Atmel Software Framework

System Clock Management
[Clock Management]


See Quick Start Guide for the System Clock Management service (UC3A0/UC3A1).

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:

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:

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

Defines

#define CONFIG_SYSCLK_CPU_DIV   0
 Configuration symbol for dividing the CPU clock frequency by $2^{CONFIG\_SYSCLK\_CPU\_DIV}$.
#define CONFIG_SYSCLK_INIT_CPUMASK
 Configuration symbol for the CPU clocks enabled at power-on after the sysclock module has been initialized.
#define CONFIG_SYSCLK_INIT_HSBMASK
 Configuration symbol for the HSB clocks enabled at power-on after the sysclock module has been initialized.
#define CONFIG_SYSCLK_INIT_HSBMASK
 Configuration symbol for the HSB clocks enabled at power-on after the sysclock module has been initialized.
#define CONFIG_SYSCLK_INIT_PBAMASK
 Configuration symbol for the PBA clocks enabled at power-on after the sysclock module has been initialized.
#define CONFIG_SYSCLK_INIT_PBBMASK
 Configuration symbol for the PBB clocks enabled at power-on after the sysclock module has been initialized.
#define CONFIG_SYSCLK_PBA_DIV   0
 Configuration symbol for dividing the PBA clock frequency by $2^{CONFIG\_SYSCLK\_PBA\_DIV}$.
#define CONFIG_SYSCLK_PBB_DIV   0
 Configuration symbol for dividing the PBB clock frequency by $2^{CONFIG\_SYSCLK\_PBB\_DIV}$.
#define CONFIG_SYSCLK_SOURCE   SYSCLK_SRC_RCSYS
#define CONFIG_USBCLK_DIV
 Configuration symbol for the USB generic clock divider setting.
#define CONFIG_USBCLK_SOURCE
 Configuration symbol for the USB generic clock source.
#define USBCLK_STARTUP_TIMEOUT   (OSC0_STARTUP_TIMEOUT*(1000000/AVR32_PM_RCOSC_FREQUENCY))
 Number of us to wait for USB clock to start.

Functions

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

Enabling and disabling synchronous clocks



void sysclk_enable_pbb_module (unsigned int index)
 Enable a module clock derived from the PBB clock.
void sysclk_disable_pbb_module (unsigned int index)
 Disable a module clock derived from the PBB clock.
static void sysclk_enable_cpu_module (unsigned int index)
 Enable a module clock derived from the CPU clock.
static void sysclk_disable_cpu_module (unsigned int index)
 Disable a module clock derived from the CPU clock.
static void sysclk_enable_hsb_module (unsigned int index)
 Enable a module clock derived from the HSB clock.
static void sysclk_disable_hsb_module (unsigned int index)
 Disable a module clock derived from the HSB clock.
static void sysclk_enable_pba_module (unsigned int index)
 Enable a module clock derived from the PBA clock.
static void sysclk_disable_pba_module (unsigned int index)
 Disable a module clock derived from the PBA clock.
static void sysclk_enable_peripheral_clock (const volatile void *module)
 Enable a peripheral's clock from its base address.
static void sysclk_disable_peripheral_clock (const volatile void *module)
 Disable a peripheral's clock from its base address.

System Clock Initialization



void sysclk_init (void)
 Initialize the synchronous clock system.

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.



static uint32_t sysclk_get_main_hz (void)
 Return the current rate in Hz of the main system clock.
static uint32_t sysclk_get_cpu_hz (void)
 Return the current rate in Hz of the CPU clock.
static uint32_t sysclk_get_hsb_hz (void)
 Return the current rate in Hz of the High-Speed Bus clock.
static uint32_t sysclk_get_pba_hz (void)
 Return the current rate in Hz of the Peripheral Bus A clock.
static uint32_t sysclk_get_pbb_hz (void)
 Return the current rate in Hz of the Peripheral Bus B clock.
static 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.

System Clock Source and Prescaler configuration



static void sysclk_set_prescalers (unsigned int cpu_shift, unsigned int pba_shift, unsigned int pbb_shift)
 Set system clock prescaler configuration.
static void sysclk_set_source (uint_fast8_t src)
 Change the source of the main system clock.

