves drawing and allows file name change.
F10 Exits program and returns control to MSDOS.
PG-UP Moves the menu select cursor up.
PG-DN Moves the menu select cursor down.
TAB Toggles through 4 columns of menu characters.
DELETE Erases the selected character.
ARROWS Moves the writing cursor horizontally and
vertically.
KPARROWS Moves the writing cursor and autorepeates starting
character when used with the right shift key.
ENTER Displays the selected graphic character.
SPACE Erases the selected character.
BACK Erases file names and choices to allow correction.
ESCAPE Aborts requests for keyboard input.
DELETE Erases a selected area.
HOME Moves cursor to far left.
END Moves cursor to far right.
ALT-R Displays selected character and its' hidden
relatives. Some characters appear to rotate.
ALT-W Dedicated to writing a line segment and line
crossing.
ALT-E Dedicated to writing and rotating a line elbow.
ALT-T Dedicated to writing and rotating a line tee.
ALT-G Dedicated to writing and rotating a ground.
ALT-C Copies character under writing cursor to buffer.
ALT-P Pastes a copied character to area under cursor.
CTRL-M Marks upper left hand corner of area to be
selected.
CTRL-C Copies the selected rectangular area to buffer.
CTRL-S Copies and the selected area to buffer then erases
the original.
CTRL-E Displays ASCII code of character under cursor and
permits its' deletion.
CTRL-B Switches to BITMAP mode.
CTRL-X Transfers pads from current drawing to designated
drawing.
CTRL-Z Toggles zoom out to show whole drawing.
LSHIFT Selects the character case.
RSHIFT The right shift key is used with the keypad
direction keys to autorepeat an existing character.
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Bitmap mode - alphanumeric keys inactive
CTRL-C Selects circle drawing submode.
CTRL-R Selects rectangle drawing submode.
CTRL-L Selects line drawing submode.
CTRL-M Marks a position on the screen.
CTRL-D Draws specified figure.
CTRL-B Enter bitmap mode or return from submode.
CTRL-I Installs selected bitmap image.
CTRL-R Rotates selected bitmap image.
CTRL-Z Toggles Zoom in to aid drawing of pixels.
ESCAPE Return to prior graphics mode.
ARROWS Move the pixel horizontally and vertically.
KPARROWS Move the pixel and writes to screen when
used with the right shift key.
CTRL-F Fill selected closed area.
F Coarse fill selected closed area.
f Fine fill selected closed area.
CHARACTER GRAPHICS MODE
The writing cursor
The writing cursor will move freely about the available
screen area under control of the direction arrow keys. Character
graphics patterns on the screen are unaffected by the cursor as it
moves by. However, bitmap patterns that have not been converted to
character graphics patterns are erased. The writing cursor will
also move freely around the screen under control of the keypad
direction keys when used together with the right shift key.
However, in this case the character under the cursor when the
movement starts will repeated until the cursor stops thus altering
the display.
The menu cursor
The menu cursor is confined to the right-hand column and will
select the visible character and also the three related hidden
characters associated with the visible one. The TAB key toggles
between the four columns of characters while the PG-UP and PG-DN
keys move the cursor vertically. Also, when the cursor wraps the
character columns are toggled. The visible menu character is
printed by the ENTER key and all four are printed sequentially by
the ALT-R combination.
Dedicated keystrokes
Certain graphic line characters are used so frequently that
their selection by the menu cursor becomes an obvious nuisance.
Four short cuts were created to speed up the drawing. These are
the dedicated ALT-W, ALT-E, ALT-T, and ALT-G key combinations. A
fifth one can be added for any character by first copying it with
ALT-C and then writing it with ATL-P. After these keys are learned
the menu characters on the right will be used primarily to write
device patterns rather than to make connections.
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EDITING CHARACTER GRAPHICS
Selecting the area
Place the writing cursor over the upper left hand corner of
the pattern to be selected and then use CTRL-M to mark this
corner. The corner character may be overwritten but this is only
temporary. Now place the writing cursor over the lower right hand
corner of the pattern and the preparation for either erasing,
copying, or copying and erasing is complete. Note that the mark
and cursor may straddle one or more window boundaries.
Erasing the selected area
Select an area to be erased as described under selecting an
area. Then press the DELETE key to erase the area you had
selected. Please note that further erasing is not possible until
another area has been selected.
Duplicating the selected area
Select an area to be duplicated as describe under selecting
an area. Then press the CTRL-C keys to copy the contents to the
buffer. The contents of the buffer may now be pasted in a new
location set by the writing cursor. That is, the writing cursor
will be locate the upper left hand corner, the position of the
marker when the area was copied. Press CTRL-P to display the image
at it's new location. Note, that the new image may be pasted
straddling one or more windows. At the edge of the drawing a
partial screen image may result but the image has not been added
to the drawing.
