CMU - Clock Management Unit
Description
Clock management unit (CMU) Peripheral API.
This module contains functions for the CMU peripheral of Silicon Labs 32-bit MCUs and SoCs. The CMU module controls oscillators, clocks gates, clock multiplexers, pre-scalers, calibration modules and wait-states.
Data Structures |
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struct | CMU_LFXOInit_TypeDef |
LFXO initialization structure.
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struct | CMU_HFXOInit_TypeDef |
HFXO initialization structure.
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Functions |
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void | CMU_UpdateWaitStates (uint32_t freq, int vscale) |
Configure various wait states to switch to a certain frequency and a certain voltage scale.
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uint32_t | getHfxoTuningMode (void) |
Get the HFXO tuning mode.
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void | setHfxoTuningMode (uint32_t mode) |
Set the HFXO tuning mode.
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void | syncReg (uint32_t mask) |
Wait for an ongoing sync of register(s) to low-frequency domain to complete.
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CMU_AUXHFRCOFreq_TypeDef | CMU_AUXHFRCOBandGet (void) |
Get the current AUXHFRCO frequency.
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void | CMU_AUXHFRCOBandSet ( CMU_AUXHFRCOFreq_TypeDef setFreq) |
Set AUXHFRCO calibration for the selected target frequency.
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uint32_t | CMU_Calibrate (uint32_t HFCycles, CMU_Osc_TypeDef reference) |
Calibrate the clock.
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void | CMU_CalibrateConfig (uint32_t downCycles, CMU_Osc_TypeDef downSel, CMU_Osc_TypeDef upSel) |
Configure the clock calibration.
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uint32_t | CMU_CalibrateCountGet (void) |
Get the calibration count register.
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CMU_ClkDiv_TypeDef | CMU_ClockDivGet ( CMU_Clock_TypeDef clock) |
Get the clock divisor/prescaler.
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void | CMU_ClockDivSet ( CMU_Clock_TypeDef clock, CMU_ClkDiv_TypeDef div) |
Set the clock divisor/prescaler.
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void | CMU_ClockEnable ( CMU_Clock_TypeDef clock, bool enable) |
Enable/disable a clock.
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uint32_t | CMU_ClockFreqGet ( CMU_Clock_TypeDef clock) |
Get the clock frequency for a clock point.
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uint32_t | CMU_ClockPrescGet ( CMU_Clock_TypeDef clock) |
Get the clock prescaler.
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void | CMU_ClockPrescSet ( CMU_Clock_TypeDef clock, CMU_ClkPresc_TypeDef presc) |
Set the clock prescaler.
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CMU_Select_TypeDef | CMU_ClockSelectGet ( CMU_Clock_TypeDef clock) |
Get the currently selected reference clock used for a clock branch.
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void | CMU_ClockSelectSet ( CMU_Clock_TypeDef clock, CMU_Select_TypeDef ref) |
Select the reference clock/oscillator used for a clock branch.
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uint16_t | CMU_LF_ClockPrecisionGet ( CMU_Clock_TypeDef clock) |
Gets the precision (in PPM) of the specified low frequency clock branch.
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void | CMU_FreezeEnable (bool enable) |
CMU low frequency register synchronization freeze control.
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CMU_HFRCOFreq_TypeDef | CMU_HFRCOBandGet (void) |
Get the current HFRCO frequency.
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void | CMU_HFRCOBandSet ( CMU_HFRCOFreq_TypeDef setFreq) |
Set the HFRCO calibration for the selected target frequency.
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void | CMU_HFXOAutostartEnable (uint32_t userSel, bool enEM0EM1Start, bool enEM0EM1StartSel) |
Enable or disable HFXO autostart.
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void | CMU_HFXOInit (const CMU_HFXOInit_TypeDef *hfxoInit) |
Set HFXO control registers.
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uint32_t | CMU_LCDClkFDIVGet (void) |
Get the LCD framerate divisor (FDIV) setting.
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void | CMU_LCDClkFDIVSet (uint32_t div) |
Set the LCD framerate divisor (FDIV) setting.
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void | CMU_LFXOInit (const CMU_LFXOInit_TypeDef *lfxoInit) |
Set LFXO control registers.
