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Create library devices with different numbers of pins and pads.

IVL

Hi Richard,

 

I have some questions regarding creating your own devices to which i didn't find an answer so far.

 

  1. Nowdays, there are a lot of complex devices availble in different packages. I'm mainly thinking about MCU's. Sometimes not all of the available packages bring every available pin to the outside due to limited number of package pads. Eagle allows to create devices in different versions (eg different packages for the same symbol) which is great. However it seems to be impossible to create a device having a symbol with some pins that are used for some packages and are not connected to a pad for other packages.
    Did i miss something ?
  2. How to deal with pins connected to multiple pads ?
    As an example, this is often the case for connectors.
    I found some mention about ROUTETAG in the release notes, wich seems to be what i'm looking for. However i didn't find any info on how to actually use this.
    Is there some tutorial about this ?
  3. On one hand it's nice Eagle combines symbols and packages into a single library instead of 2 separated libraries as in many other cad sofware packages.
    On the other hand there seems to an inconvenience with this approach as well.
    A lot of devices use standard packages. I see those packages defined over and over in all of the device libraries. On top, the different versions of the same package in different libraries are not always as consistent as they could be...
    I don't think there is way to link a symbol to a package in another library right ?
    So, are there any guidlines how to deal with this problem, to keep at least your own device libraries consistent ?

 

 

Regards,

Ivan

  • 0

    Hello Ivan,

     

    concerning your questions:

     

    1. Numbers if pins and pads in a device:

    EAGLE always expects to connect each pin connected to at least one pad. It is not allowed to have pins not connected to a pad. It is no problem if a package has more pads than pins.
    If you want to use a component where not all pins are used, you have to create a new device in EAGLE that only has the number of pins connected.

     

    2. Connect a pin to a  number of pads.

    This can be done in the CONNECT dialogue. Select a pin and a pad an click Connect. Now select a further pad and click onto Append. This adds a further pad to the selected connection. There is a blue coloured  icon visible in the connection column. Click onto it in order to change the connection mode from "all" to "any".

    All says: All pads have to be connected with a signal. Any: one of these pads has to be connected.

     

    3. A library file is a closed system that contains all symbols, packages for the devices. This gives us the possibility to create a board from a schematic without having any libraries available, for example.

    How to handle all the packages? There is ref-packages.lbr which contains all the packages used in our libraries. From there you can take a package for a new definition and copy it into your lbr file.

     

    Regards,

    Richard