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PCTRACE
Version 5.0
Users Manual
Jan 2, 1993
by
Douglas E. Ehlers
Ehlers Technical Consultants
4520 S. 58th St.
Lincoln, NE 68516
(402) 435-8440 Voice (evenings)
(402) 483-1665 BBS 9600,N,8,1 V.32, V.42bis
2
Table of Contents
Notice of Copyright............................................3
Introduction...................................................4
Installation...................................................4
System Requirements............................................5
Software Setup.................................................5
Old file Upgrades..............................................6
User support Methods...........................................6
Voice.....................................................6
BBS.......................................................7
Input/Output Menu..............................................8
Board Definition Menu..........................................9
Chip Placement...........................................10
Interactive Router............................................14
Mouse use................................................18
Autorouter....................................................18
Board Statistics..............................................19
Printer Menu..................................................21
Export Menu...................................................21
Exiting the program...........................................22
Tutorial......................................................24
RPRINT Subprogram.............................................26
DEFGEN Subprogram.............................................28
PC-Trace Keyboard control summaries...........................32
Schematic CAD.................................................33
Drawing Symbols..........................................36
Entering Components/Symbols..............................40
Making Connections.......................................43
Additional Drawing Commands..............................44
SCAD active keys.........................................49
Conclusions...................................................50
Appendix A - .NLT file format.................................51
PC-Trace Users Manual
3
Notice of Copyright
This program is protected by a copyright held by the author
and filed with the United States Government. Copying of this
software is forbidden and a criminal offense. Anyone caught
distributing this software without the author's consent will be
prosecuted to the fullest extent of the law.
Note: This program was originally marketed under the name
PCROUTE but for copyright reasons has been renamed to
PCTRACE. SCAD is short for Schematic CAD and is a
schematic capture program that is part of the PCTRACE
system.
PC-Trace Users Manual
4
Introduction
PCTRACE is a computer aided design program for printed
circuit boards. It contains programs that can take the designer
from a schematic, to a board layout, to computer control of the
machines needed to make high quality circuit boards. The program
should be quite adequate for most purposes. This program is not
meant for IBM's use to design the next PS/2 motherboard. It is
intended for the late-night engineer to build home projects. It
contains a full featured autorouter that averages a 93%
completion rate on low density boards and 70% on higher density
boards. It also supports most popular printers for its output.
PCTRACE is the general name given to all the programs that
make up this system. For example, PCTRACE includes SCAD, RPRINT,
and PCTRACE itself.
Key features include:
1. Autorouting
2. Graphic interactive routing
3. Board layout functions
4. Flexible pinouts for devices
5. 2X and 1X output for use in making PC boards
6. Disk functions built into the software
7. Sophisticated component and connection entry systems
8. General statistics
9. Up to 300 components and 1800 connections
10. Mouse support in the interactive router
11. Variable pad and trace sizes
12. Single and double sided boards
13. Manual placement of traces
14. CGA, EGA, and VGA graphics support to display the
board. CGA:80x25 EGA:80x43 VGA:80x60
15. Gerber, DXF, and Autocad Script file output
16. Actual size silkscreen creation
17. Error handling for critical errors
18. Schematic Capture for a complete cad system.
19. The authors continued support
Installation
Contents of PC-Trace directory:
PCTRACE .EXE - The board layout/main program
SCAD .EXE - Schematic CAD
RPRINT .EXE - The PC-Trace printer output program
SPRINT .EXE - The SCAD printer output program
CONVCDT .EXE - Converts 4.0 and older files to 5.0
CONVDEF .EXE - Converts 4.0 and older files to 5.0
PC-Trace Users Manual
5
* .DEF - PC-Trace part layout files
* .DIA - SCAD symbols
System Requirements:
To run this program requires:
1. CGA, EGA, or VGA graphics
2. 640k of memory with 520k free
3. 1 floppy disk drive
4. Hard Disk Drive or Large capacity floppy
5. One of the following printers:
a. IBM PC or compatible printer
b. EPSON LQ-2500 or compatible printer
c. HP Laserjet II or compatible
d. Adobe Postscript Compatible printer
e. HP Deskjet or Deskjet +
f. Epson MX-80 or compatible
g. IBM Proprinter 24pin must be in AGM mode
h. HP and Roland Plotters
6. Mouse is required for SCAD and usable in PC-Trace
A fast processor and math coprocessor are also beneficial.
Software Setup:
For PCTRACE to run reliably, a line must appear in the
config.sys files that says FILES=20. If any other major
commercial software applications are in use this command probably
exists, but it should be checked.
To install the software insert disk 1 in either drive A: or
B:. Change to the drive that the floppy disk is in. To do this
type A: or B: from the dos prompt. To start the installation
process, type INSTALL from the DOS prompt. The installation
program will run and prompt for the drive that the install disk
is in. Enter the letter and verify that it is correct. The next
prompt is for the destination drive. This should be the letter
of a hard-disk or alternate floppy disk that has at least 1mb of
free space. Verify that the destination of the program is
correct. The installation program will notify the user that it
is ready to start the installation process and that Disk 1 should
be placed in the disk drive. This should already be the case.
Press SPACE to begin. After a few moments, a prompt will appear
for the user to insert disk 2. If PCTRACE was shipped on a
single floppy (3.5 inch) disk 2 is the same as disk 1. If the
program came on two floppies (5.25 inch) insert the second disk.
Press space to finish the installation.
To execute the programs the user must change into the
PCTRACE5 directory using the command CD \PCTRACE5. The programs
PC-Trace Users Manual
6
will not run properly if run from some other directory than
PCTRACE. To run the programs type PCTRACE, SCAD, or RPRINT from
the DOS prompt. Install will also create two subdirectories
called DEFILES and DIAGRAMS to store the definition files for
PCTRACE and symbol files for SCAD.
Two programs are included to help with the update process.
CONVDEF.EXE is used to modify the old .DEF files that the user
might already have created. To use this program, copy it into
the subdirectory that holds the old .DEF files. Type CONVDEF,
the program will run and update the file format of all the old
files. CONVDEF can now be deleted from the hard-disk anywhere
that it appears.
The second program is used to update the .CDT files. This
program requires that the .CDT file be in the same directory as
CONVCDT.EXE. To convert the file, type:
CONVCDT file1.CDT file2.CDT file3.CDT.
The program will update the file from the 3.0 and 4.0 format
to the 5.0 format. The old file will be saved in a .BAK file.
One major consideration when moving a 4.0 file to the 5.0
system is the advanced silkscreening. The parts are referenced
to a most upper left corner for placement, this includes
silkscreen parts. If a part exists on an old board and is
converted to the 5.0 program, that part should be left unchanged
as far as silkscreen. If the silkscreen is drawn around that
part, it will offset the location of the pads and the existing
traces will not meet the pads in the correct place. This will be
immediately visible as the affected parts will appear to have too
many pads. If the user desires the silkscreen on the old board
with the 5.0 software, they should be prepared to move components
around in the interactive router to get the pads in the popper
places. Traces that were overwritten by the incorrectly placed
pad may have to be repaired as well.
User Support Methods
Phone Calls:
All registered users are free to call anytime to notify
the author of bugs, perceived bugs, program usage questions,
suggestions of additions, and anything else that the end
user feels the need to discuss with the author. The BBS is
also a good way to receive support for the registered user.
Un-registered users are also welcome to call during the
evening when having problems getting the demonstration
version of PCTRACE running. The support will be more
limited. A better, and preferred method by the author, is
for these users to use the BBS.
PC-Trace Users Manual
7
BBS Support:
Perhaps the best reason to register the demo version is
to get the support of the registered user section on the
BBS. The complete PCTRACE system is posted in this area for
downloading. Upon registration all users receive a password
on this system that allows them to download the most current
bug fixes any time they like. The user name and password
appear on the first page of the manual. Part and symbol
libraries will also be posted and hopefully uploaded by
users of the system. Other programs deemed useful by the
author will be posted for all users as well as the demo
version of the software.
To access the BBS, call the number listed on the
opening screen of the software with a modem control package
such as PROCOMM or QMODEM.
Support is provided courtesy of the author. Please
feel free to log in to the BBS anytime. Voice calls should
be at a decent hour and evenings are best. Please exhaust
all possibilities before making the call and be sure to try
and understand the problem before making the call to better
explain it to the author. If it is possible, please try and
isolate the problem to the point that it can be repeated by
executing a certain sequence of events. By doing this, it
becomes much easier to find and fix the errors in
programming.
PC-Trace Users Manual
8
PC-Trace Manual
Input/Output Menu
1. Load Data:
This function is used to retrieve from a disk necessary
information to design a printed circuit board. Select this
function from the menu and when prompted, enter the file
name. No extension is used, the program will add the .CDT
extension. The path should not be used on the filename
itself. There is a function that will be discussed later to
set the path name. After entering the filename, press
Return. The program will ask if this is the correct name,
enter Y or N to answer. If the file is not found the
program will reprompt for file name. The ESC key is used to
jump back to the main menu instead of entering the file
name.
2. Save Data:
This function will save a complete description of the
design layout, component list, and connection list. When
prompted, enter the filename. Again do not specify the file
extension or path name. PCTRACE will ask, after entering
the file name, if everything is correct. If so, enter a Y
or N. If the file exists the program will ask if it is
alright to overwrite the file. N will prompt for a new file
name. ESC will bypass the prompt back to the I/O menu.
3. Erase Data:
This routine clears the memory of the program. It
erases the boards, component list, and connection list. The
program will ask for confirmation before erasing the data in
memory. Answer Y or N. The program will respond with
"Erasing..." and after a few seconds drop back to the I/O
menu.
