This driver for Atmel® | SMART ARM®-based microcontrollers provides an interface for the configuration and management of the device's clocking related functions.

This includes the various clock sources, bus clocks, and generic clocks within the device, with functions to manage the enabling, disabling, source selection, and prescaling of clocks to various internal peripherals.

The following peripherals are used by this module:

GCLK (Generic Clock Management)
PM (Power Management)
OSCCTRL (Oscillators Controller)
OSC32KCTRL (32K Oscillators Controller)
MCLK (Main Clock)

The following devices can use this module:

Atmel | SMART SAM L21

The outline of this documentation is as follows:

Prerequisites

There are no prerequisites for this module.

Module Overview

The SAM devices contain a sophisticated clocking system, which is designed to give the maximum flexibility to the user application. This system allows a system designer to tune the performance and power consumption of the device in a dynamic manner, to achieve the best trade-off between the two for a particular application.

This driver provides a set of functions for the configuration and management of the various clock related functionalities within the device.

Clock Sources

The SAM devices have a number of master clock source modules, each of which being capable of producing a stabilized output frequency which can then be fed into the various peripherals and modules within the device.

Possible clock source modules include internal R/C oscillators, internal DFLL modules, as well as external crystal oscillators and/or clock inputs.

CPU / Bus Clocks

The CPU and AHB/APBx buses are clocked by the same physical clock source (referred in this module as the Main Clock). The CPU and bus clocks are divided into a number of clock domains. Each clock domain can run at different frequencies.

There are three clock domains:

CPU Clock Domain
Low Power Clock Domain(LP Clock Domain)
Backup Clock Domain(BUP Clock Domain)

Each clock domain (CPU, LP, BUP) can be changed on the fly. To ensure correct operation, frequencies must be selected so that BUPDIV ≥ LPDIV ≥ HSDIV. Also, frequencies must never exceed the specified maximum frequency for each clock domain. A module may be connected to several clock domains (for instance, AHB and APB).

The general main clock tree for the CPU and associated buses is shown in the figure below.

Clock Masking

To save power, the input clock to one or more peripherals on the AHB and APBx buses can be masked away. When masked, no clock is passed into the module. Disabling of clocks of unused modules will prevent all access to the masked module, but will reduce the overall device power consumption.

Generic Clocks

Within the SAM devices are a number of Generic Clocks; these are used to provide clocks to the various peripheral clock domains in the device in a standardized manner. One or more master source clocks can be selected as the input clock to a Generic Clock Generator, which can prescale down the input frequency to a slower rate for use in a peripheral.

Additionally, a number of individually selectable Generic Clock Channels are provided, which multiplex and gate the various generator outputs for one or more peripherals within the device. This setup allows for a single common generator to feed one or more channels, which can then be enabled or disabled individually as required.

Clock Chain Example

An example setup of a complete clock chain within the device is shown in the figure below.

Generic Clock Generators

Each Generic Clock generator within the device can source its input clock from one of the provided Source Clocks, and prescale the output for one or more Generic Clock Channels in a one-to-many relationship. The generators thus allow for several clocks to be generated of different frequencies, power usages, and accuracies, which can be turned on and off individually to disable the clocks to multiple peripherals as a group.

Generic Clock Channels

To connect a Generic Clock Generator to a peripheral within the device, a Generic Clock Channel is used. Each peripheral or peripheral group has an associated Generic Clock Channel, which serves as the clock input for the peripheral(s). To supply a clock to the peripheral module(s), the associated channel must be connected to a running Generic Clock Generator and the channel enabled.

Special Considerations

There are no special considerations for this module.

Extra Information

For extra information, see Extra Information for SYSTEM CLOCK Driver. This includes:

Examples

For a list of examples related to this driver, see Examples for System Clock Driver.

API Overview

Data Structures
struct	system_clock_source_dfll_config
	Configuration structure for DFLL. More...

struct	system_clock_source_dpll_config
	Configuration structure for DPLL. More...

struct	system_clock_source_osc16m_config
	Configuration structure for OSC16M. More...

struct	system_clock_source_osc32k_config
	Configuration structure for OSCULP32K. More...

struct	system_clock_source_osculp32k_config
	Configuration structure for OSCULP32K. More...

struct	system_clock_source_xosc32k_config
	Configuration structure for XOSC32K. More...

struct	system_clock_source_xosc_config
	Configuration structure for XOSC. More...

struct	system_gclk_chan_config
	Generic Clock configuration structure. More...

struct	system_gclk_gen_config
	Generic Clock Generator configuration structure. More...

Enumerations
enum	gclk_generator { GCLK_GENERATOR_0, GCLK_GENERATOR_1, GCLK_GENERATOR_2, GCLK_GENERATOR_3, GCLK_GENERATOR_4, GCLK_GENERATOR_5, GCLK_GENERATOR_6, GCLK_GENERATOR_7, GCLK_GENERATOR_8, GCLK_GENERATOR_9, GCLK_GENERATOR_10, GCLK_GENERATOR_11, GCLK_GENERATOR_12, GCLK_GENERATOR_13, GCLK_GENERATOR_14, GCLK_GENERATOR_15, GCLK_GENERATOR_16 }
	List of available GCLK generators. More...

enum	system_clock_apb_bus { SYSTEM_CLOCK_APB_APBA, SYSTEM_CLOCK_APB_APBB, SYSTEM_CLOCK_APB_APBC, SYSTEM_CLOCK_APB_APBD, SYSTEM_CLOCK_APB_APBE }
	List of APB peripheral buses. More...

enum	system_clock_dfll_chill_cycle { SYSTEM_CLOCK_DFLL_CHILL_CYCLE_ENABLE, SYSTEM_CLOCK_DFLL_CHILL_CYCLE_DISABLE = OSCCTRL_DFLLCTRL_CCDIS }
	Chill cycle behavior of the DFLL module. More...

enum	system_clock_dfll_loop_mode { SYSTEM_CLOCK_DFLL_LOOP_MODE_OPEN, SYSTEM_CLOCK_DFLL_LOOP_MODE_CLOSED = OSCCTRL_DFLLCTRL_MODE }
	Operating modes of the DFLL clock source. More...

enum	system_clock_dfll_quick_lock { SYSTEM_CLOCK_DFLL_QUICK_LOCK_ENABLE, SYSTEM_CLOCK_DFLL_QUICK_LOCK_DISABLE = OSCCTRL_DFLLCTRL_QLDIS }
	QuickLock settings for the DFLL module. More...

enum	system_clock_dfll_stable_tracking { SYSTEM_CLOCK_DFLL_STABLE_TRACKING_TRACK_AFTER_LOCK, SYSTEM_CLOCK_DFLL_STABLE_TRACKING_FIX_AFTER_LOCK = OSCCTRL_DFLLCTRL_STABLE }
	Fine tracking behavior for the DFLL once a lock has been acquired. More...

enum	system_clock_dfll_wakeup_lock { SYSTEM_CLOCK_DFLL_WAKEUP_LOCK_KEEP, SYSTEM_CLOCK_DFLL_WAKEUP_LOCK_LOSE = OSCCTRL_DFLLCTRL_LLAW }
	Locking behavior for the DFLL during device wake-up. More...

