MAX Layout Environment Tutorial

This is just one section of the full tutorial

Part 1

Introduction

Welcome to MAX, the full-custom layout editor from Micro Magic. MAX is more than just a simple layout editor. It is a complete layout environment.

MAX Features

• Interactive viewing and editing of hierarchical layout
• Continuous DRC feedback during layout
• Hierarchical and incremental DRC
• Built in netlisting
• Interactive connectivity tracing
• Interactive wiring tool with flylines to show connections not yet completed
• Layout generator for gates (using MAX-LS)
• Generators for large regular structures such as SRAMS, ROMs, PLA's, and DRAM's (with the optional MegaCell Compiler)
• Interfaces to other tools, including schematic capture (for example SUE), and batch DRC and LVS (for example Dracula or Calibre).
• Smart palette for easy control and feedback on layers
• Full customization and extension via Tcl/Tk scripting language and API
• Technology independence via technology description files
• Optimized for large databases
• Very Fast Redisplay for Whole Chip Viewing and Inspection
• Reads/writes GDSII
• Runs on Solaris and Linux operating systems.

This tutorial will introduce you to many of these features. Consult the Micro Magic MAX User Guide and on-line documentation for further information.

Starting up MAX

Before we get started make sure someone has already installed MAX at your site.

To run the tutorials, you need to make a personal copy of the MAX tutorial example files using mmi_tutorial.

1. To install the MAX tutorial, type the following at the UNIX prompt:

   mmi_tutorial 
    
   

Make sure that the appropriate tool (MAX) is selected and then click on Install Tutorial. The default installation directory is “mmi_private/tutorial” in your home directory. You can also select a different directory for installation. Don't worry if the directory doesn't exist, the mmi_tutorial script will make it if it can. You can also use this to reinstall a clean copy of the tutorial.

2. To start the tutorial, you must first "cd" (change directory) to the directory that you installed the tutorial into. If you used the default directory, type:

   cd ~/mmi_private/tutorial/max  
    
   

Otherwise, replace the above directory with the directory you selected. This directory contains files that you will need to run the tutorial.

3. Then to start MAX, simply type:

   max 
    
   

A window should come up that looks something like Figure 1. The rest of this portion of the tutorial will go over each section of the MAX windows.

Figure 1: MAX Window

MAX Screen Layout

On the very top of the window the title bar should say "max: UNNAMED".

"UNNAMED" means that you have not specified the file (cell) you wish to edit.

Next, across the top you should see the menu bar which contains the following menu items: File, Edit, View, Tools, Misc, Local, and Help. These are pull down menus much like any other application.

Directly to the right of the Help menu is the MAX Message Area. Depending on the location of the cursor, it currently says something like "main mode, BUT-1 selects, BUT-2 moves selection...". The MAX Message Area is a sort of mini-help feature. It tells you what each mouse button does, and when you have pulled down one of the menus from the menu bar, the message area will give you a short explanation of what the highlighted menu item does.

The remainder of this section of the tutorial goes over each area of the MAX window. Refer to the MAX User Guide for a more detailed description of the MAX window. Figure points out the different attributes of the MAX window.

Figure 2: MAX Layout Window

Cell List Boxes

Down the right side of the window are several small List boxes.

Each List Box contains cells in a given directory. That directory can be the user's "working directory" or a library.

Additional List Boxes can be added (or boxes deleted) by clicking the left mouse button (Button-1) over the List box header (the part that says users/tutorial/max in Figure 1).

Then simply click the left mouse button (Button-1) on either Make new list box, or Close this list box.

The directory the list box points to can also be changed by clicking on the desired directory. The directory list includes the directories of all cells that are currently loaded into MAX.

Your .maxrc file can specify library directories to be autoloaded at startup time.

The .maxrc file contains several other useful pieces of information. (See the Micro Magic MAX User Guide for more details.)

You can adjust the width of the list boxes by moving the mouse pointer over the vertical bar just to the left of the text. The bar will change to a little line with arrows on both the left and right sides.

When the arrows appear you can adjust the width by simply holding down the left mouse button (Button-1) and dragging the mouse to the left or right.

Navigation window

Below the list boxes is the Navigation Window. For large designs, you can use the Navigation Window to control the view you see in the main MAX window.

Simply holding down the left mouse button (Button-1) and dragging out a region in the Navigation Window will cause the main window to zoom to that region.

The small colored buttons on the right of the Navigation Window allow you to do several things.

The topmost button (green by default) will toggle between the last two zoom views. The additional buttons allow you to save and return to views.

For example, if you were at a view you knew you wanted to return to, you would simply click the right mouse button (Button-3) on the middle (blue) button to remember that location and zoom factor.

If you later wish to return to that view you simply click the left mouse button (Button-1) on that blue button to return to where you were.