4. Import Data:
This load routine works the same as the primary load
command in this menu. The difference is that it is made to
load a netlist generated by SCAD. Creation of this file is
covered in the SCAD manual. Once this file has been loaded,
assuming that it is a complete design, all that remains is
to place the parts, make any minor design changes, and
autoroute the board. This is a best case scenario and more
work is usually required.
5. Disk Directory:
This function displays a listing of the all the circuit
data files on the current drive and path. Use the space bar
to view twenty file names at a time. When no more files
PC-Trace Users Manual
9
exist, the space bar returns to the I/O menu.
6. Change drive/path:
This function changes the current path. The ESC key
will back out of the function without changing the path.
The function will display the current drive and path and
then prompt for a new one. Just enter the new one and press
Return.
Define/Edit Board Menu
1. Component Edit/Entry:
This function is used to enter components into the system.
Selecting this function will place the user in the entry/editing
environment. If no components have been entered only two
possible commands will be shown, if there are components in
memory the programs shows options to delete, copy and perform
other functions.
New Component Entry:
Typing an "A" will allow entry of new components. The
program will display the component number being entered and then
prompt for the name. The name may be up to 15 characters long
and serves only to remind the designer of what the device is.
ESC can be used at this point to return you to the entry/editing
environment.
The next question is for the designation. This is the
unique name that is given to the component and will be used in
the future to refer to it. Typical names include IC1, R1, IC2,
and A1. There are two reserved designations. The first reserved
designation starts with "V" and then a number, so V1 would not be
accepted but VI1 would be. The second reserved designation is
"GRNDP". If this is specified as a source or destination pad in
the autorouter, a connection to the ground plane will be
attempted if one is defined. ESC may be used to back up while
entering the designation name to reenter the component name.
Third, the program will prompt for the definition file name.
This is the name of a file that tells the program how the pins on
the device being entered are situated. The program first shows a
list of possible definition file names at the lower right. At
the end of the list the program will prompt for a name. Do not
enter a file extension, the program will add it for you. If the
name of the file entered exists, it will read the file and
display the chip definition to see if it is correct. If the user
answers "yes" the program will continue to the next question. If
the user answers "no", the program will reprompt for the
definition name after displaying the possible files. ESC may be
used to back up and reenter the component designation. New
definition files can be created with the subprogram DEFGEN. See
PC-Trace Users Manual
10
that section of the manual for information on its usage.
The fourth prompt asks for the pad size for the device. A
small window will pop up and prompt for a pad size between 0.05
inches and 0.15 inches. All pads are circular. Enter the
corresponding number to the pad size.
The next question the program will ask if everything is
correct. Answering "no" will restart this process with re-
prompting for the name. Answering "yes" will get the next
prompt.
The next prompt is to keep this device. Answering "no" will
skip the next prompt and ask if you wish to enter another device.
Answering "yes" displays the next prompt.
This prompt asks if the user wishes to place the device now.
Entering "no" will allow the delay of this until later. All
devices must be placed somewhere on the board before they can be
connected. Placing a chip goes as follows:
Placing Chips:
When the graphic screen comes up a representation of
the current circuit board with all other placed components
and ground planes are shown. The chip being entered will be
shown in the upper left corner of the board. The arrow keys
will move this chip around on the board. By using a shift-
arrow combination the chip can be moved faster. Move the
chip to its final place and press return. Chips cannot be
overlapped. The chip is now placed in this location. ESC
will exit without placing the chip. Confirmation of
abandoning the placement is asked. Yes will go to the next
prompt, no will return to the place before hitting ESC.
The last prompt is to enter another chip or not. Answering
"yes" will put the user back at the name prompt to enter another
chip. No will put the user back in the entry/editing
environment.
Editing Component Definitions:
Selecting E from the entry/editing environment allows
editing of any part of each definition. Simply select the letter
of the item to change. For example, to change the name, press A
after pressing E and enter the new name. Either enter the new
name, or press ESC to leave it unchanged. When done editing,
press the key that corresponds to exiting the edit.
If editing the placement of chips, the chip definition file
must be present in the DEFILES subdirectory for the placechip
function to work. The only time this is a problem is if the
board being edited is not your own, such that the chip definition
files have different names from your own.
PC-Trace Users Manual
11
Deleting Component Definitions:
This function allows removal of a component. The component
that will be deleted is the one currently displayed on the
screen. Press D and confirmation will be asked for before
deleting the component. Answer accordingly. All connections
that contained the deleted function will also be deleted.
Copying Components:
This function will allow copies of a chip definition to
speed the entry of chips. It will copy everything from the
displayed definition to a new definition except for the
designation from which it will take the alpha part and then
increment the numerical part to the next available part. It also
does not put the chip in the same location. The program will ask
if the user wishes to place the chip now or later.
Searching for a Component:
Sometimes finding the component that needs to be edited or
deleted can take some time on a large board. This function
allows a search for components by designation. When prompted,
enter the designation. PCTRACE will change the case to upper. If
it exists, the program will display that device's number. If it
doesn't exist, nothing happens.
Incrementing and Decrementing the displayed Component:
Using + and - will change the displayed component. +
increments and - decrements. The display is circular in nature,
therefore hitting + at the last component will move it to the
first and hitting - at the first will move it to the last.
Exiting the Entry/Editing Environment:
Use the N key to end these functions and return to the board
definition menu.
2. Connection Edit/ Entry:
This system allows for entry and editing of all the
connections that need to be made between the components in the
system. The functions are very similar to the component
functions.
New Connection Entry:
Typing an "A" will allow entry of new connections. The
program will display the connection number being entered and then
prompt for the name of the source designation. The name must
exist in memory as a component. ESC can be used at this point to
return to the entry/editing environment. If a ground plane has
been defined, the reserved designation "GRNDP" can be used to
connect to it. The associated pin is ignored and defaults to 1.
The next question is for the source chip pin number. Enter
PC-Trace Users Manual
12
the number of the pin that the trace is to connect to. ESC will
back up to the previous prompt.
The program will now prompt for the name of the destination
designation. The name must exist in memory as a component.
"GRNDP" can be used as a destination as well. ESC can be used at
this point to return to the previous prompt.
The next question if for the destination chip pin number.
Enter the number of the pin that the other end of the trace is to
connect to. ESC will back up to the previous prompt.
The program will now ask if this is a priority route or not.
By answering "yes", this trace will be routed before all other
non-priority routes no matter how long it may be and what other
routes it may block. This might be used for making sure a memory
access bus is all done in copper instead of using jumpers for a
vital connection.
Next, the program will want to know the desired trace width.
Traces from 0.01 to 0.07 are supported. Select the number
corresponding to the size required. The following table will
show what size trace will go between two pads of some size that
are spaced on 0.1 inch centers.
Pad Size (inches)
Trace width 0.05 0.06 0.07
0.01 Yes Yes No
0.02 Yes No No
0.03 Yes No No
0.04 No No No
0.05 No No No
0.06 No No No
0.07 No No No
These tolerances can be overridden using the interactive router
which will be discussed later.
The next question the program will ask is if everything is
correct. Answering "no" will restart this process by reprompting
for the source designation. Answering yes will bring up the next
prompt.
The next prompt is if the user wishes to keep this
connection. Answering "no" will skip the next prompt and ask if
you wish to enter another connection. Answering "yes" brings up
the next prompt.
The last prompt asks if another connection needs to be
entered. Answering "yes", will put start back up at the source
designation prompt to enter another connection. "No" returns the
program back to the entry/editing environment.
Editing Connection Definitions:
Selecting E from the entry/editing environment will gives
the user the ability to change any part of each connection.
Simply select the letter of the item to change. For example, to
PC-Trace Users Manual
13
change the source designation, press A after pressing E and enter
the new designation. Either enter the new designation, or press
ESC to leave it unchanged. Press N to exit the edit mode.
Deleting Connection Definitions:
This function allows removal of a connection. The
connection that will be deleted is the one currently displayed on
the screen. Pressing D will confirm before actually deleting the
connection. Answer accordingly.
Searching for a Connection:
Finding the connection to edit or delete can take some time
on a large board. This function allows a search for connections
by designation. When prompted, enter the designation sought.
PCTRACE will change the case to upper for you. PCTRACE then will
search from the current connection to the end. It looks at both
the source and destination designations for a match. If it finds
the search string the program will display that connection's
information. If it doesn't exist, nothing changes.
Incrementing and Decrementing the displayed Connection:
Using + and - will change the displayed connection. +
increments and - decrements. The display is circular in nature,
therefore typing + at the last connection moves it to the first
connection and pressing - at the first will move it to the last
connection.
Exiting the Entry/Editing Environment:
Use the N key to end these functions and return to the board
definition menu.
3. Ground Plane:
This function is used to set up a ground plane. The program
will display a picture of the board. It will prompt for the
width of the ground plane on all four sides on both the
component side and solder side of the board. Each digit
entered corresponds to .05 actual inches. The ground plane
may be changed at any time. ESC will also back out of the
first prompt only (top-solder side).
*** Please note that this function erases any work done in
the interactive router (discussed later).
4. Define Board Size:
This function is the first function used. It defines the
dimensions of the board. The maximum board size supported
by PCTRACE is 8" X 10". When prompted for numbers, the
PC-Trace Users Manual
14
numbers are entered as multiples of 5. Each number
represents 0.05" of actual size. So an entry of 100 would
correspond to 5". Board sizes can be changed at any time
during the design process by calling the routine again. If
the board is made smaller, the chips that were outside the
new border will have to be replaced. ESC will back up to
the previous prompt, or jump out of the routine leaving the
board size unchanged.