enum	system_clock_external { SYSTEM_CLOCK_EXTERNAL_CRYSTAL, SYSTEM_CLOCK_EXTERNAL_CLOCK }
	External clock source types. More...

enum	system_clock_source { SYSTEM_CLOCK_SOURCE_OSC16M = GCLK_SOURCE_OSC16M, SYSTEM_CLOCK_SOURCE_OSC32K = GCLK_SOURCE_OSC32K, SYSTEM_CLOCK_SOURCE_XOSC = GCLK_SOURCE_XOSC, SYSTEM_CLOCK_SOURCE_XOSC32K = GCLK_SOURCE_XOSC32K, SYSTEM_CLOCK_SOURCE_DFLL = GCLK_SOURCE_DFLL48M, SYSTEM_CLOCK_SOURCE_ULP32K = GCLK_SOURCE_OSCULP32K, SYSTEM_CLOCK_SOURCE_GCLKIN = GCLK_SOURCE_GCLKIN, SYSTEM_CLOCK_SOURCE_GCLKGEN1 = GCLK_SOURCE_GCLKGEN1, SYSTEM_CLOCK_SOURCE_DPLL = GCLK_SOURCE_FDPLL }
	Available clock sources in the system. More...

enum	system_clock_source_dpll_filter { SYSTEM_CLOCK_SOURCE_DPLL_FILTER_DEFAULT, SYSTEM_CLOCK_SOURCE_DPLL_FILTER_LOW_BANDWIDTH_FILTER, SYSTEM_CLOCK_SOURCE_DPLL_FILTER_HIGH_BANDWIDTH_FILTER, SYSTEM_CLOCK_SOURCE_DPLL_FILTER_HIGH_DAMPING_FILTER }
	Filter type of the DPLL module. More...

enum	system_clock_source_dpll_lock_time { SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_DEFAULT, SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_8MS = 0x04, SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_9MS, SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_10MS, SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_11MS }
	Lock time-out value of the DPLL module. More...

enum	system_clock_source_dpll_prescaler { SYSTEM_CLOCK_SOURCE_DPLL_DIV_1, SYSTEM_CLOCK_SOURCE_DPLL_DIV_2, SYSTEM_CLOCK_SOURCE_DPLL_DIV_4 }
	DPLL Output Clock Prescaler. More...

enum	system_clock_source_dpll_reference_clock { SYSTEM_CLOCK_SOURCE_DPLL_REFERENCE_CLOCK_XOSC32K, SYSTEM_CLOCK_SOURCE_DPLL_REFERENCE_CLOCK_XOSC, SYSTEM_CLOCK_SOURCE_DPLL_REFERENCE_CLOCK_GCLK }
	Reference clock source of the DPLL module. More...

enum	system_main_clock_div { SYSTEM_MAIN_CLOCK_DIV_1, SYSTEM_MAIN_CLOCK_DIV_2, SYSTEM_MAIN_CLOCK_DIV_4, SYSTEM_MAIN_CLOCK_DIV_8, SYSTEM_MAIN_CLOCK_DIV_16, SYSTEM_MAIN_CLOCK_DIV_32, SYSTEM_MAIN_CLOCK_DIV_64, SYSTEM_MAIN_CLOCK_DIV_128 }
	Main CPU, Lowpower and Backup clock division. More...

enum	system_osc16m_fsel { SYSTEM_OSC16M_4M, SYSTEM_OSC16M_8M, SYSTEM_OSC16M_12M, SYSTEM_OSC16M_16M }
	Frequency selection for the internal 16MHz system clock. More...

enum	system_osc32k_startup { SYSTEM_OSC32K_STARTUP_3, SYSTEM_OSC32K_STARTUP_4, SYSTEM_OSC32K_STARTUP_6, SYSTEM_OSC32K_STARTUP_10, SYSTEM_OSC32K_STARTUP_18, SYSTEM_OSC32K_STARTUP_34, SYSTEM_OSC32K_STARTUP_66, SYSTEM_OSC32K_STARTUP_130 }
	Available start-up times for the OSC32K. More...

enum	system_xosc32k_startup { SYSTEM_XOSC32K_STARTUP_2048, SYSTEM_XOSC32K_STARTUP_4096, SYSTEM_XOSC32K_STARTUP_16384, SYSTEM_XOSC32K_STARTUP_32768, SYSTEM_XOSC32K_STARTUP_65536, SYSTEM_XOSC32K_STARTUP_131072, SYSTEM_XOSC32K_STARTUP_262144 }
	Available start-up times for the XOSC32K. More...

enum	system_xosc_startup { SYSTEM_XOSC_STARTUP_1, SYSTEM_XOSC_STARTUP_2, SYSTEM_XOSC_STARTUP_4, SYSTEM_XOSC_STARTUP_8, SYSTEM_XOSC_STARTUP_16, SYSTEM_XOSC_STARTUP_32, SYSTEM_XOSC_STARTUP_64, SYSTEM_XOSC_STARTUP_128, SYSTEM_XOSC_STARTUP_256, SYSTEM_XOSC_STARTUP_512, SYSTEM_XOSC_STARTUP_1024, SYSTEM_XOSC_STARTUP_2048, SYSTEM_XOSC_STARTUP_4096, SYSTEM_XOSC_STARTUP_8192, SYSTEM_XOSC_STARTUP_16384, SYSTEM_XOSC_STARTUP_32768 }
	Available start-up times for the XOSC. More...

External Oscillator Management
static void	system_clock_source_xosc_get_config_defaults (struct system_clock_source_xosc_config *const config)
	Retrieve the default configuration for XOSC. More...

void	system_clock_source_xosc_set_config (struct system_clock_source_xosc_config *const config)
	Configure the external oscillator clock source. More...

External 32KHz Oscillator Management
static void	system_clock_source_xosc32k_get_config_defaults (struct system_clock_source_xosc32k_config *const config)
	Retrieve the default configuration for XOSC32K. More...

void	system_clock_source_xosc32k_set_config (struct system_clock_source_xosc32k_config *const config)
	Configure the XOSC32K external 32KHz oscillator clock source. More...

Internal 32KHz Oscillator Management
static void	system_clock_source_osc32k_get_config_defaults (struct system_clock_source_osc32k_config *const config)
	Retrieve the default configuration for OSC32K. More...

void	system_clock_source_osc32k_set_config (struct system_clock_source_osc32k_config *const config)
	Configure the internal OSC32K oscillator clock source. More...

Internal Ultra Low Power 32KHz Oscillator Management
static void	system_clock_source_osculp32k_get_config_defaults (struct system_clock_source_osculp32k_config *const config)
	Retrieve the default configuration for OSCULP32K. More...

void	system_clock_source_osculp32k_set_config (struct system_clock_source_osculp32k_config *const config)
	Configure the internal OSCULP32K oscillator clock source. More...

Internal 16MHz Oscillator Management
static void	system_clock_source_osc16m_get_config_defaults (struct system_clock_source_osc16m_config *const config)
	Retrieve the default configuration for OSC16M. More...

void	system_clock_source_osc16m_set_config (struct system_clock_source_osc16m_config *const config)
	Configure the internal OSC16M oscillator clock source. More...