Duplicating and erasing the selected area
Selected an area to be shifted as described under selecting
an area. Then press the CTRL-S keys. This copies the selected
image to the buffer and then erases it from the screen. The
contents of the buffer may now be pasted in a new location set by
the writing cursor. Set the writing cursor the new location of
the upper left-hand corner of the area to be relocated. Press
CTRL-P to display the image at its' new location. The new image
may be pasted straddling one or more windows. At the edge of the
drawing a partial screen image may result but the image has not
been added to the drawing.
Zoom out
CTRL-Z toggles the zoom out image. This image encompases the
the complete drawing with loss of detail. The zoom out image
allows the user to preview the printed drawing. It is intended as
an aid in positioning the various parts of a drawing.
BITMAP MODE
The CTRL-B keystroke switches the mode from the character
graphics to bitmap. In the character graphics mode the characters
are drawn using existing patterns. In the bitmap mode the images
are based on computations or are drawn freehand. The cursor
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changes on entering bitmap to a simple cross and the lower right
hand corner of the screen shows the current subdivision of bitmap.
The ESCAPE keystroke switches the mode from bitmap back to
character graphics or from a submode of bitmap back to bitmap.
Drawing a circle
You must first enter the circle submode mode from bitmap
using the CTRL-C keystroke. The cursor is now a pixel that can be
moved one pixel at a time. Next move the pixel to the spot where
you want the center of the circle located. Mark the spot with
CTRL-M and a second pixel appears to the right of the first one.
This pixel will be used to set the radius as the circle will start
and end at this pixel. Move the second pixel to the starting
point and use the keystroke CTRL-D to draw the circle.
Any keystroke that occurs while the circle is being drawn
will stop the drawing resulting in an arc instead of a circle.
Drawing a slower circle with CTRL-S will make it easier to control
the point at which the drawing ends. After the circle is drawn you
will be returned to bitmap.
Drawing a rectangle
First you must enter the rectangle submode from bitmap by
using the CTRL-R keystroke. The cursor is now a pixel that can be
moved one pixel at a time. Next move the pixel to the locate one
corner of the rectangle. Mark this corner using CTRL-M and a
second pixel will appear to the right of the first one. Again
using the direction arrow keys move the second pixel to locate the
opposite corner of your rectangle. The keystroke CTRL-D will
cause the rectangle to be drawn. After the rectangle is drawn you
will be returned to bitmap.
Drawing some lines
First you must enter the line submode from bitmap by using
the CTRL-L keystroke. Your cursor now is a single pixel under
control of the direction arrow keys. The pixel moves freely about
the screen without affecting existing images. The cursor will
also respond to the keypad direction arrow key when used with the
right shift key. In this case a line will be drawn in the
direction shown on the key. Sloping lines will be drawn if the
keys numbered 7,9,1,or 3 are pressed. The direction will be
compatible with that of the other keypad direction keys. The pixel
under the pixel cursor will be erased by the space bar.
Drawing any line
First you must enter the line submode from bitmap by using
the CTRL-L keystroke. Your cursor now is a single pixel under
control of the direction arrow keys. The pixel moves freely about
the screen without affecting existing images. Next you must enter
the line submode using ALT-L. The pixel is used to locate the
start a line. Place the pixel to locate the start of your line
and use CTRL-M to mark this spot. A second pixel will appear and
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you will move with the direction arrow keys to locate the end of
your line. With the second pixel locating the end of the line use
CTRL-D to draw the line. After the line has been drawn you will
still be in the line submode. You may mark the end of the line
with CTRL-M to use this as the start of a second line.
Rotating or turning a selected area
The selection of the area to be rotated is somewhat different
from the previous selection process. Here, the cursor may not
overlap the image in its' original position or in any rotated
position. Put another way, the hypothetical rectangle specified by
the mark and cursor, must lie completely outside of the image to
be rotated whatever its position. Set the cursor in the upper left
hand corner consistent with the limitations just discussed. Use
CTRL-M to mark this point and move the cursor to a lower right
hand position consistent with the above and press CTRL-T. The
image will disappear and after a pause will reappear rotated one
quarter of a turn clockwise. Press CTRL-T and another quarter of a
turn is executed. After the first turn, the image appears only as
a screen image. The graphic characters needed to draw this image
do not exist. Please note, that if you go to character graphics
and change the screen contents then on return to bitmap the
rotated image will not be present. It can be restored, however,
with the CTRL-O keystroke.