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void | CMU_LFXOPrecisionSet (uint16_t precision) |
Sets LFXO's crystal precision, in PPM.
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void | CMU_OscillatorEnable ( CMU_Osc_TypeDef osc, bool enable, bool wait) |
Enable/disable oscillator.
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uint32_t | CMU_OscillatorTuningGet ( CMU_Osc_TypeDef osc) |
Get the oscillator frequency tuning setting.
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void | CMU_OscillatorTuningSet ( CMU_Osc_TypeDef osc, uint32_t val) |
Set the oscillator frequency tuning control.
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bool | CMU_OscillatorTuningWait ( CMU_Osc_TypeDef osc, CMU_HFXOTuningMode_TypeDef mode) |
Wait for the oscillator tuning optimization.
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bool | CMU_OscillatorTuningOptimize ( CMU_Osc_TypeDef osc, CMU_HFXOTuningMode_TypeDef mode, bool wait) |
Start and optionally wait for the oscillator tuning optimization.
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bool | CMU_PCNTClockExternalGet (unsigned int instance) |
Determine if the currently selected PCNTn clock used is external or LFBCLK.
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void | CMU_PCNTClockExternalSet (unsigned int instance, bool external) |
Select the PCNTn clock.
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void | CMU_CalibrateCont (bool enable) |
Configure continuous calibration mode.
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void | CMU_CalibrateStart (void) |
Start calibration.
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void | CMU_CalibrateStop (void) |
Stop the calibration counters.
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uint32_t | CMU_DivToLog2 ( CMU_ClkDiv_TypeDef div) |
Convert dividend to logarithmic value.
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void | CMU_IntClear (uint32_t flags) |
Clear one or more pending CMU interrupts.
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void | CMU_IntDisable (uint32_t flags) |
Disable one or more CMU interrupts.
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void | CMU_IntEnable (uint32_t flags) |
Enable one or more CMU interrupts.
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uint32_t | CMU_IntGet (void) |
Get pending CMU interrupts.
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uint32_t | CMU_IntGetEnabled (void) |
Get enabled and pending CMU interrupt flags.
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void | CMU_IntSet (uint32_t flags) |
Set one or more pending CMU interrupts.
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void | CMU_Lock (void) |
Lock the CMU to protect some of its registers against unintended modification.
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uint32_t | CMU_Log2ToDiv (uint32_t log2) |
Convert logarithm of 2 prescaler to division factor.
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void | CMU_Unlock (void) |
Unlock the CMU so that writing to locked registers again is possible.
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CMU_HFRCOFreq_TypeDef | CMU_HFRCOFreqGet (void) |
Get the current HFRCO frequency.
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void | CMU_HFRCOFreqSet ( CMU_HFRCOFreq_TypeDef setFreq) |
Set HFRCO calibration for the selected target frequency.
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CMU_AUXHFRCOFreq_TypeDef | CMU_AUXHFRCOFreqGet (void) |
Get the current AUXHFRCO frequency.
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void | CMU_AUXHFRCOFreqSet ( CMU_AUXHFRCOFreq_TypeDef setFreq) |
Set AUXHFRCO calibration for the selected target frequency.
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uint32_t | CMU_PrescToLog2 (uint32_t presc) |
Convert prescaler dividend to a logarithmic value.
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Macros |
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#define | cmuClkDiv_1 1 |
Clock divisors.
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#define | cmuClkDiv_2 2 |
Divide clock by 2.
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#define | cmuClkDiv_4 4 |
Divide clock by 4.
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#define | cmuClkDiv_8 8 |
Divide clock by 8.
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#define | cmuClkDiv_16 16 |
Divide clock by 16.
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#define | cmuClkDiv_32 32 |
Divide clock by 32.
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#define | cmuClkDiv_64 64 |
Divide clock by 64.
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#define | cmuClkDiv_128 128 |
Divide clock by 128.
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#define | cmuClkDiv_256 256 |
Divide clock by 256.
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#define | cmuClkDiv_512 512 |
Divide clock by 512.
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#define | cmuClkDiv_1024 1024 |
Divide clock by 1024.