5. Spider Web:
This function is useful for checking to see if a chip would
be more logically placed somewhere else. By using the + and
- keys, various chips and their connections can be
displayed. As each chip is selected, it, as well as all
traces connected to it are highlighted in red. Once a chip
is highlighted, selecting M will allow movement of the chip.
After pressing M, the arrow keys become active and the chip,
as well as all its connections will be rubber banded around
the board. Pressing RETURN will place the chip at the
current location, or press ESC to not place the chip and put
it back at its original location. The ESC or E key will
exit from this function.
*** Please note, if chips are moved, the work done by the
interactive router is erased.
Interactive Router
This board editing system allows the designer to
interactively design a board. It can be very useful for finding
possible routes that the autorouter was unable to find. Upon
entry to this section, the program generates the borders and
places the pads of all the chips. If a large number of
components has been placed on the board, it could take a few
moments. It will also ask the user to place all the chips that
have not been placed yet. If you intend to route the entire
board this way, place your chips and then leave them. Moving
them around after placing the chip will distort the board.
PCTRACE has no way of connecting traces up to a chips new
location. The screen will show all the chips with their
designations centered amid each component pin unless DEFGEN is
used to lock the location of the designation. This system has
many keys that are active while in this environment. An
explanation of each follows.
S - switch sides:
This function changes the side of the board displayed. When
S is pressed, the other side of the board becomes visible.
The program supports only 2 sides, solder and component.
PC-Trace Users Manual
15
K - Silkscreen toggle:
Pressing this key toggles the silkscreen display on and off
while in the interactive router. It defaults to ON upon
entry to the interactive router.
C - move a component:
Pressing this key will give the user the option of moving a
component within the interactive router. After pressing C,
the bottom of the screen will show a brief listing of a
component. The name and designation are listed. + will
move to the next component, and - to the previous one. ESC
will exit the component movement function. Pressing M will
erase the displayed component and redraw the screen. At
this point, move the cursor to the upper left corner of the
area where the component will be placed and press G to place
it. It is important to understand that the cursor
represents the absolute upper left corner of the part
including any silkscreen extensions.
G - grab location:
The key is only active at certain times. The F1, F2, F4,
F5, F6, F7, and F10 function all use this key. The key is
normally used to mark a location on the board or a piece of
a trace.
B - Turn on background:
This key is used to turn on and off the background layer.
If editing the solder side, a lightened view of the
component side can be turned on. On a color monitor, it
will appear dotted and red. Black and white monitors will
show dotted graphics only. Pressing B again turns this mode
off.
E or ESC - end:
Pressing E or ESC will exit from the interactive router.
Cursor Keys:
The cursor keys move the solid block around on the board.
Each time an arrow key is pressed, the cursor will move 1
space. Relative coordinates are displayed at the bottom of
the screen. Using Shift-Arrow moves the cursor 10 spaces.
If the edge of the screen is encountered, but not the edge
of the board, the screen will shift the board over.
Function Keys:
The function keys numbered F1-F10 do the majority of the
work in PCTRACE. They allow placement of vias, running traces,
deleting traces, resizing traces, and deleting vias.
PC-Trace Users Manual
16
F1 - Set Source:
By pressing F1, the bottom of the screen will say to
position the cursor on the pad that will be designated as
the source and then press G to grab it. The bottom status
line will display exactly what chip and pin number have been
selected.
F2 - Set Destination:
This function works exactly as the F1 function but selects
the destination pin.
F3 - Run Trace:
Once a source and destination have been defined, pressing F3
will attempt to connect the two pins with a trace 0.01
inches wide. If it is successful, the screen will be
redrawn and the trace will appear. If it cannot complete
the route, a message will be displayed at the bottom of the
screen. At this point try placing a via and routing from
the source to it on one side and from the via to the
destination on the other.
F4 - Delete Trace:
This function will delete any part of any trace on the
board. Pressing F4 enters the delete selection mode. After
pressing F4 the screen will say to use G to grab the parts
to be deleted. As the user presses G on valid traces, the
pieces will be highlighted. Changing screens by moving the
cursor off the screen will not lose the already selected
traces. Once all the pieces to delete have been selected,
press F4 again and the program will prompt to confirm
deleting of the selected traces. Answer Y to finish the
delete operation.
F5 - Add Via:
This function key will add a via at the location of the
cursor when G is pressed. It will be V and then the next
available number. Use these for multilevel routes or just
extra pads needed. A via cannot be placed adjacent to an
existing pad. One can be placed diagonally from a pad . A
via also may not be placed in the middle of a trace. All
vias are deleted by the autorouter when it is invoked.
F6 - Del Via:
This function deletes the via at the cursor location when G
is pressed if a via exists there.
PC-Trace Users Manual
17
F7 - Resize trace:
This function will resize a trace to any valid trace size.
Select F7 and use G to select the traces to resize. Once
the traces to resize have been selected press F7 and the
program will ask for confirmation of the resize. Answer Y
to resize. The program will prompt for the trace resize
value. 1 corresponds to 0.01 up to 7 which corresponds to
0.07 inches. Be careful not to overlap other traces or pads
with this function.
F8 - Check Route:
This function will check to see if a selected pair of pads
can be connected. It will report back whether the route can
be completed, the route exists already, or if no route can
be found. This is useful for doing multi-layer routes using
vias. Checking for an available route before laying the
actual trace will save a number of deletes if later the path
is blocked.
F9 - Manual Route:
This function allows the user to manually route traces.
Place the cursor on the starting pad or trace and press F9.
A prompt will appear at the bottom of the screen asking for
the trace width. Enter the number that corresponds to the
desired size and press return. Now use the cursor control
keys to route the trace. Every time the cursor moves, the
trace is lengthened. When done, either stop in an open
space and press F9 or stop on a trace or pad and press F9,
the correct connecting piece will be added to make the
connection. Please note that moving over an existing trace
will cause PCTRACE to cut that trace in favor of the new
path. This works well for putting short jumpers on the
board. This is very useful for routing traces that would
normally block other routes if they were not placed this
way. With the interactive router any size trace can be
placed anywhere. It is possible to over-ride the autorouter
and run a 0.01 inch trace between two 0.07 pads. If the
board-making process used is accurate to 0.01 many low power
traces can be completed this way. The manual router is also
used in many advanced "tricks" for making specialized
boards.
F10 - Write Text:
Pressing F10 allows additional text to be added to the
silkscreen layer. After pressing F10, the program will ask
the user to move the cursor to the starting position for the
text and press G. After pressing G, the software will
prompt for the text string. It will accept up to 20
characters. When done entering text, press return. The
PC-Trace Users Manual
18
next prompt is for double sized text. Answer "yes" and the
text will appear double sized. The board will then be
redrawn with the text added in. The only thing to be aware
of is that normal silkscreen text takes precedence over user
added text.
Using a mouse in the interactive router:
The mouse allows a faster method to do all the functions
mentioned previously except for the manual router. The mouse
must be installed before running the PCTRACE program. When
entering the interactive program four arrows will appear in the
lower right corner of the screen. By using the mouse, putting
the cursor on one of these arrows, and pressing the left button,
the screen will be moved by half in that direction. The same
thing was accomplished by moving the cursor off the board using
the arrow keys.
Pressing the right button will pop up a menu along the
bottom of the screen. The menu corresponds to function keys F1-
F8, and F10. The exit command at the far right, exits the menu.
By placing the cursor anywhere on the command desired, execution
of that command is done by pressing the left button. If the
command selected is F1, F2, F4, F5, F6, F7, or F10, the program
will be using the "Grab" method. The left button works the same
as the G key in these cases. Use it to highlight sections and
locations on the board to work with. When using the delete and
resizing functions (F4 and F7) the user must press and release
the left button for each piece of trace.
Autorouting
Selecting this from the menu will enable the user to connect
all or most of the connections desired. The program will first
draw borders, place pads, and set up the ground planes. If a
component has not been placed, the program will ask the user to
place it. The program requires all chips to be placed before it
can route. There are four routing strategies that can be
employed. Select each strategy by pressing Y or N as the cursor
moves to each option. If Y is selected for single or double via
routing a prompt will also appear for the maximum number of tries
for each. Just enter a number. Bigger numbers are better for
bigger boards, smaller numbers for small boards.
The PCTRACE system is totally re-entrant. The first
question asked is if the user wishes to clear all traces.
Answering "yes" clears anything currently on the board. "No"
would keep the screen as it was. ESC can be pressed during any
routing strategy to exit that routine and the autorouter. The
program will then show the list of all unconnected routes still
existing. If the router has not completed one run-through the
connection list, traces may have been completed by the earlier
route and still be reported as unconnected. A design check can
PC-Trace Users Manual
19
be done to see which routes in the connection list have not been
connected, either by hand or by the autorouter, by running the
autorouter and not erasing the current traces. This is because
the autorouter will not reroute a connection that has already
been completed. Just select the double or single sided route
system. It will report any routes that are incomplete. Any
route that was completed before will be marked as complete and
not reported. The program will report whatever routes weren't
done and the ones it couldn't complete.
Single Sided Route:
This function will attempt to place all the routes on the
solder side of the board. It is the least efficient
strategy but is great for small projects where ease of
making the board itself is a priority. This function cannot
be used in conjunction with the next three strategies.
Double Sided Route:
This function will do its routing on two sides of the board.
It has a higher completion percentage than the single sided
strategy.