System Clock Sources



#define SYSCLK_SRC_RCSYS   0
 Use slow clock as main clock.
#define SYSCLK_SRC_OSC0   1
 Use OSC0 as main clock.
#define SYSCLK_SRC_PLL0   2
 Use PLL0 as main clock.

USB Clock Sources



#define USBCLK_SRC_OSC0   GENCLK_SRC_OSC0
 Use OSC0.
#define USBCLK_SRC_PLL0   GENCLK_SRC_PLL0
 Use PLL0.
#define USBCLK_SRC_PLL1   GENCLK_SRC_PLL1
 Use PLL1.

Clocks derived from the CPU clock



#define SYSCLK_OCD   AVR32_OCD_CLK_CPU
 On-Chip Debug system.
#define SYSCLK_SYSTIMER   AVR32_CORE_CLK_CPU_COUNT
 COUNT/COMPARE system registers.

Clocks derived from the HSB clock



#define SYSCLK_FLASHC_DATA   (AVR32_FLASHC_CLK_HSB % 32)
 Flash data interface.
#define SYSCLK_PBA_BRIDGE   (AVR32_HMATRIX_CLK_HSB_PBA_BRIDGE % 32)
 HSB<->PBA bridge.
#define SYSCLK_PBB_BRIDGE   (AVR32_HMATRIX_CLK_HSB_PBB_BRIDGE % 32)
 HSB<->PBB bridge.
#define SYSCLK_USBB_DATA   (AVR32_USBB_CLK_HSB % 32)
 USBB DMA and FIFO interface.
#define SYSCLK_MACB_DATA   (AVR32_MACB_CLK_HSB % 32)
 MACB DMA interface.
#define SYSCLK_PDCA_HSB   (AVR32_PDCA_CLK_HSB % 32)
 PDCA memory interface.
#define SYSCLK_EBI   (AVR32_EBI_CLK_HSB % 32)
 External Bus Interface.

Clocks derived from the PBA clock



#define SYSCLK_INTC   (AVR32_INTC_CLK_PBA % 32)
 Internal interrupt controller.
#define SYSCLK_GPIO   (AVR32_GPIO_CLK_PBA % 32)
 General-Purpose I/O.
#define SYSCLK_PDCA_PB   (AVR32_PDCA_CLK_PBA % 32)
 PDCA peripheral bus interface.
#define SYSCLK_PM   (AVR32_PM_CLK_PBA % 32)
 PM/RTC/EIM configuration.
#define SYSCLK_ADC   (AVR32_ADC_CLK_PBA % 32)
 A/D Converter.
#define SYSCLK_SPI0   (AVR32_SPI0_CLK_PBA % 32)
 SPI Controller 0.
#define SYSCLK_SPI1   (AVR32_SPI1_CLK_PBA % 32)
 SPI Controller 1.
#define SYSCLK_TWI   (AVR32_TWI_CLK_PBA % 32)
 TWI Controller.
#define SYSCLK_USART0   (AVR32_USART0_CLK_PBA % 32)
 USART 0.
#define SYSCLK_USART1   (AVR32_USART1_CLK_PBA % 32)
 USART 1.
#define SYSCLK_USART2   (AVR32_USART2_CLK_PBA % 32)
 USART 2.
#define SYSCLK_USART3   (AVR32_USART3_CLK_PBA % 32)
 USART 3.
#define SYSCLK_PWM   (AVR32_PWM_CLK_PBA % 32)
 PWM.
#define SYSCLK_SSC   (AVR32_SSC_CLK_PBA % 32)
 Synchronous Serial Controller.
#define SYSCLK_TC   (AVR32_TC_CLK_PBA % 32)
 Timer/Counter.
#define SYSCLK_DAC   (AVR32_ABDAC_CLK_PBA % 32)
 D/A Converter.

