Allegro Shortcut Keys: A Gift for Efficient PCB Layout

Key Takeaways

• Understanding Allegro shortcut keys 

• Function keys, aliases, and funckeys

• Customizing your own Allegro shortcut keys

Allegro shortcut keys can be a real gift for designers looking for more efficiency

It is true that most shortcuts in life have negative consequences associated with them. For instance, you wouldn’t want to fly on an airplane where the pilot decided to skip the takeoff checklist just to save some time. However, some shortcuts are very beneficial, like the keyboard shortcuts available in PCB design tools.

To maintain the highest levels of quality, most of the PCB design process is very structured, as it should be. We follow specific procedures, adhere to strict industry standards, conduct design reviews, and proceed only when the design has been reviewed and approved. But, there is one way designers can simplify their work into a more efficient process: keyboard shortcuts. Keyboard shortcuts can greatly reduce the time it takes for designers to type complex commands or search through extensive menus. This article will look at Cadence PCB design tools and explore how Allegro shortcut keys can help you reduce the chance of errors and improve your design productivity.

This video will demonstrate creating typed aliases, function key aliases, and hot key aliases.

The History of Shortcuts or “Hotkeys”

CAD software used in the design of printed circuit boards is responsible for a lot. The software has to track component, pin, and net data and then render this information interactively for the user by displaying complex geometrical shapes. The software will use many features and functions that require manipulation by the user through different commands to accomplish this work. These commands are arranged in menus for easy access, but there is much more involved with the commands than the user is aware of.

The user never sees many commands at work inside of their CAD tools. For example, during component placement, a simple rotate command found in a pulldown menu may trigger multiple commands to select the part, pick it up, rotate it, and then release it. Other commands that most users rarely use may be deeper inside a menu. Using these unique triggers or a rarely used command usually requires the user to navigate through multiple menus or enter a string on the command line, which can considerably slow down the design process. Fortunately, there is a way that users can access these commands more efficiently and get quick and easy access to commonly repeated commands without using the menu.

Cadence has provided easy command access for its users through Allegro’s shortcut keys, or as some refer to them, hotkeys. These keys are broken up into three categories:

• Function keys: The function keys on your keyboard are predefined in Cadence Allegro for specific commands. For example, using the control key and the function key F5 will bring up the Color Dialog menu, as shown in the picture below.

• Alias: This process is used to map a command string you would normally enter on the keyboard to a specific key or phrase. The alias still needs to be entered on the keyboard, but you can shorten the amount of typing considerably by using the alias instead of the command string.

• Hotkey: This is essentially the same as a predefined function key, but it can be assigned to any key on the keyboard.

First, let’s look at the existing function keys that are already defined for you in the Cadence Allegro PCB Editor.

The Color Dialog menu can be accessed by using a function key

Function Keys in Cadence Allegro

Many commands in the Cadence Allegro PCB Editor are available in predefined function keys. These typically are common functions within the system that are also found in the pulldown menus, with corresponding function key assignments for easier access. Allegro defines these function keys for the user in the menu by designating the key assignment next to the command, as you can see in the picture at the bottom of this section. Here is a list of the predefined function keys in Allegro and their corresponding functions:

As you can see, the function keys by themselves provide very common function and navigation commands such as redraw and zoom control. By combining shift with the function key, more complex commands have been mapped, including copy, move, and vertex and slide commands associated with trace routing. Allegro also has four more keys in combination with the control key mapped:

• Control F2    Next
• Control F5    Color dialog menu
• Control F6    Layer priority
• Control D      Delete

Now that we’ve looked at the predefined function keys, we’ll next discuss the roles that aliases and hotkeys play in Allegro shortcut keys.

Predefined function key assignments in the pulldown menu next to their associated command

Allegro Shortcut Keys, Aliases, and Hotkeys

Cadence gives Allegro users the ability to assign their own shortcut keys, and we will discuss the procedure for that in the next section. However, before we get there, we need to explain the role of aliases and function keys in the definition of user-assigned shortcut keys. To find out what keys have been assigned in an Allegro session, enter “alias” (without the quotes) in the command line. Allegro will pop up a list of all the predefined shortcut keys, and you will probably notice that most of them have already been shown above as predefined function keys.

In the alias list, you will see the terms “alias” and “funckey” used for key definitions. Here is a portion of the list from our Allegro session:

• alias F9               cancel
• alias F10            grid toggle
• alias F11             zoom in
• alias F12             zoom out
• funckey Down  roam y $roamInc
• funckey F1         help
• funckey Left       roam x -$roamInc
• funckey Right   roam x $roamInc
• funckey Up        roam y -$roamInc

Alias

In this list of defined shortcut keys, the term “alias” refers to a letter, key, or string of text that has to be entered on a command line to execute the command. Therefore, by typing “F9” on the command line and hitting the enter key, you will cancel the current function in the tools just as if you hit the actual function key F9.

Funckey

The term “funckey” is used to describe those keys that will behave like a function key. In other words, when you press the key, it will perform the function assigned to it without entering it on the command line. As you can see in the list, the down, left, right, and up arrows are all assigned to move the display within the design window, or roam, by pressing the corresponding arrow key. The difference between the two is that the alias requires you to type the letter or phrase onto the command line and hit enter, a two-step process, while the funckey executes the command simply by pressing the key.

Now that we’ve discussed the nature of these shortcut keys, let’s look at how you can assign commands to them yourself.

Using the user-defined key, the part is rotated in 45-degree increments

Defining a New Shortcut Key

The process for defining a shortcut key using either alias or funckey is similar. To define the key, you will need to enter one of the two examples below into the command line:

• alias [command string] [command to execute]
  • To set the letter “r” as a command-line function to rotate a part while moving it manually, enter “alias r iangle 45” on the command line. This will give you the capability to rotate the selected part 45 degrees when r is entered on the command line.
• funckey [key or key sequence] [command to execute]
  • To set the “r” key as a function key to rotate a part while moving it manually, enter “funckey r iangle 45” on the command line. This will allow you to rotate the selected part 45 degrees when r is pressed while working within the PCB editing window.

There is one last thing that you must be aware of: any alias or funckey assignments made within the current session of Allegro PCB Editor will only be valid while that session is open. Once the session is closed, the key assignments will be gone. To preserve these commands permanently, the alias and funckey assignments must be added to the Allegro PCB Editor’s environment file along with other settings and parameters. With the assignments in the env file, Allegro will load them each time it is invoked. You can find this file at $HOME/PCBENV/env.

Allegro shortcut keys are one of the many procedures that can be used to simplify the PCB design process. For more information on the basics of PCB layout, take a look at this E-book.

Leading electronics providers rely on Cadence products to optimize power, space, and energy needs for a wide variety of market applications. If you’re looking to learn more about our innovative solutions, talk to our team of experts or subscribe to our YouTube channel.