File content as of revision 592:a274ee790e56:

#ifndef SYSTEM_H_INCLUDED
#define SYSTEM_H_INCLUDED

#include <compiler.h>
#include <clock.h>
#include <gclk.h>
#include <pinmux.h>
#include <power.h>
#include <reset.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \defgroup asfdoc_sam0_system_group SAM System Driver (SYSTEM)
 *
 * This driver for Atmel庐 | SMART SAM devices provides an interface for the configuration
 * and management of the device's system relation functionality, necessary for
 * the basic device operation. This is not limited to a single peripheral, but
 * extends across multiple hardware peripherals.
 *
 * The following peripherals are used by this module:
 * \if DEVICE_SAML21_SUPPORT
 *  - PM (Power Manager)
 *  - RSTC(Reset Controller)
 *  - SUPC(Supply Controller)
 * \else
 *  - SYSCTRL (System Control)
 *  - PM (Power Manager)
 * \endif
 *
 * The following devices can use this module:
 * \if DEVICE_SAML21_SUPPORT
 *  - Atmel | SMART SAM L21
 * \else
 *  - Atmel | SMART SAM D20/D21
 *  - Atmel | SMART SAM R21
 *  - Atmel | SMART SAM D10/D11
 * \endif
 *
 * The outline of this documentation is as follows:
 *  - \ref asfdoc_sam0_system_prerequisites
 *  - \ref asfdoc_sam0_system_module_overview
 *  - \ref asfdoc_sam0_system_special_considerations
 *  - \ref asfdoc_sam0_system_extra_info
 *  - \ref asfdoc_sam0_system_examples
 *  - \ref asfdoc_sam0_system_api_overview
 *
 *
 * \section asfdoc_sam0_system_prerequisites Prerequisites
 *
 * There are no prerequisites for this module.
 *
 *
 * \section asfdoc_sam0_system_module_overview Module Overview
 *
 * The System driver provides a collection of interfaces between the user
 * application logic, and the core device functionality (such as clocks, reset
 * cause determination, etc.) that is required for all applications. It contains
 * a number of sub-modules that control one specific aspect of the device:
 *
 * - System Core (this module)
 * - \ref asfdoc_sam0_system_clock_group "System Clock Control" (sub-module)
 * - \ref asfdoc_sam0_system_interrupt_group "System Interrupt Control" (sub-module)
 * - \ref asfdoc_sam0_system_pinmux_group "System Pin Multiplexer Control" (sub-module)
 *
 *
 * \if DEVICE_SAML21_SUPPORT
 * \subsection asfdoc_sam0_system_module_overview_vreg Voltage Regulator
 * The SAM device controls the voltage regulators for the core (VDDCORE) and
 * backup (VDDBU) domains. It sets the voltage regulators according to the sleep
 * modes, the performance level, or the user configuration.
 *
 * In active mode, the voltage regulator can be chosen on the fly between a LDO
 * or a Buck converter.In standby mode, the low power voltage regulator is used
 * to supply VDDCORE.
 *
 * \subsection asfdoc_sam0_system_module_overview_bbps Battery Backup Power Switch
 * The SAM device supports connection of a battery backup to the VBAT power pin.
 * It includes functionality that enables automatic power switching between main
 * power and battery backup power. This will ensure power to the backup domain,
 * when the main battery or power source is unavailable.
 * \endif
 *
 * \subsection asfdoc_sam0_system_module_overview_vref Voltage References
 * The various analog modules within the SAM devices (such as AC, ADC, and
 * DAC) require a voltage reference to be configured to act as a reference point
 * for comparisons and conversions.
 *
 * The SAM devices contain multiple references, including an internal
 * temperature sensor, and a fixed band-gap voltage source. When enabled, the
 * associated voltage reference can be selected within the desired peripheral
 * where applicable.
 *