Internal DFLL Management
static void	system_clock_source_dfll_get_config_defaults (struct system_clock_source_dfll_config *const config)
	Retrieve the default configuration for DFLL. More...

void	system_clock_source_dfll_set_config (struct system_clock_source_dfll_config *const config)
	Configure the DFLL clock source. More...

Clock Source Management
enum status_code	system_clock_source_write_calibration (const enum system_clock_source system_clock_source, const uint16_t calibration_value, const uint8_t freq_range)

enum status_code	system_clock_source_enable (const enum system_clock_source system_clock_source)

enum status_code	system_clock_source_disable (const enum system_clock_source clk_source)
	Disables a clock source. More...

bool	system_clock_source_is_ready (const enum system_clock_source clk_source)
	Checks if a clock source is ready. More...

uint32_t	system_clock_source_get_hz (const enum system_clock_source clk_source)
	Retrieve the frequency of a clock source. More...

Main Clock Management
static void	system_main_clock_set_failure_detect (const bool enable)
	Enable or disable the main clock failure detection. More...

static void	system_cpu_clock_set_divider (const enum system_main_clock_div divider)
	Set main CPU clock divider. More...

static void	system_low_power_clock_set_divider (const enum system_main_clock_div divider)
	Set Low-Power Clock divider. More...

static void	system_backup_clock_set_divider (const enum system_main_clock_div divider)
	Set Backup Clock divider. More...

static uint32_t	system_cpu_clock_get_hz (void)
	Retrieves the current frequency of the CPU core. More...

static uint32_t	system_low_power_clock_get_hz (void)
	Retrieves the current frequency of Low-Power clock. More...

static uint32_t	system_backup_clock_get_hz (void)
	Retrieves the current frequency of backup clock. More...

Bus Clock Masking
static void	system_ahb_clock_set_mask (const uint32_t ahb_mask)
	Set bits in the clock mask for the AHB bus. More...

static void	system_ahb_clock_clear_mask (const uint32_t ahb_mask)
	Clear bits in the clock mask for the AHB bus. More...

static enum status_code	system_apb_clock_set_mask (const enum system_clock_apb_bus bus, const uint32_t mask)
	Set bits in the clock mask for an APBx bus. More...

static enum status_code	system_apb_clock_clear_mask (const enum system_clock_apb_bus bus, const uint32_t mask)
	Clear bits in the clock mask for an APBx bus. More...

Internal DPLL Management
static void	system_clock_source_dpll_get_config_defaults (struct system_clock_source_dpll_config *const config)
	Retrieve the default configuration for DPLL. More...

void	system_clock_source_dpll_set_config (struct system_clock_source_dpll_config *const config)
	Configure the DPLL clock source. More...

System Clock Initialization
void	system_clock_init (void)
	Initialize clock system based on the configuration in conf_clocks.h. More...

System Flash Wait States
static void	system_flash_set_waitstates (uint8_t wait_states)
	Set flash controller wait states. More...

Generic Clock Management
void	system_gclk_init (void)
	Initializes the GCLK driver. More...

Generic Clock Management (Generators)
static void	system_gclk_gen_get_config_defaults (struct system_gclk_gen_config *const config)
	Initializes a Generic Clock Generator configuration structure to defaults. More...

void	system_gclk_gen_set_config (const uint8_t generator, struct system_gclk_gen_config *const config)
	Writes a Generic Clock Generator configuration to the hardware module. More...

void	system_gclk_gen_enable (const uint8_t generator)
	Enables a Generic Clock Generator that was previously configured. More...

void	system_gclk_gen_disable (const uint8_t generator)
	Disables a Generic Clock Generator that was previously enabled. More...

bool	system_gclk_gen_is_enabled (const uint8_t generator)
	Determins if the specified Generic Clock Generator is enabled. More...

Generic Clock Management (Channels)
static void	system_gclk_chan_get_config_defaults (struct system_gclk_chan_config *const config)
	Initializes a Generic Clock configuration structure to defaults. More...

void	system_gclk_chan_set_config (const uint8_t channel, struct system_gclk_chan_config *const config)
	Writes a Generic Clock configuration to the hardware module. More...

void	system_gclk_chan_enable (const uint8_t channel)
	Enables a Generic Clock that was previously configured. More...

void	system_gclk_chan_disable (const uint8_t channel)
	Disables a Generic Clock that was previously enabled. More...

bool	system_gclk_chan_is_enabled (const uint8_t channel)
	Determins if the specified Generic Clock channel is enabled. More...

void	system_gclk_chan_lock (const uint8_t channel)
	Locks a Generic Clock channel from further configuration writes. More...

bool	system_gclk_chan_is_locked (const uint8_t channel)
	Determins if the specified Generic Clock channel is locked. More...

Generic Clock Frequency Retrieval
uint32_t	system_gclk_gen_get_hz (const uint8_t generator)
	Retrieves the clock frequency of a Generic Clock generator. More...

uint32_t	system_gclk_chan_get_hz (const uint8_t channel)
	Retrieves the clock frequency of a Generic Clock channel. More...

enum gclk_generator

List of available GCLK generators.

List of Available GCLK generators. This enum is used in the peripheral device drivers to select the GCLK generator to be used for its operation.

The number of GCLK generators available is device dependent.

Enumerator
GCLK_GENERATOR_0	GCLK generator channel 0.
GCLK_GENERATOR_1	GCLK generator channel 1.
GCLK_GENERATOR_2	GCLK generator channel 2.
GCLK_GENERATOR_3	GCLK generator channel 3.
GCLK_GENERATOR_4	GCLK generator channel 4.
GCLK_GENERATOR_5	GCLK generator channel 5.
GCLK_GENERATOR_6	GCLK generator channel 6.
GCLK_GENERATOR_7	GCLK generator channel 7.
GCLK_GENERATOR_8	GCLK generator channel 8.
GCLK_GENERATOR_9	GCLK generator channel 9.
GCLK_GENERATOR_10	GCLK generator channel 10.
GCLK_GENERATOR_11	GCLK generator channel 11.
GCLK_GENERATOR_12	GCLK generator channel 12.
GCLK_GENERATOR_13	GCLK generator channel 13.
GCLK_GENERATOR_14	GCLK generator channel 14.
GCLK_GENERATOR_15	GCLK generator channel 15.
GCLK_GENERATOR_16	GCLK generator channel 16.

enum system_clock_apb_bus

List of APB peripheral buses.

Available bus clock domains on the APB bus.

Enumerator
SYSTEM_CLOCK_APB_APBA	Peripheral bus A on the APB bus.
SYSTEM_CLOCK_APB_APBB	Peripheral bus B on the APB bus.
SYSTEM_CLOCK_APB_APBC	Peripheral bus C on the APB bus.
SYSTEM_CLOCK_APB_APBD	Peripheral bus D on the APB bus.
SYSTEM_CLOCK_APB_APBE	Peripheral bus E on the APB bus.

enum system_clock_dfll_chill_cycle

Chill cycle behavior of the DFLL module.

DFLL chill cycle behavior modes of the DFLL module. A chill cycle is a period of time when the DFLL output frequency is not measured by the unit, to allow the output to stabilize after a change in the input clock source.

