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

/**
 * \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 */