How to Read Physical Dimensions From .brd File
(Selected materials from SparkFun.com)
This tutorial is the start of a two-part Using Hawkeye series, and it'south devoted entirely to the schematic-designing side of Hawkeye. In part 2, Using EAGLE: Board Layout, we'll use the schematic designed in this tutorial as the basis for our instance board layout.
If you'd like to follow along with this tutorial, make sure y'all've installed and setup the EAGLE software. The Tutorial 1 'PCB Nuts' covers the nuts of what EAGLE is and what makes it peachy. It as well covers how to download and install the SparkFun Hawkeye libraries nosotros'll be using in this tutorial. Definitely read through that tutorial earlier you continue on.
Create a Project We'll start by making a new projection folder for our blueprint. In the command panel, under the "Projects" tree, correct click on the directory where you want the project to live (by default EAGLE creates an "eagle" directory in your home binder), and select "New Project". You can come across in the figure below, I accept my projection 'mfcwells' already sits there.
I expand the drib downwards menu of my 'mfcwells' project, you lot tin run into that, for the same projection, yous can have many Schematics and Boards in it (.brd is the board layout, .pro is the project file, .sch is the schematic file). This makes perfectly sense. Recall about that you have a massive project chosen the 'Laptop Mother Lath', you may have many of the functional modules on the board, for example the ability supply module, the DRAM module, and the Video Carte module, etc. These modules take very express connections (probably only share the same power supply) merely they do belongs to the same project - the 'Laptop Mother Board' Projection. You'd like to put them into one projection in lodge to organize them well.
Let'southward create a project chosen Exam.
Right click the Test project, and select New - Schematic
In the beginning, you tin discover the name of this new schematic is 'untitiled'. Yous may desire to alter it to a different name before you move forward. Keep in mind that, a unmarried project tin have many schematics. I named information technology equally 'test1'. It'south better to make the proper name without spaces and unusual symbols.
Adding Parts to a Schematic Schematic blueprint is a two step process. First y'all take to add all of the parts to the schematic sheet, then those parts need to exist wired together. You lot tin can intermix the steps – add together a few parts, wire a few parts, and then add some more – but since nosotros already take a reference blueprint we'll just add everything in one swoop.
Using the Add Tool
The ADD tool – (on the left toolbar, or nether the Edit menu) – is what yous'll apply to place every single component on the schematic. The ADD tool opens up a library navigator, where yous can expand specific libraries and expect at the parts information technology holds. With a part selected on the left side, the view on the correct one-half should update to testify both the schematic symbol of the role and its package. (Press Ctrl + A will practice the same job).
For example if I select CD4013, on the right side of the window, you lot volition run into the chip's schematic view and its layout view. The layout view shows the outline of the scrap, and the PADS of the chip. If you come across circle pads, that means this layout is for DIP IC packages, there volition exist through holes being drilled on the bowrd in order to insert the chip into it and get information technology soldered.
If you meet the layout view similar the following ane, then it is a 'SMT (surface mount)' layout. No holes volition be drilled on the board, and you need to buy the corresponding SMT version of the IC to fit to this layout.
Nosotros are non adding these 2 fries to our circuit but just show you two examples.
The ADD tool also has search functionality – very helpful when you accept to navigate through dozens of libraries to find a office. The search is very literal, so don't misspell stuff! You can add wildcards to your search by placing an asterisk (*) before and/or after your search term. For example if you search for atmega328 you should detect a single office/package combo in the SparkFun-DigitalIC library, but if you search *atmega328* (note asterisks before and after), you'll discover two more versions of the IC (because they're really named "ATMEGA328P"). You'll probably want to get accustomed to always adding an asterisk before and afterward your search term.
Pace one: Add a Frame
The frame isn't a critical component for what will be the final PCB layout, but it keeps your schematic looking clean and organized. The frame we want should be in the SparkFun-Aesthetics library, and it'south named FRAME-Letter. Find that by either searching or navigating and add it to your schematic.
Later on selecting the role you want to add together, it'll "glow" and start hovering effectually following your mouse cursor. To place the role, left-click (one time!). Allow's place the frame so its bottom-left corner runs correct over our origin (the pocket-size dotted cross, in a static spot on the schematic). You lot can observe the title and the date of the schematic is showing at the right lesser corner.
Later placing a part, the add tool will assume y'all want to add another – a new frame should start following your cursor. To go out of the add-fashion either hit escape (ESC) twice or but select a different tool.
Pace 2: Save (And Salvage Often)
Step 3: Adding the Power Input Next we'll add four different parts all devoted to our voltage supply input. Use the add tool for these parts:
Next nosotros'll add four different parts all devoted to our voltage supply input. Utilise the add tool for these parts:.
i. Capacitors
ii. Resistor
3. VCC
4. GND
All the components have a '+' in or abreast the symbol, employ your mouse, left click the cross and concord it then you can move it around.