Enumerator
SYSTEM_CLOCK_DFLL_CHILL_CYCLE_ENABLE	Enable a chill cycle, where the DFLL output frequency is not measured.
SYSTEM_CLOCK_DFLL_CHILL_CYCLE_DISABLE	Disable a chill cycle, where the DFLL output frequency is not measured.

enum system_clock_dfll_loop_mode

Operating modes of the DFLL clock source.

Available operating modes of the DFLL clock source module.

Enumerator
SYSTEM_CLOCK_DFLL_LOOP_MODE_OPEN	The DFLL is operating in open loop mode with no feedback.
SYSTEM_CLOCK_DFLL_LOOP_MODE_CLOSED	The DFLL is operating in closed loop mode with frequency feedback from a low frequency reference clock.

enum system_clock_dfll_quick_lock

QuickLock settings for the DFLL module.

DFLL QuickLock settings for the DFLL module, to allow for a faster lock of the DFLL output frequency at the expense of accuracy.

Enumerator
SYSTEM_CLOCK_DFLL_QUICK_LOCK_ENABLE	Enable the QuickLock feature for looser lock requirements on the DFLL.
SYSTEM_CLOCK_DFLL_QUICK_LOCK_DISABLE	Disable the QuickLock feature for strict lock requirements on the DFLL.

enum system_clock_dfll_stable_tracking

Fine tracking behavior for the DFLL once a lock has been acquired.

DFLL fine tracking behavior modes after a lock has been acquired.

Enumerator
SYSTEM_CLOCK_DFLL_STABLE_TRACKING_TRACK_AFTER_LOCK	Keep tracking after the DFLL has gotten a fine lock.
SYSTEM_CLOCK_DFLL_STABLE_TRACKING_FIX_AFTER_LOCK	Stop tracking after the DFLL has gotten a fine lock.

enum system_clock_dfll_wakeup_lock

Locking behavior for the DFLL during device wake-up.

DFLL lock behavior modes on device wake-up from sleep.

Enumerator
SYSTEM_CLOCK_DFLL_WAKEUP_LOCK_KEEP	Keep DFLL lock when the device wakes from sleep.
SYSTEM_CLOCK_DFLL_WAKEUP_LOCK_LOSE	Lose DFLL lock when the devices wakes from sleep.

enum system_clock_external

External clock source types.

Available external clock source types.

Enumerator
SYSTEM_CLOCK_EXTERNAL_CRYSTAL	The external clock source is a crystal oscillator.
SYSTEM_CLOCK_EXTERNAL_CLOCK	The connected clock source is an external logic level clock signal.

enum system_clock_source

Available clock sources in the system.

Clock sources available to the GCLK generators.

Enumerator
SYSTEM_CLOCK_SOURCE_OSC16M	Internal 16MHz RC oscillator.
SYSTEM_CLOCK_SOURCE_OSC32K	Internal 32KHz RC oscillator.
SYSTEM_CLOCK_SOURCE_XOSC	External oscillator.
SYSTEM_CLOCK_SOURCE_XOSC32K	External 32KHz oscillator.
SYSTEM_CLOCK_SOURCE_DFLL	Digital Frequency Locked Loop (DFLL)
SYSTEM_CLOCK_SOURCE_ULP32K	Internal Ultra Low Power 32KHz oscillator.
SYSTEM_CLOCK_SOURCE_GCLKIN	Generator input pad.
SYSTEM_CLOCK_SOURCE_GCLKGEN1	Generic clock generator one output.
SYSTEM_CLOCK_SOURCE_DPLL	Digital Phase Locked Loop (DPLL)

enum system_clock_source_dpll_filter

Filter type of the DPLL module.

Enumerator
SYSTEM_CLOCK_SOURCE_DPLL_FILTER_DEFAULT	Default filter mode.
SYSTEM_CLOCK_SOURCE_DPLL_FILTER_LOW_BANDWIDTH_FILTER	Low bandwidth filter.
SYSTEM_CLOCK_SOURCE_DPLL_FILTER_HIGH_BANDWIDTH_FILTER	High bandwidth filter.
SYSTEM_CLOCK_SOURCE_DPLL_FILTER_HIGH_DAMPING_FILTER	High damping filter.

enum system_clock_source_dpll_lock_time

Lock time-out value of the DPLL module.

Enumerator
SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_DEFAULT	Set no time-out as default.
SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_8MS	Set time-out if no lock within 8ms.
SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_9MS	Set time-out if no lock within 9ms.
SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_10MS	Set time-out if no lock within 10ms.
SYSTEM_CLOCK_SOURCE_DPLL_LOCK_TIME_11MS	Set time-out if no lock within 11ms.

enum system_clock_source_dpll_prescaler

DPLL Output Clock Prescaler.

Enumerator
SYSTEM_CLOCK_SOURCE_DPLL_DIV_1	DPLL output is divided by 1.
SYSTEM_CLOCK_SOURCE_DPLL_DIV_2	DPLL output is divided by 2.
SYSTEM_CLOCK_SOURCE_DPLL_DIV_4	DPLL output is divided by 4.

enum system_clock_source_dpll_reference_clock

Reference clock source of the DPLL module.

Enumerator
SYSTEM_CLOCK_SOURCE_DPLL_REFERENCE_CLOCK_XOSC32K	Select XOSC32K as clock reference.
SYSTEM_CLOCK_SOURCE_DPLL_REFERENCE_CLOCK_XOSC	Select XOSC as clock reference.
SYSTEM_CLOCK_SOURCE_DPLL_REFERENCE_CLOCK_GCLK	Select GCLK as clock reference.

enum system_main_clock_div

Main CPU, Lowpower and Backup clock division.

Available division ratios for the CPU and Lowpower and Backup clocks.

Enumerator
SYSTEM_MAIN_CLOCK_DIV_1	Divide Main clock by one.
SYSTEM_MAIN_CLOCK_DIV_2	Divide Main clock by two.
SYSTEM_MAIN_CLOCK_DIV_4	Divide Main clock by four.
SYSTEM_MAIN_CLOCK_DIV_8	Divide Main clock by eight.
SYSTEM_MAIN_CLOCK_DIV_16	Divide Main clock by 16.
SYSTEM_MAIN_CLOCK_DIV_32	Divide Main clock by 32.
SYSTEM_MAIN_CLOCK_DIV_64	Divide Main clock by 64.
SYSTEM_MAIN_CLOCK_DIV_128	Divide Main clock by 128.

enum system_osc16m_fsel

Frequency selection for the internal 16MHz system clock.

Available frequency selection for the internal 16MHz (nominal) system clock.

Enumerator
SYSTEM_OSC16M_4M	Frequency Selection 4MHz.
SYSTEM_OSC16M_8M	Frequency Selection 8MHz.
SYSTEM_OSC16M_12M	Frequency Selection 12MHz.
SYSTEM_OSC16M_16M	Frequency Selection 16MHz.

enum system_osc32k_startup

Available start-up times for the OSC32K.

Available internal 32KHz oscillator start-up times, as a number of internal OSC32K clock cycles.