Clocks derived from the PBB clock



#define SYSCLK_HMATRIX   (AVR32_HMATRIX_CLK_PBB % 32)
 HSB Matrix configuration.
#define SYSCLK_USBB_REGS   (AVR32_USBB_CLK_PBB % 32)
 USBB registers.
#define SYSCLK_FLASHC_REGS   (AVR32_FLASHC_CLK_PBB % 32)
 Flash Controller registers.
#define SYSCLK_MACB_REGS   (AVR32_MACB_CLK_PBB % 32)
 MACB Controller registers.
#define SYSCLK_SMC_REGS   (AVR32_SMC_CLK_PBB % 32)
 Static Memory Controller registers.
#define SYSCLK_SDRAMC_REGS   (AVR32_SDRAMC_CLK_PBB % 32)
 SDRAM Controller registers.

#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.

#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.

#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.

#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.

#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.

#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.

#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.

#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.

#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 SYSCLK_ADC   (AVR32_ADC_CLK_PBA % 32)
#define SYSCLK_DAC   (AVR32_ABDAC_CLK_PBA % 32)
#define SYSCLK_EBI   (AVR32_EBI_CLK_HSB % 32)

External Bus Interface.

#define SYSCLK_FLASHC_DATA   (AVR32_FLASHC_CLK_HSB % 32)

Flash data interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_FLASHC_REGS   (AVR32_FLASHC_CLK_PBB % 32)

Flash Controller registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_GPIO   (AVR32_GPIO_CLK_PBA % 32)
#define SYSCLK_HMATRIX   (AVR32_HMATRIX_CLK_PBB % 32)
#define SYSCLK_INTC   (AVR32_INTC_CLK_PBA % 32)

Internal interrupt controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_MACB_DATA   (AVR32_MACB_CLK_HSB % 32)
#define SYSCLK_MACB_REGS   (AVR32_MACB_CLK_PBB % 32)

MACB Controller registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_OCD   AVR32_OCD_CLK_CPU

On-Chip Debug system.

Referenced by reset_do_soft_reset().

#define SYSCLK_PBA_BRIDGE   (AVR32_HMATRIX_CLK_HSB_PBA_BRIDGE % 32)

HSB<->PBA bridge.

#define SYSCLK_PBB_BRIDGE   (AVR32_HMATRIX_CLK_HSB_PBB_BRIDGE % 32)

HSB<->PBB bridge.

#define SYSCLK_PDCA_HSB   (AVR32_PDCA_CLK_HSB % 32)

PDCA memory interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PDCA_PB   (AVR32_PDCA_CLK_PBA % 32)

PDCA peripheral bus interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PM   (AVR32_PM_CLK_PBA % 32)

PM/RTC/EIM configuration.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_PWM   (AVR32_PWM_CLK_PBA % 32)
#define SYSCLK_SDRAMC_REGS   (AVR32_SDRAMC_CLK_PBB % 32)

SDRAM Controller registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_SMC_REGS   (AVR32_SMC_CLK_PBB % 32)

Static Memory Controller registers.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_SPI0   (AVR32_SPI0_CLK_PBA % 32)
#define SYSCLK_SPI1   (AVR32_SPI1_CLK_PBA % 32)
#define SYSCLK_SRC_OSC0   1

Use OSC0 as main clock.

Referenced by main(), and sysclk_get_main_hz().

#define SYSCLK_SRC_PLL0   2

Use PLL0 as main clock.

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

#define SYSCLK_SRC_RCSYS   0

Use slow clock as main clock.

Referenced by main(), and sysclk_get_main_hz().

#define SYSCLK_SSC   (AVR32_SSC_CLK_PBA % 32)

Synchronous Serial Controller.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_SYSTIMER   AVR32_CORE_CLK_CPU_COUNT

COUNT/COMPARE system registers.

#define SYSCLK_TC   (AVR32_TC_CLK_PBA % 32)
#define SYSCLK_TWI   (AVR32_TWI_CLK_PBA % 32)
#define SYSCLK_USART0   (AVR32_USART0_CLK_PBA % 32)
#define SYSCLK_USART1   (AVR32_USART1_CLK_PBA % 32)
#define SYSCLK_USART2   (AVR32_USART2_CLK_PBA % 32)
#define SYSCLK_USART3   (AVR32_USART3_CLK_PBA % 32)
#define SYSCLK_USBB_DATA   (AVR32_USBB_CLK_HSB % 32)

USBB DMA and FIFO interface.

