System Clock Management

See Quick Start Guide for the System Clock Management service (SAM4L).

The sysclk API covers the system clock and all clocks derived from it. The system clock is a chip-internal clock on which all synchronous clocks, 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 synchronous clocks, since they always run synchronously with respect to each other, as opposed to generic clocks 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.

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.

Modules
	System Clock internals

Macros
#define	CONFIG_HCACHE_ENABLE   1
#define	CONFIG_SYSCLK_CPU_DIV   0
	Configuration symbol for dividing the CPU clock frequency by \(2^{CONFIG\_SYSCLK\_CPU\_DIV}\). More...
#define	CONFIG_SYSCLK_INIT_CPUMASK
	Configuration symbol for the CPU clocks enabled at power-on after the sysclock module has been initialized. More...
#define	CONFIG_SYSCLK_INIT_HSBMASK
	Configuration symbol for the HSB clocks enabled at power-on after the sysclock module has been initialized. More...
#define	CONFIG_SYSCLK_INIT_PBAMASK
	Configuration symbol for the PBA clocks enabled at power-on after the sysclock module has been initialized. More...
#define	CONFIG_SYSCLK_INIT_PBBMASK
	Configuration symbol for the PBB clocks enabled at power-on after the sysclock module has been initialized. More...
#define	CONFIG_SYSCLK_INIT_PBCMASK
	Configuration symbol for the PBC clocks enabled at power-on after the sysclock module has been initialized. More...
#define	CONFIG_SYSCLK_INIT_PBDMASK
	Configuration symbol for the PBD clocks enabled at power-on after the sysclock module has been initialized. More...
#define	CONFIG_SYSCLK_PBA_DIV   0
	Configuration symbol for dividing the PBA clock frequency by \(2^{CONFIG\_SYSCLK\_PBA\_DIV}\). More...
#define	CONFIG_SYSCLK_PBB_DIV   0
	Configuration symbol for dividing the PBB clock frequency by \(2^{CONFIG\_SYSCLK\_PBB\_DIV}\). More...
#define	CONFIG_SYSCLK_PBC_DIV   0
	Configuration symbol for dividing the PBC clock frequency by \(2^{CONFIG\_SYSCLK\_PBC\_DIV}\). More...
#define	CONFIG_SYSCLK_PBD_DIV   0
	Configuration symbol for dividing the PBD clock frequency by \(2^{CONFIG\_SYSCLK\_PBD\_DIV}\). More...
#define	CONFIG_SYSCLK_SOURCE   SYSCLK_SRC_RCSYS
#define	CONFIG_USBCLK_DIV
	Configuration symbol for the USB generic clock divider setting. More...
#define	CONFIG_USBCLK_SOURCE
	Configuration symbol for the USB generic clock source. More...
#define	USBCLK_STARTUP_TIMEOUT   (OSC0_STARTUP_TIMEOUT*(1000000/OSC_RCSYS_NOMINAL_HZ))
	Number of us to wait for USB clock to start. More...

Functions
void	sysclk_disable_usb (void)
	Disable the USB generic clock. More...
void	sysclk_enable_usb (void)
	Enable the USB generic clock. More...
void	sysclk_priv_disable_module (uint32_t bus_id, uint32_t module_index)
	Disable a maskable module clock. More...
void	sysclk_priv_enable_module (uint32_t bus_id, uint32_t module_index)
	Enable a maskable module clock. More...

System clock source
#define	SYSCLK_SRC_RCSYS   0
	System RC oscillator. More...
#define	SYSCLK_SRC_OSC0   1
	Oscillator 0. More...
#define	SYSCLK_SRC_PLL0   2
	Phase Locked Loop 0. More...
#define	SYSCLK_SRC_DFLL   3
	Digital Frequency Locked Loop. More...
#define	SYSCLK_SRC_RC80M   4
	80 MHz RC oscillator More...
#define	SYSCLK_SRC_RCFAST   5
	4-8-12 MHz RC oscillator More...
#define	SYSCLK_SRC_RC1M   6
	1 MHz RC oscillator More...

USB Clock Sources
#define	USBCLK_SRC_OSC0   GENCLK_SRC_OSC0
	Use OSC0. More...
#define	USBCLK_SRC_PLL0   GENCLK_SRC_PLL0
	Use PLL0. More...
#define	USBCLK_SRC_DFLL   GENCLK_SRC_DFLL
	Use DFLL. More...
#define	USBCLK_SRC_GCLKIN0   GENCLK_SRC_GCLKIN0
	Use GCLKIN0. More...

Bus index of maskable module clocks
#define	PM_CLK_GRP_CPU   0
#define	PM_CLK_GRP_HSB   1
#define	PM_CLK_GRP_PBA   2
#define	PM_CLK_GRP_PBB   3
#define	PM_CLK_GRP_PBC   4
#define	PM_CLK_GRP_PBD   5

Clocks derived from the CPU clock
#define	SYSCLK_OCD   0
	On-Chip Debug system. More...

Clocks derived from the HSB clock
#define	SYSCLK_PDCA_HSB   0
	PDCA memory interface. More...
#define	SYSCLK_HFLASHC_DATA   1
	Flash data interface. More...
#define	SYSCLK_HRAMC1_DATA   2
	HRAMC data interface. More...
#define	SYSCLK_USBC_DATA   3
	USBC DMA and FIFO interface. More...
#define	SYSCLK_CRCCU_DATA   4
	CRCCU data interface. More...
#define	SYSCLK_PBA_BRIDGE   5
	HSB<->PBA bridge. More...
#define	SYSCLK_PBB_BRIDGE   6
	HSB<->PBB bridge. More...
#define	SYSCLK_PBC_BRIDGE   7
	HSB<->PBC bridge. More...
#define	SYSCLK_PBD_BRIDGE   8
	HSB<->PBD bridge. More...
#define	SYSCLK_AESA_HSB   9
	Advanced Encryption Standard. More...

