OpenRTX/lib/miosix-kernel/miosix/interfaces/gpio.h

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/***************************************************************************
* Copyright (C) 2010 by Terraneo Federico *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* As a special exception, if other files instantiate templates or use *
* macros or inline functions from this file, or you compile this file *
* and link it with other works to produce a work based on this file, *
* this file does not by itself cause the resulting work to be covered *
* by the GNU General Public License. However the source code for this *
* file must still be made available in accordance with the GNU General *
* Public License. This exception does not invalidate any other reasons *
* why a work based on this file might be covered by the GNU General *
* Public License. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, see <http://www.gnu.org/licenses/> *
***************************************************************************/
#ifndef GPIO_H
#define GPIO_H
/**
* \addtogroup Interfaces
* \{
*/
/**
* \file gpio.h
* The interface to gpios provided by Miosix is in the form of templates,
* therefore this file can only include gpio_impl.h with the architecture
* dependand code.
*
* The interface should be as follows:
* First a class Mode containing an enum Mode_ needs to be defined. Its minimum
* implementation is this:
* \code
* class Mode
* {
* public:
* enum Mode_
* {
* INPUT,
* OUTPUT
* };
* private:
* Mode(); //Just a wrapper class, disallow creating instances
* };
* \endcode
*
* This class should define the possible configurations of a gpio pin.
* The minimum required is INPUT and OUTPUT, but this can be extended to other
* options to reflect the hardware capabilities of gpios. For example, if
* gpios can be set as input with pull up, it is possible to add INPUT_PULL_UP
* to the enum.
*
* Then a template Gpio class should be provided, with at least the following
* member functions:
* \code
* template<unsigned int P, unsigned char N>
* class Gpio
* {
* public:
* static void mode(Mode::Mode_ m);
* static void high();
* static void low();
* static int value();
* unsigned int getPort() const;
* unsigned char getNumber() const;
* private:
* Gpio();//Only static member functions, disallow creating instances
* };
* \endcode
*
* mode() should take a Mode::Mode_ enum and set the mode of the gpio
* (input, output or other architecture specific)
*
* high() should set a gpio configured as output to high logic level
*
* low() should set a gpio configured as output to low logic level
*
* value() should return either 1 or 0 to refect the state of a gpio configured
* as input
*
* getPort() should return the gpio port
*
* getNumber() should return the gpio pin number
*
* Lastly, a number of constants must be provided to be passed as first template
* parameter of the Gpio class, usually identifying the gpio port, while the
* second template parameter should be used to specify a gpio pin within a port.
*
* The intended use is this:
* considering an architecture with two ports, PORTA and PORTB each with 8 pins.
* The header gpio_impl.h should provide two constants, for example named
* GPIOA_BASE and GPIOB_BASE.
*
* The user can declare the hardware mapping between gpios and what is connected
* to them, usually in an header file. If for example PORTA.0 is connected to
* a button while PORTB.4 to a led, the header file might contain:
*
* \code
* typedef Gpio<GPIOA_BASE,0> button;
* typedef Gpio<GPIOB_BASE,4> led;
* \endcode
*
* This allows the rest of the code to be written in terms of leds and buttons,
* without a reference to which pin they are connected to, something that might
* change.
*
* A simple code using these gpios could be:
* \code
* void blinkUntilButtonPressed()
* {
* led::mode(Mode::OUTPUT);
* button::mode(Mode::INPUT);
* for(;;)
* {
* if(button::value()==1) break;
* led::high();
* Thread::sleep(250);
* led::low();
* Thread::sleep(250);
* }
* }
* \endcode
*
*/
/**
* \}
*/
#include "interfaces-impl/gpio_impl.h"
#endif //GPIO_H