Single Via Route:
This function requires that the double sided strategy be
selected first. This function is used after the double
sided strategy to try to complete any uncompleted routes.
It places a via and tries to do the single route with a
trace on each side of the board. A number such as 50 is
good for the maximum number of tries prompt.
Double Via Route:
This function also requires that double sided routing be
selected to work. It uses two vias to attempt to complete
the route. A good maximum number of tries is 30 or so.
This function can take a great deal of time so be patient.
Board Statistics
This function displays 5 statistics.
Equivalent Integrated Circuit Count:
This function is the total number of pins divided by 16.
Board Density: This is the amount of space total that each chip
has to occupy. It is calculated by taking the
area of the board and dividing by the Equivalent
IC count.
PC-Trace Users Manual
20
Total Trace Length: The function gives the total length of all
the traces on the board. The smaller the
number, the better the design.
Board size: The board dimensions in inches.
File name: This is the file name currently in memory.
PC-Trace Users Manual
21
Printer Menu
1. Print Components: This function will generate a list of
all the components. It can be sorted by
name or designation.
2. Print Connections: This function will generate a list of
all the connections in memory. It can
be sorted by the source or destination
designation.
Export Menu
The export menu allows for files to be created that various
other cad software and board producers use. After selecting the
Export menu from the main menu, four export choices will be seen.
1. Write Autocad Script file:
This function will write a file that can in turn be
read into and edited with Autocad. The process is one way,
no way is provided to read autocad files back into PCTRACE.
Call this function from the Export menu and give a name when
prompted. Specify no path or file extension. The extension
.SCR will be added to the file. Once the program is done
writing the file, Autocad may be started. Use the command
"SCRIPT" from the "Command:" prompt. Autocad will ask for
the script file name. Specify the same name (with path if
needed) as the one created in PCTRACE and Autocad will read
in the file. Autocad will display three layers: solder,
component, and silkscreen. Each may be edited and saved as
Autocad drawing files. Doing this greatly increases the
number of printers that can be used for output as Autocad
supports a large number of printers.
2. Write a DXF file:
The DXF file is used by many cad packages to
incorporate data into their systems. Autocad is one prime
example. The DXF file includes all three layers in its
output (Solder, Component, and Silkscreen). The command
will prompt for a file name. Enter the filename with no
extension. The extension .DXF will be added. After the
filename has been entered, the DXF file output will be
created. Autocad will load this file using the command
"DXFIN" from the Autocad "Command:" prompt. Wordperfect
will also read a DXF file and convert it to its own graphics
format (WPG files).
PC-Trace Users Manual
22
3. Write a Gerber file:
A Gerber file is the standard file type that is used by
professional board manufacturers. The PC-Trace software
will generate this file format and is accurate to 3 decimal
places. Upon selection of this option, the user is prompted
to enter aperture names to be used. The aperture is used to
describe an entity on the board. If the photo plotter that
the board maker is using requires that a pad 0.05 inches in
diameter be specified as D23, then the 0.05 inch pad
aperture name must be changed to reflect this. The software
will ask if the aperture list is OK. If it is, press Y for
yes and the program will continue. If N for no is pressed,
each aperture must be re-entered as the cursor goes down the
column. ESC will bypass a selection without erasing.
Retyping will change the selection and return will erase the
selection which would make it necessary to re-edit the
aperture list. Once the list is determined to be correct,
the program prompts for the board side to be plotted to the
file. Press the number that corresponds to the desired
selection. Last of all the program will ask for an output
filename. Enter the filename with no extension. Upon
pressing the return key, the program will generate the
Gerber file. Two files will be created. The first file
will be the filename plus the extension .GER for the actual
Gerber file. The second file is the filename plus the
extension .AP for the aperture list. Both of these files
should be sent to the manufacturer. A file must be
generated for each board side that is desired to be
manufactured. Only one aperture file need be sent.
4. Write a CNC Drill file:
A CNC drill file contains the information for a
Computer Numerically Controlled drill press to drill the
holes for the pins of the components to be placed though.
The software will prompt for the drill bit (tool number)
size that should be used for each different sized pad. The
entry system works the same as that of the Gerber aperture
definition screen. The user will next be prompted for the
output file name. It should be entered without an
extension. After pressing return at the end of the filename
the computer will create the filename with the extension
.NC. The file contains the X,Y coordinates of all the pads.
Exiting the Program
Selecting 8 from the main menu will exit from PCTRACE back
to DOS. If there is data in memory the program will ask if you
wish to save it. Answering "Yes" will prompt for a file name.
PC-Trace Users Manual
23
Enter the file name as was done in the save data function in the
Input/Output menu. ESC will abort the save, but it will not
return the user to the program. Answering "No" to the save query
will cause the program to go immediately to DOS.
PC-Trace Users Manual
24
Brief Tutorial
The following is intended as a method of getting up and
running with the program. It will give a general idea of how the
program works.
1. Begin by running PCTRACE. This information can be found
back in the section on setting up PCTRACE for your machine.
2. Once at the main menu, press 3 for define/edit board, and
then select 4 for define board dimensions. For our purposes
we will use a board size of 80 x 80, which translates into a
4 inch square board.
3. Select function 1 to enter new components. You will see
that no data has been entered yet. Press A to enter data.
We will put three chips on the board and two resistors.
Answer each prompt below with the following data. When
asked to place each chip answer Y and place the chip with
the cursor keys. After you have entered the last item,
answer N to the "Enter another component?" prompt.
Name: 8051 uP Designation: IC1
Definition file: DIP40V6 Placement: Left side
Pad Size: 0.05
Name: 74ls373 Designation: IC2
Definition file: DIP20V3 Placement: Upper right
Pad Size: 0.05
Name: 2716 Designation: IC3
Definition file: DIP24V6 Placement: Lower right
Pad Size: 0.05
Name: 100k resistor Designation: R1
Definition file: 2PAD50V Placement: Upper middle
Pad Size: 0.06
Name: 10k resistor Designation: R2
Definition file: 2PAD50V Placement: Lower middle
Pad Size: 0.07
N exits to the board definition menu.
4. Next, enter the list of connection between chips. Select 2
from the menu to enter the connection entry section. Enter
the following connections. All traces should be 0.02 inches
wide. Answer N to each prompt of "Is this a priority
connection?". When the last connection has been entered
answer N to the "Enter another connection prompt?".
Source Device Pin Destination Device Pin
PC-Trace Users Manual
25
IC1 2 IC3 2
IC1 3 IC2 16
IC3 22 IC2 6
R1 1 IC2 4
R2 1 IC1 8
R2 2 IC3 6
R1 2 IC1 31
IC2 8 IC3 17
IC1 21 IC1 15
IC2 8 IC3 8
IC2 9 IC3 9
IC2 10 IC3 10
IC1 14 IC2 9
N returns to the menu.
5. Ok, let's autoroute the board. Go back to the main menu and
select 4 to autoroute the board. When prompted to use
single sided routing or not, answer Y. Now hit the ESC key
and watch the machine route. When it is done is will
display the list of uncompleted connections to the printer
or screen. Select whichever you wish. We will now be
dropped back to the main menu. We can take a look at what
we have done by selecting number 5 from the menu. Cursor
around and see a representation of the board on the screen.
Hit ESC when done.
Now let's re-route the board using double sided techniques.
This time say N to single sided and Y to double sided and
then hit ESC. The machine will route double sided and again
give a list of incomplete connections if any exist. Select
printer or screen for this list. Let's take a look at the
board again. This time we may also want to use the S key to
change sides of the board that we are viewing. When you are
done hit ESC.
6. From the main menu, hit 6 for statistics. Displayed are
five statistics that tell you how good your design is. Hit
space when you are done with this.
7. Last of all we'll print out our design. Follow instructions
in the section on the RPRINT Subprogram to do this.
PC-Trace Users Manual
26
RPRINT.EXE Subprogram
Execute this program by typing RPRINT from the dos prompt.
Upon entry into this program the user will be prompted for a
printer type. Enter the corresponding number. The second prompt
is for the board name. Type the name with no extension. The
main control panel will now explode onto the screen. A math
coprocessor is particularly useful in this program.
1. File name: Selecting 1 will allow changing of the file to be
printed. Enter the filename with no extension.
2. Board side: This selects the board side to print. Selecting
this number will toggle between three possible
sides to print (Solder, Component, and
Silkscreen). Single sided boards are done on the
solder side.
3. Mirroring: This selection toggles between mirroring and not
mirroring the board.
4. Negative: This function will allow the user to select
between printing a negative or a positive of the
actual board.
5. Actual size: Laser printers and 24 pin dot matrix printers
can output the images at actual size. If the
selected printer lacks the resolution to
achieve acceptable results, this menu choice
will not exist. Selection of this choice
allows toggling between actual size and
double sized printing.
6. Pin1 square: Toggling this to the on position will print
the number one pin of all components as a
square. This is useful for identifying the
number one pin when placing the components on
the finished circuit board.
7. Output file: After selecting this menu choice, the user is
prompted for an output file name. Enter the
filename without an extension. The printout
of the file will now be sent to the file that
was designated. The file will be given the
extension .PRT. Be careful if printing
multiple files not to overwrite a previous
printing.
8. Print Board: This selection starts the printing of the
board.
9. Exit program: This selection exits the RPRINT program back
to DOS.
Plotter Notes:
In using RPRINT with plotters, no provision is made to print
to a serial port. With DOS 3.3 and later, the MODE command can
be used to redirect printer output to the serial port. Two
PC-Trace Users Manual
27
commands are needed.