Clocks derived from the PBA clock
#define	SYSCLK_IISC   0
	IISC Controller. More...
#define	SYSCLK_SPI   1
	SPI Controller. More...
#define	SYSCLK_TC0   2
	Timer/Counter 0. More...
#define	SYSCLK_TC1   3
	Timer/Counter 1. More...
#define	SYSCLK_TWIM0   4
	TWI Master 0. More...
#define	SYSCLK_TWIS0   5
	TWI Slave 0. More...
#define	SYSCLK_TWIM1   6
	TWI Master 1. More...
#define	SYSCLK_TWIS1   7
	TWI Slave 1. More...
#define	SYSCLK_USART0   8
	USART 0. More...
#define	SYSCLK_USART1   9
	USART 1. More...
#define	SYSCLK_USART2   10
	USART 2. More...
#define	SYSCLK_USART3   11
	USART 3. More...
#define	SYSCLK_ADCIFE   12
	A/D Converter. More...
#define	SYSCLK_DACC   13
	D/A Converter. More...
#define	SYSCLK_ACIFC   14
	Analog Comparator. More...
#define	SYSCLK_GLOC   15
	Glue Logic Controller. More...
#define	SYSCLK_ABDACB   16
	ABDACB Controller. More...
#define	SYSCLK_TRNG   17
	TRNG Controller. More...
#define	SYSCLK_PARC   18
	PARC Controller. More...
#define	SYSCLK_CATB   19
	Capacitive Touch. More...
#define	SYSCLK_TWIM2   21
	TWI Master 2. More...
#define	SYSCLK_TWIM3   22
	TWI Master 3. More...
#define	SYSCLK_LCDCA   23
	LCD Controller. More...

Clocks derived from the PBB clock
#define	SYSCLK_HFLASHC_REGS   0
	Flash Controller registers. More...
#define	SYSCLK_HRAMC1_REGS   1
	HRAMC Controller registers. More...
#define	SYSCLK_HMATRIX   2
	HSB Matrix configuration. More...
#define	SYSCLK_PDCA_PB   3
	PDCA peripheral bus interface. More...
#define	SYSCLK_CRCCU_REGS   4
	CRCCU registers. More...
#define	SYSCLK_USBC_REGS   5
	USBC registers. More...
#define	SYSCLK_PEVC   6
	PEVC Controller. More...

Clocks derived from the PBC clock
#define	SYSCLK_PM   0
	PM configuration. More...
#define	SYSCLK_CHIPID   1
	CHIPID Controller. More...
#define	SYSCLK_SCIF   2
	System Control Interface. More...
#define	SYSCLK_FREQM   3
	Frequency Meter. More...
#define	SYSCLK_GPIO   4
	General-Purpose I/O. More...

Clocks derived from the PBD clock
#define	SYSCLK_BPM   0
	BPM configuration. More...
#define	SYSCLK_BSCIF   1
	BSCIF configuration. More...
#define	SYSCLK_AST   2
	Asynchronous Timer. More...
#define	SYSCLK_WDT   3
	Watchdog Timer. More...
#define	SYSCLK_EIC   4
	External Interrupt Controller. More...
#define	SYSCLK_PICOUART   5
	PICOUART. More...

Divided clock mask derived from the PBA clock
#define	PBA_DIVMASK_TIMER_CLOCK2   (1u << 0)
	TIMER_CLOCK2 mask. More...
#define	PBA_DIVMASK_TIMER_CLOCK3   (1u << 2)
	TIMER_CLOCK3 mask. More...
#define	PBA_DIVMASK_CLK_USART   (1u << 2)
	CLK_USART/DIV mask. More...
#define	PBA_DIVMASK_TIMER_CLOCK4   (1u << 4)
	TIMER_CLOCK4 mask. More...
#define	PBA_DIVMASK_TIMER_CLOCK5   (1u << 6)
	TIMER_CLOCK5 mask. More...
#define	PBA_DIVMASK_Msk   (0x7Fu << 0)
	Bitfield mask. More...

Querying the system clock and its derived clocks
The following functions may be used to query the current frequency of the system clock and the CPU and bus clocks derived from it. sysclk_get_main_hz() and sysclk_get_cpu_hz() can be assumed to be available on all platforms, although some platforms may define additional accessors for various chip-internal bus clocks. These are usually not intended to be queried directly by generic code.
uint32_t	sysclk_get_peripheral_bus_hz (const volatile void *module)
	Retrieves the current rate in Hz of the Peripheral Bus clock attached to the specified peripheral. More...
static uint32_t	sysclk_get_main_hz (void)
	Return the current rate in Hz of the main system clock. More...
static uint32_t	sysclk_get_cpu_hz (void)
	Return the current rate in Hz of the CPU clock. More...
static uint32_t	sysclk_get_hsb_hz (void)
	Return the current rate in Hz of the High-Speed Bus clock. More...
static uint32_t	sysclk_get_pba_hz (void)
	Return the current rate in Hz of the Peripheral Bus A clock. More...
static uint32_t	sysclk_get_pbb_hz (void)
	Return the current rate in Hz of the Peripheral Bus B clock. More...
static uint32_t	sysclk_get_pbc_hz (void)
	Return the current rate in Hz of the Peripheral Bus C clock. More...
static uint32_t	sysclk_get_pbd_hz (void)
	Return the current rate in Hz of the Peripheral Bus D clock. More...