When you want to delete the component, you lot must unmarried left click the cross to select the component, and press the 'delete' button on the keyboard.
Allow's make an RC excursion out of these components. Make sure you don't connect VCC to GND, this will short the power supply.
Click the schematic to lath 'SCH BRD' push button, Eagle will ask y'all if you desire to create a new brd view since you don't accept one so far. Click Yep/.
You'll see the brd view as follows, and the layout of the components are outside of the layout window:
Y'all have noticed that there is no layout view for VCC and GND, merely only a single resitor and a single capacitor.
The reason is the VCC and GND symbols in the schematic view doesn't correspond a REAL component but only an electric node.
Then we need to go back to the schematic view to put connectors, which are real components, for VCC and GND.
Search for '*CONN_08*:
Now, I connect VCC and GND to the header, and go on the VCC and GND symbol at in the RC circuit. This will allow Eagle know that all the voltage nodes with VCC and GND connected to them are electrically connected (the same voltage node).
At present, click the SCH BRD button on the meridian, yous will run into this:
The dashed wire (airwires) highlighted at that place indicates electrical connectedness and does not mean you take a Physical copper wire there. You need to identify the components on the layout area and Route all the traces with copper wires to complete this.
Now, let'south move the components in the BRD view to the black area.
You lot tin can change the Grid settings to have the components aligned well:
To name the aforementioned voltage node, you exercise non have to connect them with the wires. You can also right click and give the node the same name. The nodes with the aforementioned names will be connected in the physical layout.
Right click the resistor, select 'value', change information technology to the desired value. This will only modify the characterization of this component, resistors with unlike values can be in the same layout (package). The resistor package we use hither is SMT 0805, which is one of many standard SMT packages. Change the falue of the resitor and the capacitor, also label the node between the resistor and the capacitor equally 'VOUT'.
Now switch to the BRD view, you lot will see the labels take been changed.
Layers Overview
PCB composition is all nigh layering one textile over another. The thickest, center role of the board is a insulating substrate (usually FR4). On either side of that is a thin layer of copper, where our electric signals pass through. To insulate and protect the copper layers, we comprehend them with a thin layer of lacquer-like soldermask, which is what gives the PCB color (dark-green, red, blue, etc.). Finally, to acme it all off, we add together a layer of ink-like silkscreen, which tin add text and logos to the PCB.
Eagle'southward Layers The EAGLE board designer has layers only similar an actual PCB, and they overlap likewise. We apply a palette of colors to represent the different layers. Here are the layers you'll exist working with in the board designer:
Get to View - Layer settings, you can turn on or off layers past selecting or deselecting it.
Selecting From Overlapping Objects Here's one terminal tip before we go to laying our board out. This is an interface play tricks that trips a lot of people up. Since the board view is entirely two-dimensional, and dissimilar layers are bound to overlap, sometimes you accept to do some finagling to select an object when at that place are others on height of it. Normally, you utilise the mouse'southward left-click to select an object (whether it's a trace, via, function, etc.), only when in that location are two parts overlapping exactly where you lot're clicking, EAGLE doesn't know which i you desire to pick upwards. In cases similar that, Hawkeye will pick ane of the two overlapping objects, and inquire if that's the one you want. If it is, you have to left-click again to confirm. If you were trying to grab ane of the other overlapping objects, right-click to wheel to the next part. EAGLE's status box, in the very bottom-left of the window, provides some helpful information when you're trying to select a role.
Nosotros only accept three components, the board tin can be very tiny. Alter the Dimension layer's outline to fit to the three components. The Dimension layer is in the bronze color. If you check this color in the BRD window and the 'Visible Layers' window, you will see color is consistent.
Routing the Board Routing is the nearly fun office of this entire process. Information technology's like solving a puzzle! Our job will be turning each of those gold airwires into acme or bottom copper traces. At the same time, you also have to make sure not to overlap two unlike signals.
Layer: On a ii-layer board like this, you'll have to choose whether you lot want to start routing on the tiptop (i) or bottom (16) layer.
Bend Mode: Normally you'll want to utilize 45� angles for your routes (wire bend styles 1 and iii), merely it can be fun to make loopy traces too.
Width: This defines how broad your copper will be. Commonly 0.01" is a good default size. You shouldn't become any smaller than 0.007" (or you lot'll probably end up paying extra). Wider traces can let for more than current to safely pass through. If you need to supply 1A through a trace, information technology'd need to exist much wider (to detect out how much, exactly, use a trace width calculator).
Via Options: You lot can too set up a few via characteristics here. The shape, bore, and drill can be set up, only unremarkably the defaults (round, auto, and 0.02" respectively) are perfect.
