Functions

Functions
cy_en_sysclk_status_t	Cy_SysClk_ClkLfSetSource (cy_en_sysclk_clklf_src_t source)
	Selects the source of the LFCLK. More...
uint32_t	Cy_SysClk_ClkLfGetFrequency (void)
	Reports the frequency of the LFCLK. More...
__STATIC_INLINE cy_en_sysclk_clklf_src_t	Cy_SysClk_ClkLfGetSource (void)
	Reports the source of the LFCLK. More...

Detailed Description

Function Documentation

Cy_SysClk_ClkLfSetSource()

cy_en_sysclk_status_t Cy_SysClk_ClkLfSetSource

(

cy_en_sysclk_clklf_src_t

source

)

Selects the source of the LFCLK.

Parameters

source

cy_en_sysclk_clklf_src_t

Returns

Error / status code cy_en_sysclk_status_t :
CY_SYSCLK_SUCCESS - the source is successfully set;
CY_SYSCLK_INVALID_STATE - the selected clock source is not enabled or does not working;
CY_SYSCLK_BAD_PARAM - the source parameter is invalid.

Note

Applicable to PSOC4 HVMS/PA only.

Warning

The Watchdog timer should be unlocked before set source of the LFCLK. Call the Cy_WDT_Unlock() API to unlock the WDT.

Note

It takes about (3 + 1) LF clock cycles of the new selected clock to switch away from the old clock to the new clock. Do not disable the original clock during this time.

If a clock source is disabled while selected, then the clock merely stops to all sources that receive it. In such a scenario, the disabled clock must be re-enabled, prior to switching FROM this clock source.

This function is not re-entrant.

Function Usage

    /* The Watchdog timer should be unlocked before PILO being enabled. */
    Cy_WDT_Unlock();

    /* Enable the PILO */
    Cy_SysClk_PiloEnable();

    /* Now switch the LFCLK source to PILO */
    if (CY_SYSCLK_SUCCESS != Cy_SysClk_ClkLfSetSource(CY_SYSCLK_CLKLF_IN_PILO))
    {
        /* Insert error handling */
    }

Cy_SysClk_ClkLfGetFrequency()

uint32_t Cy_SysClk_ClkLfGetFrequency

(

void

)

Reports the frequency of the LFCLK.

Returns

The frequency is in Hz units and equals 0 in case of an unknown frequency.

Note

The reported value may be zero, which indicates the frequency is unknown.

Applicable to PSOC4 HVMS/PA only.

Function Usage

    uint32_t clkLfFreq = 0;

    /* The Watchdog timer should be unlocked before PILO being enabled. */
    Cy_WDT_Unlock();

    /* Enable the PILO */
    Cy_SysClk_PiloEnable();

    /* Enable the ILO */
    Cy_SysClk_IloEnable();

    /* Now switch the LFCLK source to PILO */
    cy_en_sysclk_status_t retVal = Cy_SysClk_ClkLfSetSource(CY_SYSCLK_CLKLF_IN_PILO);
    if (CY_SYSCLK_SUCCESS == retVal)
    {
        /* LFCLK clock frequency should match with PILO frequency */
        clkLfFreq = Cy_SysClk_ClkLfGetFrequency();
    }

    /* Now switch the LFCLK source to ILO */
    retVal = Cy_SysClk_ClkLfSetSource(CY_SYSCLK_CLKLF_IN_ILO);
    if (CY_SYSCLK_SUCCESS == retVal)
    {
        /* LFCLK clock frequency should match with ILO frequency */
        clkLfFreq = Cy_SysClk_ClkLfGetFrequency();
    }

Cy_SysClk_ClkLfGetSource()

__STATIC_INLINE cy_en_sysclk_clklf_src_t Cy_SysClk_ClkLfGetSource

(

void

)

Reports the source of the LFCLK.

Returns

cy_en_sysclk_clklf_src_t :
CY_SYSCLK_CLKLF_IN_ILO - ILO - Internal Low Frequency Oscillator.
CY_SYSCLK_CLKLF_IN_PILO - PILO - Precision Internal Low Frequency Oscillator.

Note

Only applicable for PSOC4 HVMS/PA.

Function Usage

    /* The Watchdog timer should be unlocked before PILO being enabled. */
    Cy_WDT_Unlock();

    /* Enable the PILO */
    Cy_SysClk_PiloEnable();

    /* Now switch the LFCLK source to PILO */
    if (CY_SYSCLK_SUCCESS != Cy_SysClk_ClkLfSetSource(CY_SYSCLK_CLKLF_IN_PILO))
    {
        /* Insert error handling */
    }