Enabling and disabling synchronous clocks
void	sysclk_enable_pba_module (uint32_t module_index)
	Enable a module clock derived from the PBA clock. More...
void	sysclk_disable_pba_module (uint32_t module_index)
	Disable a module clock derived from the PBA clock. More...
void	sysclk_enable_pbb_module (uint32_t module_index)
	Enable a module clock derived from the PBB clock. More...
void	sysclk_disable_pbb_module (uint32_t module_index)
	Disable a module clock derived from the PBB clock. More...
void	sysclk_enable_peripheral_clock (const volatile void *module)
	Enable a peripheral's clock from its base address. More...
void	sysclk_disable_peripheral_clock (const volatile void *module)
	Disable a peripheral's clock from its base address. More...
static void	sysclk_enable_cpu_module (uint32_t module_index)
	Enable a module clock derived from the CPU clock. More...
static void	sysclk_disable_cpu_module (uint32_t module_index)
	Disable a module clock derived from the CPU clock. More...
static void	sysclk_enable_hsb_module (uint32_t module_index)
	Enable a module clock derived from the HSB clock. More...
static void	sysclk_disable_hsb_module (uint32_t module_index)
	Disable a module clock derived from the HSB clock. More...
static void	sysclk_enable_pbc_module (uint32_t module_index)
	Enable a module clock derived from the PBC clock. More...
static void	sysclk_disable_pbc_module (uint32_t module_index)
	Disable a module clock derived from the PBC clock. More...
static void	sysclk_enable_pbd_module (uint32_t module_index)
	Enable a module clock derived from the PBD clock. More...
static void	sysclk_disable_pbd_module (uint32_t module_index)
	Disable a module clock derived from the PBD clock. More...
static void	sysclk_enable_pba_divmask (uint32_t mask)
	Enable divided clock mask derived from the PBA clock. More...
static void	sysclk_disable_pba_divmask (uint32_t mask)
	Disable divided clock mask derived from the PBA clock. More...

System Clock Source and Prescaler configuration
void	sysclk_set_prescalers (uint32_t cpu_shift, uint32_t pba_shift, uint32_t pbb_shift, uint32_t pbc_shift, uint32_t pbd_shift)
	Set system clock prescaler configuration. More...
void	sysclk_set_source (uint32_t src)
	Change the source of the main system clock. More...

System Clock Initialization
void	sysclk_init (void)
	Initialize the synchronous clock system. More...

#define CONFIG_HCACHE_ENABLE   1

#define CONFIG_SYSCLK_CPU_DIV   0

Configuration symbol for dividing the CPU clock frequency by \(2^{CONFIG\_SYSCLK\_CPU\_DIV}\).

If this symbol is not defined, the CPU clock frequency is not divided.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_get_cpu_hz(), and sysclk_get_hsb_hz().

#define CONFIG_SYSCLK_INIT_CPUMASK

Configuration symbol for the CPU clocks enabled at power-on after the sysclock module has been initialized.

By default, all CPU clocks are left enabled, however to save power these can be automatically disabled by defining this value to a mask of SYSCLOCK_xxx settings.

If this symbol is not defined, then all CPU clocks are left enabled.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_init().

#define CONFIG_SYSCLK_INIT_HSBMASK

Configuration symbol for the HSB clocks enabled at power-on after the sysclock module has been initialized.

By default, all HSB clocks are left enabled, however to save power these can be automatically disabled by defining this value to a mask of SYSCLOCK_xxx settings.

If this symbol is not defined, then all HSB clocks are left enabled.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_init().

#define CONFIG_SYSCLK_INIT_PBAMASK

Configuration symbol for the PBA clocks enabled at power-on after the sysclock module has been initialized.

By default, all PBA clocks are left enabled, however to save power these can be automatically disabled by defining this value to a mask of SYSCLOCK_xxx settings.

If this symbol is not defined, then all PBA clocks are left enabled.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_init().

#define CONFIG_SYSCLK_INIT_PBBMASK

Configuration symbol for the PBB clocks enabled at power-on after the sysclock module has been initialized.

By default, all PBB clocks are left enabled, however to save power these can be automatically disabled by defining this value to a mask of SYSCLOCK_xxx settings.

If this symbol is not defined, then all PBB clocks are left enabled.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_init().

#define CONFIG_SYSCLK_INIT_PBCMASK

Configuration symbol for the PBC clocks enabled at power-on after the sysclock module has been initialized.

By default, all PBC clocks are left enabled, however to save power these can be automatically disabled by defining this value to a mask of SYSCLOCK_xxx settings.

If this symbol is not defined, then all PBC clocks are left enabled.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_init().

#define CONFIG_SYSCLK_INIT_PBDMASK

Configuration symbol for the PBD clocks enabled at power-on after the sysclock module has been initialized.

By default, all PBD clocks are left enabled, however to save power these can be automatically disabled by defining this value to a mask of SYSCLOCK_xxx settings.

If this symbol is not defined, then all PBD clocks are left enabled.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_init().

#define CONFIG_SYSCLK_PBA_DIV   0

Configuration symbol for dividing the PBA clock frequency by \(2^{CONFIG\_SYSCLK\_PBA\_DIV}\).

If this symbol is not defined, the PBA clock frequency is not divided.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_get_pba_hz().