Referenced by sysclk_disable_peripheral_clock(), and sysclk_enable_peripheral_clock().

#define SYSCLK_USBB_REGS   (AVR32_USBB_CLK_PBB % 32)
#define USBCLK_SRC_OSC0   GENCLK_SRC_OSC0

Use OSC0.

#define USBCLK_SRC_PLL0   GENCLK_SRC_PLL0

Use PLL0.

#define USBCLK_SRC_PLL1   GENCLK_SRC_PLL1

Use PLL1.

#define USBCLK_STARTUP_TIMEOUT   (OSC0_STARTUP_TIMEOUT*(1000000/AVR32_PM_RCOSC_FREQUENCY))

Number of us to wait for USB clock to start.


static void sysclk_disable_cpu_module ( unsigned int  index  )  [inline, static]

Disable a module clock derived from the CPU clock.

Parameters:
index Index of the module clock in the CPUMASK register

References sysclk_priv_disable_module().

static void sysclk_disable_hsb_module ( unsigned int  index  )  [inline, static]

Disable a module clock derived from the HSB clock.

Parameters:
index Index of the module clock in the HSBMASK register

References sysclk_priv_disable_module().

Referenced by sysclk_disable_peripheral_clock().

static void sysclk_disable_pba_module ( unsigned int  index  )  [inline, static]

Disable a module clock derived from the PBA clock.

Parameters:
index Index of the module clock in the PBAMASK register

References sysclk_priv_disable_module().

Referenced by sysclk_disable_peripheral_clock().

void sysclk_disable_pbb_module ( unsigned int  index  ) 

Disable a module clock derived from the PBB clock.

Parameters:
index Index of the module clock in the PBBMASK register

Referenced by nvram_write(), and sysclk_disable_peripheral_clock().

static void sysclk_disable_peripheral_clock ( const volatile void *  module  )  [inline, static]

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, SYSCLK_ADC, SYSCLK_DAC, sysclk_disable_hsb_module(), sysclk_disable_pba_module(), sysclk_disable_pbb_module(), SYSCLK_FLASHC_DATA, SYSCLK_FLASHC_REGS, SYSCLK_GPIO, SYSCLK_HMATRIX, SYSCLK_INTC, SYSCLK_MACB_DATA, SYSCLK_MACB_REGS, SYSCLK_PDCA_HSB, SYSCLK_PDCA_PB, SYSCLK_PM, SYSCLK_PWM, SYSCLK_SDRAMC_REGS, SYSCLK_SMC_REGS, SYSCLK_SPI0, SYSCLK_SPI1, SYSCLK_SSC, SYSCLK_TC, SYSCLK_TWI, SYSCLK_USART0, SYSCLK_USART1, SYSCLK_USART2, SYSCLK_USART3, SYSCLK_USBB_DATA, and SYSCLK_USBB_REGS.

void sysclk_disable_usb ( void   ) 

Disable the USB generic clock.

Referenced by otg_dual_disable(), and udd_disable().

static void sysclk_enable_cpu_module ( unsigned int  index  )  [inline, static]

Enable a module clock derived from the CPU clock.

Parameters:
index Index of the module clock in the CPUMASK register

References sysclk_priv_enable_module().

Referenced by reset_do_soft_reset().

static void sysclk_enable_hsb_module ( unsigned int  index  )  [inline, static]

Enable a module clock derived from the HSB clock.

Parameters:
index Index of the module clock in the HSBMASK register

References sysclk_priv_enable_module().

Referenced by memories_initialization(), and sysclk_enable_peripheral_clock().

static void sysclk_enable_pba_module ( unsigned int  index  )  [inline, static]

Enable a module clock derived from the PBA clock.

Parameters:
index Index of the module clock in the PBAMASK register

References sysclk_priv_enable_module().

Referenced by arch_ioport_init(), main(), spi_master_init(), sysclk_enable_peripheral_clock(), twi_master_setup(), uart_open(), and usart_spi_init().

void sysclk_enable_pbb_module ( unsigned int  index  ) 

Enable a module clock derived from the PBB clock.

