![[-]](https://theultimatetone.com/images/collapse.png "[-]")
09-23-2018, 04:11 PM
Drawing Symbols in Eagle
With the Library open, a window is present that has all the DEVICES listed. At the bottom of the window are three buttons to select between DEVICE, PACKAGE and SYMBOL. If you left-click on each in turn, you will see the appropriate list of devices, packages and symbols. Click on SYMBOLs. Between the three buttons and the list is a small window called NEW. Type in the name of the symbol you wish to view, or the name of the new symbol you wish to create.
For a new symbol, Eagle asks: "Create new symbol (name you typed in)?". Select OK and the library editor window opens.
The layers available for the symbols are:
91 - nets
92 - Busses
93 - Pins
94 - Symbols
95 - Names
96 - Values
Nets and Busses you generally do not use.
Pins are the exact points on the symbol where schematic connections are made and these MUST BE ON 0.1" (100-mil) GRID.
Names are the geographic designator: R1, R2, etc
Values is the part value: 100, 1k43, 470nF, 2N3904, etc
Make sure the bottom four layers are ON (93,94,95,96)
You can draw the symbol using the WIRE tool down the left-hand menu. When you left-click on WIRE, the top tool bar will show how the wire will bend, its width and its style. The default width is 0.01" (10-mil) and bend is 90-degrees.The default GRID is 0.1" which is too large to draw most symbols unless we want very large schematics! Reset the grid to 0.05" (50-mil) or smaller. You will have to reset the grid smaller or larger when performing certain functions, or drawing different shapes.
Suppose we are drawing something simple like a capacitor. We need two parallel lines with perpendicular lines coming out of the centre of each of the parallel ones. Or, we could see it as two Ts in a mirror-image placement.
Note where the origin (0,0) for the space is, generally right in the middle. As you move the cursor around, you will see its X-Y position in the box beside the command line, which shows the grid selected also. Wherever you stop the cursor and left-click will begin drawing the symbol. The wire stuck to the cursor is hollow and becomes a red wire on the symbol layer when you left-click again. Move the cursor again and another segment of the wire will be dropped. To end the wire draw, click a second time at the last end made. You can move the cursor to a new location, left-click and begin a new wire.
Cursor over the ends of the capacitor symbol that represent the leads for the part. make sure they fall exactly on the 0.1" grid. If they do not, you can use the MOVE tool to move them to the correct position. Cursor to the MOVE icon, left-click, then cursor over the end of the wire to be moved. Left-click and the wire is attached to the cursor; left click where the end should be dropped.
PINS are needed for the connections to be made. Left-click on the PINS icon on the left menu. A hollow circle will be attached to the cursor and a pin-length selection will appear on the top tool-bar. Click on POINT, which is about halfway along the row, then cursor on to the editor space and drop the pin at the lead end. The hollow pin is still attached to the cursor allowing you to drop more pins as required, so drop a second pin at the other end of the capacitor symbol. To stop laying pins, cursor up to the STOP SIGN and left-click. The hollow pin will disappear. Then press SAVE.
Remember to SAVE frequently.
Each pin will have text around it: "I/O 0" and "P$1" The first represents the pin function and its "swap level". The second represents the geographic name of the pin, and they are numbered in sequence as they are dropped, P$1, P$2, etc. For a non-polarised capacitor we can leave the function and names as they are, but we do not want to see these on the schematic. Left-click on the CHANGE icon (wrench) then scroll down to VISIBLE - left-click - then to OFF - left-click. Now cursor to the pin and left-click and see P$1 disappear, then cursor to the next pin, left-click and see P$2 disappear. Go to STOP to end this function.
Select the TEXT icon and type ">NAME" (without the quotes) into the window that appears. This text will be attached to the cursor. Move the cursor up to the SELECT LAYER window, click the 'down' arrow then click on NAMES. Cursor over to the SIZE window and scroll up to 0.05" and click on that. Now cursor to where you want to place the name of the part beside the symbol.
Repeat the above to place ">VALUE" beside the part on the VALUES layer.
To make the symbol look nicer, you can change the grid and move the >NAME and >VALUE closer to the part, or however it looks best to you.
If the capacitor is supposed to be polarised, we should change the names of the pins. Go to the NAME icon, left-click, then cursor to the bottom pin, left-click and the text box will open with P$1 highlighted. Type in "M" (for minus), or "NEG" for negative. Press OK. Then cursor to the second pin and left-click, the text window appears again with P$2 highlighted, type in"P" for plus, or "POS" for positive. Then OK. Then SAVE. Select TEXT and enter "+", then OK, then cursor to the layer and select SYMBOL, then over to SIZE and select 0.07, left-click, then cursor to where you want to drop the plus-sign. Change the grid to move it to a good position relative to the symbol, as required.
Note that at any time later you can go back in to the library and edit the symbol. SAVE the symbol before exiting the library editor or before going to another device, symbol or package. Eagle should ask you if you want the file saved before you close it.
