Introducing Schematic Wiring and Global Connections | Altium Designer 17 Essentials | Module 8

Introducing Schematic Wiring and Global Connections | Altium Designer 17 Essentials | Module 8


[Chris Jennings] Welcome to Altium Designer Making the Connection. In this module we will
add wires and ports, discussing the scope of each
for making these connections. As we continue our design capture by wiring up our place components. Wires provide a means of connection between components within a page. Either by direct connections
or based on the net labels. One thing I must caution you about is the major difference between
wires and graphic lines. I once saw an entire design
with graphic lines used to connect components with the
net labels from a costumer. He called in asking why his PC board didn’t show any connections or net names. I had to break the news to him that the design needed wires added in. That the graphic lines
needed to be removed. Needless to say, he and
his boss were not happy. Adding wires is straight forward. Click on the wire icon and then click on the start of the wire. And then the end points or
the intermediate points. I know that pin 1 and pin
17 of J-one are tied together so I will illustrate making
that wire connection. Notice the cross hairs indicating
the vertices of the wire. That’s to help guide you when you’re actually placing the end points. You may have seen also that
when I’m drawing a wire that wants to move in both
the X and the Y direction, that the preview shows where the tool will place the segments. Both vertically and horizontally. If you want to change the
direction that those are going, you can either manually
place the end points. Or you can hit the space bar
to flip the ending of the wire, like so. Instead of entering
each wire one at a time, we can draw the one wire and copy it. Selecting the wire, we
notice it’s hilighted, just hit the Control C to copy it. Now we can use the typical Control V to paste one copy of the wire at every pin on the connector like so. Or we can use the smart paste feature found on the edit drop down menu. Note it knows we have copied a wire. The listing shows what we have copied. If we had copied more than just a wire when we had done the copy, we could now check the check
box for just the wire alone, for the smart paste operation. Now comes the smart paste part. In the choose paste action column there are a number of choices. For now we’ll select the
paste as themselves option. Click on the enable paste array box to create an array of
wires with set spacing. Here we’ll set a single column. And have 20 copies. Hit okay. And now we can place the wire group. We can move or copy these generated wires to add them to the other pins. Now to add the power and round connections. Altium Designer provides
power port symbols for both power and ground. These are global in scope. By that I mean these nets are connected throughout the design automatically. Any signal name assigned to a power port is globally available throughout the design. Here we see power and ground symbols. Clicking on the ground icon
to place this power port, we can now add it to
wires or pins as needed. To open up the properties
window for it, hit tab. And we can assign
another global name like, analog ground or AGND
to the ground symbol. As well as change the style of the symbol. We will leave it as ground for now. But to illustrate the
various symbol styles, hit to pull down menu and
select another symbol. And we’ll place a couple
of those power ports for the connector. One on either side. Let’s extend the wires
between pins 3 and 37. We would begin by selecting them. And now let’s click on their end points. With their end points
selected we can drag them out or shrink them as needed. To make the connection
between the ground port and the pins with wires
already assigned to them simply add a wire connecting
the end points up. You’ll notice dots indicating
the physical connections being made. Let’s place the 3.3 volt and 5 volt power ports as well. Again using the power port icon and tabbing to make
changes to the net names. We’ll finish adding wires
and connecting up J1 now. If you have a device pin needing
to be connected to power, you may place the power
port directly on the pin. One typical example of this
practice is for the capacitors. Simply place the power and
ground ports on the pins and they are connected. Now that we have power
and ground connections, we can add the net names
to the remaining wires. In Altium this is done using net labels. Click on the net labels
icon or alternately right click on the schematic, and pick place and then net label. So let’s begin. With the net label active
we can use the tab key and enter the name that we needed. Let’s enter GPI02. And now we can start placing
net labels on the wires. It’s important that they
be on the wires or the pin, otherwise they are not
electrically connected to the wire or the components pins
and will be floating. You will see the net labels
incrementing as they are placed. This is a really nice feature as it speeds up assigning
sequential net labels. This works for any name
that ends in a number. If needed the net labels
can be changed afterwords by double clicking on the net label and editing the name. Note some of the net labels
created will not be used and can simply be deleted as needed. One more useful feature
involves using net labels to automatically generate wires. First let’s select some net labels and we’ll place them
directly on their respective J1 connector pins. Now with them still selected
we hold the control key down and use the mouse to drag