MODE ComX:9600,N,8,1,p (press return) X is the com number
MODE LPT1:=ComX: (press return)
MODE LPT1: (press return) will return to normal operation
PC-Trace Users Manual
28
DEFGEN
Subprogram
The program needs to know the exact pin layout of any
component placed on the board. This function allows creation of
these definitions. The largest difference between this version
and previous versions of PCTRACE is that surface mount support
can be acheived more easily. When a device is defined, all pins
of the surface mount part must be terminated at a through-holed
pad. That is the same as before. With version 5.0, pads and
traces can be defined within the definition file allowing the
user to draw small traces with flat pads to serve as locations to
mount a surface mount part. A silkscreen outline can also be
drawn with the manual router in "SILKSCREEN" mode.
The program is started by typing "DEFGEN" from the dos
prompt in the PCTRACE subdirectory.
***Note: Most chip dimensions are available in data books such
as RCA cross reference manuals. Radio Shack also puts
device dimensions on the back of their packages.
When running DEFGEN to create new chip layout patterns many
keys are active. A summary of each key follows:
S - switch sides:
This function changes the side of the board displayed. When
S is entered from the keyboard, the other side of the board
will be displayed. The program supports only 2 sides,
solder and component.
K - Silkscreen toggle:
Pressing this key toggles the drawing on the silkscreen
layer as opposed to the solder or component layers. When K
is pressed a green "SILKSCREEN" appears at the bottom of the
screen. The only commands that are available at this point
are the F9, manual router, which is used to draw the part
outline, F10 which allows placing text in addition to the
component designation, F1 which is Load, F2 which is Save,
and F3 which is erase.
G - grab location:
The key is only active at certain times. The F4, F5, F7 and
F10 functions all use this key.
B - Turn on background:
This key is used to turn on and off the background layer.
If the user is editing the solder side, this key will show a
PC-Trace Users Manual
29
lightened view of the component side. On a color monitor,
it will appear dotted and red. Black and white monitors
will show dotted graphics only. Pressing B again turns this
mode off.
E or ESC - end:
Pressing E or ESC will exit from the DEFGEN program. The
exit is immediate and should be used carefully.
Cursor Keys:
The cursor keys move the solid block around on the board.
Each time the arrow key is pressed, the cursor will move 1
space. Relative coordinates are displayed at the bottom of
the screen. Using Shift-Arrow moves the cursor 10 spaces.
If the cursor comes to the edge of the screen, but not the
edge of the board, the screen will shift the board over.
Function Keys:
The function keys numbered F1-F10 do the majority of the
work in DEFGEN. They allow the user to place vias, run
traces, delete traces, resize traces, add pads, and draw
component outlines.
F1 - Load Definition:
By pressing F1, the bottom of the screen will prompt for an
input definition file name. Enter the filename with no
extension. If the file is found it will be displayed on the
screen for editing. Please feel free to use the provided
definition files in creating others.
F2 - Save Definition:
This function will prompt for a save filename for the
definition. Enter the save filename with no extension. The
program will notify the user if the file already exists and
check to make sure that it is alright to rewrite the file.
Once the file has been written with this command, DEFGEN can
be exited and the definition used in PCTRACE.
F3 - Erase:
This command has four options. Option 1 will erase the
component layer of everything except the pads. The second
option deletes everything but the pads off the solder layer.
The third layer will remove everything off the silkscreen
layer except for the placement of the designation text.
Option 4 deletes everything, including the pads. Option 5
exits without deleting anything.
PC-Trace Users Manual
30
F4 - Delete Trace:
This function will delete any part of any trace that exists
in the definition. Pressing F4 enters the delete selection
mode. After pressing F4 the screen will say to use G to
grab the parts to be deleted. As G is pressed on valid
traces, the pieces will be highlighted. The user can change
screens by moving the cursor off the screen without losing
the already selected traces. Once all the traces to delete
have been selected, press F4 again and the program will
prompt to make sure you wish to delete the selected traces.
Answer Y to finish the delete operation.
F5 - Add New Pad:
This function key will add a pad at the location of the
cursor when G is pressed. All components must have pad
definitions. The router is unable to route to a trace that
cannot be specified by an attached pad. The pads are placed
in sequence so be sure to place them in the package
numbering order.
F6 - Delete Last Pad:
This function deletes the last placed pad from the screen.
It requires that the definition be regenerated so the screen
will be redrawn.
F7 - Resize trace:
This function will resize a trace to any valid trace size.
Select F7 and then use G to select the traces to resize.
Once you have selected the traces to resize, press F7 and
you will be asked if you really wish to resize the traces,
answer Y if you do. Next the program will prompt for the
trace size. 1 corresponds to 0.01 up to 7 which corresponds
to 0.07 inches. Be careful not to overlap other traces or
pads with this function.
F8 - Coordinates for Designation:
This function will anchor the location of the part
designation. Normally the designation moves to the centroid
of the area defined by the pads. For most applications,
like DIPs, this is acceptable. Some parts, such as
transistors, benefit from having the designation text placed
above or below the pads. Selecting this option will prompt
for a location for the center of the designation text. Move
to that location and press G. The next prompt asks if the
user desires double sized text. If "yes" is entered, the
designation will be drawn 0.1 inches high on the silkscreen
layer. "No" will draw text 0.05 inches high.
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31
F9 - Manual Route:
This function allows the user to manually route traces.
Place the cursor on the starting pad, trace, or open area
and press F9. Now use the cursor control keys to route the
trace. Every time the cursor moves, the trace is
lengthened. When done, press F9. If the end is on another
trace, pressing F9 will add the proper connecting point. If
the green SILKSCREEN indicator is on, the trace will be
routed in green. This should be used to draw the outline of
the part. This outline will be displayed in the interactive
router and when printing the silkscreen.
F10 - Write Text:
Pressing F10 allows the addition of text to the silkscreen
layer. After pressing F10, you will be asked to move the
cursor to the starting position for the text and press G.
After pressing G, the software will prompt for the text
string. It will accept up to 20 characters. When done
entering text, press return. The next prompt is for double
sized text. Answer "yes" and the text will appear double
sized. The board will then be redrawn with the text added
in.
Using a mouse in the DEFGEN program:
The mouse allows usage of all the functions mentioned
previously except for the manual router. The mouse driver must
be installed before running the DEFGEN program. When entering
the interactive program, four arrows will appear in the lower
right corner of the screen. By using the mouse, putting the
cursor on one of these arrows, and pressing the left button the
screen will be moved by half in that direction. The same thing
was accomplished by moving the cursor off the board using the
arrow keys.
Pressing the right mouse button will pop up a menu along the
bottom of the screen. The menu corresponds to function keys F1-
F8, and F10. The exit command at the far right, exits the menu.
By placing the cursor anywhere on the command desired, that
command can be executed by pressing the left button. If the
command selected is F4, F5, F7, F8, or F10, the "Grab" method
will be in use. The left button works the same as the G key in
these cases. Use it to highlight sections and locations on the
board to work with. When using the delete and resizing functions
(F4 and F7) the user must press and release the left button for
each piece of trace.
PC-Trace Users Manual
32
Keyboard Summaries
for PCTRACE
Chip Placement Screen:
ESC - Option to Abandon Placement
RET - Place chip at current location
Cursor Keys - Moves chip one space for each depression
Shift Cursor Key - Moves chip 10 spaces for each depression
Spider Web System:
M* - Set system to move highlighted chip
Cursor keys - Move chip one space on board
RET - Place chip at current location
ESC - Abandon placement
+,-* - Increment and Decrement through chips
E* - Exit Web System
* - Denotes that this selection is displayed on screen at all
times.
Interactive Router:
S - Display other side of board
G - Grab a piece of trace at cursor
E,ESC - Exit interactive router
B - Turns on and off background
C - Allows movement of devices
K - Turns silkscreen layer on and off
F1 - Select source pad
F2 - Select destination pad
F3 - Attempt to connect source and destination
F4 - Delete traces
F5 - Place via at cursor location
F6 - Delete via at cursor location
F7 - Resize selected trace
F8 - See if route is possible between source
and destination pads
F9 - Enters and exits the manual router
F10 - Puts user text on the silkscreen layer
PC-Trace Users Manual
33
SCAD
Schematic Capture
Version 1.0
Users Manual
June 21, 1992
by
Douglas E. Ehlers
Copyright (C) 1991,1992
Introduction
Schematic CAD is a program for drawing electrical
schematics. While this drawing is being made, the software keeps
track of all components and connections between them. It is then
possible to create an export file (.NLT) that PC-Trace can load
and create a board from. This allows the designer a complete
cycle for production of a circuit board. From conceptual design
to computer controlled manufacture of the board, this system has
it all.
Menu Usage:
The menu system in SCAD requires the use of a mouse for
complete use of the system. Some functions can be accomplished
with the use of the keyboard only. Using a mouse, move the
cursor to the area of the desired menu selection. By pressing
the left mouse button, a pull down menu will appear. Move the
mouse down the menu until the desired choice is highlighted and
release the button. The menu choice will be executed. Another
way to make menu choices is to open the menu by pressing the ALT
key and the highlighted menu area key. For example ALT-F will
open the Files Menu. The cursor keys can be used to move the
highlight bar up and down the menu. Pressing return will select
the menu choice. Once the menu appears, pressing the first
letter of the desired choice will move the highlight bar to that
choice.
Some menus have small arrows that point to the right. By
moving the mouse across that arrow a submenu will appear. That
menu responds the same way as the rest of the menus. Many
functions use this concept including Print, Draw, Delete, and
Move.