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#define | cmuClkDiv_2048 2048 |
Divide clock by 2048.
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#define | cmuClkDiv_4096 4096 |
Divide clock by 4096.
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#define | cmuClkDiv_8192 8192 |
Divide clock by 8192.
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#define | cmuClkDiv_16384 16384 |
Divide clock by 16384.
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#define | cmuClkDiv_32768 32768 |
Divide clock by 32768.
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#define | CMU_HFRCO_MIN cmuHFRCOFreq_1M0Hz |
HFRCO minimum frequency.
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#define | CMU_HFRCO_MAX cmuHFRCOFreq_38M0Hz |
HFRCO maximum frequency.
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#define | CMU_AUXHFRCO_MIN cmuAUXHFRCOFreq_1M0Hz |
AUXHFRCO minimum frequency.
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#define | CMU_AUXHFRCO_MAX cmuAUXHFRCOFreq_38M0Hz |
AUXHFRCO maximum frequency.
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#define | CMU_LFXOINIT_DEFAULT |
Default LFXO initialization values.
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#define | CMU_LFXOINIT_EXTERNAL_CLOCK |
Default LFXO initialization for external clock.
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#define | CMU_HFXOINIT_DEFAULT |
Default HFXO initialization values for Platform 2 devices, which contain a separate HFXOCTRL register.
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#define | CMU_HFXOINIT_EXTERNAL_CLOCK |
Init of HFXO with external clock.
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Typedefs |
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typedef uint32_t | CMU_ClkDiv_TypeDef |
Clock divider configuration.
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typedef uint32_t | CMU_ClkPresc_TypeDef |
Clockprescaler configuration.
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Function Documentation
◆ CMU_UpdateWaitStates()
void CMU_UpdateWaitStates | ( | uint32_t |
freq,
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int |
vscale
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Configure various wait states to switch to a certain frequency and a certain voltage scale.
This function will set up the necessary flash, bus, and RAM wait states. Updating the wait state configuration must be done before increasing the clock frequency and it must be done after decreasing the clock frequency. Updating the wait state configuration must be done before core voltage is decreased and it must be done after a core voltage is increased.
- Parameters
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[in] freq
The core clock frequency to configure wait-states. [in] vscale
The voltage scale to configure wait-states. Expected values are 0 or 2, higher number is lower voltage.
- 0 = 1.2 V (VSCALE2)
- 2 = 1.0 V (VSCALE0)
◆ getHfxoTuningMode()
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inline |
Get the HFXO tuning mode.
- Returns
- The current HFXO tuning mode from the HFXOCTRL register.
◆ setHfxoTuningMode()
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inline |
Set the HFXO tuning mode.
- Parameters
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[in] mode
The new HFXO tuning mode. This can be HFXO_TUNING_MODE_AUTO or HFXO_TUNING_MODE_CMD.
◆ syncReg()
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inline |
Wait for an ongoing sync of register(s) to low-frequency domain to complete.
- Parameters
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[in] mask
A bitmask corresponding to SYNCBUSY register defined bits, indicating registers that must complete any ongoing synchronization.
◆ CMU_AUXHFRCOBandGet()
CMU_AUXHFRCOFreq_TypeDef CMU_AUXHFRCOBandGet | ( | void |
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Get the current AUXHFRCO frequency.
- Returns
- AUXHFRCO frequency.
◆ CMU_AUXHFRCOBandSet()
void CMU_AUXHFRCOBandSet | ( | CMU_AUXHFRCOFreq_TypeDef |
setFreq
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Set AUXHFRCO calibration for the selected target frequency.
- Parameters
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[in] setFreq
AUXHFRCO frequency to set
◆ CMU_Calibrate()
uint32_t CMU_Calibrate | ( | uint32_t |
HFCycles,
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CMU_Osc_TypeDef |
reference
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Calibrate the clock.
Run a calibration for HFCLK against a selectable reference clock. See the reference manual, CMU chapter, for more details.
- Note
- This function will not return until the calibration measurement is completed.