The top button always toggles to the last view. If you desire, you can add additional buttons to save views. Both the number of view-save buttons, and their colors, can be changed in your .maxrc file.

Scroll and Zoom bars

Scroll Bars are laid across the bottom and right side of the Layout Window (and on the right side of the List boxes). These work like the scroll bars in most other applications.

Below the bottom scroll bar is the Zoom Bar. Pulling the slider button to the left zooms in, and to the right zooms out.

Mouse Coordinates and Box Size Location

In the lower right hand corner the Box Size (in microns) is displayed. (More about the Box later.) This is useful when you wish to make an object a precise size. It is also useful for when you select an object and want to know how big it is.

Just to the left of the Box Size is the Mouse Coordinates display. Mouse coordinates are oriented with respect to the top level cell.

DRC Control and Status

In the lower left corner is the DRC Status Box. It tells you the current status of the continuous interactive DRC which runs in MAX. The DRC Status Box also has a small radio button to turn the interactive DRC on or off with left mouse button.

The Palette

Down the left side of the window is the Smart Palette. The Smart Palette provides many features:

• It controls which layers are visible, and lets you choose layers for `painting' (drawing rectangles).
• It gives feedback on what is currently under the cursor, and what is currently selected.
• It allows you to control which layers can be selected.
• And finally, it allows you change the color or stipple patterns of any of the layers.

Refer to the MAX User Guide for more details.

Layers

Just above the palette are several buttons (Active:, -cells-, -all-).

Active lets you select the active layer. If you start a wire, it starts in the current Active layer. If Active is set to auto, the wire starts on the layer the cursor is currently over, or the default layer (usually set to M1).

Cells controls whether or not sub-cells and gcells can be selected.

All allows you to make all of the layers visible or invisible at the same time.

Getting Help

Before we go any further, here is how to get help if you ever need it.

There are several levels of help available "on-line" to MAX users. You already know about the quick Help listed in the MAX Message Area. In addition, you can access the complete on-line manual, the complete list of active hotkeys, and complete documentation of the text commands at any time.

1. Assuming you have MAX running, click and hold down the left mouse button (Button-1) on the Help menu. This should pop up a sub menu as shown in Figure 3.

About MAX tells you the version of MAX you are running, the technology you are using, etc. You should make sure that you are running the mmi18 technology for this tutorial.

2. If the technology is NOT set to mmi18 then quit out of MAX (Hotkey: Ctrl-d) and restart it by typing:

   max -tech mmi18 
    
   

mmi18 is a generic 0.18um CMOS technology provided by Micro Magic. It is similar (although not exactly the same) to many current 0.18um technologies and is a good place to start if you need to generate your own technology file.

About MAX will also tell you where the MMI_TOOLS environment variable points to. (This is the directory where the MMI tools are installed at your site.)

Figure 3: MAX Help Menu



Current Hot Keys gives you a list of all available hot keys. You can also hit the Space bar to bring up this list.

Text Commands/Variables brings up documentation for the MAX text commands and variables. Text commands are useful for writing scripts, generators, and other helpful programs. Text commands and the Tcl/Tk interface are the MAX API. They allow the user to add their own features to the Local and Tool menus.

MAX Manual brings up the MAX manual in your browser. The default browser is Netscape. This can be changed in your .maxrc file.

MAX Tutorial brings up this tutorial.

MMI Documentation Guide brings up all of the documentation for all of the Micro Magic software. This document has links to items like the Micro Magic SUE User Guide, the Micro Magic MAX User Guide, other Micro Magic software programs, and even to this tutorial.

Before proceeding you should bring up the Micro Magic MAX User Guide and see what's there. The User Guide is the reference manual to MAX and contains lots of information that you will not find in this simple tutorial.

You might also want to look at the menu items just to familiarize yourself with what's there.

Tear Off Menus

Sometimes it is convenient to make a menu its own window.

For example:

1. Going back to the Help menu: when you hold down the left mouse button (Button-1) over the Help menu notice that there is a dotted line just before the About MAX menu item (not shown in the above figure).

2. If you release the button while over the dotted line the menu will "tear off". The menu then becomes a full-fledged window, like any other window on your desktop. The exact behavior will depend upon which OS and window environment you are running.

If you are running SUN's Common Desktop Environment (CDE) then the following applies:

• The window iconifies by clicking the small dot in the top right corner.
• You can move the window by clicking and holding down the left mouse button (Button-1) over the top title bar and dragging it around (release button to stop).
• Or you can close the window by holding down the right mouse button (Button-3) over the top title bar and selecting Close from the menu that pops up, or typing Alt-F4.

If you are running another window manager, your windows might behave a little differently. Consult your window system documentation for more details.

The chosen menu will stay pulled-down until you select a menu item, or another menu.