Enumerator
SYSTEM_OSC32K_STARTUP_3	Wait three clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_4	Wait four clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_6	Wait six clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_10	Wait ten clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_18	Wait 18 clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_34	Wait 34 clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_66	Wait 66 clock cycles until the clock source is considered stable.
SYSTEM_OSC32K_STARTUP_130	Wait 130 clock cycles until the clock source is considered stable.

enum system_xosc32k_startup

Available start-up times for the XOSC32K.

Available external 32KHz oscillator start-up times, as a number of external clock cycles.

Enumerator
SYSTEM_XOSC32K_STARTUP_2048	Wait 2048 clock cycles until the clock source is considered stable.
SYSTEM_XOSC32K_STARTUP_4096	Wait 4096 clock cycles until the clock source is considered stable.
SYSTEM_XOSC32K_STARTUP_16384	Wait 16384 clock cycles until the clock source is considered stable.
SYSTEM_XOSC32K_STARTUP_32768	Wait 32768 clock cycles until the clock source is considered stable.
SYSTEM_XOSC32K_STARTUP_65536	Wait 65536 clock cycles until the clock source is considered stable.
SYSTEM_XOSC32K_STARTUP_131072	Wait 131072 clock cycles until the clock source is considered stable.
SYSTEM_XOSC32K_STARTUP_262144	Wait 262144 clock cycles until the clock source is considered stable.

enum system_xosc_startup

Available start-up times for the XOSC.

Available external oscillator start-up times, as a number of external clock cycles.

Enumerator
SYSTEM_XOSC_STARTUP_1	Wait one clock cycle until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_2	Wait two clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_4	Wait four clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_8	Wait eight clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_16	Wait 16 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_32	Wait 32 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_64	Wait 64 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_128	Wait 128 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_256	Wait 256 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_512	Wait 512 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_1024	Wait 1024 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_2048	Wait 2048 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_4096	Wait 4096 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_8192	Wait 8192 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_16384	Wait 16384 clock cycles until the clock source is considered stable.
SYSTEM_XOSC_STARTUP_32768	Wait 32768 clock cycles until the clock source is considered stable.

static void system_ahb_clock_clear_mask ( const uint32_t ahb_mask )

inlinestatic

Clear bits in the clock mask for the AHB bus.

This function will clear bits in the clock mask for the AHB bus. Any bits set to 1 will disable that clock, zero bits in the mask will be ignored.

Parameters

[in] ahb_mask AHB clock mask

static void system_ahb_clock_set_mask ( const uint32_t ahb_mask )

inlinestatic

Set bits in the clock mask for the AHB bus.

This function will set bits in the clock mask for the AHB bus. Any bits set to 1 will enable that clock, 0 bits in the mask will be ignored

Parameters

[in] ahb_mask AHB clock mask

static enum status_code system_apb_clock_clear_mask	(	const enum system_clock_apb_bus	bus,
		const uint32_t	mask
	)

inlinestatic

Clear bits in the clock mask for an APBx bus.

This function will clear bits in the clock mask for an APBx bus. Any bits set to 1 will disable the corresponding module clock, zero bits in the mask will be ignored.

Parameters

[in]	mask	APBx clock mask, a `SYSTEM_CLOCK_APB_APBx` constant from the device header files
[in]	bus	Bus to clear clock mask bits

Returns: Status indicating the result of the clock mask change operation.

Return values

STATUS_ERR_INVALID_ARG	Invalid bus ID was given
STATUS_OK	The clock mask was changed successfully

References Assert, STATUS_ERR_INVALID_ARG, STATUS_OK, SYSTEM_CLOCK_APB_APBA, SYSTEM_CLOCK_APB_APBB, SYSTEM_CLOCK_APB_APBC, SYSTEM_CLOCK_APB_APBD, and SYSTEM_CLOCK_APB_APBE.

static enum status_code system_apb_clock_set_mask	(	const enum system_clock_apb_bus	bus,
		const uint32_t	mask
	)

inlinestatic

Set bits in the clock mask for an APBx bus.

This function will set bits in the clock mask for an APBx bus. Any bits set to 1 will enable the corresponding module clock, zero bits in the mask will be ignored.

Parameters

[in]	mask	APBx clock mask, a `SYSTEM_CLOCK_APB_APBx` constant from the device header files
[in]	bus	Bus to set clock mask bits for, a mask of `PM_APBxMASK_*` constants from the device header files

Returns: Status indicating the result of the clock mask change operation.

Return values

STATUS_ERR_INVALID_ARG	Invalid bus given
STATUS_OK	The clock mask was set successfully

References Assert, STATUS_ERR_INVALID_ARG, STATUS_OK, SYSTEM_CLOCK_APB_APBA, SYSTEM_CLOCK_APB_APBB, SYSTEM_CLOCK_APB_APBC, SYSTEM_CLOCK_APB_APBD, and SYSTEM_CLOCK_APB_APBE.

Referenced by spi_init(), system_gclk_init(), and usart_init().

static uint32_t system_backup_clock_get_hz ( void )

inlinestatic

Retrieves the current frequency of backup clock.

Retrieves the operating frequency of backup clock, obtained from backup clock and the set backup clock divider.

Returns: Current CPU frequency in Hz.

References GCLK_GENERATOR_0, and system_gclk_gen_get_hz().

static void system_backup_clock_set_divider ( const enum system_main_clock_div divider )

inlinestatic

Set Backup Clock divider.

Sets the clock divider used on the main clock to provide the CPU clock.

Parameters

[in] divider CPU clock divider

Referenced by system_clock_init().

void system_clock_init ( void )

Initialize clock system based on the configuration in conf_clocks.h.

This function will apply the settings in conf_clocks.h when run from the user application. All clock sources and GCLK generators are running when this function returns.

Note: OSC16M is always enabled and if user selects other clocks for GCLK generators, the OSC16M default enable can be disabled after system_clock_init. Make sure the clock switches successfully before disabling OSC8M.

Referenced by system_init().

static void system_clock_source_dfll_get_config_defaults ( struct system_clock_source_dfll_config *const config )

inlinestatic

Retrieve the default configuration for DFLL.

Fills a configuration structure with the default configuration for a DFLL oscillator module:

Open loop mode
QuickLock mode enabled
Chill cycle enabled
Output frequency lock maintained during device wake-up
Continuous tracking of the output frequency
Default tracking values at the mid-points for both coarse and fine tracking parameters
Don't run in STANDBY sleep mode
Run only when requested by peripheral (on demand)

Parameters

[out] config Configuration structure to fill with default values

Referenced by system_clock_init().

void system_clock_source_dfll_set_config ( struct system_clock_source_dfll_config *const config )

Configure the DFLL clock source.

Configures the Digital Frequency Locked Loop clock source with the given configuration settings.

Note: The DFLL will be running when this function returns, as the DFLL module needs to be enabled in order to perform the module configuration.

Parameters

[in] config DFLL configuration structure containing the new config

Referenced by system_clock_init().

enum status_code system_clock_source_disable ( const enum system_clock_source clock_source )

Disables a clock source.

Disables a clock source that was previously enabled.