- Parameters
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[in] HFCycles
The number of HFCLK cycles to run the calibration. Increasing this number increases precision but the calibration will take more time. [in] reference
The reference clock used to compare HFCLK.
- Returns
- The number of ticks the reference clock after HFCycles ticks on the HF clock.
◆ CMU_CalibrateConfig()
void CMU_CalibrateConfig | ( | uint32_t |
downCycles,
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CMU_Osc_TypeDef |
downSel,
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CMU_Osc_TypeDef |
upSel
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Configure the clock calibration.
Configure a calibration for a selectable clock source against another selectable reference clock. See the reference manual, CMU chapter, for more details.
- Note
- After configuration, a call to CMU_CalibrateStart() is required and the resulting calibration value can be read out with the CMU_CalibrateCountGet() function call.
- Parameters
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[in] downCycles
The number of downSel clock cycles to run the calibration. Increasing this number increases precision but the calibration will take more time. [in] downSel
The clock, which will be counted down downCycles. [in] upSel
The reference clock; the number of cycles generated by this clock will be counted and added up and the result can be given with the CMU_CalibrateCountGet() function call.
◆ CMU_CalibrateCountGet()
uint32_t CMU_CalibrateCountGet | ( | void |
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Get the calibration count register.
- Note
- If continuous calibration mode is active, calibration busy will almost always be off and only the value needs to be read. In a normal case, this function call is triggered by the CALRDY interrupt flag.
- Returns
- The calibration count, the number of UPSEL clocks in the period of DOWNSEL oscillator clock cycles configured by a previous write operation to CMU->CALCNT.
◆ CMU_ClockDivGet()
CMU_ClkDiv_TypeDef CMU_ClockDivGet | ( | CMU_Clock_TypeDef |
clock
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Get the clock divisor/prescaler.
- Parameters
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[in] clock
A clock point to get the divisor/prescaler for. Notice that not all clock points have a divisor/prescaler. See the CMU overview in the reference manual.
- Returns
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The current clock point divisor/prescaler. 1 is returned if
clock
specifies a clock point without a divisor/prescaler.
◆ CMU_ClockDivSet()
void CMU_ClockDivSet | ( | CMU_Clock_TypeDef |
clock,
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CMU_ClkDiv_TypeDef |
div
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Set the clock divisor/prescaler.
- Note
- If setting an LF clock prescaler, synchronization into the low-frequency domain is required. If the same register is modified before a previous update has completed, this function will stall until the previous synchronization has completed. See CMU_FreezeEnable() for a suggestion on how to reduce the stalling time in some use cases.
HFCLKLE prescaler is automatically modified when peripherals with clock domain HFBUSCLK is chosen based on the maximum HFLE frequency allowed.
- Parameters
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[in] clock
Clock point to set divisor/prescaler for. Notice that not all clock points have a divisor/prescaler. See the CMU overview in the reference manual. [in] div
The clock divisor to use (<= cmuClkDiv_512).
◆ CMU_ClockEnable()
void CMU_ClockEnable | ( | CMU_Clock_TypeDef |
clock,
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bool |
enable
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Enable/disable a clock.
In general, module clocking is disabled after a reset. If a module clock is disabled, the registers of that module are not accessible and reading from such registers may return undefined values. Writing to registers of clock-disabled modules has no effect. Avoid accessing module registers of a module with a disabled clock.
- Note
- If enabling/disabling an LF clock, synchronization into the low-frequency domain is required. If the same register is modified before a previous update has completed, this function will stall until the previous synchronization has completed. See CMU_FreezeEnable() for a suggestion on how to reduce the stalling time in some use cases.
HFCLKLE prescaler is automatically modified when peripherals with clock domain HFBUSCLK is chosen based on the maximum HFLE frequency allowed.
- Parameters
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[in] clock
The clock to enable/disable. Notice that not all defined clock points have separate enable/disable control. See the CMU overview in the reference manual. [in] enable
- true - enable specified clock.
- false - disable specified clock.
◆ CMU_ClockFreqGet()
uint32_t CMU_ClockFreqGet | ( | CMU_Clock_TypeDef |
clock
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) |
Get the clock frequency for a clock point.
- Parameters
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[in] clock
A clock point to fetch the frequency for.
