Prototype PCBs design session

Transcription

1 Prototype PCBs design session By: Dr. Ahmed ElShafee ١ Dr. Ahmed ElShafee, ACU : Spring 2018, EEP04 Practical Applications in Electrical

2 Before start You will be making a schematic (astable.sch) file which contains your circuit diagram & a PCB board layout (astable.brd) file. Each file has its own editor window. At any time you will change just one of these but the two are linked, so that the connections & components on the schematic always exist on the board. For example if you try to delete components on the board you will be asked to make the change on the schematic first. To undo command (Edit >Undo or Ctrl Z) to refresh the display View >Redraw (F2) ٢

3 Start the EAGLE control panel. Options >Directories gives a list of directories. Change the projects directory if necessary to something convenient that you can write, e.g. ٣

4 All new projects will be created inside this directory, and the EAGLE project navigator in the control panel uses this as a root. ٤

5 Schematic Creation Start the EAGLE Control Panel application. Create a new project: File >New >Project. ٥

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7 Rename the project if you wish as follows: the control panel window indicates whether a project is open with a green circle next to the project name. Click this if necessary to close the project. Then Right click >Rename on the project's name. After having renamed the project you can reopen it. ٧

8 Right click on the Project name >New >Schematic. The schematic window will open. Inside the schematic window: ٨

9 File >Save as (choose a suitable name for your schematic sheet ٩

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12 Add components to your schematic: Edit >Add > Select component. ١٢

13 Click on add icon ١٣

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17 Left click to place each component. Right click before placing to rotate the component. Any number of the selected component can be added. To stop the ADD procedure select Edit >Stop Command. ١٧

18 Press esc to end add command ١٨

19 components can also be moved after adding, with the Edit >Move command, ١٩

20 or rotated with the Edit >Rotate command. ٢٠

21 Copy, delete ٢١

22 Rest of components used in astable circuit Name Library Device Package Electrolytic cap 220uF rcl > CPOL-EU CPOL-EUE E5-10,5 Resistors 1/4W normal fit rcl > R-EU_ R-EU_0207/ /10 ٢٢

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26 Change value ٢٦

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29 move block ٢٩

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32 Add more components Name Library Device Package 78xx Voltage regulator linear > 78* 7805TV TO220V Vertical Power socket Con-jack DCJ0202 DCJ0202 LED 5mm Led > LED > LED5MM LED5MM ٣٢

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34 Add supply ٣٤

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37 Connecting components using net ٣٧

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39 Where a wire joins the middle of another there must be a green circle (Draw >Junction) to indicate connection. Sometimes two nets are adjacent and appear joined but in fact are not. The View >Show tool () is invaluable here. If you click on any part of a net it will highlight all connected wires and component endpoints. You can then easily check what is missing. When you encounter such an error simply delete (Edit >Delete) line segments around the problem and rewire again (Draw >Net). ٣٩

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41 Electrical Rule Check When you think you have connected everything you must do an ERC which will identify disconnected pins, nets which are next to each other but not connected, etc. Tools >ERC ٤١

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46 Add docfield: ٤٦

47 Edit >Global attributes >New and add name=drawing_author, value= <your text>. View >Redraw (F2) will update the displayed text as in Figure 5. ٤٧

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49 Printing a Parts List : You can print a parts list for a schematic (including resistor and capacitor values) with File >Export >Partslist. ٤٩

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52 Board Creation & Layout File >Switch to Board ٥٢

53 The board consists of all your components, with connections shown as a ratsnest, and a rectangular wire outline (default 100mmX80mm) which represents the board area. ٥٣

54 You can do this any time, but it is easier before you have populated the board outline. The wire rectangle defines where the board will be cut. To change the board size Edit >Move and left click near the middle of the top or right side of the rectangle to pick it up. Re position making sure the board stays rectangular, and left click again to terminate. Don t ever reposition the bottom or left sides, which should intersect very near the origin cross. ٥٤

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56 Position the components inside the board outline Move the components one by one inside the rectangular board outline (Edit >Move) and position them where you want. Note that you must move components into the allowed 100*80mm area and cannot rearrange them outside the allowed area ٥٦

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59 Use EEE custom DRC and autoroute parameters In order for board manufacture to allow easy soldering we need to make pads bigger by changing the default DRC rules File Allows you to pick which DRC file to use. Layers layers can be added by changing Setup to be something like (1*2*15*16) Clearance This tells Eagle how much room you want between the different types of electrical contacts on the board. 20 Dr. mils Ahmed ElShafee, is a reasonable ACU : Spring 2018, EEP04 clearance. Practical Applications in Electrical ٥٩

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61 Distance Copper/Dimension is the distance from any routing to the edge of the board. Drill/Hole is the distance from any routing to a hole in the board. Sizes Set the minimum sizes. ٦١

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63 Restring Restring controls the size of the through hole pads/vias. Typically I just leave these at their default values. Shapes Allows you to make pads have rounded edges. Typically I don't touch this one either. Supply The checkbox allows you to turn on thermals for vias, and Thermal Isolation lets you pick the length of the thermal traces. Typically I don't touch these values at all. ٦٣

64 Masks When PCBs are fabricated, they have a coating that covers and insulates all of the board, except for areas designated by the stop mask. After fabrication, if they are being assembled by a machine (or a person with a reflow oven), a stencil is created and solder paste is applied via that stencil to the pads/vias that need to be soldered. Stop controls the size of the openings in the stop mask for the various parts, and Cream controls the size of the openings in the stencil. Once again, the default values work just fine for our typical usage. ٦٤

65 DRC check ٦٥

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67 Rotate and move some components ٦٧

68 ratsnest ٦٨

69 Auto route ٦٩

70 After auto route ٧٠

71 Add missing wires on top layer ٧١

72 Another trial ٧٢

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75 And that s the manual solution ٧٥

76 AStable PCB ٧٦

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78 MonoStable PCB ٧٨

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80 Thanks,.. ٨٠ Dr. Ahmed ElShafee, ACU : Spring 2018, EEP04 Practical Applications in Electrical