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@CHIP-RTOS C Library - RTOS API


RTX_FineTickInit

Initialize data required by the RTX_GetFineTick and RTX_GetTick_us API.

void RTX_FineTickInit (void);

Return Value

-- none --

Comments

This function is implicitly called by the RTX_GetFineTick and RTX_GetTick_us API if it has not already been called explicitly by the user.

Interrupts are enabled within the @Chip-RTOS API call made here.   Consequently, it may be advisable to call this function from your application program's initialization area to avoid this action during your real-time operation.   After a single call here, this one-shot function performs no operation on subsequent calls since its job is already done (unless the power mode has been adjusted).

Some global constants are initialized by this API.   This data is used internally by the other C-library functions, but may also be of general use to the application.   (The names given these have been preceded with an underscore to avoid name space conflicts.)   These constants are listed here.

unsigned long far   *_pRti_Tick ;

    This pointer references the 32 bit Real-Time Interrupt up counter internal to the @Chip-RTOS.  This location should never be written to from outside the @Chip-RTOS!    Note that for reliable reads, interrupts must be momentarily masked if both 16 bit halves are sampled.

unsigned int   _RTI_kHz ;

    The Real-Time Interrupt rate in kHz.  (For SC1x systems this value will always be 1.)

unsigned int   _us_per_RTI ;

    Number of microseconds per Real-Time Interrupt.   (For SC1x systems this value will always be 1000.)

unsigned int   _Timer2_Limit ;

    Hardware TIMER2 ticks per Real-Time Interrupt.

unsigned int   _Timer2Tick_per_us ;

    Number of hardware TIMER2 ticks per microsecond.

SC1x3/SC2x Comments

For some selected Real-Time Interrupt rates, the _us_per_RTI and _Timer2Tick_per_us values computed here will not be accurate.   This is the case for any RTI rates which do not divide 1000 an integral number of times, e.g. 15 kHz.   Consequently the RTX_GetTick_us API should not be used for such configurations, since the computation done within that API relies on the accuracy of these constants.

See Also

RTOS API

This library function invokes a RTOS software interrupt.   Refer to this RTOS API function's documentation for more details.

Related Topics

RTX API   Overview

Supported since or modified in @CHIP-RTOS version

    SC12SC13SC11SC1x3SC2x
    V1.20V1.20V1.20V1.05V1.00

Supported by @CHIP-RTOS C Library since version

    CLIB
    V2.04

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