Creating the characters
Any image that is not created exclusively with predefined
characters from the menus will need to be installed. In this case
some or all of the screen image will not be linked to a character
in the character file. Installation is a process where the
character file is scanned for characters that match those in the
screen image, linking to them if they exist and creating a new
character if they don't exist. If any part of a drawing is created
in the bit image mode or if an image is rotated it will need to be
installed.
The area to be installed must be selected with the same
cautions that pertained to image rotation. The mark on the upper
left hand corner and the cursor on the lower right hand corner
both must be outside the area to be installed. CTRL-I will run the
installation routine that creates the needed characters, places
them in the character file, and links them to the image. After
installation all editing operations may be used on the new image.
This installed image is your only link to the new character
so do not forget to place the sketch on a library drawing and save
the drawing. Also, do not forget to save the character additions
to disk when you exit the program. Of course, if you are
experimenting you will only waste file space if you save the
character file with the additions. When you have carefully
crafted a new electrical representation or mechanical outline then
place them on a library drawing and add the newly created
characters to your character file on disk.
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An installation routine that insures that there will be
little or no duplication of any existing character will be much
slower than one that uses the next available space for a new
character. This type of routine will search the existing file
using existing characters when available and will create a new
character only when it will be unique.
A trade off is provided that uses two files each of which
avoid duplication of characters internally but duplication
of characters between the files is allowed. This trade off
provides two character files, one to support my library drawings
and one to support the users own library drawings. This method has
two important benefits: first, it allows compatibility between the
two different sources of characters, and secondly, installation of
a new character in each file will be faster.
EDITING IN BITMAP
The chief editing feature of bitmap is the ability to erase
an image pixel under the cursor pixel. This is done with the space
bar. You must of course, move the cursor pixel away from the
erased one to see the result.
Figures such as the circle or line drawings that were made in
bitmap mode can be erased selectively with the character mode
cursor or moving to another window and returning to the original
window. Only the uninstalled bitmap images will be lost.
Zoom in
CTRL-Z toggles the zoom in Bitmap. The object to be magnified
must first be selected from an area of the screen other than the
lower right hand quadrant. The selected area is a 20 by 20 pixel
area to the right and just below the marker. A magnified image
that shows the individual pixels appears in the lower right hand
quadrant. The flashing pixel is now the cursor and is controlled
by the direction arrow keys. The pixel under the flashing pixel is
turned on by the ENTER key and turned off by the SPACE bar. This
feature allows both editing and drawing of objects that are 20 by
20 pixels in size. On leaving this mode the magnified image is
erased and the original image is updated.
LOADING DRAWINGS
Loading a single drawing
The procedure for loading a drawing is initiated by the F3
keystroke. A window appears at the bottom center requesting a file
name. A three character name is all that is needed since the body
of the art file name is common to all drawings. The name you use
is as you guessed the extension that will be used to distinguish
one drawing from another. The keystroke ENTER following the naming
of the file will load and display that file if it is on the
current disk. If not an I/O error message will alert you that
there is a problem and allow you to correct it. You may load up
to eight drawings simultaneously by repeating this procedure. To
avoid overwriting a loaded drawing switch to an unused drawing
before loading another one. You may select drawing slots 1 to 8
using the ALT-1 to ALT-8 keystrokes. The drawing will load into
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the current slot and the name will appear in the lower left hand
corner of the screen. The name will correspond to the drawing
that is displayed.
Loading multiple drawings
A menu for selecting multiple drawings to load is now located
on the show directory screen. You are given the choice between
selecting four drawings from the directory above, or loading four
previously selected drawings, or returning to the drawing screen.
To make the selection simply enter the letter corresponding to
your choice. When entering drawing names, please note that the
names are limited to three characters.
SAVING A DRAWING
The procedure for saving a drawing is quite similar to that
for loading the drawing. The procedure is started by the F9
keystroke. A window will appear with a request for a three
character file name. After the file name has been entered the
ENTER keystroke will cause the drawing to be saved. In the case
of an open gate or a full disk an I/O error message will be
displayed for a short time and prior conditions will be restored.
PRINTING THE DRAWING
There are two printing modes available for your use: a fast
mode, and an accurate mode that prints to the dimensions of the
screen scale. You may want to use the fast but rough mode for most
of your printing needs. However, before you try to print a
drawing you must verify the default printer codes or enter the
codes required by your printer.
