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   PCA9555 AVR Driver
   Copyright 2010 Dave Fletcher
   <fletch@fletchtronics.net> http://fletchtronics.net

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License. 

NOTE: The PCA9555 driver code and demos are distributed under the terms of the
Apache 2.0 software license. The other pieces of this package including Dean
Camera's LUFA and Peter Fleury's I2C Master are redistributed under the
respective authors' terms.

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Summary
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AVR driver for PCA9555. Wraps all PCA9555 functions in a simple C interface.

The PCA9555 driver requres Peter Fleury's I2C master library, which is
included in this package. AVRs with a TWI interface can replace the
i2cmaster.S source in the makefile with twimaster.c, which uses the AVR's i2c
hardware. If using the software i2cmaster.S version, configure the I2C pins
at the top of the i2cmaster.S file.

An example schematic, Cadsoft Eagle files, and other details can be found at:
http://fletchtronics.net/pca9555


Files
-----------------------
  ./
    demos/    - demonstrations for various microcontrollers
    LUFA/     - shared LUFA installation for USB AVRs
    PCA9555/  - core C language driver
    api.html  - programming details
    ChangeLog - project history
    makefile  - targets include "all", "clean", "doc", "dist"
    README    - [you are here]


Links
-----------------------

  PCA9555 @ fletchtronics: http://fletchtronics.net/pca9555
  LUFA: http://www.fourwalledcubicle.com/LUFA.php
  i2c: http://homepage.hispeed.ch/peterfleury/group__pfleury__ic2master.html
  Datasheet: http://www.nxp.com/documents/data_sheet/PCA9555.pdf