File content as of revision 592:a274ee790e56:

#ifndef POWER_H_INCLUDED
#define POWER_H_INCLUDED

#include <compiler.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * \addtogroup asfdoc_sam0_system_group
 * @{
 */

/**
 * \brief Voltage references within the device.
 *
 * List of available voltage references (VREF) that may be used within the
 * device.
 */
enum system_voltage_reference {
    /** Temperature sensor voltage reference. */
    SYSTEM_VOLTAGE_REFERENCE_TEMPSENSE,
    /** Bandgap voltage reference. */
    SYSTEM_VOLTAGE_REFERENCE_BANDGAP,
};

/**
 * \brief Device sleep modes.
 *
 * List of available sleep modes in the device. A table of clocks available in
 * different sleep modes can be found in \ref asfdoc_sam0_system_module_overview_sleep_mode.
 */
enum system_sleepmode {
    /** IDLE 0 sleep mode. */
    SYSTEM_SLEEPMODE_IDLE_0,
    /** IDLE 1 sleep mode. */
    SYSTEM_SLEEPMODE_IDLE_1,
    /** IDLE 2 sleep mode. */
    SYSTEM_SLEEPMODE_IDLE_2,
    /** Standby sleep mode. */
    SYSTEM_SLEEPMODE_STANDBY,
};



/**
 * \name Voltage References
 * @{
 */

/**
 * \brief Enable the selected voltage reference
 *
 * Enables the selected voltage reference source, making the voltage reference
 * available on a pin as well as an input source to the analog peripherals.
 *
 * \param[in] vref  Voltage reference to enable
 */
static inline void system_voltage_reference_enable(
    const enum system_voltage_reference vref)
{
    switch (vref) {
        case SYSTEM_VOLTAGE_REFERENCE_TEMPSENSE:
            SYSCTRL->VREF.reg |= SYSCTRL_VREF_TSEN;
            break;

        case SYSTEM_VOLTAGE_REFERENCE_BANDGAP:
            SYSCTRL->VREF.reg |= SYSCTRL_VREF_BGOUTEN;
            break;

        default:
            Assert(false);
            return;
    }
}

/**
 * \brief Disable the selected voltage reference
 *
 * Disables the selected voltage reference source.
 *
 * \param[in] vref  Voltage reference to disable
 */
static inline void system_voltage_reference_disable(
    const enum system_voltage_reference vref)
{
    switch (vref) {
        case SYSTEM_VOLTAGE_REFERENCE_TEMPSENSE:
            SYSCTRL->VREF.reg &= ~SYSCTRL_VREF_TSEN;
            break;

        case SYSTEM_VOLTAGE_REFERENCE_BANDGAP:
            SYSCTRL->VREF.reg &= ~SYSCTRL_VREF_BGOUTEN;
            break;

        default:
            Assert(false);
            return;
    }
}

/**
 * @}
 */


/**
 * \name Device Sleep Control
 * @{
 */

/**
 * \brief Set the sleep mode of the device
 *
 * Sets the sleep mode of the device; the configured sleep mode will be entered
 * upon the next call of the \ref system_sleep() function.
 *
 * For an overview of which systems are disabled in sleep for the different
 * sleep modes, see \ref asfdoc_sam0_system_module_overview_sleep_mode.
 *
 * \param[in] sleep_mode  Sleep mode to configure for the next sleep operation
 *
 * \retval STATUS_OK               Operation completed successfully
 * \retval STATUS_ERR_INVALID_ARG  The requested sleep mode was invalid or not
 *                                 available
 */
static inline enum status_code system_set_sleepmode(
    const enum system_sleepmode sleep_mode)
{
#if (SAMD20 || SAMD21)
    /* Errata: Make sure that the Flash does not power all the way down
     * when in sleep mode. */
    NVMCTRL->CTRLB.bit.SLEEPPRM = NVMCTRL_CTRLB_SLEEPPRM_DISABLED_Val;
#endif

    switch (sleep_mode) {
        case SYSTEM_SLEEPMODE_IDLE_0:
        case SYSTEM_SLEEPMODE_IDLE_1:
        case SYSTEM_SLEEPMODE_IDLE_2:
            SCB->SCR &= ~SCB_SCR_SLEEPDEEP_Msk;
            PM->SLEEP.reg = sleep_mode;
            break;

        case SYSTEM_SLEEPMODE_STANDBY:
            SCB->SCR |=  SCB_SCR_SLEEPDEEP_Msk;
            break;

        default:
            return STATUS_ERR_INVALID_ARG;
    }

    return STATUS_OK;
}

/**
 * \brief Put the system to sleep waiting for interrupt
 *
 * Executes a device DSB (Data Synchronization Barrier) instruction to ensure
 * all ongoing memory accesses have completed, then a WFI (Wait For Interrupt)
 * instruction to place the device into the sleep mode specified by
 * \ref system_set_sleepmode until woken by an interrupt.
 */
static inline void system_sleep(void)
{
    __DSB();
    __WFI();
}

/**
 * @}
 */

/** @} */
#ifdef __cplusplus
}
#endif

#endif /* POWER_H_INCLUDED */