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/**
* \file
*
* \brief SAM D20 GPIO Port Driver Quick Start
*
* Copyright (C) 2012-2013 Atmel Corporation. All rights reserved.
*
* \asf_license_start
*
* \page License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name of Atmel may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an
* Atmel microcontroller product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* \asf_license_stop
*
*/
/**
* \page asfdoc_samd20_port_basic_use_case Quick Start Guide for PORT - Basic
*
* In this use case, the PORT module is configured for:
* \li One pin in input mode, with pull-up enabled
* \li One pin in output mode
*
* This use case sets up the PORT to read the current state of a GPIO pin set as
* an input, and mirrors the opposite logical state on a pin configured as an
* output.
*
* \section asfdoc_samd20_port_basic_use_case_setup Setup
*
* \subsection asfdoc_samd20_port_basic_use_case_setup_prereq Prerequisites
* There are no special setup requirements for this use-case.
*
* \subsection asfdoc_samd20_port_basic_use_case_setup_code Code
* Copy-paste the following setup code to your user application:
* \snippet qs_port_basic.c setup
*
* Add to user application initialization (typically the start of \c main()):
* \snippet qs_port_basic.c setup_init
*
* \subsection asfdoc_samd20_port_basic_use_case_setup_flow Workflow
* -# Create a PORT module pin configuration struct, which can be filled out to
* adjust the configuration of a single port pin.
* \snippet qs_port_basic.c setup_1
* -# Initialize the pin configuration struct with the module's default values.
* \note This should always be performed before using the configuration
* struct to ensure that all values are initialized to known default
* settings.
*
* \snippet qs_port_basic.c setup_2
* -# Adjust the configuration struct to request an input pin.
* \snippet qs_port_basic.c setup_3
* -# Configure GPIO10 with the initialized pin configuration struct, to enable
* the input sampler on the pin.
* \snippet qs_port_basic.c setup_4
* -# Adjust the configuration struct to request an output pin.
* \note The existing configuration struct may be re-used, as long as any
* values that have been altered from the default settings are taken
* into account by the user application.
*
* \snippet qs_port_basic.c setup_5
* -# Configure GPIO11 with the initialized pin configuration struct, to enable
* the output driver on the pin.
* \snippet qs_port_basic.c setup_6
*
* \section asfdoc_samd20_port_basic_use_case_use_main Use Case
*
* \subsection asfdoc_samd20_port_basic_use_case_code Code
* Copy-paste the following code to your user application:
* \snippet qs_port_basic.c main
*
* \subsection asfdoc_samd20_port_basic_use_case_flow Workflow
* -# Read in the current input sampler state of GPIO10, which has been
* configured as an input in the use-case setup code.
* \snippet qs_port_basic.c main_1
* -# Write the inverted pin level state to GPIO11, which has been configured as
* an output in the use-case setup code.
* \snippet qs_port_basic.c main_2
*/