138 lines
5.6 KiB
Plaintext
138 lines
5.6 KiB
Plaintext
/*
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ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.
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This file is part of ChibiOS/RT.
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ChibiOS/RT is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3 of the License, or
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(at your option) any later version.
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ChibiOS/RT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @defgroup IO I/O
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* @brief I/O related services.
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* @details This section contains the I/O related services.
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*
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* The I/O subsystem is a collection of device driver poertable interfaces and
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* platform dependent implementations.<br>
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* Under ChibiOS/RT a device driver is split in two layers:
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* - High Level Device Driver (<b>HLD</b>). This layer contains the definitions
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* of the driver's APIs and the platform independent part of the driver.<br>
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* An HLD is composed by two files:
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* - @<driver@>.c, the high level implementation file. This file must be
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* included in the Makefile in order to use the driver.
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* - @<driver@>.h, the high level header file. This file must be included
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* by the application code in order to access the driver's APIs.
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* .
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* - Low Level Device Driver (<b>LLD</b>). This layer contains the platform
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* dependent part of the driver.<br>
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* A LLD is composed by two files:
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* - @<driver@>_lld.c, the low level implementation file. This file must be
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* included in the Makefile in order to use the driver.
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* - @<driver@>_lld.h, the high level header file. This file is implicitly
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* included by the HLD header file.
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* .
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* .
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* <h2>Available Device Drivers</h2>
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* The I/O subsystem currently includes support for:
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* - @ref PAL.
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* - @ref SERIAL.
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* .
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*/
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/**
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* @defgroup PAL Ports Abstraction Layer (PAL)
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* @brief I/O Ports Abstraction Layer
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* @details This module defines an abstract interface for digital I/O ports.
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* Note that most I/O ports functions are just macros. The macros
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* have default software implementations that can be redefined in a
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* @ref PAL_LLD if the target hardware supports special features like, as
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* example, atomic bit set/reset/masking. Please refer to the ports specific
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* documentation for details.<br>
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* The @ref PAL has the advantage to make the access to the I/O ports platform
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* independent and still be optimized for the specific architectures.<br>
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* Note that the @ref PAL_LLD may also offer non standard macro and functions
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* in order to support specific features but, of course, the use of such
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* interfaces would not be portable. Such interfaces shall be marked with
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* the architecture name inside the function names.
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*
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* <h2>Implementation Rules</h2>
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* In implementing an @ref PAL_LLD there are some rules/behaviors that
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* should be respected.
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*
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* <h3>Writing on input pads</h3>
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* The behavior is not specified but there are implementations better than
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* others, this is the list of possible implementations, preferred options
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* are on top:
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* -# The written value is not actually output but latched, should the pads
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* be reprogrammed as outputs the value would be in effect.
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* -# The write operation is ignored.
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* -# The write operation has side effects, as example disabling/enabling
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* pull up/down resistors or changing the pad direction. This scenario is
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* discouraged, please try to avoid this scenario.
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* .
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* <h3>Reading from output pads</h3>
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* The behavior is not specified but there are implementations better than
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* others, this is the list of possible implementations, preferred options
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* are on top:
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* -# The actual pads states are read (not the output latch).
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* -# The output latch value is read (regardless of the actual pads states).
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* -# Unspecified, please try to avoid this scenario.
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* .
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* <h3>Writing unused or unimplemented port bits</h3>
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* The behavior is not specified.
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*
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* <h3>Reading from unused or unimplemented port bits</h3>
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* The behavior is not specified.
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*
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* <h3>Reading or writing on pins associated to other functionalities</h3>
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* The behavior is not specified.
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*
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* <h2>Usage</h2>
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* The use of I/O ports requires the inclusion of the header file @p pal.h,
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* this file is not automatically included @p ch.h like the other header
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* files.
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*
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* @ingroup IO
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*/
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/**
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* @defgroup PAL_LLD PAL Low Level Driver Template
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* @brief @ref PAL low level driver template.
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* @details This file is a template for an I/O port low level driver.
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*
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* @ingroup PAL
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*/
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/**
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* @defgroup SERIAL Serial Driver
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* @brief Generic Serial Drivers.
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* @details This module implements a generic full duplex serial driver. The
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* driver implements a @p SerialDriver interface and uses I/O Queues for
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* communication between the upper and the lower driver. Event flags are used
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* to notify the application about incoming data, outgoing data and other I/O
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* events.<br>
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* The module also contains functions that make the implementation of the
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* interrupt service routines much easier.<br>
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*
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* @ingroup IO
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*/
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/**
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* @defgroup SERIAL_LLD Serial Low Level Driver Template
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* @brief @ref SERIAL low level driver template.
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* @details This file is a template for a serial low level driver.
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*
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* @ingroup SERIAL
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*/
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