 * \subsection asfdoc_sam0_system_module_overview_reset_cause System Reset Cause
 * In some applications there may be a need to execute a different program
 * flow based on how the device was reset. For example, if the cause of reset
 * was the Watchdog timer (WDT), this might indicate an error in the application
 * and a form of error handling or error logging might be needed.
 *
 * For this reason, an API is provided to retrieve the cause of the last system
 * reset, so that appropriate action can be taken.
 *
 * \if DEVICE_SAML21_SUPPORT
 * There are three groups of reset sources:
 *   - Power supply reset: Resets caused by an electrical issue. It covers POR and BODs reset.
 *   - User reset: Resets caused by the application. It covers external reset,
 *             system resetrequest and watchdog reset.
 *   - Backup reset: Resets caused by a backup mode exit condition.
 *
 * \subsection asfdoc_sam0_system_module_overview_performance_level Performance Level
 * Performance level allows use to adjust the regulator output voltage to reduce
 * power consumption. The user can select on the fly the performance level
 * configuration which best suits its application.
 *
 * The SAM device embeds up to three performance level (PL0, PL1 and PL2).
 * Each performance level defines a maximum frequency and a corresponding
 * consumption in 渭A/MHz,when the application selects a new performance level,
 * the voltage applied on the full logic area moves from a value to another,
 * it can reduce the active consumption while decreasing the maximum frequency
 * of the device.
 *
 * Performance level transition is possible only when the device is in active
 * mode, after a reset, the device starts in the lowest performance level
 * (lowest power consumption and lowest max. frequency). The application can then
 * switch to another performance level at anytime without any stop in the code
 * execution. As shown in \ref asfdoc_sam0_system_performance_level_transition_figure.
 *
 * \note When scaling down the performance level,the bus frequency should be first
 *  scaled down in order to not exceed the maximum frequency allowed for the
 *  low performance level.
 *  When scaling up the performance level (for example from PL0 to PL2), the bus
 *  frequency can be increased only once the performance level transition is
 *  completed,check the performance level status.
 *
 * \anchor asfdoc_sam0_system_performance_level_transition_figure
 * \image html performance_level_transition.gif "The performance level  transition"
 *
 * \subsection asfdoc_sam0_system_module_overview_power_domain Power Domain Gating
 * Power domain gating  can  turn on or off power domain voltage to save power
 * while keeping other domain powered up. It can be used in standby sleep mode,
 * in standby mode, when power-gated, the internal state of the logic can be
 * retained  allowing the application context to be kept.
 *
 * Power domain can be in three states:
 * - Active state: the power domain is powered on.
 * - Retention state: the main voltage supply for the power domain is switched off,
 * while maintaining a secondary low-power supply for the sequential cells. The
 * logic context is restored when waking up.
 * - Off state: the power domain is entirely powered off. The logic context is lost.
 *
 * The SAM L21 device has three power domains: PD0, PD1 and PD2.
 * - By default, a power domain is set automatically to retention state in standby
 * sleep mode if no activity is required in it, the application can force all power
 * domains to remain in active state during standby sleep mode in order to accelerate
 * wakeup time.
