Schematic wiring, Part 2

In this chapter we will continue where we left of last time. We will complete the wiring of the shift registers.

The shift register that is connected to LED Bank 1 will be wired directly to the connector. We will start by adding net labels. Pin #14 is data, pin #11 is clock, pin #12 is latch, pin #10 is Vcc, and pin 13 will be left unconnected. Here’s the result:


Added labels to pins 14, 11, 12, connected pin 10 to VCC, and marked pin 13 as unconnected.

On to the second shift register now. The second shift register receives its data in pin 14 from pin 9 of the first shift register. We could use a wire to do this connection, but the schematic will look better with a label, so let’s do that. Add the net label “DATA_S” (“S” stands for serial) to both pin 9 of the first shift register, and pin 14 of the second shift register. The end result is this:


Pin 9 of register 1 and pin 14 of register 2 are connected via net labels.

Let’s finish the labelling of shift register 2. Create labels, as you did for shift register 1. In addition, attach the Unconnected component to register 2 pin 9. Eventually, register 2 will look like this:


Register 2 labelling complete!

With this, the wiring of the circuit is complete. Save the schematic, and zoom out to see what we have:


The complete 16-LED project schematic.

We have got all the LEDs with their current limiting resistors, connected to VCC on side, and then via a bus to each one of the shift registers. We have the connector down the left side, and we’ve got the bypass capacitor at the top.

Let’s do the annotation now. Click on the annotate schematic components button. The default settings are good, so we can accept them as they are. Click on Annotate.


The schematic is now annotated.

All the components now have a unique designator. The connector is P1, the first shift register U1, the second U2, and then all the LEDs also have got their own designators. Save the project again.

Finally, let’s do an electrical rules check:


Nothing to worry about!

Excellent, no errors!

In the next chapter we’ll do the component-footprint associations and export the netlist for Pcbnew,

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