With the Library open, a window is present that has all the DEVICES listed. At the bottom of the window are three buttons to select between DEVICE, PACKAGE and SYMBOL. If you left-click on each in turn, you will see the appropriate list of devices, packages and symbols. Click on SYMBOLs. Between the three buttons and the list is a small window called NEW. Type in the name of the symbol you wish to view, or the name of the new symbol you wish to create.
For a new symbol, Eagle asks: "Create new symbol (name you typed in)?". Select OK and the library editor window opens.
The layers available for the symbols are:
91 - nets
92 - Busses
93 - Pins
94 - Symbols
95 - Names
96 - Values
Nets and Busses you generally do not use.
Pins are the exact points on the symbol where schematic connections are made and these MUST BE ON 0.1" (100-mil) GRID.
Names are the geographic designator: R1, R2, etc
Values is the part value: 100, 1k43, 470nF, 2N3904, etc
Make sure the bottom four layers are ON (93,94,95,96)
You can draw the symbol using the WIRE tool down the left-hand menu. When you left-click on WIRE, the top tool bar will show how the wire will bend, its width and its style. The default width is 0.01" (10-mil) and bend is 90-degrees.The default GRID is 0.1" which is too large to draw most symbols unless we want very large schematics! Reset the grid to 0.05" (50-mil) or smaller. You will have to reset the grid smaller or larger when performing certain functions, or drawing different shapes.
Suppose we are drawing something simple like a capacitor. We need two parallel lines with perpendicular lines coming out of the centre of each of the parallel ones. Or, we could see it as two Ts in a mirror-image placement.
Note where the origin (0,0) for the space is, generally right in the middle. As you move the cursor around, you will see its X-Y position in the box beside the command line, which shows the grid selected also. Wherever you stop the cursor and left-click will begin drawing the symbol. The wire stuck to the cursor is hollow and becomes a red wire on the symbol layer when you left-click again. Move the cursor again and another segment of the wire will be dropped. To end the wire draw, click a second time at the last end made. You can move the cursor to a new location, left-click and begin a new wire.
Cursor over the ends of the capacitor symbol that represent the leads for the part. make sure they fall exactly on the 0.1" grid. If they do not, you can use the MOVE tool to move them to the correct position. Cursor to the MOVE icon, left-click, then cursor over the end of the wire to be moved. Left-click and the wire is attached to the cursor; left click where the end should be dropped.
PINS are needed for the connections to be made. Left-click on the PINS icon on the left menu. A hollow circle will be attached to the cursor and a pin-length selection will appear on the top tool-bar. Click on POINT, which is about halfway along the row, then cursor on to the editor space and drop the pin at the lead end. The hollow pin is still attached to the cursor allowing you to drop more pins as required, so drop a second pin at the other end of the capacitor symbol. To stop laying pins, cursor up to the STOP SIGN and left-click. The hollow pin will disappear. Then press SAVE.
Remember to SAVE frequently.
Each pin will have text around it: "I/O 0" and "P$1" The first represents the pin function and its "swap level". The second represents the geographic name of the pin, and they are numbered in sequence as they are dropped, P$1, P$2, etc. For a non-polarised capacitor we can leave the function and names as they are, but we do not want to see these on the schematic. Left-click on the CHANGE icon (wrench) then scroll down to VISIBLE - left-click - then to OFF - left-click. Now cursor to the pin and left-click and see P$1 disappear, then cursor to the next pin, left-click and see P$2 disappear. Go to STOP to end this function.
Select the TEXT icon and type ">NAME" (without the quotes) into the window that appears. This text will be attached to the cursor. Move the cursor up to the SELECT LAYER window, click the 'down' arrow then click on NAMES. Cursor over to the SIZE window and scroll up to 0.05" and click on that. Now cursor to where you want to place the name of the part beside the symbol.
Repeat the above to place ">VALUE" beside the part on the VALUES layer.
To make the symbol look nicer, you can change the grid and move the >NAME and >VALUE closer to the part, or however it looks best to you.
If the capacitor is supposed to be polarised, we should change the names of the pins. Go to the NAME icon, left-click, then cursor to the bottom pin, left-click and the text box will open with P$1 highlighted. Type in "M" (for minus), or "NEG" for negative. Press OK. Then cursor to the second pin and left-click, the text window appears again with P$2 highlighted, type in"P" for plus, or "POS" for positive. Then OK. Then SAVE. Select TEXT and enter "+", then OK, then cursor to the layer and select SYMBOL, then over to SIZE and select 0.07, left-click, then cursor to where you want to drop the plus-sign. Change the grid to move it to a good position relative to the symbol, as required.
Note that at any time later you can go back in to the library and edit the symbol. SAVE the symbol before exiting the library editor or before going to another device, symbol or package. Eagle should ask you if you want the file saved before you close it.