File Menu:
New Diagram:
The New Diagram function from the FILES menu will clear
the drawing space that SCAD uses to store files. A dialogue
box is used to confirm this selection.
Load Diagram:
The Load Diagram file will load a schematic that was
saved previously. The program will prompt for the file
name. Enter the name without the extension (.SCH). The
program will add the extension. If the program cannot find
the file it will report it and give the user another chance
to enter the filename or to exit back to the drawing area.
Save Diagram:
The Save Diagram function saves whatever is in the
memory of the system at a given point. When prompted for a
save name, enter the name with no extension. SCAD will add
the extension (.SCH). If the program can't find the entered
file name, it will save the information from the given mode.
If the program finds that the save filename exists, it will
prompt to see if the old file should be overwritten, or a
new file name should be specified.
PC-Trace Users Manual
35
Export DXF:
The Export DXF function is used for creating a file
format that can be read by many popular CAD programs and
word-processing packages. The DXF format used is compatible
back to Autocad Version 2.6. The program will prompt for a
save name. Give the file name with no extension. The
program will add it (.DXF) automatically. If the filename
already exists on the disk, the program will prompt as to
whether or not to overwrite the file. Answering yes will
overwrite the old filename, and answering no will cause SCAD
to prompt for a new file name.
Export PC-Trace:
The function is used to create a netlist that PCTRACE
can load. It contains a list of all components and
connections that have been entered while using the SCAD
software. All that will be required on the PCTRACE side is
to place the components and start the autorouter. The
program prompts for the export filename. Enter the filename
with no extension, the program will add it automatically.
If the program finds that the entered filename exists, the
program will allow the option of overwriting the file or re-
entering a new filename.
Print Total/Window:
Print has two options, one, the option called Total,
that will find the extents of the drawing and scale it to
fit on a page. The second, or Window, essentially prints
what is currently being viewed on the screen. Once the
program is told to print, it will create a print file, save
the current drawing and chain to the sprint.exe program.
The first prompt in this program is for the printer type.
The user should select their printer or one that their
printer emulates. The sprint menu can print to a file and
that is toggled with option 1. When prompted for a print
filename, enter the filename with no extension. The second
option will allow printing in portrait or landscape mode.
Option 3 actually prints the drawing, and option 4 exits
sprint.exe and returns to SCAD.
Show Drawing Info:
This function will show basic drawing information
including the current SNAP value, the current window size,
the amount of free memory, and the currently loaded
filename.
Exit:
The exit function exits whichever mode the program is
currently running in. This function can also be activated
by pressing ALT-X. If the user is currently operating in
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the Component Drawing area, it will exit the drawing pad.
If the user is editing the main drawing, it will allow exit
of the program. No option is given to the user to save the
file once exiting the program is answered with an OKAY.
Drawing Symbols:
When Draw Component is selected from the Components menu, a
box appears in the center of the screen. This is the drawing
area for creation of components. A component in this case is
defined to be the schematic symbol for any part that will be
placed in the drawing. A small library of common symbols is
included with the system for the user. Invariably, a symbol will
be needed that is not included. That is the purpose of this
editor.
Once the box appears in the middle of the screen, the Files
menu and the Entities menu come into play. Only certain
functions may be used in each. The unusable functions will be
grayed out and the user will be unable to use them. The Load,
Save, New, and Exit functions in the Files menu work as described
previously, except that they only apply to the current symbol
being drawn. For example, if an AND gate is drawn in this area,
saving it will only save the representation of the AND gate and
not the overall drawing.
The save routine itself is different at this point as well.
It includes a short routine that asks the user to outline the
symbol with a bounding box before the save takes place. Select
the upper left and lower right of the drawing to save. The
entire drawing will be shifted to call the upper left corner of
the bounding box the origin for later use.
The following overview tells how the various Entities
commands work and what they do. Their usage here is essentially
the same as their usage in the main drawing area.
Draw-Line:
This function is used to draw lines within the drawing
window. At the bottom of the screen, SCAD will prompt the
user as to what the program expects. The current
coordinates are shown at the bottom right. Select the
location of the starting point of the line and click the
left or right button. Clicking the left button will anchor
the start of the line at the current mouse location.
Clicking the right button will anchor the start point at the
current point, plus it will draw a connection dot at this
point. The dot will not appear until the start and end
points of the line have been specified. After clicking the
left or right button, the program will prompt for the end
point. Click either the right or left button. The buttons
have the same effect as when picking the start point. ESC
will exit or back up while drawing lines. To draw another
line, select this function again.
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Draw-Arc:
This function is used to draw an arc of some size. It
can be used to draw 1/4 arcs from any start point to any end
point and at any diameter. The first prompt is for the
center point of the arc. Move the mouse to this location
and click a button. The second prompt is for the radius of
the arc. Move the pointer to the location that shows the
desired radius. A floating line reminds the user as to the
current length. The next point is for the start of the arc.
Pick this point as before. The last prompt is for the arc
ending point. Click on this point. The arc will be drawn
from the start point, counter-clockwise, to the end point at
the given radius. ESC will back up at any time to the
previous prompt or will exit the function. To draw another
arc, pick this function again.
Draw-Circle:
This function draws a circle at some center point and
some radius. When prompted, pick the center point and click
a mouse button. The second prompt is for the radius of the
circle. Click on this point and the circle will be drawn on
the screen. ESC will back up to the previous prompt or exit
the function. To draw another circle, pick this function
again.
Draw-Text:
This function is used place text on the screen. The
first prompt is for the starting location of the text. This
point is located at the top, left corner of the text string.
Select this point by moving the mouse to the desired
location and click a button. The second prompt is for the
scale of the text. This number is the size of the text. A
value of 0.25 will create a string with characters every
0.25 units. The third prompt is for horizontal versus
vertical text. Answering yes will draw the text horizontal
and no will draw the string vertically. The letters are
always upright, they are not rotated for vertical text. The
last prompt is for the text string itself. This string will
be displayed on the drawing itself. When entering text
pressing return at the end of the string will draw the
normal text. If the up-arrow cursor key is pressed instead
of return, the text will be drawn with a line over it. This
is useful for digital systems when a signal is active low.
Delete-Line:
This function is used to delete lines from the current
drawing area. A line will be highlighted in red and made
dotted. If this line is to be deleted press Y for yes.
Another line will be highlighted. Pressing Y for yes will
delete that line as well. Other options for keys are to
press N for no. Saying no will move to the next line, or if
no other lines exist, will exit the function. Pressing B
for back will back up to the previous line. This was added
in the case of many lines on the screen and user
inadvertently bypassed the desired line. ESC will exit at
any time, leaving the current line shown on the screen in
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the correct color.
Delete-Circle/arc:
This function is used to delete circles/arcs from the
current drawing area. A circle/arc will be highlighted in
red and made dotted. If this circle/arc is to be deleted
press Y for yes. Another circle/arc will be highlighted.
Pressing Y for yes will delete that circle/arc as well.
Other options for keys are to press N for no. Saying no
will move to the next circle/arc, or if no other
circles/arcs exist, will exit the function. Pressing B for
back will back up to the previous circle/arc. This was
added in the case of many circles/arcs on the screen and the
user inadvertently bypassed the desired circle/arc. ESC
will exit at any time, leaving the current circle/arc shown
on the screen in the correct color.
Delete-Text:
This function is used to delete text from the current
drawing area. A text string will be highlighted in red and
made dotted. If this text is to be deleted press Y for yes.
Another text string will be highlighted. Pressing Y for yes
will delete that text as well. Other options for keys are
to press N for no. Saying no will move to the next text
string, or if no other text exists, will exit the function.
Pressing B for back will back up to the previous text. This
was added in the case of many text strings on the screen and
the user inadvertently bypassed the desired text. ESC will
exit at any time, leaving the current text shown on the
screen in the correct color.
Regenerate:
Selecting this function will redraw the current screen.
SCAD sometimes creates a little garbage on the screen when
adding and deleting lines. This function will clean it up.
Set Snap:
The Snap function is used to set absolute units and
endpoints for drawing operations. If the Snap function has
already been turned on, selecting it again will prompt the
user that it will now be turned off. If the Snap function
is currently off, a text entry dialogue box will appear and
the snap value will be given. Common values are 0.1 or
0.25. Any value between 0 and 1 can be entered and used.
All subsequent usage of drawing commands will move endpoints
of lines, arcs, circles and text to the grid points shown.
Scale:
The scale menu selection is used to change the size of
the current symbol uniformly across its entire area. The
value that is entered when the dialogue box opens is
multiplied by the dimensions of all the entities in the
symbol. For example, if the symbol was 1 unit long and a
scale factor of 0.5 was entered, the final length of the
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39
symbol would be 0.5 units. Pressing ESC will exit with no
changes.
Shift Space:
The shift space routine will move the entire drawing
some offset specified by entering a starting and ending
point of a line. If a line from 1,1 to 2,2 is drawn, the
entire drawing will be shifted 1 unit right and 1 unit down.
To draw the line, when prompted, click on the starting point
and ending point. After the second click the drawing will
be shifted. ESC will exit backwards or out of this routine.
Extend/Trim:
This function allows a line to be extended/trimmed
to/by another line, or a circle to be extended/trimmed to/by
a line, or a line to be extended/trimmed to/by a circle.