Printer control codes and performance
Entering the graphics control codes is the second step you
take after the welcome screen appears. Enter a Y at this point and
you will be asked for the line spacing code. This code is used to
set the printer for the fast print mode. The data input routine is
expecting is expecting to receive two numbers. For example, the
complete code for the EPSON MX80 printer is 27,51,24 to set the
spacing for graphics. The escape code 27 is built in and MUST not
be entered here. The code you enter for the EPSON MX80 is simply
51,24. You cannot enter more or less that two numbers as you will
be hounded until the correct number of entries are made.
Note that the "24" sets the line spacing to 24/216 inches or
8 dots, the effective height of the print head. This eliminates
gaps that would appear if the normal text spacing were to be used.
If your printer does not support the 1/216 inch increment use two
numbers that set the spacing to 8/72 or to 16/144. In the case
of the Epson the code also could be 65,8. The 65, ASCII code for
"A", sets the increment to 1/72 inches and the 8 sets the spacing
to 8 dots.
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After entering the code for the fast print mode and you will
be asked for the code for 12/216 inch line spacing. You must enter
two numbers here even if you printer does not support this mode.
For the EPSON MX80 the code to be entered is 51,12. This sets the
spacing to four dots with the capability for adjustments to 1/3 of
a dot. If your printer does not support this mode enter 51,8
In this case, you will only be able to use the fast printer mode.
Finally, you will want to set the printer to the 960 dots per
line graphics mode. Most printers support this mode and use the
same code. The Epson code for this is 76,192,3. 76 is the ASCII
code for "L" and the two other numbers call for the number of dots
per line to be 192 + 3 * 256 or 960. This time, you MUST enter
three numbers separated by two commas. Sorry, about this stubborn
data input, but other approaches failed causing my printer to
print the control codes, a nasty state of affairs.
The F8 key starts the printing process. The printer will
always print the displayed drawing so you must switch to the
drawing to be printed before pressing F8.
Table of line spacing codes
PRINTER FAST MODE CORRECTED MODE
EPSON MX80 51,24 51,12
STAR NX1000 51,24 51,12
PANASONIC 1091/1091I 51,24 51,12
GEMINI 10X/15X 51,16 51,8 *
TANDY (IBM EMULATION) 51,24 51,12
IBM PROWRITER I 51,24 51,12
* Although the line spacing will not be correct you must
enter some code.
Printing circuit board artwork
The corrected printing mode was designed primarily for
use when printing circuit board artwork. When this choice is made
two printing variations are offered. The multiple strike option
allows the image to be darkened by reprinting each line according
to the number of strikes entered in the dialog box. The
positive/negative option allows the user to adjust to the type of
processing to be used. Please note that the negative option may
cause overheating of the print head. See precautions and tips item
7.
PRECAUTIONS and TIPS
1. You will want to keep a BACKUP of all your original files,
of course.
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2. If and when you change the art file names limit the
changes to the three character file name extension. The body of
the file name MUST not be changed.
3. PC-Schematic requires approximately 512k of available RAM
for the program and its' files. If your don't have 640 k of
installed RAM you may have to remove or limit your resident
programs.
4. When additions to the character definition file have been
made you MUST save the modified file when you exit the program.
You must always save any drawings that have been altered BEFORE
exiting the program.
5. Keep your additions to the library on separate drawings.
This will prevent compatibility problems when character files are
updated.
6. Note that you have access to ANY installed graphic
character that is displayed on the screen but is not available on
the menu. Simply place the character mode cursor over the
character, copy with ALT-C, and paste in a new location with ALT-
P. The autorepeat feature can also be used to duplicate any
installed character.
7. Negative printouts are hard on the print head. If doubt
about the printer's ability to handle the load, form your drawing
so as to limit the dark areas in your artwork. This also will have
the advantage of stretching your etchant.
8. It is recommended that the predefined characters be added
to the bitmap image after installation rather than before hand.
9. Note that the user character file has not been included on
the original disk because of space limitations. If it had been
provided it would have been empty. The you will create your own
character file when exiting the program if you choose the "Y"
option.
CONCLUSION
PC-SCHEMATIC is a general purpose program for casual
electronic design work with the ability to perform tasks that are
unrelated to electronics. It has features that make both the
drawing and editing very easy once a few simple procedures are
learned. If you find this program useful and use it after a trial
period please remember that it is being offered as Shareware!
Also, you are encouraged to pass the program on to others who may
find it useful.
REFERENCES
Russ Davies, Computes Mapping of the IBM PC
William Barden, Jr., Graphics and Sound for the Tandy 1000s
and PC Compatibles
Waite and Morgan, Graphics Primer for the IBM PC
Edward H. Kidera, PC-KEY-DRAW
Joel Goldberg, How to Make Printed Circuit Boards
Nicholas M. Raskhodoff, Electronic Drafting and Design
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