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Time Narration
00:01 Welcome to the spoken tutorial on Subcircuit Builder in eSim.
00:08 In this tutorial, using eSim we will learn to-
00:13 Create a Subcircuit and
00:17 Create a Component Schematic.
00:19 To record this tutorial, we will use-

Ubuntu Linux OS version 16.04

00:28 eSim version 2.0
00:32 To practice this tutorial, you should know how to create and simulate a circuit in eSim.
00:40 If not, watch the prerequisite eSim tutorials on this website.
00:46 The subcircuit file always begins with the dot SUBCKT statement.
00:53 Subname is the subcircuit component name.
00:58 N1,N2 are the nodes.
01:02 The subcircuit ends with dot Ends followed by the subcircuit name.
01:09 To launch eSim, you need to double-click on the eSim icon on your Desktop.
01:16 I have already opened eSim.
01:20 Let us now create a Subcircuit for a Half adder.
01:25 On the eSim window, click on the Subcircuit button from the left toolbar.
01:32 A subcircuit tab will open up.
01:36 In the Subcircuit tab, click on the 'New Subcircuit Schematic' button.
01:43 A New Schematic pop up window appears.
01:47 Enter Schematic Name as Halfadder underscore new.
01:54 Click on the OK button.
01:57 Now, click the Yes button in the confirmation dialog box.
02:02 The schematic editor window opens up.
02:06 The user can create a schematic or import an existing schematic.
02:13 We will use the latter method.
02:16 To create a new schematic, you can refer to the previous tutorials in this series.
02:23 I have already created a Half adder circuit using basic gates in eSim.

Pause the video here.

02:32 Download the Half Adder Basic Gates project file from the Code file section.
02:38 Extract and save the project file on the Desktop.
02:43 On eeschema, click on the File option from the top menu.
02:49 Select Append Schematic Sheet option.
02:54 In the Confirmation dialog box, click on the Yes button.

Click on Desktop.

03:01 Double-click on Half adder basic gates folder.
03:06 The schematic file, sch will be selected.
03:11 Click on the Open button in the file window.
03:15 You can see the schematic of the Half adder is added to the editor.
03:22 Press the F1 key, to zoom in the schematic.
03:25 Now we will connect ports to the input and output terminals of the gates.
03:32 Click on the Place component tool from the right toolbar.

Click on the editor.

03:40 In the Filter field, type eSim underscore Miscellaneous.
03:46 Select PORT and press the drop-down arrow.
03:52 Click on Unit A and click on the OK button.
03:58 Port Unit A will be tied to the cursor.
04:02 Place it near the input pin 1 of the XOR gate.
04:07 Similarly, place Port Unit B, near the input pin 1 of the AND gate.
04:14 Place Port Unit C and Port Unit D near the output pin of the XOR gate and AND gate respectively.
04:24 Here the Port unit indicates pins of the subcircuit.
04:30 Unit A is pin 1, Unit B, C and D are the pin number 2, 3, 4 of the subcircuit respectively.
04:41 To rotate the Port C, place the cursor on Port Unit C and press the R key.
04:49 A clarify selection pop-up window appears.
04:53 Select Port U and press the R key.

Similarly, rotate Port D.

05:02 Connect the ports to the pins with wires.
05:06 Place the cursor on the pin1 of PORT A and press the W key to start the wire.
05:15 Drag it to the wire connecting the pin 1 of XOR gate and AND gate.
05:22 Click once to end the wire.
05:26 A junction will be placed on the wire.
05:30 Similarly, connect all the ports to the pins as shown here.
05:36 Let us now Annotate the schematic.
05:40 Click on the Annotate schematic components icon from the top toolbar.
05:47 Keep the default settings.
05:50 Click on the Annotate button.

Click on the OK button.

05:56 Save the schematic by pressing Ctrl+S keys together.
06:02 Let us generate a netlist for the schematic.
06:06 Click on the Generate netlist icon from the top toolbar.
06:11 Select the Spice tab and check the Default format.
06:17 Click on Generate button and then click the Save button.
06:23 This creates a KiCad netlist file.
06:27 Now, let us go back to the eSim window.
06:31 In the Subcircuit tab, click on the Convert Kicad to Ngspice button.
06:38 You can specify the transient analysis parameters or leave it blank.
06:45 I am leaving these values blank.
06:49 If any Device model or Subcircuit is used, specify them under Device modeling or Subcircuit tab.
06:58 In the KiCad to Ngspice tab, press the Convert button.
07:03 Click on the OK button in the Information dialog box.
07:08 This creates a Ngspice netlist of the subcircuit created.
07:14 You can see, the subcircuit Half Adder new is added to the subcircuit library in the eSim directory.
07:23 Now, let us create a component schematic for the Half Adder subcircuit.
07:29 The components are also referred to as Parts or symbols.
07:34 Go back to the eSim editor of Half Adder schematic.
07:39 Click on the Library Editor icon from the top toolbar.
07:44 The schematic window of the Part Library Editor opens up.
07:49 You can also find the Library Editor option from the Tools option on the top menu.
07:56 Click on the File option from the top menu.
07:59 Click on the Current Library option.
08:03 Choose eSim underscore Subckt option.
08:08 Click on the OK button.
08:11 The current library path of the library selected is displayed at the top of the Part Library editor window.
08:20 To create a new component, click on Create a new Component icon from the top toolbar.
08:28 A Component Properties window opens up.
08:32 Enter the following.