#define CONFIG_SYSCLK_PBB_DIV   0

Configuration symbol for dividing the PBB clock frequency by \(2^{CONFIG\_SYSCLK\_PBB\_DIV}\).

If this symbol is not defined, the PBB clock frequency is not divided.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_get_pbb_hz().

#define CONFIG_SYSCLK_PBC_DIV   0

Configuration symbol for dividing the PBC clock frequency by \(2^{CONFIG\_SYSCLK\_PBC\_DIV}\).

If this symbol is not defined, the PBC clock frequency is not divided.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_get_pbc_hz().

#define CONFIG_SYSCLK_PBD_DIV   0

Configuration symbol for dividing the PBD clock frequency by \(2^{CONFIG\_SYSCLK\_PBD\_DIV}\).

If this symbol is not defined, the PBD clock frequency is not divided.

This symbol may be defined in conf_clock.h.

Referenced by sysclk_get_pbd_hz().

#define CONFIG_SYSCLK_SOURCE   SYSCLK_SRC_RCSYS

Referenced by sysclk_get_main_hz().

#define CONFIG_USBCLK_DIV

Configuration symbol for the USB generic clock divider setting.

Sets the clock division for the USB generic clock. If a USB clock source is selected with CONFIG_USBCLK_SOURCE, this configuration symbol must also be defined.

Define this as any value that does not exceed GENCLK_DIV_MAX, and which will give a 48 MHz clock frequency from the selected source.

#define CONFIG_USBCLK_SOURCE

Configuration symbol for the USB generic clock source.

Sets the clock source to use for the USB. The source must also be properly configured.

Define this to one of the USBCLK_SRC_xxx settings. Leave it undefined if USB is not required.

#define PBA_DIVMASK_CLK_USART   (1u << 2)

CLK_USART/DIV mask.

Referenced by sysclk_enable_peripheral_clock().

#define PBA_DIVMASK_Msk   (0x7Fu << 0)

Bitfield mask.

Referenced by sysclk_disable_peripheral_clock().

#define PBA_DIVMASK_TIMER_CLOCK2   (1u << 0)

TIMER_CLOCK2 mask.

Referenced by sysclk_enable_peripheral_clock().

#define PBA_DIVMASK_TIMER_CLOCK3   (1u << 2)

TIMER_CLOCK3 mask.

Referenced by sysclk_enable_peripheral_clock().

#define PBA_DIVMASK_TIMER_CLOCK4   (1u << 4)

TIMER_CLOCK4 mask.

Referenced by sysclk_enable_peripheral_clock().

#define PBA_DIVMASK_TIMER_CLOCK5   (1u << 6)

TIMER_CLOCK5 mask.

Referenced by sysclk_enable_peripheral_clock().

#define PM_CLK_GRP_CPU   0

Referenced by sysclk_disable_cpu_module(), and sysclk_enable_cpu_module().

#define PM_CLK_GRP_HSB   1

Referenced by sysclk_disable_hsb_module(), and sysclk_enable_hsb_module().

#define PM_CLK_GRP_PBA   2

Referenced by sysclk_disable_pba_module(), and sysclk_enable_pba_module().

#define PM_CLK_GRP_PBB   3

Referenced by sysclk_disable_pbb_module(), and sysclk_enable_pbb_module().

#define PM_CLK_GRP_PBC   4

Referenced by sysclk_disable_pbc_module(), and sysclk_enable_pbc_module().

#define PM_CLK_GRP_PBD   5

Referenced by sysclk_disable_pbd_module(), and sysclk_enable_pbd_module().

#define SYSCLK_ABDACB   16

ABDACB Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_ACIFC   14

Analog Comparator.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_ADCIFE   12

A/D Converter.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_AESA_HSB   9

Advanced Encryption Standard.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_AST   2

Asynchronous Timer.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_BPM   0

BPM configuration.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_BSCIF   1

BSCIF configuration.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_CATB   19

Capacitive Touch.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_CHIPID   1

CHIPID Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_CRCCU_DATA   4

CRCCU data interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_CRCCU_REGS   4

CRCCU registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_DACC   13

D/A Converter.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_EIC   4

External Interrupt Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_FREQM   3

Frequency Meter.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_GLOC   15

Glue Logic Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_GPIO   4

General-Purpose I/O.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_HFLASHC_DATA   1

Flash data interface.

Referenced by sysclk_enable_peripheral_clock().

#define SYSCLK_HFLASHC_REGS   0

Flash Controller registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_HMATRIX   2

HSB Matrix configuration.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_HRAMC1_DATA   2

HRAMC data interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_HRAMC1_REGS   1

HRAMC Controller registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_IISC   0

IISC Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_LCDCA   23

LCD Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_OCD   0

On-Chip Debug system.

#define SYSCLK_PARC   18

PARC Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PBA_BRIDGE   5

HSB<->PBA bridge.

Referenced by sysclk_disable_pba_module(), and sysclk_enable_pba_module().

#define SYSCLK_PBB_BRIDGE   6

HSB<->PBB bridge.

Referenced by sysclk_disable_pbb_module(), and sysclk_enable_pbb_module().

#define SYSCLK_PBC_BRIDGE   7

HSB<->PBC bridge.

#define SYSCLK_PBD_BRIDGE   8

HSB<->PBD bridge.

#define SYSCLK_PDCA_HSB   0

PDCA memory interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PDCA_PB   3

PDCA peripheral bus interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PEVC   6

PEVC Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PICOUART   5

PICOUART.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PM   0

PM configuration.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_SCIF   2

System Control Interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_SPI   1

SPI Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_SRC_DFLL   3

Digital Frequency Locked Loop.