Parameters

[in] clock_source Clock source to disable

Return values

STATUS_OK	Clock source was disabled successfully
STATUS_ERR_INVALID_ARG	An invalid or unavailable clock source was given

References Assert, _system_clock_dfll_config::control, _system_clock_module::dfll, STATUS_ERR_INVALID_ARG, STATUS_OK, SYSTEM_CLOCK_SOURCE_DFLL, SYSTEM_CLOCK_SOURCE_DPLL, SYSTEM_CLOCK_SOURCE_OSC16M, SYSTEM_CLOCK_SOURCE_OSC32K, SYSTEM_CLOCK_SOURCE_ULP32K, SYSTEM_CLOCK_SOURCE_XOSC, and SYSTEM_CLOCK_SOURCE_XOSC32K.

Referenced by _system_clock_source_osc16m_freq_sel().

static void system_clock_source_dpll_get_config_defaults ( struct system_clock_source_dpll_config *const config )

inlinestatic

Retrieve the default configuration for DPLL.

Fills a configuration structure with the default configuration for a DPLL oscillator module:

Run only when requested by peripheral (on demand)
Don't run in STANDBY sleep mode
Lock bypass disabled
Fast wake up disabled
Low power mode disabled
Output frequency is 48MHz
Reference clock frequency is 32768Hz
Not divide reference clock
Select REF0 as reference clock
Set lock time to default mode
Use default filter

Parameters

[out] config Configuration structure to fill with default values

Referenced by system_clock_init().

void system_clock_source_dpll_set_config ( struct system_clock_source_dpll_config *const config )

Configure the DPLL clock source.

Configures the Digital Phase-Locked Loop clock source with the given configuration settings.

Note: The DPLL will be running when this function returns, as the DPLL module needs to be enabled in order to perform the module configuration.

Parameters

[in] config DPLL configuration structure containing the new config

Referenced by system_clock_init().

enum status_code system_clock_source_enable ( const enum system_clock_source system_clock_source )

uint32_t system_clock_source_get_hz ( const enum system_clock_source clock_source )

Retrieve the frequency of a clock source.

Determines the current operating frequency of a given clock source.

Parameters

[in] clock_source Clock source

Returns: Frequency of the given clock source, in Hz.

References _system_dfll_wait_for_sync(), _system_clock_dfll_config::control, _system_clock_module::dfll, _system_clock_module::dpll, _system_clock_dpll_config::frequency, _system_clock_xosc_config::frequency, _system_clock_dfll_config::mul, SYSTEM_CLOCK_SOURCE_DFLL, SYSTEM_CLOCK_SOURCE_DPLL, SYSTEM_CLOCK_SOURCE_OSC16M, SYSTEM_CLOCK_SOURCE_OSC32K, SYSTEM_CLOCK_SOURCE_ULP32K, SYSTEM_CLOCK_SOURCE_XOSC, SYSTEM_CLOCK_SOURCE_XOSC32K, system_gclk_chan_get_hz(), _system_clock_module::xosc, and _system_clock_module::xosc32k.

Referenced by system_gclk_gen_get_hz().

bool system_clock_source_is_ready ( const enum system_clock_source clock_source )

Checks if a clock source is ready.

Checks if a given clock source is ready to be used.

Parameters

[in] clock_source Clock source to check if ready

Returns: Ready state of the given clock source.

Return values

true	Clock source is enabled and ready
false	Clock source is disabled or not yet ready

References CONF_CLOCK_DFLL_LOOP_MODE, SYSTEM_CLOCK_DFLL_LOOP_MODE_CLOSED, SYSTEM_CLOCK_SOURCE_DFLL, SYSTEM_CLOCK_SOURCE_DPLL, SYSTEM_CLOCK_SOURCE_OSC16M, SYSTEM_CLOCK_SOURCE_OSC32K, SYSTEM_CLOCK_SOURCE_ULP32K, SYSTEM_CLOCK_SOURCE_XOSC, and SYSTEM_CLOCK_SOURCE_XOSC32K.

Referenced by _system_clock_source_osc16m_freq_sel(), and system_clock_init().

static void system_clock_source_osc16m_get_config_defaults ( struct system_clock_source_osc16m_config *const config )

inlinestatic

Retrieve the default configuration for OSC16M.

Fills a configuration structure with the default configuration for an internal 16MHz (nominal) oscillator module:

Clock output frequency select 4MHz
Don't run in STANDBY sleep mode
Run only when requested by peripheral (on demand)

Parameters

[out] config Configuration structure to fill with default values

References Assert, system_clock_source_osc16m_config::fsel, system_clock_source_osc16m_config::on_demand, system_clock_source_osc16m_config::run_in_standby, and SYSTEM_OSC16M_4M.

Referenced by _system_clock_source_osc16m_freq_sel().

void system_clock_source_osc16m_set_config ( struct system_clock_source_osc16m_config *const config )

Configure the internal OSC16M oscillator clock source.

Configures the 16MHz (nominal) internal RC oscillator with the given configuration settings.

Note: Frequency selection can be done only when OSC16M is disabled.

Parameters

[in] config OSC16M configuration structure containing the new config

References system_clock_source_osc16m_config::fsel, system_clock_source_osc16m_config::on_demand, and system_clock_source_osc16m_config::run_in_standby.

Referenced by _system_clock_source_osc16m_freq_sel().

static void system_clock_source_osc32k_get_config_defaults ( struct system_clock_source_osc32k_config *const config )

inlinestatic

Retrieve the default configuration for OSC32K.

Fills a configuration structure with the default configuration for an internal 32KHz oscillator module:

1KHz clock output enabled
32KHz clock output enabled
Don't run in STANDBY sleep mode
Run only when requested by peripheral (on demand)
Set start-up time to 130 cycles
Don't lock registers after configuration has been written

Parameters

[out] config Configuration structure to fill with default values

References Assert, system_clock_source_osc32k_config::enable_1khz_output, system_clock_source_osc32k_config::enable_32khz_output, system_clock_source_osc32k_config::on_demand, system_clock_source_osc32k_config::run_in_standby, system_clock_source_osc32k_config::startup_time, SYSTEM_OSC32K_STARTUP_130, and system_clock_source_osc32k_config::write_once.

Referenced by system_clock_init().

void system_clock_source_osc32k_set_config ( struct system_clock_source_osc32k_config *const config )

Configure the internal OSC32K oscillator clock source.

Configures the 32KHz (nominal) internal RC oscillator with the given configuration settings.

Parameters

[in] config OSC32K configuration structure containing the new config

References system_clock_source_osc32k_config::enable_1khz_output, system_clock_source_osc32k_config::enable_32khz_output, system_clock_source_osc32k_config::on_demand, system_clock_source_osc32k_config::run_in_standby, system_clock_source_osc32k_config::startup_time, and system_clock_source_osc32k_config::write_once.

Referenced by system_clock_init().

static void system_clock_source_osculp32k_get_config_defaults ( struct system_clock_source_osculp32k_config *const config )

inlinestatic

Retrieve the default configuration for OSCULP32K.

Fills a configuration structure with the default configuration for an internal Ultra Low Power 32KHz oscillator module:

1KHz clock output enabled
32KHz clock output enabled

Parameters

[out] config Configuration structure to fill with default values

References Assert, and system_clock_source_osculp32k_config::write_once.

void system_clock_source_osculp32k_set_config ( struct system_clock_source_osculp32k_config *const config )

Configure the internal OSCULP32K oscillator clock source.

