rt-thread-official/bsp/samd21/sam_d2x_asflib/common/services/clock/sysclk.h

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/**
* \file
*
* \brief System clock management
*
* Copyright (c) 2010-2015 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
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* \asf_license_stop
*
*/
/*
* Support and FAQ: visit <a href="http://www.atmel.com/design-support/">Atmel Support</a>
*/
#ifndef SYSCLK_H_INCLUDED
#define SYSCLK_H_INCLUDED
#include "parts.h"
#include "conf_clock.h"
#if SAM3S
# include "sam3s/sysclk.h"
#elif SAM3U
# include "sam3u/sysclk.h"
#elif SAM3N
# include "sam3n/sysclk.h"
#elif SAM3XA
# include "sam3x/sysclk.h"
#elif SAM4S
# include "sam4s/sysclk.h"
#elif SAM4E
# include "sam4e/sysclk.h"
#elif SAM4C
# include "sam4c/sysclk.h"
#elif SAM4CM
# include "sam4cm/sysclk.h"
#elif SAM4CP
# include "sam4cp/sysclk.h"
#elif SAM4L
# include "sam4l/sysclk.h"
#elif SAM4N
# include "sam4n/sysclk.h"
#elif SAMG
# include "samg/sysclk.h"
#elif SAMV71
# include "samv71/sysclk.h"
#elif SAMV70
# include "samv70/sysclk.h"
#elif SAME70
# include "same70/sysclk.h"
#elif SAMS70
# include "sams70/sysclk.h"
#elif (UC3A0 || UC3A1)
# include "uc3a0_a1/sysclk.h"
#elif UC3A3
# include "uc3a3_a4/sysclk.h"
#elif UC3B
# include "uc3b0_b1/sysclk.h"
#elif UC3C
# include "uc3c/sysclk.h"
#elif UC3D
# include "uc3d/sysclk.h"
#elif UC3L
# include "uc3l/sysclk.h"
#elif XMEGA
# include "xmega/sysclk.h"
#elif MEGA
# include "mega/sysclk.h"
#else
# error Unsupported chip type
#endif
/**
* \defgroup clk_group Clock Management
*/
/**
* \ingroup clk_group
* \defgroup sysclk_group System Clock Management
*
* See \ref sysclk_quickstart.
*
* The <em>sysclk</em> API covers the <em>system clock</em> and all
* clocks derived from it. The system clock is a chip-internal clock on
* which all <em>synchronous clocks</em>, i.e. CPU and bus/peripheral
* clocks, are based. The system clock is typically generated from one
* of a variety of sources, which may include crystal and RC oscillators
* as well as PLLs. The clocks derived from the system clock are
* sometimes also known as <em>synchronous clocks</em>, since they
* always run synchronously with respect to each other, as opposed to
* <em>generic clocks</em> which may run from different oscillators or
* PLLs.
*
* Most applications should simply call sysclk_init() to initialize
* everything related to the system clock and its source (oscillator,
* PLL or DFLL), and leave it at that. More advanced applications, and
* platform-specific drivers, may require additional services from the
* clock system, some of which may be platform-specific.
*
* \section sysclk_group_platform Platform Dependencies
*
* The sysclk API is partially chip- or platform-specific. While all
* platforms provide mostly the same functionality, there are some
* variations around how different bus types and clock tree structures
* are handled.
*
* The following functions are available on all platforms with the same
* parameters and functionality. These functions may be called freely by
* portable applications, drivers and services:
* - sysclk_init()
* - sysclk_set_source()
* - sysclk_get_main_hz()
* - sysclk_get_cpu_hz()
* - sysclk_get_peripheral_bus_hz()
*
* The following functions are available on all platforms, but there may
* be variations in the function signature (i.e. parameters) and
* behavior. These functions are typically called by platform-specific
* parts of drivers, and applications that aren't intended to be
* portable:
* - sysclk_enable_peripheral_clock()
* - sysclk_disable_peripheral_clock()
* - sysclk_enable_module()
* - sysclk_disable_module()
* - sysclk_module_is_enabled()
* - sysclk_set_prescalers()
*
* All other functions should be considered platform-specific.
* Enabling/disabling clocks to specific peripherals as well as
* determining the speed of these clocks should be done by calling
* functions provided by the driver for that peripheral.
*
* @{
*/
//! \name System Clock Initialization
//@{
/**
* \fn void sysclk_init(void)
* \brief Initialize the synchronous clock system.
*
* This function will initialize the system clock and its source. This
* includes:
* - Mask all synchronous clocks except for any clocks which are
* essential for normal operation (for example internal memory
* clocks).
* - Set up the system clock prescalers as specified by the
* application's configuration file.
* - Enable the clock source specified by the application's
* configuration file (oscillator or PLL) and wait for it to become
* stable.
* - Set the main system clock source to the clock specified by the
* application's configuration file.
*
* Since all non-essential peripheral clocks are initially disabled, it
* is the responsibility of the peripheral driver to re-enable any
* clocks that are needed for normal operation.
*/
//@}
//! @}
#endif /* SYSCLK_H_INCLUDED */