Component name as HA underscore new.

08:39 Default Reference Designator as X.
08:43 The designator is different for each eSim component.
08:48 D is used for Diode.
08:51 Q is used for BJT and so on.
08:55 Keep the default settings.
08:57 Click on the OK button in the window.
09:01 Press F1 key to zoom in the schematic name and designator.
09:07 You can add a rectangle, circle, arc or polygons as the component body.
09:15 I will add a rectangle as a component body.
09:20 Click on Add graphic rectangle to component body tool from the right toolbar.
09:27 Click on the editor.
09:30 Click and drag the rectangle.
09:34 Click again to end the rectangle body.
09:38 Arrange the designator and name of the component.
09:42 Place the cursor on the name and designator and press the key M.
09:48 Now add input and output pins.
09:53 Click on Add pins to component tool from the right toolbar.
09:59 Click on the Editor.

Pin Properties window will appear.

10:04 Enter: Pin name as A.
10:09 Pin Number as 1.
10:11 Orientation as Right.
10:14 Electrical Type as Input.
10:17 Graphic Style as Line.
10:20 Click on the OK button in the window.
10:24 The pin is tied to the cursor. Connect it as shown.
10:30 Click on the editor again.

In a similar way, add Pin number 2 with Pin name as B.

10:40 Click again on the editor.

Enter the following.

10:45 Pin name as Sum.
10:48 Pin Number as 3.
10:51 Orientation as left.
10:54 Electrical Type as output.
10:57 Graphic Style as Line.
11:00 Click on the OK button.
11:04 In a similar way add Pin number 4 with Pin name Cy.
11:11 Let us save the schematic symbol.
11:15 Click on File option from the top menu.
11:19 Click on the Save Current Library option.
11:23 Click the Yes button in the confirmation box.
11:28 You can see here, the component is added to eSim underscore Subcircuit library.
11:36 Click once again the Yes button in the confirmation box.
11:41 Close the Part Library editor window.
11:45 This will save the new component to the current library eSim underscore Subcircuit .
11:52 The eSim underscore Subckt library file is found in the Kicad library as shown here.
12:00 As you can see the component HA underscore new is defined here.
12:06 If you want to delete any component, you can also delete the component in this file.
12:13 Now we can verify the created Subcircuit and its component schematic.
12:20 You can use the Half Adder example project from the eSim Examples folder or create a new project.
12:27 You can also download the example HA underscore Test from the Code file section.
12:36 You can verify the component and subcircuit created.
12:41 I have created a new project HA underscore Test.
12:46 The project is already added to eSim window under the Project section.
12:52 Select HA test and click on the Open schematic button from the left toolbar.
13:00 It directs us to the eSim schematic window.
13:04 You can see, the HA underscore new component will be present under eSim_Subckt library.
13:13 Let us go back to the eSim window.
13:16 In the Kicad to Ngspice analysis tab, I have already specified transient parameters.
13:23 In the Source details tab, the voltage sources are assigned as 5 volts.
13:29 In the Subcircuit tab, the path of the Halfadder underscore new is added.
13:36 You can see the Ngspice plots and terminal.
13:41 Since both the inputs are 5 volts, Sum will be 0 and carry will be 5 volts.
13:48 You can also see the values in the Ngspice terminal.
13:53 Close the Ngspice terminal and plots.
13:57 In the Python plot window, check the Sum and Cy node.
14:03 Click on the Plot button.
14:06 The sum is 0 volts and Carry is 5 volts.

Close the Python plot window.

14:14 In this tutorial, we learnt how to,
14:17 Create a Subcircuit and Create a Component Schematic.
14:24 Do you have questions in this Spoken Tutorial?

Please visit this site.

14:31 For any general or technical questions on eSim, visit the FOSSEE forum and post your question.
14:39 The FOSSEE team coordinates the Circuit Simulation project.
14:44 We give Certificates and Honorarium to the contributors.

For more details, please visit this site.

14:53 The FOSSEE team coordinates the Lab Migration project.

For more details, please visit this site.

15:02 Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India.

For more details, visit this site.

15:11 This is Gloria N from IIT Bombay signing off.

Thank you

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