library.txt

老外的PCB设计软件,是免费的.可以上网更新.

GENERAL COMMENTS ABOUT EAGLE COMPONENT LIBRARIES
================================================

The component libraries supplied with EAGLE have been compiled with
great care as an additional service to you, our customer.  However,
the large number of available components and suppliers of these
components means that the occasional discrepancy is unavoidable.
Please note, therefore, that CadSoft takes no responsibility for the
complete accuracy of information included in library files.

Please note that libraries are not necessarily identical to former
libraries with the same name. Therefore, it is advisable to back up
your old libraries before installing the new ones.

Additional new libraries, that have not yet been officially released,
can be found on CadSoft's internet site in the download section
(www.cadsoftusa.com).

Please note, that libraries can be edited very conveniently with the
commands EXPORT and SCRIPT.

All packages are defined in such a way, that tNames contains the
names of the components and tPlace contains the additional pc board
print. For the documentation print, tDocu is selected additionally.
This layer contains graphical objects which must not be printed onto
the board.

If components are placed on the bottom side of the board, the related
information changes from t.. to b.. layers (e.g. from tNames to
bNames).

Further usage of layers:

Holes:       mounting holes
TFinish:     finish, e.g. AT-Slot
TStop:       areas without solder stop mask, e.g. for bridging connections
TRestrict:   area without tracks, e.g. around mounting holes
TKeepout:    area without components, e.g. EURO-19"


Defining your own Libraries
===========================

All of the libraries for this EAGLE-Version have been designed
according to the following rules, with exceptions where useful.

Symbols:

  - Origin in the center
  - Width: 16 Mil
  - Pin Lenght for IC's: Middle
  - Text Size for >Name and >Value: 70 Mil, Ratio: 8
  - Inputs on the left
  - Outputs on the right
  - Pin distance: 100 Mil
  - Pins only on the left and right, if possible
  - "Set" at the upper part of the symbol, "Reset" at lower part,
    Clock in the center
  - Data lines at the upper part, control lines at lower part
  - Counting starts from top (e.g. D0 above D1 etc.)
  - Ouput pins start 100 Mil from upper edge of symbol
  - Outputs opposite to related inputs
    (e.g. In0 opposite to Out0)
  - Symbol height of ICs as small as possible
  - Symbol width of ICs as small as possible

Packages:

  - Origin in the center
  - Text Size for >NAME and >VALUE: 70 Mil, Ratio: 10
  - Wire Width for outlines: 5 Mil
  - Pad Shape:    Octagon
  - Pad Diameter: 63 Mil
  - Pad Drill:    32 Mil
  - Rectangle on SMD pads in tDocu (for documentation print)

Devices:

  - Value On
  - Power pins for VCC and GND in separate symbol
  - Power pins for VDD, VSS etc. not in separate symbol