 * - Static Power_SleepWalking: When entering standby mode, if a peripheral needs to
 * remain in run mode to perform sleepwalking task, its power domain (PDn) remains in
 * active state as well as the inferior power domains (<PDn).
 * - Dynamic Power_SleepWalking: During standby mode, a power domain (PDn) in active
 * state (using the static Power_SleepWalking principle), can wakeup a superior power
 * domain (>PDn) in order to perform a sleepwalking task. The superior power domain is
 * then automatically set to active state. At the end of the sleepwalking task, either
 * the device can be waken-up or the superior power domain can be set again to retention
 * state.
 *
 * Power domains can be linked each other,it allows a power domain (PDn) to be kept
 * in active state if the inferior power domain (PDn-1) is in active state too.
 *
 * The table \ref asfdoc_sam0_system_power_domain_overview_table illustrates the
 * four cases to consider in standby mode
 *
 * \anchor asfdoc_sam0_system_power_domain_overview_table
 * <table>
 *  <caption>Sleep Mode versus Power Domain State Overview</caption>
 *  <tr>
 *      <th>Sleep mode</th>
 *      <th></th>
 *      <th>PD0</th>
 *      <th>PD1</th>
 *      <th>PD2</th>
 *      <th>PDTOP</th>
 *      <th>PDBACKUP</th>
 *  </tr>
 *  <tr>
 *      <td>IDLE</td>
 *      <td></td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>active</td>
 *  </tr>
 *  <tr>
 *      <td>Standby</td>
 *      <td>Case 1</td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>active</td>
 *  </tr>
 *  <tr>
 *      <td>Standby</td>
 *      <td>Case 2</td>
 *      <td>active</td>
 *      <td>active</td>
 *      <td>retention</td>
 *      <td>active</td>
 *      <td>active</td>
 *  </tr>
 *  <tr>
 *      <td>Standby</td>
 *      <td>Case 3</td>
 *      <td>active</td>
 *      <td>retention</td>
 *      <td>retention</td>
 *      <td>active</td>
 *      <td>active</td>
 *  </tr>
 *  <tr>
 *      <td>Standby</td>
 *      <td>Case 4</td>
 *      <td>retention</td>
 *      <td>retention</td>
 *      <td>retention</td>
 *      <td>active</td>
 *      <td>active</td>
 *  </tr>
 *  <tr>
 *      <td>Backup</td>
 *      <td></td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>active</td>
 *  </tr>
 *  <tr>
 *      <td>Off</td>
 *      <td></td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *  </tr>
 * </table>
 *
 * \subsection asfdoc_sam0_system_module_overview_ram_state RAMs Low Power Mode
 * By default, in standby sleep mode, RAM is in low power mode (back biased)
 * if its power domain is in retention state.
 * The table \ref asfdoc_sam0_system_power_ram_state_table lists RAMs low power mode.
 *
 * \anchor asfdoc_sam0_system_power_ram_state_table
 * <table>
 *  <caption>RAM Back-biasing mode</caption>
 *  <tr>
 *      <th>RAM mode</th>
 *      <th>Description</th>
 *  </tr>
 *  <tr>
 *      <td>Retention Back-biasing mode</td>
 *      <td>RAM is back-biased if its power domain is in retention mode</td>
 *  </tr>
 *  <tr>
 *      <td>Standby Back-biasing mode</td>
 *      <td>RAM is back-biased if the device is in standby mode</td>
 *  </tr>
 *  <tr>
 *      <td>Standby OFF mode</td>
 *      <td>RAM is OFF if the device is in standby mode</td>
 *  </tr>
 *  <tr>
 *      <td>Always OFF mode</td>
 *      <td>RAM is OFF if the device is in RET mode</td>
 *  </tr>
 * </table>
 *
 * \endif
 *
 * \subsection asfdoc_sam0_system_module_overview_sleep_mode Sleep Modes
 * The SAM devices have several sleep modes, where the sleep mode controls
 * which clock systems on the device will remain enabled or disabled when the
 * device enters a low power sleep mode.