Configures the Ultra Low Power 32KHz internal RC oscillator with the given configuration settings.

Note: The OSCULP32K is enabled by default after a Power On Reset (POR) and will always run except during POR.

Parameters

[in] config OSCULP32K configuration structure containing the new config

References system_clock_source_osculp32k_config::write_once.

enum status_code system_clock_source_write_calibration	(	const enum system_clock_source	system_clock_source,
		const uint16_t	calibration_value,
		const uint8_t	freq_range
	)

static void system_clock_source_xosc32k_get_config_defaults ( struct system_clock_source_xosc32k_config *const config )

inlinestatic

Retrieve the default configuration for XOSC32K.

Fills a configuration structure with the default configuration for an external 32KHz oscillator module:

External Crystal
Start-up time of 16384 external clock cycles
Automatic crystal gain control mode disabled
Frequency of 32.768KHz
1KHz clock output disabled
32KHz clock output enabled
Don't run in STANDBY sleep mode
Run only when requested by peripheral (on demand)
Don't lock registers after configuration has been written

Parameters

[out] config Configuration structure to fill with default values

References Assert, system_clock_source_xosc32k_config::enable_1khz_output, system_clock_source_xosc32k_config::enable_32khz_output, system_clock_source_xosc32k_config::external_clock, system_clock_source_xosc32k_config::frequency, system_clock_source_xosc32k_config::on_demand, system_clock_source_xosc32k_config::run_in_standby, system_clock_source_xosc32k_config::startup_time, SYSTEM_CLOCK_EXTERNAL_CRYSTAL, SYSTEM_XOSC32K_STARTUP_16384, and system_clock_source_xosc32k_config::write_once.

Referenced by system_clock_init().

void system_clock_source_xosc32k_set_config ( struct system_clock_source_xosc32k_config *const config )

Configure the XOSC32K external 32KHz oscillator clock source.

Configures the external 32KHz oscillator clock source with the given configuration settings.

Parameters

[in] config XOSC32K configuration structure containing the new config

Referenced by system_clock_init().

static void system_clock_source_xosc_get_config_defaults ( struct system_clock_source_xosc_config *const config )

inlinestatic

Retrieve the default configuration for XOSC.

Fills a configuration structure with the default configuration for an external oscillator module:

External Crystal
Start-up time of 16384 external clock cycles
Automatic crystal gain control mode disabled
Frequency of 12MHz
Don't run in STANDBY sleep mode
Run when it's enabled (not on demand)

Parameters

[out] config Configuration structure to fill with default values

References Assert, system_clock_source_xosc_config::auto_gain_control, system_clock_source_xosc_config::external_clock, system_clock_source_xosc_config::frequency, system_clock_source_xosc_config::on_demand, system_clock_source_xosc_config::run_in_standby, system_clock_source_xosc_config::startup_time, SYSTEM_CLOCK_EXTERNAL_CRYSTAL, and SYSTEM_XOSC_STARTUP_16384.

Referenced by system_clock_init().

void system_clock_source_xosc_set_config ( struct system_clock_source_xosc_config *const config )

Configure the external oscillator clock source.

Configures the external oscillator clock source with the given configuration settings.

Parameters

[in] config External oscillator configuration structure containing the new config

References system_clock_source_xosc_config::auto_gain_control, system_clock_source_xosc_config::external_clock, _system_clock_xosc_config::frequency, system_clock_source_xosc_config::frequency, system_clock_source_xosc_config::on_demand, system_clock_source_xosc_config::run_in_standby, system_clock_source_xosc_config::startup_time, SYSTEM_CLOCK_EXTERNAL_CRYSTAL, and _system_clock_module::xosc.

Referenced by system_clock_init().

static uint32_t system_cpu_clock_get_hz ( void )

inlinestatic

Retrieves the current frequency of the CPU core.

Retrieves the operating frequency of the CPU core, obtained from the main generic clock and the set CPU bus divider.

Returns: Current CPU frequency in Hz.

References GCLK_GENERATOR_0, and system_gclk_gen_get_hz().

Referenced by system_clock_init().

static void system_cpu_clock_set_divider ( const enum system_main_clock_div divider )

inlinestatic

Set main CPU clock divider.

Sets the clock divider used on the main clock to provide the CPU clock.

Parameters

[in] divider CPU clock divider

Referenced by system_clock_init().

static void system_flash_set_waitstates ( uint8_t wait_states )

inlinestatic

Set flash controller wait states.

Will set the number of wait states that are used by the onboard flash memory. The number of wait states depend on both device supply voltage and CPU speed. The required number of wait states can be found in the electrical characteristics of the device.

Parameters

[in] wait_states Number of wait states to use for internal flash

References Assert.

Referenced by system_clock_init().

void system_gclk_chan_disable ( const uint8_t channel )

Disables a Generic Clock that was previously enabled.

Stops the clock generation of a Generic Clock that was previously started via a call to system_gclk_chan_enable().

Parameters

[in] channel Generic Clock channel to disable

References Assert, system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

Referenced by system_gclk_chan_set_config().

void system_gclk_chan_enable ( const uint8_t channel )

Enables a Generic Clock that was previously configured.

Starts the clock generation of a Generic Clock that was previously configured via a call to system_gclk_chan_set_config().

Parameters

[in] channel Generic Clock channel to enable

References system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

Referenced by sercom_set_gclk_generator(), spi_init(), system_clock_init(), and usart_init().

static void system_gclk_chan_get_config_defaults ( struct system_gclk_chan_config *const config )

inlinestatic

Initializes a Generic Clock configuration structure to defaults.

Initializes a given Generic Clock configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application.

The default configuration is as follows:

The clock is sourced from the Generic Clock Generator channel 0
The clock configuration will not be write-locked when set

Parameters

[out] config Configuration structure to initialize to default values

References Assert, GCLK_GENERATOR_0, and system_gclk_chan_config::source_generator.

Referenced by sercom_set_gclk_generator(), spi_init(), system_clock_init(), and usart_init().

uint32_t system_gclk_chan_get_hz ( const uint8_t channel )

Retrieves the clock frequency of a Generic Clock channel.

Determines the clock frequency (in Hz) of a specified Generic Clock channel, used as a source to a device peripheral module.

Parameters

[in] channel Generic Clock Channel index

Returns: The frequency of the generic clock channel, in Hz.

References system_gclk_gen_get_hz(), system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

Referenced by _spi_set_config(), _usart_set_config(), spi_set_baudrate(), and system_clock_source_get_hz().

bool system_gclk_chan_is_enabled ( const uint8_t channel )

Determins if the specified Generic Clock channel is enabled.

Parameters

[in] channel Generic Clock Channel index

Returns: The enabled status.

Return values

true	The Generic Clock channel is enabled
false	The Generic Clock channel is disabled

References system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

bool system_gclk_chan_is_locked ( const uint8_t channel )

Determins if the specified Generic Clock channel is locked.

Parameters

[in] channel Generic Clock Channel index

Returns: The lock status.

