Functions

General Description

Functions
cy_en_sysclk_status_t	Cy_SysClk_WcoEnable (uint32_t timeoutus)
	Enables the WCO. More...
bool	Cy_SysClk_WcoOkay (void)
	Reports the status of the WCO_OK bit. More...
void	Cy_SysClk_WcoDisable (void)
	Disables the WCO. More...
void	Cy_SysClk_WcoBypass (cy_en_wco_bypass_modes_t bypass)
	Sets whether the WCO is bypassed or not. More...

Function Documentation

Cy_SysClk_WcoEnable()

cy_en_sysclk_status_t Cy_SysClk_WcoEnable

(

uint32_t

timeoutus

)

Enables the WCO.

Parameters

timeoutus

amount of time in microseconds to wait for the WCO to be ready. If WCO is not ready, WCO is stopped. To avoid waiting for WCO ready set this to 0, and manually check if WCO is okay using Cy_SysClk_WcoOkay.

Returns

Error / status code:
CY_SYSCLK_SUCCESS - WCO successfully enabled
CY_SYSCLK_TIMEOUT - Timeout waiting for WCO to stabilize

Function Usage

    /* Scenario: The WCO needs to source the backup clock for the real-time clock
                 operation. Timeout of 2ms is tolerable. The WCO pins are configured
                 using the gpio driver(SRSS_WCO_IN_PIN, SRSS_WCO_OUT_PIN). */
 
    /* Enable the WCO with a timeout of 2000 microseconds */
    if(CY_SYSCLK_SUCCESS != Cy_SysClk_WcoEnable(2000))
    {
        /* Insert error handling */
    }
 
    /* Set the backup clock source to WCO */
    Cy_SysClk_ClkBakSetSource(CY_SYSCLK_BAK_IN_WCO);

Cy_SysClk_WcoOkay()

bool Cy_SysClk_WcoOkay

(

void

)

Reports the status of the WCO_OK bit.

Returns

true = okay
false = not okay

Function Usage

    /* Scenario: The WCO needs to source the backup clock for the real-time
                 clock operation. It needs to be enabled in a non-blocking
                 manner. The WCO pins are configured using the gpio driver
                 (SRSS_WCO_IN_PIN, SRSS_WCO_OUT_PIN). */
 
    /* Enable the WCO without timeout */
    (void)Cy_SysClk_WcoEnable(0UL);
    while(!Cy_SysClk_WcoOkay())
    {
        /* WCO is not yet ready. Perform some other operation. */
    }
 
    /* Set the backup clock source to WCO */
    Cy_SysClk_ClkBakSetSource(CY_SYSCLK_BAK_IN_WCO);

Cy_SysClk_WcoDisable()

void Cy_SysClk_WcoDisable

(

void

)

Disables the WCO.

Note

We need to set writable option using Cy_RTC_WriteEnable before disabling WCO, and clear writable option after disabling WCO.

Function Usage

    /* Scenario: LFCLK needs to be sourced by the PILO instead of the WCO. All
                 peripherals clocked by the LFCLK are disabled and the Watchdog
                 timer (WDT) is unlocked. */
 
    /* Disable the WCO */
    Cy_SysClk_WcoDisable();
 
    /* Enable the PILO */
    Cy_SysClk_PiloEnable();
 
    /* Set the LFCLK source to the PILO */
    Cy_SysClk_ClkLfSetSource(CY_SYSCLK_CLKLF_IN_PILO);

Cy_SysClk_WcoBypass()

void Cy_SysClk_WcoBypass

(

cy_en_wco_bypass_modes_t

bypass

)

Sets whether the WCO is bypassed or not.

If it is bypassed, then a 32-kHz clock must be provided on the wco_out pin.

Parameters

bypass

cy_en_wco_bypass_modes_t

Function Usage

    /* Scenario: An external watch crystal oscillator needs to be connected to
                 the WCO pins instead of a watch crystal. This signal needs
                 to source the backup clock for the real-time clock operation.
                 The WCO pins are configured using the gpio driver
                 (SRSS_WCO_IN_PIN, SRSS_WCO_OUT_PIN). */
 
    /* WCO bypassed mode - 32768 kHz square-wave supplied through SRSS_WCO_OUT_PIN pin */
    Cy_SysClk_WcoBypass(CY_SYSCLK_WCO_BYPASSED);
 
    /* Enable the WCO with a timeout of 2000 microsecond */
    if(CY_SYSCLK_SUCCESS != Cy_SysClk_WcoEnable(2000UL))
    {
        /* Insert error handling */
    }
 
    /* Set the backup clock source to WCO */
    Cy_SysClk_ClkBakSetSource(CY_SYSCLK_BAK_IN_WCO);