- Returns
- The current frequency in Hz.
◆ CMU_ClockPrescGet()
uint32_t CMU_ClockPrescGet | ( | CMU_Clock_TypeDef |
clock
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) |
Get the clock prescaler.
- Parameters
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[in] clock
A clock point to get the prescaler for. Notice that not all clock points have a prescaler. See the CMU overview in the reference manual.
- Returns
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The prescaler value of the current clock point. 0 is returned if
clock
specifies a clock point without a prescaler.
◆ CMU_ClockPrescSet()
void CMU_ClockPrescSet | ( | CMU_Clock_TypeDef |
clock,
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CMU_ClkPresc_TypeDef |
presc
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Set the clock prescaler.
- Note
- If setting an LF clock prescaler, synchronization into the low-frequency domain is required. If the same register is modified before a previous update has completed, this function will stall until the previous synchronization has completed. See CMU_FreezeEnable() for a suggestion on how to reduce the stalling time in some use cases.
HFCLKLE prescaler is automatically modified when peripherals with clock domain HFBUSCLK is chosen based on the maximum HFLE frequency allowed.
- Parameters
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[in] clock
A clock point to set the prescaler for. Notice that not all clock points have a prescaler. See the CMU overview in the reference manual. [in] presc
The clock prescaler.
◆ CMU_ClockSelectGet()
CMU_Select_TypeDef CMU_ClockSelectGet | ( | CMU_Clock_TypeDef |
clock
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) |
Get the currently selected reference clock used for a clock branch.
- Parameters
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[in] clock
Clock branch to fetch selected ref. clock for. One of:
- Returns
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The reference clock used for clocking the selected branch,
cmuSelect_Error
if invalid
clock
provided.
◆ CMU_ClockSelectSet()
void CMU_ClockSelectSet | ( | CMU_Clock_TypeDef |
clock,
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CMU_Select_TypeDef |
ref
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) |
Select the reference clock/oscillator used for a clock branch.
Notice that if a selected reference is not enabled prior to selecting its use, it will be enabled and this function will wait for the selected oscillator to be stable. It will however NOT be disabled if another reference clock is selected later.
This feature is particularly important if selecting a new reference clock for the clock branch clocking the core. Otherwise, the system may halt.
- Note
- HFCLKLE prescaler is automatically modified when peripherals with clock domain HFBUSCLK is chosen based on the maximum HFLE frequency allowed.
- Parameters
-
[in] clock
A clock branch to select reference clock for. One of: [in] ref
A reference selected for clocking. See the reference manual for details about references available for a specific clock branch.
◆ CMU_LF_ClockPrecisionGet()
uint16_t CMU_LF_ClockPrecisionGet | ( | CMU_Clock_TypeDef |
clock
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) |
Gets the precision (in PPM) of the specified low frequency clock branch.
- Parameters
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[in] clock
Clock branch.
- Returns
- Precision, in PPM, of the specified clock branch.
- Note
- This function is only for internal usage.
- The current implementation of this function is used to determine if the clock has a precision <= 500 ppm or not (which is the minimum required for BLE). Future version of this function should provide more accurate precision numbers to allow for further optimizations from the stacks.
◆ CMU_FreezeEnable()
void CMU_FreezeEnable | ( | bool |
enable
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) |
CMU low frequency register synchronization freeze control.
Some CMU registers require synchronization into the low-frequency (LF) domain. The freeze feature allows for several such registers to be modified before passing them to the LF domain simultaneously (which takes place when the freeze mode is disabled).
Another use case for this feature is using an API (such as the CMU API) for modifying several bit fields consecutively in the same register. If freeze mode is enabled during this sequence, stalling can be avoided.
- Note
- When enabling freeze mode, this function will wait for all current ongoing CMU synchronization to LF domain to complete (normally synchronization will not be in progress.) However, for this reason, when using freeze mode, modifications of registers requiring LF synchronization should be done within one freeze enable/disable block to avoid unnecessary stalling.
- Parameters
-
[in] enable
- true - enable freeze, modified registers are not propagated to the LF domain
- false - disable freeze, modified registers are propagated to the LF domain