This function is useful for designing symbols whose
intersection of points aren't on convenient dimensions. A
good example of this is the OR gate. The function works by
first prompting to see if the object that will be used to
extend or trim with is a line or a circle/arc. Press L for
line or C for circle. The software will now use the same
procedure as is used for deleting objects to select the
extend/trim edge. Once it is selected it will be colored in
Magenta. The second prompt is for the object to extend or
trim. This is the object that will have its dimensions
modified. If the trim object was a line, the program will
give the option of a line or a circle/arc to modify. If the
trim object was a circle/arc the program will automatically
select the second object to be a line. The program will
highlight each object in succession until the user picks the
desired object to modify. The next prompt is for the user
to select a point, with the mouse, near the end point of the
object to modify. One more prompt exists if a circle is one
of the affected entities. This prompt is to pick a point
near the projected intersection. At the end of the prompts
the entity will be modified as per the user instructions. A
regeneration may be required as well to clean up the screen.
The tools that have been described above should be adequate
for drawing most objects. Sometimes some creative usage of the
Snap function and Extend/Trim is required.
Placing Components/Symbols:
This function is used to place symbols on the main drawing
area. This area is separate from the previous area and has no
limits in size for practical use. The only limiting factor is
the amount of available memory.
When a set of graphic symbols are put together to make a
meaningful electrical symbol, they are grouped as an object.
They can only be edited by choosing from the Components menu the
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Place Component command. The Move, Delete, and other commands in
the Entities section only affect the objects that have been drawn
not using this menu selection.
When Place Components is selected with the mouse or keyboard
a window will appear in the center of the screen. If no
components have been entered, only two choices will appear: N to
exit or A to enter new symbols. ESC will also exit the function.
A-Enter new Components:
This function will clear the window and prompt for the name
of the symbol that will be placed. This name will not appear on
the symbol itself and is used only to tell the designer exactly
what the part is.
The second prompt if for the part designation. This is
later placed on the name of the part and is used by PCTRACE to
specify autorouter connections. This designation need not be
unique as it must be in PCTRACE. The reason for this is that
some parts, such as AND gates like the 74LS08 have more than one
part in them. This allows the user to connect multiple parts
under one name. No automatic provision is provided for
specifying which part of the overall part is being connected to,
other than the pin number. The program will notify the user if a
duplicate designation is specified to verify that this is
desired.
The next prompt is a filename for the actual parts layout
information. This is the same file as that used by PCTRACE to
specify pad locations. The program will pop up a small window
with lists of names that are available for use. Enter the name
of the part without the extension and the program will display it
on the screen in a small window. Information about the part
appears on the bottom of the screen. If it is correct press Y
for yes or click in the Yes box. If it is not correct, click on
the No box or press N, the program will reprompt for the name.
This entry is not significant for drawing the schematic itself,
but is needed for export to PCTRACE.
The next prompt is for the Pad size. Enter 1 for 0.05, 2
for 0.06, 3 for 0.07 and so forth.
The last text prompt is for the name of the schematic symbol
that will be drawn on the main drawing area. The program will
open a window showing a list of valid diagram files. Enter the
diagram file with no extension and it will be drawn to check for
user approval. Answering Y will move to the main drawing area
for placement, and N will go back and reprompt for the diagram
file name.
Once the diagram file has been selected the text window will
disappear and two crosshairs will be shown on the screen. This
is the size of the part that has been selected and is being
placed. Moving the mouse to the desired location and pressing a
mouse button will anchor the location of the part. The next
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prompt appears at the bottom of the screen and asks for the
location of the text. The text that will be drawn is the
designation name entered earlier. Remember that the point
selected is the upper left corner of the first character in the
string. The next prompt is for the text scale and is the actual
size, in units, of the characters that will be drawn. The last
prompt is for horizontal text. Answering Y for yes will draw the
text in a horizontal line and N for no will draw the text
vertically.
At this point the user is prompted as to whether or not they
want to enter another component. Click on the appropriate space.
Answering Y will start the process again, and N will put the user
on the last entered component and give other options as well as
display the current data. At any point in the previous component
entry routine, ESC will back the user up.
From a Display of Component Data:
Once a component has been entered various editing options
can be used on it. Those options are discussed below:
E - Edit Component:
This will allow the user to change things such as the name,
designation, pad size, actual part layout filename, location of
the diagram, orientation of the diagram, and the location of the
text that is associated with this component. The letters that do
each of these are discussed below:
A-Name: This will prompt for a new name, enter the new name or
press ESC to leave it unchanged.
B-Designation: This will prompt for a new designation name, enter
the name or ESC to exit.
C-Definition: This will prompt for a new component pad layout
definition. Enter the new file or ESC to exit.
D-Pad Size: This will open a window with three different pad
sizes. Enter the desired value.
E-Move Comp: This will allow the user to move the current
symbol to a new location. The crosshairs will
appear and mouse will move them. Click the button
on the location for the new location. ESC will
exit.
F-Rotate: This function will rotate all elements associated with
this component. The device can be rotated 90, 180, or
270 degrees counter-clockwise. It may require some
movement of text to make everything look right.
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G-Move Text: This function allows the user to first select the
text, using the previously mentioned method or
moving forward, backward, and selecting. A box
appears that is the outline of the text. Using
the mouse, move the text to the desired location
and click a mouse button. The new text location
will now be at this point.
H-Exit Edit: Selecting H, will exit the edit function.
A-Enter new Components:
This function allows entry of more components and is the
same routine that was discussed at the beginning of this section.
Delete:
This function will allow deletion of the component that is
currently on screen. The entire component can be deleted or just
the text. Enter the number that is desired. An entry of 3 will
exit with no deletions taking place. If the component is
deleted, all associated connections will be deleted as well.
Search:
This will allow the user to search from the current location
to the end of the list of components. Only the Designation can
be searched on. Follow the prompts to do either.
+ - Next:
Pressing the + key will display the next component on the
screen. If at the end of the list, the first component is
displayed.
- - Previous:
Pressing the - key will display the next component on the
screen. If that the beginning of the list, the last component is
displayed.
Text Entry:
This function allows text entry that can be placed on the
main drawing area. This text will be linked in to the component
that is currently displayed. This text entry should only be used
for text that is associated with the component. It can only be
modified from this component. More general text entry should be
done from the Entities menu while running in the main drawing
area.
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N to End Component Entry and Editing:
N or ESC will move the user back to main drawing area. All
work will be held in memory.
Connection Entry:
Only one choice exists from the Nconnections menu and that
is to make connections between existing components. The input
routine was created to minimize the amount of time spent typing
and maximize the ease with which connections are drawn and
recorded. When the selection is executed it automatically starts
entry of a new connection.
The first prompt is to pick a point inside the source
component. The crosshair will show on the screen under mouse
control. Place the crosshair in the "bounding box" of the source
component and click a button. When prompted for the destination
component do the same thing. This will tell the program the
source and destination components.
The next step is to tell the program the source pin number.
Enter it at the bottom of the screen when prompted. The second
step is to use the mouse to specify the starting point of the
number just entered. The third step is to enter the scale of the
pin number. The destination pin number is done exactly the same
was as the source pin.
The source and destination pin number that are entered
during this process will be normal text. The source number will
become part of the source component object and will not be
editable from the main drawing area. It will be necessary to go
into the Place Components section to edit or move the text. One
reason for this is to move the pin numbers or change the letters
to have an overline. The same is true for the destination
number, it will be attached to the destination component.
After both the source and destination have been entered, a
dialogue box appears to show the user that source and
destinations that have been chosen. If the information is
incorrect click on the No box or press N, the connection entry
will be restarted at the beginning. If yes is selected the line
draw routine will started and the user can draw the connection
with as many straight lines as desired. The e key for endpoint
and right mouse buttons are active for finding endpoints and
making connection dots. The lines drawn will be attached to the
current connection object. Deleting this object will remove the
lines that are associated with this connection. The only other
difference between connections and components is that the lines
drawn in a connection can be edited in the main drawing area.
After the last line has been entered, pressing ESC will end the
line drawing routine. After pressing ESC, the program prompts
asks if the user wants to enter another connection or not.
Answer yes to restart this procedure and create another
connection. No will put the user at the connection editing
facilities.
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Connection List Menus:
Several options are available from this point. A list of
commands is shown as the last line in the window. The edit
command allows the user to change the source and destination
names and pin numbers. Changing this information will not change
the graphic data that was entered. To change the graphic
representation of the number that are on the drawing will require
finding the component that they are associated with.
A)enter new will allow entry of other connections are
described above.
Delete will delete the listed connection and the lines that
are associated with it.
Search will prompt for a designation name and search from
the current location to the end of all connections for a matching
source or destination designation.
'+' and '-' move to next or previous connection entry.
These keys loop from start to end or end to start depending on
the key.
Line will allow the user to draw lines in addition to those
that were drawn during the initial connection entry. These lines
are drawn the same as during connection entry. ESC will exit the
line drawing routine.
N for end or ESC will exit this menu and return the user to
the main drawing area.
Drawing Entities:
Draw-Line:
This function is used to draw lines within the main
drawing area. At the bottom of the screen, SCAD will prompt
the user as to what the program expects. The current
coordinates are shown at the bottom right. Select the
location of the starting point of the line and click the
left or right button. Clicking the left button will anchor
the start of the line at the current mouse location.
Clicking the right button will anchor the start point at the
current point, plus it will draw a connection dot at this
point. The dot will not appear until the start and end
points of the line have been specified. After clicking the
left or right button, the program will prompt for the end
point. Click either the right or left button. The buttons
have the same effect as when picking the start point.
Another option for selecting the desired point is to press
'E' while the program is asking for the start or end point.
Pressing 'E' at this time will draw a small box on the
screen. Placing this box at or near the endpoint of another
line will select the exact endpoint of that line or arc.