Referenced by sysclk_get_main_hz(), and sysclk_init().

#define SYSCLK_SRC_OSC0   1

Oscillator 0.

Referenced by sysclk_get_main_hz(), and sysclk_init().

#define SYSCLK_SRC_PLL0   2

Phase Locked Loop 0.

Referenced by sysclk_get_main_hz(), and sysclk_init().

#define SYSCLK_SRC_RC1M   6

1 MHz RC oscillator

Referenced by sysclk_get_main_hz(), sysclk_init(), and sysclk_set_source().

#define SYSCLK_SRC_RC80M   4

80 MHz RC oscillator

Referenced by sysclk_get_main_hz(), and sysclk_init().

#define SYSCLK_SRC_RCFAST   5

4-8-12 MHz RC oscillator

Referenced by sysclk_get_main_hz(), and sysclk_init().

#define SYSCLK_SRC_RCSYS   0

System RC oscillator.

Referenced by sysclk_get_main_hz(), and sysclk_init().

#define SYSCLK_TC0   2

Timer/Counter 0.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TC1   3

Timer/Counter 1.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TRNG   17

TRNG Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TWIM0   4

TWI Master 0.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TWIM1   6

TWI Master 1.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TWIM2   21

TWI Master 2.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TWIM3   22

TWI Master 3.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TWIS0   5

TWI Slave 0.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_TWIS1   7

TWI Slave 1.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_USART0   8

USART 0.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_USART1   9

USART 1.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_USART2   10

USART 2.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_USART3   11

USART 3.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_USBC_DATA   3

USBC DMA and FIFO interface.

Referenced by sysclk_disable_peripheral_clock(), sysclk_enable_peripheral_clock(), and sysclk_enable_usb().

#define SYSCLK_USBC_REGS   5

USBC registers.

Referenced by sysclk_disable_peripheral_clock(), sysclk_enable_peripheral_clock(), and sysclk_enable_usb().

#define SYSCLK_WDT   3

Watchdog Timer.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define USBCLK_SRC_DFLL   GENCLK_SRC_DFLL

Use DFLL.

#define USBCLK_SRC_GCLKIN0   GENCLK_SRC_GCLKIN0

Use GCLKIN0.

#define USBCLK_SRC_OSC0   GENCLK_SRC_OSC0

Use OSC0.

#define USBCLK_SRC_PLL0   GENCLK_SRC_PLL0

Use PLL0.

#define USBCLK_STARTUP_TIMEOUT   (OSC0_STARTUP_TIMEOUT*(1000000/OSC_RCSYS_NOMINAL_HZ))

Number of us to wait for USB clock to start.

static void sysclk_disable_cpu_module ( uint32_t  module_index )

inlinestatic

Disable a module clock derived from the CPU clock.

Parameters

module_index

Index of the module clock in the CPUMASK register

References PM_CLK_GRP_CPU, and sysclk_priv_disable_module().

static void sysclk_disable_hsb_module ( uint32_t  module_index )

inlinestatic

Disable a module clock derived from the HSB clock.

Parameters

module_index

Index of the module clock in the HSBMASK register

References PM_CLK_GRP_HSB, and sysclk_priv_disable_module().

Referenced by sysclk_disable_pba_module(), sysclk_disable_pbb_module(), and sysclk_disable_peripheral_clock().

static void sysclk_disable_pba_divmask ( uint32_t  mask )

inlinestatic

Disable divided clock mask derived from the PBA clock.

Parameters

mask	mask of the divided clock in the PBADIVMASK register

Referenced by sysclk_disable_peripheral_clock().

void sysclk_disable_pba_module

(

uint32_t

module_index

)

Disable a module clock derived from the PBA clock.

Parameters

module_index

Index of the module clock in the PBAMASK register

References cpu_irq_restore(), cpu_irq_save(), PM_CLK_GRP_PBA, sysclk_disable_hsb_module(), SYSCLK_PBA_BRIDGE, and sysclk_priv_disable_module().

Referenced by sysclk_disable_peripheral_clock().

void sysclk_disable_pbb_module

(

uint32_t

module_index

)

Disable a module clock derived from the PBB clock.

Parameters

module_index

Index of the module clock in the PBBMASK register

References cpu_irq_restore(), cpu_irq_save(), PM_CLK_GRP_PBB, sysclk_disable_hsb_module(), SYSCLK_PBB_BRIDGE, and sysclk_priv_disable_module().

Referenced by sysclk_disable_peripheral_clock().

static void sysclk_disable_pbc_module ( uint32_t  module_index )

inlinestatic

Disable a module clock derived from the PBC clock.

Parameters

module_index

Index of the module clock in the PBAMASK register

References PM_CLK_GRP_PBC, and sysclk_priv_disable_module().

Referenced by sysclk_disable_peripheral_clock().

static void sysclk_disable_pbd_module ( uint32_t  module_index )

inlinestatic

Disable a module clock derived from the PBD clock.

Parameters

module_index

Index of the module clock in the PBAMASK register

References PM_CLK_GRP_PBD, and sysclk_priv_disable_module().

Referenced by sysclk_disable_peripheral_clock().

void sysclk_disable_peripheral_clock

(

const volatile void *

module

)

Disable a peripheral's clock from its base address.

Disables the clock to a peripheral, given its base address. If the peripheral has an associated clock on the HSB bus, this will be disabled also.

Parameters

module

Pointer to the module's base address.

