Before editing the circuit, we need to know some options and their functionalities.

S.No	Name	Symbol	Description	Shortcut
1	Display Libraries		To search components in libraries, we can open libraries using this option	–
2	Library Editor		It is shortcut option from Eeschema to Library editor	–
3	Annotate		This option will help us to assign sequence names for  un-named components in circuit.	–
4	ERC		After finishing circuit to check Electrical rules of the circuit.	–
5	Net List		After finishing our work in Eeschema, for further work we need to generate a net list. This option creates net list.	–
6	Generate BOM		Kicad can generate automatic bill of materials. After assigning proper footprints to the components, we can generate BOM by using this option.	–
7	Edit footprints		If footprints are not suited to the components then we can use this option to edit footprints.
8	Pcb new		By using this option we can associate components and footprints.	–
9	Add components		This is short cut option to open libraries and for searching and placing components.	“ A “
10	Power symbol selector		To add power supplies and ground we use this option directly  when there is a need to search in any library.	–
11	Draw a Wire		This is a shortcut option to select wire. Wire can be used to connect components in the circuit.	“ Z “
12	Draw a Bus		This option will help us to add bus in circuit	“ / “
13	Draw Wire to Bus entry points		In digital circuits we need connect wire to Bus and Bus to wire, these two options  can be used to place entry points.	–
14	Draw bus to Wire entry points		In digital circuits we need to connect wire to Bus and Bus to wire, these two options  can be used to place entry points.	–
15	Not connected		In circuit, if we have any not connected pins, then we need to place this option. Or else in ERC it will show as an error.	“  Q “
16	Junction		If more than two wires are meeting at a point, then we can place junction by using this option.	“ J”
17	Local Labels		If we need to connect same Net for different components, sometimes it’s quite complex. In  such situations, we can add labels. These are local labels  that can be used within a sheet only.	“ L”
18	Global Labels		Global labels are also same as local labels but these  can be used out of sheet also. So we can place this in any sheet.	“ Ctrl + H “
19	Hierarchical Labels		It will connect parent sheet and remaining sheets.	“ H”
20	Hierarchical Sheets		If we are creating very big circuit, then we need huge work space, in kicad we can create and use different sheets. By using this  option we can place a sheet.	“ S “
21	Import hierarchical labels		It is useful to place hierarchical pin imported from the corresponding hierarchical label.	–
22	Place hierarchical pin in sheet		By using this option, we can place hierarchical pin within the sheet.	–
23	Graphical line		It will help to draw polygons.	“ | “
24	Textual comments		By using this option, we can assign text comments.	“ T “
25	Delete		We can delete any component and Net etc, by using this option.	Select component + Delete key

 

Fig. 1: Screenshot of KICad Main Window

 

Note:  Above table contains only some commonly used and important Eeschema options. I haven’t covered all  of them. After knowing about these options, please refer to more shortcut keys, by selecting hotkeys option in the preferences menu. If any changes are needed, we can assign our own preferences also.

I am selecting a circuit from Engineersgarage.com,  which consists of 8051 microcontroller, 16×2 LCD, ADC0804 and some other components.

Open the KiCad software and create a new project with a suitable name (Ex: EGtutorials).

Open KiCad > File menu > New project > Assign name and save it.

After creating the new project, we can see the project with sub files at the left side of the KICad main window.

Fig. 1: Screenshot of KICad Main Window

We can see that the saved folder has “.pro“ file extension and in sub-files “.sch ” file is schematic file (Eeschema).

Now we can start building the circuit. Open Eeschema and add components by selecting “Add components” option in the right toolbar. Or follow the steps.

Eeschema > Press “A” key> search component by typing its name > select component.

Ex: press “A” key and window will appear with libraries on screen. Many libraries are available like -74xx, -Atmel, – ADC-DAC etc. From these libraries, select the required component. If  you want 16×2 LCD, then type name and search. If you find it, check it and add it  to the worksheet. If not found, create 16×2 LCD using library editor. Repeat the same procedure unless  all the required components are obtained.

In selected circuit, all that components are available except ADC0804. Actually, another series of ADC is available, but ADC0804 is not available. ADC0804 is 20 pin DIP IC. So, I am going to create it in the library editor.

Note: In the previous tutorial, I explained how to create a component in library editor. Please follow the same procedure here.

Steps to edit component:

1. Refer to the data sheet for pin diagram.

2. Open library editor > click on “create new component” > give the name as ADC0804.

3. Click on Place pin option > assign a name and number of the pin > select the Electrical type of the pin> click on “ok”.

4. Repeat the same procedure up to 20 pins. (precaution : be careful when selecting Electrical type of the pin)

5. Place Graphical rectangle that touches all the pins.

6. Save the component in the library folder.

7. Close the library editor > open the Add components > select ADC0804> place the component on worksheet.

Now we have all the components. Place the components properly (as per convenience), and select “place wire” to connect components. I am connecting 16×2 LCD pins to microcontroller connections directly with the wire. To connect pins 1, 2, and 3 of LCD, we have to overlap some wires or else we have to connect using very long wires. So, in this case, I am using Nets and Local labels. (Please watch the video tutorial to understand better). In the same way, I am connecting potentiometers also. Pot has three pins; one pin is connected to Vcc another pin to Ground and third (middle) pin to pin 2 of LCD. Similarly, one more pot is connected to pin 9 of ADC0804. In the same manner, I made capacitor and resistor circuits also. Use local labels to connect ADC connections (name the labels carefully). After finishing all connections, connect power supply using “Vcc” and “GND” local labels as well as global labels. If we need this supply, we can use it in  other sheets  as well.  Also, place “not connected” “ ” at every not connected pin in the circuit.

Note: When connecting circuit use shortcut to move the component, to place labels, etc. it will save your time.

After completing all connections, edit the component values like resistor values, capacitor values, etc. and “annotate” the circuit. Annotating is nothing but assigning names to components, for example, if we use 10 resistors in our circuit, initially, every component has the same name like “R?” If we left these components with same names without assigning different names, we will definitely get confused in PCB editing. So, Annotating is very important, do not skip it.

1. When connecting the wire between components, observe and connect them properly. If it is not connected properly, we will get the Errors at ERC.

2. Assign names to the labels selectively.

3. When creating a new component, take care about the Electrical type of the pin.