The mouse buttons have the same effect. This function is
active much of time when in the main drawing area and should
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be tested whenever it is needed. ESC will exit or back up
while drawing lines. To draw another line, select a start
and end point again. This function will continue this
sequence until ESC is pressed to exit it.
Draw-Arc:
This function is used to draw an arc of some size. It
can be used to draw any length arc from any start point to
any end point and at any diameter. The first prompt is for
the center point of the arc. Move the mouse to this
location and click a button. The second prompt is for the
radius of the arc. Move the pointer to the location that
shows the desired radius. A floating line reminds the user
as to the current length. The next point is for the start
of the arc. Pick this point as before. The last prompt is
for the arc ending point. Click on this point. The arc
will be drawn from the angle of the start point, at the
selected radius, counter-clockwise, to the end angle. ESC
will back up at any time to the previous prompt or will exit
the function. To draw another arc, pick this function
again.
Draw-Circle:
This function draws a circle at some center point and
some radius. When prompted, pick the center point and click
a mouse button. The second prompt is for the radius of the
circle. Click on this point and the circle will be drawn on
the screen. ESC will back up to the previous prompt or exit
the function. To draw another circle, pick this function
again.
Draw-Text:
This function is used place text on the screen. The
first prompt is for the scale of the text. This number is
the size of the text. A value of 0.25 will create a string
with characters every 0.25 units. The second prompt is for
horizontal versus vertical text. Answering yes will draw
the text horizontal and no will draw the string vertically.
The letters are always upright, they are not rotated for
vertical text. The third prompt is for the text string
itself. This string will be displayed on the drawing
itself. The last prompt is for the starting location of the
text. This point is located at the top, left corner of the
text string. Select this point by moving the mouse to the
desired location and click a button. When entering text
pressing return at the end of the string will draw the
normal text. If the up-arrow cursor key is pressed instead
of return, the text will be drawn with a line over it. This
is useful for digital systems when a signal is active low.
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Move-Line:
The move line is used to change the placement of an
existing line. When this selection is made, the program
will highlight lines in succession until the user responds
with a Y for yes. At this point the user will be asked to
select, with the mouse, a base point of movement. Click on
that point. E is active to select the endpoint of the line,
or any other, for movement. After the basepoint has been
selected and the mouse button clicked, the entire line will
move with the movement of the mouse. Position the line at
the desired location and click a button to permanently place
the line. E is active to select an endpoint. ESC will back
up or exit the function.
Move-Circle/Arc:
The move circle/arc function is used to change the
placement of an existing circle/arc. When this selection is
made, the program will highlight circles and arcs in
succession until the user responds with a Y for yes. At
this point the user will be asked to select, with the mouse,
a base point of movement. Click on that point. E is active
to select the endpoint of the arc, or any other, for
movement. After the basepoint has been selected and the
mouse button clicked, the entire circle/arc will move with
the movement of the mouse. Position the circle/arc at the
desired position and click a button to permanently place the
circle/arc. E is active to select an endpoint. ESC is
active to back up or exit the function.
Move-Text:
The move text function is used to change the placement
of an existing text string. When this selection is made,
the program will highlight text strings in succession until
the user responds with a Y for yes. At this point the user
will be asked to select, with the mouse, a base point of
movement. After the basepoint has been selected and the
mouse button clicked, a box representing the text will move
with the movement of the mouse. Position the text box at
the desired position and click a button to permanently place
the text. E is active to select an endpoint. ESC is active
to back up or exit the function.
Delete-Line:
This function is used to delete lines from the main
drawing area. A line will be highlighted in red and made
dotted. If this line is to be deleted press Y for yes.
Another line will be highlighted. Pressing Y for yes will
delete that line as well. Other options for keys are to
press N for no. Saying no will move to the next line, or if
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no other lines exist, will exit the function. Pressing B
for back will back up to the previous line. This was added
in the case of many lines on the screen and user
inadvertently bypassed the desired line. ESC will exit at
any time, leaving the current line shown on the screen in
the correct color.
Delete-Circle/arc:
This function is used to delete circles/arcs from the
current drawing area. A circle/arc will be highlighted in
red and made dotted. If this circle/arc is to be deleted
press Y for yes. Another circle/arc will be highlighted.
Pressing Y for yes will delete that circle/arc as well.
Other options for keys are to press N for no. Saying no
will move to the next circle/arc, or if no other
circles/arcs exist, will exit the function. Pressing B for
back will back up to the previous circle/arc. This was
added in the case of many circles/arcs on the screen and the
user inadvertently bypassed the desired circle/arc. ESC
will exit at any time, leaving the current circle/arc shown
on the screen in the correct color.
Delete-Text:
This function is used to delete text from the current
drawing area. A text string will be highlighted in red and
made dotted. If this text is to be deleted press Y for yes.
Another text string will be highlighted. Pressing Y for yes
will delete that text as well. Other options for keys are
to press N for no. Saying no will move to the next text
string, or if no other text exists, will exit the function.
Pressing B for back will back up to the previous text. This
was added in the case of many text strings on the screen and
the user inadvertently bypassed the desired text. ESC will
exit at any time, leaving the current text shown on the
screen in the correct color.
Regenerate:
Selecting this function will redraw the current screen.
SCAD sometimes creates a little garbage on the screen when
adding and deleting lines. This function will clean it up.
Set Snap:
The Snap function is used to set absolute units and
endpoints for drawing operations. If the Snap function has
already been turned on, selecting it again will prompt the
user that it will now be turned off. If the Snap function
is currently off, a text entry dialogue box will appear and
the snap value will be given. Common values are 0.1 or
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0.25. Any value between 0 and 1 can be entered and used.
All subsequent usage of drawing commands will move endpoints
of lines, arcs, circles and text to the grid points shown.
Zoom In:
This function requires the use of the mouse to pick a
bounding box for an area to zoom in on. Click the mouse on
one corner of the area to zoom in on and click the mouse on
the opposite corner. SCAD will show the boxed in region on
screen as the full screen while maintaining the aspect
ratio.
Zoom Out:
The Zoom out function prompts for a zoom out factor.
Enter a value. A value of 2, for example, will double the
area being viewed. A value of three will triple the area
and so forth.
Zoom Total:
The Zoom Total will zoom out so that all of the drawing
is shown on the screen. This function finds the overall
size of the drawing and adjusts the viewing area
accordingly.
Shift Space:
The shift space routine will move the entire drawing
some offset specified by entering a starting and ending
point of a line. If a line from 1,1 to 2,2 is drawn, the
entire drawing will be shifted 1 unit right and 1 unit down.
To draw the line, when prompted, click on the starting point
and ending point. After the second click the drawing will
be shifted. ESC will exit backwards or out of this routine.
Extend/Trim:
This function allows a line to be extended/trimmed
to/by another line, or a circle to be extended/trimmed to/by
a line, or a line to be extended/trimmed to/by a circle.
This function is useful for designing symbols whose
intersection of points aren't on convenient dimensions. A
good example of this is the OR gate. The function works by
first prompting to see if the object that will be used to
extend or trim with is a line or a circle/arc. Press L for
line or C for circle. The software will now use the same
procedure as is used for deleting objects to select the
extend/trim edge. Once it is selected it will be colored in
Magenta. The second prompt is for the object to extend or
trim. This is the object that will have its dimensions
modified. If the trim object was line, the program will
give the option of a line or a circle/arc to modify. If the
PC-Trace Users Manual
49
trim object was a circle/arc the program will automatically
select the second object to be a line. The program will
highlight each object in succession until the user picks the
desired object to modify. The next prompt is for the user
to select a point, with the mouse, near the end point of the
object to modify. One more prompt exists if a circle is one
of the affected entities. This prompt is to pick a point
near the projected intersection. At the end of the prompts
the entity will be modified as per the user instructions. A
regeneration may be required as well to clean up the screen.
Keyboard Summaries
for SCAD
When Entering Text on the schematic:
RETURN - enters the text normally
Cursor Up Arrow - overlines the text
When drawing points, lines, arcs, and text:
E - gives user box to find endpoints
R. Mouse Button - puts connection dot on point of line
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50
Conclusion:
The PCTRACE circuit design system was written by Doug Ehlers
for use by himself. This was done without ever having used
another design package. The decisions made were chosen to be
intuitive to the author. The program is under constant
refinement, so the user should try and maintain contact with the
author through one of the previously mentioned support methods.
As always the author is interested in user input on the software.
The program has evolved as it has through the input and support
of its users. In the words of a famous gentleman (almost) "Thank
you for your support."
PC-Trace Users Manual
Appendix A
.NLT File Format
The file created by the export function of SCAD and read by the
import function of PC-TRACE can be used as a mechanism for
importing netlists from other CAD software. It is currently not
feasible for the author to offer this support. If conversions
are written by users, they are encouraged to let the author know
so that they can be shared by other users. The -> signifies a
line in the file. The following is the file format:
->Number of Components in list
Each component looks like:
->Name of component 15 characters
->Component Designation 5 characters
->Definition file name 12 characters
->Pincount & Padsize 2 Integers with 2 spaces between
Pincount is an integer signifying the number of pins in the file.
The Padsize is a 3 bit number in the 5th, 6th, and 7th bits of
the number. 0 is 0.05, 1 (=32) is 0.06, and 2 (=64) is a 0.07
inch diameter pad. The lower five bits of Padsize should be
zero. The bit 0 signifies if the component has been placed on
the board yet.
->Number of Connections in list
Each Connection looks like:
->Source Designation 5 characters
->Source Pin Number Integer
->Destination Designation 5 characters
->Destination Pin Number Integer