References Assert, PBA_DIVMASK_Msk, PBADIV_CLKSRC_MASK, SYSCLK_ABDACB, SYSCLK_ACIFC, SYSCLK_ADCIFE, SYSCLK_AESA_HSB, SYSCLK_AST, SYSCLK_BPM, SYSCLK_BSCIF, SYSCLK_CATB, SYSCLK_CHIPID, SYSCLK_CRCCU_DATA, SYSCLK_CRCCU_REGS, SYSCLK_DACC, sysclk_disable_hsb_module(), sysclk_disable_pba_divmask(), sysclk_disable_pba_module(), sysclk_disable_pbb_module(), sysclk_disable_pbc_module(), sysclk_disable_pbd_module(), SYSCLK_EIC, SYSCLK_FREQM, SYSCLK_GLOC, SYSCLK_GPIO, SYSCLK_HFLASHC_REGS, SYSCLK_HMATRIX, SYSCLK_HRAMC1_DATA, SYSCLK_HRAMC1_REGS, SYSCLK_IISC, SYSCLK_LCDCA, SYSCLK_PARC, SYSCLK_PDCA_HSB, SYSCLK_PDCA_PB, SYSCLK_PEVC, SYSCLK_PICOUART, SYSCLK_PM, SYSCLK_SCIF, SYSCLK_SPI, SYSCLK_TC0, SYSCLK_TC1, SYSCLK_TRNG, SYSCLK_TWIM0, SYSCLK_TWIM1, SYSCLK_TWIM2, SYSCLK_TWIM3, SYSCLK_TWIS0, SYSCLK_TWIS1, SYSCLK_USART0, SYSCLK_USART1, SYSCLK_USART2, SYSCLK_USART3, SYSCLK_USBC_DATA, SYSCLK_USBC_REGS, and SYSCLK_WDT.

Referenced by flashcalw_picocache_disable(), spi_disable_clock(), wdt_disable(), and wdt_init().

void sysclk_disable_usb

(

void

)

Disable the USB generic clock.

References genclk_disable().

static void sysclk_enable_cpu_module ( uint32_t  module_index )

inlinestatic

Enable a module clock derived from the CPU clock.

Parameters

module_index

Index of the module clock in the CPUMASK register

References PM_CLK_GRP_CPU, and sysclk_priv_enable_module().

static void sysclk_enable_hsb_module ( uint32_t  module_index )

inlinestatic

Enable a module clock derived from the HSB clock.

Parameters

module_index

Index of the module clock in the HSBMASK register

References PM_CLK_GRP_HSB, and sysclk_priv_enable_module().

Referenced by sysclk_enable_pba_module(), sysclk_enable_pbb_module(), sysclk_enable_peripheral_clock(), and sysclk_enable_usb().

static void sysclk_enable_pba_divmask ( uint32_t  mask )

inlinestatic

Enable divided clock mask derived from the PBA clock.

Parameters

mask	mask of the divided clock in the PBADIVMASK register

Referenced by sysclk_enable_peripheral_clock().

void sysclk_enable_pba_module

(

uint32_t

module_index

)

Enable a module clock derived from the PBA clock.

Parameters

module_index

Index of the module clock in the PBAMASK register

References cpu_irq_restore(), cpu_irq_save(), PM_CLK_GRP_PBA, sysclk_enable_hsb_module(), SYSCLK_PBA_BRIDGE, and sysclk_priv_enable_module().

Referenced by sysclk_enable_peripheral_clock().

void sysclk_enable_pbb_module

(

uint32_t

module_index

)

Enable a module clock derived from the PBB clock.

Parameters

module_index

Index of the module clock in the PBBMASK register

References cpu_irq_restore(), cpu_irq_save(), PM_CLK_GRP_PBB, sysclk_enable_hsb_module(), SYSCLK_PBB_BRIDGE, and sysclk_priv_enable_module().

Referenced by sysclk_enable_peripheral_clock(), and sysclk_enable_usb().

static void sysclk_enable_pbc_module ( uint32_t  module_index )

inlinestatic

Enable a module clock derived from the PBC clock.

Parameters

module_index

Index of the module clock in the PBAMASK register

References PM_CLK_GRP_PBC, and sysclk_priv_enable_module().

Referenced by sysclk_enable_peripheral_clock().

static void sysclk_enable_pbd_module ( uint32_t  module_index )

inlinestatic

Enable a module clock derived from the PBD clock.

Parameters

module_index

Index of the module clock in the PBAMASK register

References PM_CLK_GRP_PBD, and sysclk_priv_enable_module().

Referenced by sysclk_enable_peripheral_clock().

void sysclk_enable_peripheral_clock

(

const volatile void *

module

)

Enable a peripheral's clock from its base address.

Enables the clock to a peripheral, given its base address. If the peripheral has an associated clock on the HSB bus, this will be enabled also.

Parameters

module

Pointer to the module's base address.