 * \ref asfdoc_sam0_system_module_sleep_mode_table "The table below" lists the
 * clock settings of the different sleep modes.
 *
 * \anchor asfdoc_sam0_system_module_sleep_mode_table
 * <table>
 *  <caption>SAM Device Sleep Modes</caption>
 * \if DEVICE_SAML21_SUPPORT
 *  <tr>
 *      <th>Sleep mode</th>
 *      <th>System clock</th>
 *      <th>CPU clock</th>
 *      <th>AHB/AHB clock</th>
 *      <th>GCLK clocks</th>
 *      <th>Oscillators (ONDEMAND  = 0)</th>
 *      <th>Oscillators (ONDEMAND  = 1)</th>
 *      <th>Regulator mode</th>
 *      <th>RAM mode</th>
 *  </tr>
 *  <tr>
 *      <td>IDLE</td>
 *      <td>Run</td>
 *      <td>Stop</td>
 *      <td>Run if requested</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run if requested</td>
 *      <td>Normal</td>
 *      <td>Normal</td>
 *  </tr>
 *  <tr>
 *      <td>Standby</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Run if requested</td>
 *      <td>Run if requested</td>
 *      <td>Run if requested or RUNSTDBY  = 1</td>
 *      <td>Run if requested</td>
 *      <td>Low pwer</td>
 *      <td>Low pwer</td>
 *  </tr>
 *  <tr>
 *      <td>Backup</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Backup</td>
 *      <td>OFF</td>
 *  </tr>
 *  <tr>
 *      <td>Off</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *      <td>OFF</td>
 *  </tr>
 * \else
 *  <tr>
 *      <th>Sleep mode</th>
 *      <th>CPU clock</th>
 *      <th>AHB clock</th>
 *      <th>APB clocks</th>
 *      <th>Clock sources</th>
 *      <th>System clock</th>
 *      <th>32KHz</th>
 *      <th>Reg mode</th>
 *      <th>RAM mode</th>
 *  </tr>
 *  <tr>
 *      <td>IDLE 0</td>
 *      <td>Stop</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Normal</td>
 *      <td>Normal</td>
 *  </tr>
 *  <tr>
 *      <td>IDLE 1</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Normal</td>
 *      <td>Normal</td>
 *  </tr>
 *  <tr>
 *      <td>IDLE 2</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Run</td>
 *      <td>Normal</td>
 *      <td>Normal</td>
 *  </tr>
 *  <tr>
 *      <td>STANDBY</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Stop</td>
 *      <td>Low Power</td>
 *      <td>Source/Drain biasing</td>
 *  </tr>
 * \endif
 * </table>
 *
 * To enter device sleep, one of the available sleep modes must be set, and the
 * function to enter sleep called. The device will automatically wake up in
 * response to an interrupt being generated or other device event.
 *
 * Some peripheral clocks will remain enabled during sleep, depending on their
 * configuration; if desired, modules can remain clocked during sleep to allow
 * them to continue to operate while other parts of the system are powered down
 * to save power.
 *
 *
 * \section asfdoc_sam0_system_special_considerations Special Considerations
 *
 * Most of the functions in this driver have device specific restrictions and
 * caveats; refer to your device datasheet.
 *
 *
 * \section asfdoc_sam0_system_extra_info Extra Information
 *
 * For extra information, see \ref asfdoc_sam0_system_extra. This includes:
 *  - \ref asfdoc_sam0_system_extra_acronyms
 *  - \ref asfdoc_sam0_system_extra_dependencies
 *  - \ref asfdoc_sam0_system_extra_errata
 *  - \ref asfdoc_sam0_system_extra_history
 *
 *
 * \section asfdoc_sam0_system_examples Examples
 *
 * For SYSTEM module related examples, refer to the sub-modules listed in
 * the \ref asfdoc_sam0_system_module_overview "system module overview".
 *
 * \if DEVICE_SAML21_SUPPORT
 * For a list of examples related to this driver, see
 * \ref asfdoc_sam0_drivers_power_exqsg.
 * \endif
 *
 *
 * \section asfdoc_sam0_system_api_overview API Overview
 * @{
 */