them away from the connector, causing wires to be created. This is simple quick and just one more way to get wires added to the schematics. As mentioned earlier net labels and wires only connect on their particular sheet. They are not global in scope. To make external connections,
Altium uses ports. We saw the concept of ports in the context of power port connections. Instead of using the
port icon to place ports, we will use the right mouse
button within the schematic to open up a window menu, where we can select place and then ports to start placing ports. Again in Altium there are many
ways to do the same thing. Note the place sub menu
has a lot more options. You can right click on the schematic. And on the place pull down menu for placing a number of elements. We’ll start placing ports now. With a port attached to the
mouse and ready to be placed, hit the tab key so we can
enter the proper name. The port properties window provides a way to customize the color and name as well as the direction of the port. We will enter SDA1, and select bi-directional
for this first port. Hit carriage return and start
placing the port on the wire. Which is on pin 3. The first click defines
the left side of the port. And then the second click
completes the length sizing and the location of the port, allowing the length to be
tailored to suit your needs. Now we can go ahead and place more ports. First hitting the tab key to
assign names and directions and then placing them. Just like with the net
labels, once placed, the port definition can be
edited by double clicking on it and modifying the properties window. Here we have the processor
interface with ports, net labels, and the wire
connections completed. Let’s save this as complete. And now open up the
CAN interface schematic to continue wiring up the design. Looking at the CAN interface
you’ll notice we’ve already added some wires and net
labels, as well as power ports. We want to underscore an
important connectivity feature within Altium. If within a single schematic sheet two wires are labeled
with the same net label they will be connected on the PC board. One example of this
connection using net labels is illustrated with
the CAN_RXD connection. Which is between UC1and UC2. You’ll notice UC1 pin
2 has the net label CAN_RXD on the wire attached to it. UC2 pin 4 has a
resistor connected to a wire with the same net label. These will be connected on the PC board. This is one way to
eliminate a tangle of wires while providing proper connections. It’s important to ensure that
the net labels match exactly. Otherwise they will not be connected. We will use the smart paste feature to automatically create
ports based on net labels. First we would select the
net labels, copy them, and then we do the
typical edit, smart paste. You want to make sure then
enable array is not set ’cause we only want to create one set of ports at this point. So let’s hit okay. Now we have new ports with
net labels assigned to them. We can place them and if needed we can adjust their location. Looking at the IO reset port, we should resize it’s
height to show the overbar. Click on the port in the middle. Grab that square vertices
to stretch it up. Now we can clearly read the
name and see the overbar. Altium has a few more handy methods for adding wires that we should learn. Opening up the Digital IO schematics we see that it has no wiring yet. To automatically add a
wire between components using their pins, we’d select one, move it
over so that it’s pins are overlapping completely
on another component. Now you would grab it, hold the control key down, and drag away. Notice as you drag away, wires
are automatically generated. So to sum up, wires can be
placed manually, copy-pasted, and auto-generated using
components or ports or net labels. Looking at the J1 IMU connector we notice that the 3.3 Volt
power port is rotated. Again, like with placing regular components this is done using the space bar while you are actively moving a part. Or in this case a power port. So grabbing it, starting to
move and hitting the space bar, rotate it counter-clockwise. Or again shift and tap space
bar, rotates it clockwise. I normally avoid rotating power ports as a personal preference. But will do it if it simplifies
the look of the schematics. In this case I think it does. One more thing with wires. While actively routing a wire, you can change the routing mode by holding the shift key down
and tapping on the space bar. The wire mode is reflected
in the bottom of the window. You can try cycling through
the various options, like so. 90 degrees, 45 degrees, and any angle are the ones that are normally used. I generally do not use
the any angle option. I prefer the right angles. I think it can make the
schematics look cluttered but again it’s a personal preference. Now skipping forward we can
see that all of the schematics are wired up with ports and net labels as needed. This is a multi-sheet flat design without a top level schematic to make the connections
between the sheets. They are done automatically
with the ports. To recap this module, the net labels are
local to the sheet only, and ports are used for
making external connections. So it’s the ports that connect together the various parts of the
design on different sheets, relying on the same name
matching to make the connections. It’s as simple as that. This concludes the Altium Designer Making the Connections Module. In this module we added wires, net labels, power ports, and ports. In addition we explored
the use of copy-paste and the smart copy as
a design capture aid.


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