References Assert, PBA_DIVMASK_CLK_USART, PBA_DIVMASK_TIMER_CLOCK2, PBA_DIVMASK_TIMER_CLOCK3, PBA_DIVMASK_TIMER_CLOCK4, PBA_DIVMASK_TIMER_CLOCK5, SYSCLK_ABDACB, SYSCLK_ACIFC, SYSCLK_ADCIFE, SYSCLK_AESA_HSB, SYSCLK_AST, SYSCLK_BPM, SYSCLK_BSCIF, SYSCLK_CATB, SYSCLK_CHIPID, SYSCLK_CRCCU_DATA, SYSCLK_CRCCU_REGS, SYSCLK_DACC, SYSCLK_EIC, sysclk_enable_hsb_module(), sysclk_enable_pba_divmask(), sysclk_enable_pba_module(), sysclk_enable_pbb_module(), sysclk_enable_pbc_module(), sysclk_enable_pbd_module(), SYSCLK_FREQM, SYSCLK_GLOC, SYSCLK_GPIO, SYSCLK_HFLASHC_DATA, SYSCLK_HFLASHC_REGS, SYSCLK_HMATRIX, SYSCLK_HRAMC1_DATA, SYSCLK_HRAMC1_REGS, SYSCLK_IISC, SYSCLK_LCDCA, SYSCLK_PARC, SYSCLK_PDCA_HSB, SYSCLK_PDCA_PB, SYSCLK_PEVC, SYSCLK_PICOUART, SYSCLK_PM, SYSCLK_SCIF, SYSCLK_SPI, SYSCLK_TC0, SYSCLK_TC1, SYSCLK_TRNG, SYSCLK_TWIM0, SYSCLK_TWIM1, SYSCLK_TWIM2, SYSCLK_TWIM3, SYSCLK_TWIS0, SYSCLK_TWIS1, SYSCLK_USART0, SYSCLK_USART1, SYSCLK_USART2, SYSCLK_USART3, SYSCLK_USBC_DATA, SYSCLK_USBC_REGS, and SYSCLK_WDT.

Referenced by arch_ioport_init(), flashcalw_picocache_enable(), spi_enable_clock(), sysclk_init(), tmr_init(), usart_serial_init(), wdt_enable(), and wdt_init().

void sysclk_enable_usb

(

void

)

Enable the USB generic clock.

Precondition

The USB generic clock must be configured to 48MHz. CONFIG_USBCLK_SOURCE and CONFIG_USBCLK_DIV must be defined with proper configuration. The selected clock source must also be configured.

References CONFIG_USBCLK_DIV, CONFIG_USBCLK_SOURCE, genclk_enable_config(), sysclk_enable_hsb_module(), sysclk_enable_pbb_module(), SYSCLK_USBC_DATA, and SYSCLK_USBC_REGS.

static uint32_t sysclk_get_cpu_hz ( void  )

inlinestatic

Return the current rate in Hz of the CPU clock.

Todo:

This function assumes that the CPU always runs at the system clock frequency. We want to support at least two more scenarios: Fixed CPU/bus clock dividers (config symbols) and dynamic CPU/bus clock dividers (which may change at run time). Ditto for all the bus clocks.

Returns

Frequency of the CPU clock, in Hz.

References CONFIG_SYSCLK_CPU_DIV, and sysclk_get_main_hz().

Referenced by sysclk_init(), and wdt_set_ctrl().

static uint32_t sysclk_get_hsb_hz ( void  )

inlinestatic

Return the current rate in Hz of the High-Speed Bus clock.

Returns

Frequency of the High Speed Peripheral Bus clock, in Hz.

References CONFIG_SYSCLK_CPU_DIV, and sysclk_get_main_hz().

static uint32_t sysclk_get_main_hz ( void  )

inlinestatic

Return the current rate in Hz of the main system clock.

Todo:

This function assumes that the main clock source never changes once it's been set up, and that PLL0 always runs at the compile-time configured default rate. While this is probably the most common configuration, which we want to support as a special case for performance reasons, we will at some point need to support more dynamic setups as well.

References BOARD_OSC0_HZ, CONFIG_RCFAST_FRANGE, CONFIG_SYSCLK_SOURCE, dfll_get_default_rate, OSC_RC1M_NOMINAL_HZ, OSC_RC80M_NOMINAL_HZ, OSC_RCFAST12M_NOMINAL_HZ, OSC_RCFAST4M_NOMINAL_HZ, OSC_RCFAST8M_NOMINAL_HZ, OSC_RCSYS_NOMINAL_HZ, pll_get_default_rate, SYSCLK_SRC_DFLL, SYSCLK_SRC_OSC0, SYSCLK_SRC_PLL0, SYSCLK_SRC_RC1M, SYSCLK_SRC_RC80M, SYSCLK_SRC_RCFAST, and SYSCLK_SRC_RCSYS.

Referenced by sysclk_get_cpu_hz(), sysclk_get_hsb_hz(), sysclk_get_pba_hz(), sysclk_get_pbb_hz(), sysclk_get_pbc_hz(), and sysclk_get_pbd_hz().

static uint32_t sysclk_get_pba_hz ( void  )

inlinestatic

Return the current rate in Hz of the Peripheral Bus A clock.

Returns

Frequency of the Peripheral Bus A clock, in Hz.

References CONFIG_SYSCLK_PBA_DIV, and sysclk_get_main_hz().

Referenced by spi_master_setup_device(), and sysclk_get_peripheral_bus_hz().

static uint32_t sysclk_get_pbb_hz ( void  )

inlinestatic

Return the current rate in Hz of the Peripheral Bus B clock.

Returns

Frequency of the Peripheral Bus B clock, in Hz.

References CONFIG_SYSCLK_PBB_DIV, and sysclk_get_main_hz().

Referenced by sysclk_get_peripheral_bus_hz().

static uint32_t sysclk_get_pbc_hz ( void  )

inlinestatic

Return the current rate in Hz of the Peripheral Bus C clock.

Returns

Frequency of the Peripheral Bus C clock, in Hz.

References CONFIG_SYSCLK_PBC_DIV, and sysclk_get_main_hz().

