Creating a Schematic with Design Architect
1. Opening Design Architect - IC
3. Setting up Design Architect - IC
7. Save and Register Your Design
10. Saving and Registering a Symbol
11. Checking Your Symbol Design
Design
architect (DA) is a tool for managing schematic level design entry for both
analog and digital designs. Design architect is now one of the tools in the
larger Design Architect – IC package. DA
consists of commands for drawing, annotating, checking, instantiating components,
defining downstream properties, saving, etc. Commands can be found in pull-down
menus from the menus bar, pop-up menus using the mouse buttons (right mouse
button), function keys, keyboard entry, and mouse strokes (using the middle
mouse button).
A CMOS inverter is used as an example to illustrate the steps for entering schematics to Design Architect.
1. Opening Design Architect - IC
- Navigate to a directory where you want to store your design files.
- Issued the wd or swd command from the Unix command prompt in a terminal window to set the working directory. This sets an environmental variable named MGC_WD that is used to locate the design files. Therefore, you MUST always open Mentor Graphics applications from the same working directory that they were created. The MGC_WD variable becomes part of the file name path, so if you don’t launch the application from the original working directory the path names will be incorrect. Please contact the laboratory instructor if you experience any problems.
- Open Design Architect – IC using the command “adk_daic”. This command starts the Design Architect application with references to the ASIC Design Kit (ADK) SCMOS library and discrete parts.
Schematics are created on what is known as a “sheet.” To open a new sheet for editing, click the following.
File -> Open ->
Schematic
the following dialog box should appear
The procedures to open a file and create a file are identical. The default location is $MGD_WD; the mentor working directory where the file will be placed. In this case the name inv for inverter was chosen as the name of the sheet. Editable mode must be selected so that we may create our design.
3. Setting up Design Architect - IC
The next step is to ensure that the necessary toolbars and pallets are visible. To do this click on
MGC -> Setup
The following dialog box should appear.
Make absolutely certain that “Show Palette” is checked. This will ensure that you have access to the ADK library.
The ADK library is a set of predefined components such as transistors and basic logic gates. The ADK library is provided so students have access to basic components and do not have to “reinvent the wheel” i.e. create every component themselves.
The palette should now be docked on the right hand portion
of the screen.
**Important – palette
and menu items vary depending upon what is selected. I.E. the palette is not a static menu; you
can navigate through the palette by clicking on the blue entries, such as
schematic and standard cells. If ever
you cannot get back to a menu you were previously at; you can right click on
the palette and navigate using your right click options.
With your sheet selected as active (the frame of the window is colored to represent an active window. i.e. not gray).
a) Find the ADK library; by clicking “library” in the palette.
b) Drag and drop the following components; Input port, output port, VDD, ground, nmos and pmos transistors.
Your schematic should now look as follows.
Note: the palette on the right is the ADK and IC palette. Components are taken from this palette.
Note: You can rotate or flip the
part/parts in the schematic. To perform this operation: Select the part/parts
in the design by clicking on it. Make sure you are in the “schematic” portion
of the palette. Then choose rotate/flip
button on the palette.
Note: Components can be moved
after they are placed, by clicking once on the component and then dragging it
to the desired location.
The palette on the right hand side of the screen should have the title “Schematic edit.”
Note: blue entries in the palette are used to navigate through the palette.
If the palette is not titled “schematic edit” navigate back to the schematic palette using the blue entries. The title should now be “Schematic edit.”
a) Select “Wire”
under the “Add” submenu, to enable
the wire tool.
b)
Click the place on the figure where you wish to begin your wire.
c)
Double Click the place on the figure where you wish to end your wire.
Note: “F2” is a convenient way to deselect selected items.
Note: While connecting MOS
devices, make sure that your pins -Drain (D), Gate (G), Source(S) and Bulk (B)
are connected correctly.
a)
Place the cursor on the old port name. Press Shift key with F7.
b) A “Display Prompt Bar” appears in the
bottom of the schematic window. Input the new name in the “New Value” box, and then click 'OK'.
c)
Move each device to appropriate place in the window. Save the design. The fully
wired and correctly named schematic can be seen below.
7. Save and Register Your Design
Save your design using the following path from the file menu
File -> Save Sheet
-> Options
The following save menu should appear.
Make sure that your design name is entered into the “add registration to interface” box.. Click the “ok” button.
Note – after this
initial save, you may save using File
-> Save Sheet -> Default
In order to check your design go to
File -> Check
Design
This will check your design for errors.
The figure below shows the result of error checking.
Note: Ignore warnings regarding the parameter “lambda.” This parameter is technology-specific and therefore will depend upon the chosen technology and vendor; i.e ami05, ami1.2, ext.
Note: The schematic interface warning can be taken care of by creating a symbol, which we will do next.
A symbol is a small graphical view of your design. This makes your design easier to manage. After a symbol is created you can save it to a library or include it as a small part of a larger design.
To create a symbol
a) use the pull down menu item.
Miscellaneous ->
Generate Symbol
b.) choose “activate symbol”, “save and edit”, and make sure the other settings are identical to the figure below.
c) to choose a custom shape for your symbol; select “choose shape” this should bring up the choose shape dialog box as shown at the bottom of the figure below. Choose the shape of your choice. I chose buffer because our current design is an inverter.
the following shape should appear
You have now created a symbol for your design.
10. Saving and Registering a Symbol
Save your symbol using the following path from the file menu
File -> Save
Symbol -> Options
The following save menu should appear.
Select yes in the change interface check box. Make sure that your interface inv is the currently registered interface. As shown in the figure below; this is the case. If it was not simply type it into the “register with interface” text box, click “ok” to finish save and register.
11. Checking Your Symbol Design
Go to file ->check symbol to check your symbol for errors
The following text should appear.
You can now go back to the schematic and recheck the schematic for errors. It should now have one less warning. First minimize the symbol and make the schematic window the active window, then follow the same procedure.
File -> Check
Schematic
You should now have only the four warnings related to the parameter lambda.
UNIX Keyboard Commands
Ctrl-Q
Resumes a suspended process. This key combination cannot start a stopped process.
Ctrl-\
Ends the session immediately and provides information on events occurring at the time the session ends.
Ctrl-C
Stops userware execution. You cannot continue a userware program after invoking this interrupt.
Ctrl-S
Suspends the current process. To resume the process, you type Ctrl-Q.
Design Architect – IC
Command Line
The popup command line is a one-line area in which you enter commands. It appears at the mouse pointer location when you begin typing in a non-text window or use the Command key.
CTRL P
Returns the previous entry to the window.
CTRL H
Displays a complete History List. Select the entry you want.
CTRL N
Moves forward in the History List and returns that entry.
Type “*” into the command line then CTRL+SHIFT+? To view all commands.
Click here to continue to Creating the Design Viewpoint