Return values

true	The Generic Clock channel is locked
false	The Generic Clock channel is not locked

References system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

void system_gclk_chan_lock ( const uint8_t channel )

Locks a Generic Clock channel from further configuration writes.

Locks a generic clock channel from further configuration writes. It is only possible to unlock the channel configuration through a power on reset.

Parameters

[in] channel Generic Clock channel to enable

References system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

void system_gclk_chan_set_config	(	const uint8_t	channel,
		struct system_gclk_chan_config *const	config
	)

Writes a Generic Clock configuration to the hardware module.

Writes out a given configuration of a Generic Clock configuration to the hardware module. If the clock is currently running, it will be stopped.

Note: Once called the clock will not be running; to start the clock, call system_gclk_chan_enable() after configuring a clock channel.

Parameters

[in]	channel	Generic Clock channel to configure
[in]	config	Configuration settings for the clock

References Assert, system_gclk_chan_config::source_generator, and system_gclk_chan_disable().

Referenced by sercom_set_gclk_generator(), spi_init(), system_clock_init(), and usart_init().

void system_gclk_gen_disable ( const uint8_t generator )

Disables a Generic Clock Generator that was previously enabled.

Stops the clock generation of a Generic Clock Generator that was previously started via a call to system_gclk_gen_enable().

Parameters

[in] generator Generic Clock Generator index to disable

References system_gclk_is_syncing(), system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

void system_gclk_gen_enable ( const uint8_t generator )

Enables a Generic Clock Generator that was previously configured.

Starts the clock generation of a Generic Clock Generator that was previously configured via a call to system_gclk_gen_set_config().

Parameters

[in] generator Generic Clock Generator index to enable

References system_gclk_is_syncing(), system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

static void system_gclk_gen_get_config_defaults ( struct system_gclk_gen_config *const config )

inlinestatic

Initializes a Generic Clock Generator configuration structure to defaults.

Initializes a given Generic Clock Generator configuration structure to a set of known default values. This function should be called on all new instances of these configuration structures before being modified by the user application.

The default configuration is:

The clock is generated undivided from the source frequency
The clock generator output is low when the generator is disabled
The input clock is sourced from input clock channel 0
The clock will be disabled during sleep
The clock output will not be routed to a physical GPIO pin

Parameters

[out] config Configuration structure to initialize to default values

References Assert, system_gclk_gen_config::division_factor, system_gclk_gen_config::high_when_disabled, system_gclk_gen_config::output_enable, system_gclk_gen_config::run_in_standby, and system_gclk_gen_config::source_clock.

Referenced by _system_clock_source_osc16m_freq_sel().

uint32_t system_gclk_gen_get_hz ( const uint8_t generator )

Retrieves the clock frequency of a Generic Clock generator.

Determines the clock frequency (in Hz) of a specified Generic Clock generator, used as a source to a Generic Clock Channel module.

Parameters

[in] generator Generic Clock Generator index

Returns: The frequency of the generic clock generator, in Hz.

References system_clock_source_get_hz(), system_gclk_is_syncing(), system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

Referenced by system_backup_clock_get_hz(), system_cpu_clock_get_hz(), system_gclk_chan_get_hz(), and system_low_power_clock_get_hz().

bool system_gclk_gen_is_enabled ( const uint8_t generator )

Determins if the specified Generic Clock Generator is enabled.

Parameters

[in] generator Generic Clock Generator index to check

Returns: The enabled status.

Return values

true	The Generic Clock Generator is enabled
false	The Generic Clock Generator is disabled

References system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

void system_gclk_gen_set_config	(	const uint8_t	generator,
		struct system_gclk_gen_config *const	config
	)

Writes a Generic Clock Generator configuration to the hardware module.

Writes out a given configuration of a Generic Clock Generator configuration to the hardware module.

Note: Changing the clock source on the fly (on a running generator) can take additional time if the clock source is configured to only run on-demand (ONDEMAND bit is set) and it is not currently running (no peripheral is requesting the clock source). In this case the GCLK will request the new clock while still keeping a request to the old clock source until the new clock source is ready.; This function will not start a generator that is not already running; to start the generator, call system_gclk_gen_enable() after configuring a generator.

Parameters

[in]	generator	Generic Clock Generator index to configure
[in]	config	Configuration settings for the generator

References Assert, system_gclk_gen_config::division_factor, system_gclk_gen_config::high_when_disabled, system_gclk_gen_config::output_enable, system_gclk_gen_config::run_in_standby, system_gclk_gen_config::source_clock, system_gclk_is_syncing(), system_interrupt_enter_critical_section(), and system_interrupt_leave_critical_section().

Referenced by _system_clock_source_osc16m_freq_sel().

void system_gclk_init ( void )

Initializes the GCLK driver.

Initializes the Generic Clock module, disabling and resetting all active Generic Clock Generators and Channels to their power-on default values.

References system_apb_clock_set_mask(), and SYSTEM_CLOCK_APB_APBA.

Referenced by system_clock_init().

static uint32_t system_low_power_clock_get_hz ( void )

inlinestatic

Retrieves the current frequency of Low-Power clock.

Retrieves the operating frequency of Low-Power, obtained from Low-Power clock and the set Low-Power clock divider.

Returns: Current CPU frequency in Hz.

References GCLK_GENERATOR_0, and system_gclk_gen_get_hz().

static void system_low_power_clock_set_divider ( const enum system_main_clock_div divider )

inlinestatic

Set Low-Power Clock divider.

Sets the clock divider used on the main clock to provide the CPU clock.

Parameters

[in] divider CPU clock divider to set

Referenced by system_clock_init().

static void system_main_clock_set_failure_detect ( const bool enable )

inlinestatic

Enable or disable the main clock failure detection.

This mechanism allows switching automatically the main clock to the safe RCSYS clock, when the main clock source is considered off.

This may happen for instance when an external crystal is selected as the clock source of the main clock and the crystal dies. The mechanism is to detect, during a RCSYS period, at least one rising edge of the main clock. If no rising edge is seen the clock is considered failed. As soon as the detector is enabled, the clock failure detector (CFD) will monitor the divided main clock. When a clock failure is detected, the main clock automatically switches to the RCSYS clock and the CFD interrupt is generated if enabled.

Note: The failure detect must be disabled if the system clock is the same or slower than 32KHz as it will believe the system clock has failed with a too slow clock.

Parameters

[in] enable Boolean true to enable, false to disable detection

Referenced by system_clock_init().

Microchip® Advanced Software Framework

Prerequisites

Module Overview

Clock Sources

CPU / Bus Clocks

Clock Masking

Generic Clocks

Clock Chain Example

Generic Clock Generators

Generic Clock Channels

Special Considerations

Extra Information

Examples

API Overview

Data Structures

Enumerations

External Oscillator Management

External 32KHz Oscillator Management

Internal 32KHz Oscillator Management

Internal Ultra Low Power 32KHz Oscillator Management

Internal 16MHz Oscillator Management

Internal DFLL Management

Clock Source Management

Main Clock Management

Bus Clock Masking

Internal DPLL Management

System Clock Initialization

System Flash Wait States

Generic Clock Management

Generic Clock Management (Generators)

Generic Clock Management (Channels)

Generic Clock Frequency Retrieval