/**
 * \name System Debugger
 * @{
 */

/**
 * \brief Check if debugger is present.
 *
 * Check if debugger is connected to the onboard debug system (DAP).
 *
 * \return A bool identifying if a debugger is present.
 *
 * \retval true  Debugger is connected to the system
 * \retval false Debugger is not connected to the system
 *
 */
static inline bool system_is_debugger_present(void)
{
    return DSU->STATUSB.reg & DSU_STATUSB_DBGPRES;
}

/**
 * @}
 */

/**
 * \name System Identification
 * @{
 */

/**
 * \brief Retrieve the device identification signature.
 *
 * Retrieves the signature of the current device.
 *
 * \return Device ID signature as a 32-bit integer.
 */
static inline uint32_t system_get_device_id(void)
{
    return DSU->DID.reg;
}

/**
 * @}
 */

/**
 * \name System Initialization
 * @{
 */

void system_init(void);

/**
 * @}
 */


/**
 * @}
 */

/**

* \page asfdoc_sam0_drivers_power_exqsg Examples for Power Driver
 *
 * This is a list of the available Quick Start Guides (QSGs) and example
 * applications. QSGs are simple examples with step-by-step instructions to
 * configure and use this driver in a selection of
 * use cases. Note that QSGs can be compiled as a standalone application or be
 * added to the user application.
 *
 *  - \subpage asfdoc_sam0_power_basic_use_case
 *
 * \page asfdoc_sam0_system_extra Extra Information for SYSTEM Driver
 *
 * \section asfdoc_sam0_system_extra_acronyms Acronyms
 * Below is a table listing the acronyms used in this module, along with their
 * intended meanings.
 *
 * <table>
 *  <tr>
 *      <th>Acronym</th>
 *      <th>Definition</th>
 *  </tr>
 *  <tr>
 *      <td>PM</td>
 *      <td>Power Manager</td>
 *  </tr>
 * \if DEVICE_SAML21_SUPPORT
 *  <tr>
 *      <td>SUPC</td>
 *      <td>Supply Controller</td>
 *  </tr>
 *  <tr>
 *      <td>RSTC</td>
 *      <td>Reset Controller</td>
 *  </tr>
 * \else
 *  <tr>
 *      <td>SYSCTRL</td>
 *      <td>System control interface</td>
 *  </tr>
 * \endif
 * </table>
 *
 *
 * \section asfdoc_sam0_system_extra_dependencies Dependencies
 * This driver has the following dependencies:
 *
 *  - None
 *
 *
 * \section asfdoc_sam0_system_extra_errata Errata
 * There are no errata related to this driver.
 *
 *
 * \section asfdoc_sam0_system_extra_history Module History
 * An overview of the module history is presented in the table below, with
 * details on the enhancements and fixes made to the module since its first
 * release. The current version of this corresponds to the newest version in
 * the table.
 *
 * <table>
 *  <tr>
 *      <th>Changelog</th>
 *  </tr>
 * \if DEVICE_SAML21_SUPPORT
 *  <tr>
 *      <td>Initial Release</td>
 *  </tr>
 * \else
 *  <tr>
 *      <td>Added low power features and support for SAML21</td>
 *  </tr>
 *  <tr>
 *      <td>Added support for SAMD21</td>
 *  </tr>
 *  <tr>
 *      <td>Added new \c system_reset() to reset the complete MCU with some exceptions</td>
 *  </tr>
 *  <tr>
 *      <td>Added new \c system_get_device_id() function to retrieved the device
 *          ID.</td>
 *  </tr>
 *  <tr>
 *      <td>Initial Release</td>
 *  </tr>
 * \endif
 * </table>
 *
 * \page asfdoc_sam0_system_document_revision_history Document Revision History
 *
 * <table>
 * <tr>
 *      <th>Doc. Rev.</td>
 *      <th>Date</td>
 *      <th>Comments</td>
 *  </tr>
 * \if DEVICE_SAML21_SUPPORT
 *  <tr>
 *      <td>A</td>
 *      <td>12/2014</td>
 *      <td>Initial release.</td>
 * </tr>
 * \else
 *  <tr>
 *      <td>D</td>
 *      <td>12/2014</td>
 *      <td>Added support for SAMR21 and SAMD10/D11.</td>
 * </tr>
 * <tr>
 *      <td>C</td>
 *      <td>01/2014</td>
 *      <td>Added support for SAMD21.</td>
 *  </tr>
 *  <tr>
 *      <td>B</td>
 *      <td>06/2013</td>
 *      <td>Corrected documentation typos.</td>
 *  </tr>
 *  <tr>
 *      <td>A</td>
 *      <td>06/2013</td>
 *      <td>Initial release</td>
 *  </tr>
 * \endif
 * </table>
 */

#ifdef __cplusplus
}
#endif

#endif /* SYSTEM_H_INCLUDED */