Connections

In typeCAD, connections are created by calling the Schematic::net() function. Connections are made between components in the same Schematic.

The net() function takes a list of Pin objects.

Connecting Pins

Let’s add a decoupling capacitor to the ATtiny85 example we’ve been working with.

import { Capacitor } from '@typecad/passives/0805'
import { ATtiny85_20S } from './ATtiny85_20S';
import { PCB } from '@typecad/typecad';

let typecad = new PCB('typecad_docs');
let u1 = new ATtiny85_20S();
let c1 = new Capacitor({ value: '1uF' });

typecad.net(u1.VCC, c1.pin(1));     // power
typecad.net(u1.GND, c1.pin(2));     // ground

We’ve connected pin 1 of the capacitor to the VCC pin of the ATtiny85 and pin 2 to the GND pin.

::net() takes any number of Pin objects, so you can connect multiple pins at once.

Named Connections

Sometimes it is useful to name the connection. The net name will be visible in KiCAD, it can be useful when laying out the board. Some typeCAD utility functions will only pay attention to named connections as well. If you don’t name the connection, it will be net#.

typecad.net(u1.VCC, c1.pin(1));
typecad.named('power').net(u1.VCC, c1.pin(1));

The connection in KiCAD will now be labled power.

Common Connection Patterns

Power Distribution

Connect multiple components to the same power rail:

// Power distribution pattern
typecad.named('VCC').net(
  microcontroller.VDD,
  cap1.pin(1),
  cap2.pin(1),
  connector.pin(1)
);

Ground Distribution

Connect multiple ground pins together:

// Ground distribution pattern  
typecad.named('GND').net(
  microcontroller.GND,
  microcontroller.GND_2,  // if component has multiple ground pins
  cap1.pin(2),
  cap2.pin(2),
  connector.pin(2)
);

Signal Connections

Connect signal pins between components:

// Signal connections
typecad.named('SDA').net(microcontroller.PB0, sensor.SDA);
typecad.named('SCL').net(microcontroller.PB1, sensor.SCL);