I hope you all are good; this is the eighth part of the series of tutorials on “Introduction to Allegro PCB Designer”. Allegro PCB Designer is an important software for designing the layout of the printed circuit boards (PCBs) used at the professional level. In the previous tutorials I have discussed about the basic commands used frequently at the basic level and also discussed about how to use them.
Introduction to Allegro PCB Designer (Copper Shape and Assign Net: Part 8)
In this tutorial (orcad pcb editor tutorial)I will discuss about the other basic commands and techniques for designing the PCBs. I will discuss about how to add shapes of copper in the PCB and how to assign net to the shapes. I will also discuss how to customize the copper shapes in order to optimize the performance of the PCB.
PCB Copper Shapes:
While designing the layout of the PCBs the PCB designers has to follow to follow a specific set of constraints that defines width of the copper etch for signals, air gap between the copper etch, bent angle of the copper etch and many more. As the copper etches for the power has to dissipate more power as compared to other signals in the board, therefor special care and technique needs to be established in order to route the power pins.
Generally the power pins are connected to each other and to the power source on the board with the help of the copper shapes. For example instead of the Copper lines the power pins are connected to each other with the help of the copper rectangles or any other customized copper shape. The following image shows the copper shapes connecting the 3V3 and 5V pins. The copper shape in green represents the 3V3 connection and copper in blue represents the connection of 5V pins as shown in the following image:
In order to insert the copper shapes and assign net to the shapes is not difficult, let us see how to insert shapes. The commands that are involved while working with the shapes are shown in the following image:
- Shape Add.
- Shape Add Rect.
- Shape Add Circle.
- Shape Select.
- Shape Void Element.
- Shape Void Polygon.
- Shape Void Rectangle.
- Shape Void.
- Shape Edit Boundary.
I will discuss “Shape Add Rect” in the beginning.
Shape Add Rect:
“Shape Add Rect” is command that is used to add rectangular shapes of the copper on the PCBs. In order to add shape in the PCB first you need to identify all the pins that are to be connected with the copper shapes. For example let us assume that in the following image we need to add copper shape on all 3V3 pins. So we need to see where all the pins are located so we can place the copper shape efficiently. Notice in the following image that all the 3v3 pins are highlighted in yellow color.
Let us learn how highlight all the 3V3 pins simultaneously. So select the “Assign Color” command and open the “Find” window, in the potion saying “Find by name” select the “Net” from the drop down list and then click on the “More” as shown in the following image:
The list of all nets will appear, select the net and then click okay as shown in the following image:
When you click okay all the 3V3 pins will be highlighted with the selected color. If you do not know about the “Assign Color” and “Find window” go through my previous tutorial.
When you find out the location of all desired pins select the “Shape Add Rect” command and place it on the PCB so that it covers all the pins. When placed right click on the shape and select “Assign Net”. When you click on the “Assign Net” command window will display the message saying “Pick object whose net is be assigned to the shape” as shown in the following image. Then left click on any 3V3 pin and the copper shape will then connect all the 3V3 pins.
That is all for now, I hope this tutorial will be helpful for you. In the next tutorial I will discuss other basic commands used frequently at beginners’ level. Till then stay connected, keep reading and enjoy learning.