Referenced by sysclk_get_peripheral_bus_hz().

static uint32_t sysclk_get_pbd_hz ( void  )

inlinestatic

Return the current rate in Hz of the Peripheral Bus D clock.

Returns

Frequency of the Peripheral Bus D clock, in Hz.

References CONFIG_SYSCLK_PBD_DIV, and sysclk_get_main_hz().

Referenced by sysclk_get_peripheral_bus_hz().

uint32_t sysclk_get_peripheral_bus_hz

(

const volatile void *

module

)

Retrieves the current rate in Hz of the Peripheral Bus clock attached to the specified peripheral.

Parameters

module

Pointer to the module's base address.

Returns

Frequency of the bus attached to the specified peripheral, in Hz.

References Assert, sysclk_get_pba_hz(), sysclk_get_pbb_hz(), sysclk_get_pbc_hz(), and sysclk_get_pbd_hz().

Referenced by tmr_init(), and usart_serial_init().

void sysclk_init

(

void

)

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.

References Assert, bpm_configure_power_scaling(), bpm_enable_fast_wakeup(), bpm_get_status(), BPM_PS_0, BPM_PS_1, BPM_PS_2, BPM_PSCM_CPU_NOT_HALT, CONFIG_SYSCLK_CPU_DIV, CONFIG_SYSCLK_INIT_CPUMASK, CONFIG_SYSCLK_INIT_HSBMASK, CONFIG_SYSCLK_INIT_PBAMASK, CONFIG_SYSCLK_INIT_PBBMASK, CONFIG_SYSCLK_INIT_PBCMASK, CONFIG_SYSCLK_INIT_PBDMASK, CONFIG_SYSCLK_PBA_DIV, CONFIG_SYSCLK_PBB_DIV, CONFIG_SYSCLK_PBC_DIV, CONFIG_SYSCLK_PBD_DIV, CONFIG_SYSCLK_SOURCE, cpu_irq_restore(), cpu_irq_save(), dfll_enable_config_defaults(), FLASH_FREQ_PS1_FWS_0_MAX_FREQ, FLASH_FREQ_PS1_FWS_1_MAX_FREQ, flash_set_bus_freq, osc_enable(), OSC_ID_OSC0, OSC_ID_RC1M, OSC_ID_RC80M, OSC_ID_RCFAST, osc_wait_ready(), pll_enable_config_defaults(), sysclk_enable_peripheral_clock(), sysclk_get_cpu_hz(), SYSCLK_INIT_MINIMAL_CPUMASK, SYSCLK_INIT_MINIMAL_HSBMASK, SYSCLK_INIT_MINIMAL_PBAMASK, SYSCLK_INIT_MINIMAL_PBBMASK, SYSCLK_INIT_MINIMAL_PBCMASK, SYSCLK_INIT_MINIMAL_PBDMASK, sysclk_set_prescalers(), sysclk_set_source(), SYSCLK_SRC_DFLL, SYSCLK_SRC_OSC0, SYSCLK_SRC_PLL0, SYSCLK_SRC_RC1M, SYSCLK_SRC_RC80M, SYSCLK_SRC_RCFAST, and SYSCLK_SRC_RCSYS.

Referenced by main().

void sysclk_priv_disable_module	(	uint32_t	bus_id,
		uint32_t	module_index
	)

Disable a maskable module clock.

Parameters

bus_id	Bus index, given by the PM_CLK_GRP_xxx definitions.
module_index	Index of the module to be disabled. This is the bit number in the corresponding xxxMASK register.

References cpu_irq_restore(), and cpu_irq_save().

Referenced by sysclk_disable_cpu_module(), sysclk_disable_hsb_module(), sysclk_disable_pba_module(), sysclk_disable_pbb_module(), sysclk_disable_pbc_module(), and sysclk_disable_pbd_module().

void sysclk_priv_enable_module	(	uint32_t	bus_id,
		uint32_t	module_index
	)

Enable a maskable module clock.

Parameters

bus_id	Bus index, given by the PM_CLK_GRP_xxx definitions.
module_index	Index of the module to be enabled. This is the bit number in the corresponding xxxMASK register.

References cpu_irq_restore(), and cpu_irq_save().

Referenced by sysclk_enable_cpu_module(), sysclk_enable_hsb_module(), sysclk_enable_pba_module(), sysclk_enable_pbb_module(), sysclk_enable_pbc_module(), and sysclk_enable_pbd_module().

void sysclk_set_prescalers	(	uint32_t	cpu_shift,
		uint32_t	pba_shift,
		uint32_t	pbb_shift,
		uint32_t	pbc_shift,
		uint32_t	pbd_shift
	)

Set system clock prescaler configuration.

This function will change the system clock prescaler configuration to match the parameters.

Note

The parameters to this function are device-specific.

Parameters

cpu_shift	The CPU clock will be divided by \(2^{cpu\_shift}\)
pba_shift	The PBA clock will be divided by \(2^{pba\_shift}\)
pbb_shift	The PBB clock will be divided by \(2^{pbb\_shift}\)
pbc_shift	The PBC clock will be divided by \(2^{pbc\_shift}\)
pbd_shift	The PBD clock will be divided by \(2^{pbd\_shift}\)

References Assert, cpu_irq_restore(), and cpu_irq_save().

Referenced by sysclk_init().

void sysclk_set_source

(

uint32_t

src

)

Change the source of the main system clock.

Parameters

src	The new system clock source. Must be one of the constants from the System Clock Sources section.

References Assert, cpu_irq_restore(), cpu_irq_save(), and SYSCLK_SRC_RC1M.

Referenced by sysclk_init().