Parameters:
index Index of the module clock in the PBBMASK register

Referenced by memories_initialization(), nvram_write(), and sysclk_enable_peripheral_clock().

static void sysclk_enable_peripheral_clock ( const volatile void *  module  )  [inline, static]

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, SYSCLK_ADC, SYSCLK_DAC, sysclk_enable_hsb_module(), sysclk_enable_pba_module(), sysclk_enable_pbb_module(), SYSCLK_FLASHC_DATA, SYSCLK_FLASHC_REGS, SYSCLK_GPIO, SYSCLK_HMATRIX, SYSCLK_INTC, SYSCLK_MACB_DATA, SYSCLK_MACB_REGS, SYSCLK_PDCA_HSB, SYSCLK_PDCA_PB, SYSCLK_PM, SYSCLK_PWM, SYSCLK_SDRAMC_REGS, SYSCLK_SMC_REGS, SYSCLK_SPI0, SYSCLK_SPI1, SYSCLK_SSC, SYSCLK_TC, SYSCLK_TWI, SYSCLK_USART0, SYSCLK_USART1, SYSCLK_USART2, SYSCLK_USART3, SYSCLK_USBB_DATA, and SYSCLK_USBB_REGS.

Referenced by ili9341_interface_init(), main(), memories_initialization(), and usart_serial_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.

Referenced by otg_dual_enable(), and udd_enable().

static uint32_t sysclk_get_cpu_hz ( void   )  [inline, static]

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 sysclk_get_main_hz().

Referenced by gfx_et024006dhu_init(), main(), memories_initialization(), run_sync_clock_test(), sensor_timestamp(), and usart_spi_setup_device().

static uint32_t sysclk_get_hsb_hz ( void   )  [inline, static]

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

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

References sysclk_get_main_hz().

static uint32_t sysclk_get_main_hz ( void   )  [inline, static]

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 CONFIG_SYSCLK_SOURCE, pll_get_default_rate, SYSCLK_SRC_OSC0, SYSCLK_SRC_PLL0, and SYSCLK_SRC_RCSYS.

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

static uint32_t sysclk_get_pba_hz ( void   )  [inline, static]

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

Returns:
Frequency of the Peripheral Bus A clock, in Hz.

References sysclk_get_main_hz().

Referenced by init_timer_isr(), main(), memories_initialization(), run_sync_clock_test(), sysclk_get_peripheral_bus_hz(), tc_init(), twi_master_setup(), uart_config(), and uart_open().

static uint32_t sysclk_get_pbb_hz ( void   )  [inline, static]

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

Returns:
Frequency of the Peripheral Bus B clock, in Hz.

References sysclk_get_main_hz().

Referenced by gfx_et024006dhu_init(), memories_initialization(), run_sync_clock_test(), and sysclk_get_peripheral_bus_hz().

static uint32_t sysclk_get_peripheral_bus_hz ( const volatile void *  module  )  [inline, static]

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(), and sysclk_get_pbb_hz().

Referenced by spi_master_setup_device(), 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.

Referenced by main(), run_sync_clock_test(), and sensor_platform_init().

void sysclk_priv_disable_module ( unsigned int  bus_id,
unsigned int  module_index 
)

Disable a maskable module clock.

For internal use only.

Parameters:
bus_id Bus index, given by the AVR32_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(), and sysclk_disable_pba_module().

void sysclk_priv_enable_module ( unsigned int  bus_id,
unsigned int  module_index 
)

Enable a maskable module clock.

For internal use only.

Parameters:
bus_id Bus index, given by the AVR32_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(), and sysclk_enable_pba_module().

static void sysclk_set_prescalers ( unsigned int  cpu_shift,
unsigned int  pba_shift,
unsigned int  pbb_shift 
) [inline, static]

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 $2^{pbb\_shift}$

References Assert.

Referenced by main().

static void sysclk_set_source ( uint_fast8_t  src  )  [inline, static]

Change the source of the main system clock.

Precondition:
The appropriate Flash Wait state must be set previously.
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_PLL0.

Referenced by main().

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