With those all prepare, you start a route by left-clicking on a pin where a airwire terminates. The airwire, and connected pins volition "glow", and a scarlet or blue line will start on the pivot. You terminate the trace by left-clicking once again on top of the other pin the airwire connects to. Between the pins, you can left-click as much equally you need to "glue" a trace down.
With those all set, you showtime a route past left-clicking on a pin where a airwire terminates. The airwire, and continued pins will "glow", and a red or bluish line will start on the pin. You finish the trace by left-clicking again on top of the other pin the airwire connects to. Betwixt the pins, you can left-click as much equally you need to "glue" a trace down.
If traces do cross each other, make sure they do and then on reverse sides of the board. It's perfectly acceptable for a trace on the top side to intersect with ane on the bottom. That's why in that location are two layers! If you need more precise control over your routes, y'all can agree down the ALT key on your keyboard to access the alternating grid.
Placing Vias
Vias are actually tiny drill holes that are filled with copper. We employ them mid-road to move a trace from i side of the board to the other. To place a via mid-road, offset left-click in the black ether between pins to "gum" your trace downwards. Then yous can either change the layer manually in the options bar up summit, or click your heart mouse button to swap sides. And keep routing to your destination. Hawkeye will automatically add a via for you.
You lot can likewise place 'vias' manually. 'vias' are through holes.
Ripping Upward Traces
Much like the WIRE tool isn't actually used to make wires, the DELETE tool tin can't actually be used to delete traces. If you demand to go back and re-piece of work a route, use the RIPUP tool – – to remove traces. This tool turns routed traces back into airwires. You lot can also apply Disengage and REDO to back/forrad-rails.
Or Apply the Autorouter (Cheater!)
If you're brusk on time, or having trouble solving the routing puzzle, you tin can try loading up Hawkeye's Autorouter
Checking for Errors
Before nosotros package the design up and transport information technology off to the fabrication house, there are a few tools we can employ to bank check our design for errors. Ratsnest – Nothing To Exercise! The first cheque is to brand certain you've actually routed all of the nets in your schematic. To do this, hit the RATSNEST icon – – and and then immediately cheque the bottom left status box. If you've routed everything, it should say "Ratsnest: Nada to practise!"
Every bit denoted by the exclamation mark, having "nothing to practice" is very exciting. Information technology means you've made every road required. If ratsnest says you have "Due north airwires" left to route, double check your board for whatever floating golden lines and route them up. If you lot've looked all over, and can't observe the suspect airwire, try turning off every layer except 19 Unrouted.
Pattern Rule Check One time you're done routing there'due south only one more than check to be made: the design rule check (DRC).
The results of the DRC check can exist plant at the lesser of the folio:
Adding Copper
Pours Copper pours are normally a neat improver to a board. They wait professional person and they really have a good reason for existing. Not to mention they brand routing much easier. Ordinarily, when you're calculation a copper cascade information technology's for the footing signal. So permit'south add some ground pours to the design.
First by selecting the POLYGON tool. Select the elevation copper (ane) layer. Likewise adjust the Isolate setting which defines how much clearance the footing cascade gives other signals, 0.012" for this is usually skillful. Change 'width' to be 0.01, alter spacing to be 0.05.
Right click the polygon and name it as GND. This works but like naming nets on a schematic.
The last step is to hitting ratsnest, to watch the glorious red pour fill just most the entire area of your board. You lot'll probably hate me for telling you this now, but adding ground pours to your blueprint at the very beginning (after placing parts, earlier routing) makes manual routing much easier. You lot can (and probably should) have ground pours on both sides of the lath, and so follow the same ready of steps on the bottom layer.
The copper was poured to all the remaining space on the lath, and connected to the GND pad.
Adding Silkscreen
Although it has no real effect on the circuit your designing, silkscreen can be a critical office of the PCB design. Y'all want it to look good, right? Some silkscreen – like part outlines – is automatically placed on the board considering it's a piece of the part. We can manually add together other information, like labels, logos, and names. A variety of depict tools – wire, text, circle, arc, rectangle, and polygon – tin be used to describe on the silkscreen layer (tPlace for top, bPlace for bottom). Have fun and explore with these tools. You could add labels for the headers, or values for the resistors, or even create a nifty logo.
Select 'T' from the side bar.
Add texts. Correct click the cross beside the text and modify the size of the text.
You lot can fifty-fifty draw a Fort Lewis College logo:
This final version of this project looks similar this:
It is not a robot car circuit at all, information technology is just a elementary RC circuit. You should exist able to blueprint a simple PCB now.
However, you cannot always notice the package for the chips being used in your robot machine excursion. In this case, you lot need to measure the dimension of the component and pattern the component library in eagle past yourself. The datasheet pdf of the components usually have the dimension information. For instance:
Source: http://www.yilectronics.com/Tutorials/Eagle_PCB/2_SCH_BRD/2_SCH_BRD.html
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