Timers

This page documentation on the use of Timer Functions within SUBLIBinal.

Structures:

• Timer_Config

Enumerations:

• Timer_Type
• Clock_Divider

Functions available:

• initialize_Timer
• enable_Timer
• disable_Timer

Structures

Timer_Config

Definition:

    typedef struct TIMER_CONFIG {
        Timer_Type which_timer; 
        uint frequency;
        uint pbclk;
        void (*callback); 
        boolean enabled; 
    }Timer_Config; 

The Timer_Config structure accepts 5 different parameters.

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Enumerations

Timer_Type

typedef enum {
    Timer_1,
    Timer_2,
    Timer_3,
    Timer_4,
    Timer_5
} Timer_Type;

The timer type parameter is simply used to determine which timer in the microcontroller the library should configure.

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Clock_Divider

typedef enum {
    Div_1,
    Div_2,
    Div_4,
    Div_8,
    Div_16,
    Div_32,
    Div_64,
    Div_256
} Clock_Divider;

The Clock_Divider enumeration is a specification of clock dividers to use. This parameter is only used if you are trying to manually override the clock divider and period registers. Please note, if you are modifying the divider of Timer_1, only Div_1, Div_8, Div_64, and Div_256 are available for use. If you attempt to use another divider, it will be automatically upgraded to the closest available divider. For example, if you attempt to update to Div_2, the divider will be set to Div_8 instead. This is only true for Timer_1.

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Functions

initialize_Timer

Prototype
void initialize_Timer(Timer_Config config);

Description:
This function will initialize a timer. The function will attempt to generate appropriate dividers and periods to acquire the provided frequency. If the function can not achieve the required frequency, it will set parameters to as close as it can to the defined frequency. That is, if a frequency is supplied that is beyond the capabilities of the timer, it will be set for the maximum divider and the maximum period.

Parameters:

• config: config is a Timer_Config structure that has been filled out with all relevant parameters. All parameters should be filled out with the exception of the callback function, which is optional.

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disable_Timer

Prototype
void disable_Timer(Timer_Config config);

Description:
This function will disable a timer and its associated interrupts. The current TIMER value is not reset.

Parameters:

• config: config is a Timer_Config structure that has been filled out. The only parameter that must strictly be filled out for this function is the which_timer parameter so that the function can properly disable the correct timer.

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enable_Timer

Prototype
void enable_Timer(Timer_Config config);

Description:
This function will enable a timer and its associated interrupt. The interrupt is only activated if the callback function parameter is not NULL.

Parameters:

• config: config is a Timer_Config structure that has been filled out. The only parameter that must strictly be filled out for this function is the which_timer parameter so that the function can properly disable the correct timer.

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update_period_Timer

Prototype
void update_period_Timer(Timer_Config config, int period);

Description:
This function updates the period of a timer. This function will only touch the period register of a timer and will not change the divider or the enable of the timer. This function will also reset the current value in the timer register to avoid problems associated with timer overflow.

Parameters:

• config: config is a Timer_Config structure that has been filled out. The only parameter that must strictly be filled out for this function is the which_timer parameter so that the function can properly disable the correct timer.
• period: The period parameter should be an integer that you would like the timer period to be set to.

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update_frequency_Timer

Prototype
void update_frequency_Timer(Timer_Config config, float frequency);

Description:
This function will manually update the frequency of the supplied timer. Both the divider and the period of the timer will be changed. The calculation that update_frequency_Timer completes to determine divider and period is identical to that used by the initialize_Timer function, and behavior will be identical. The TIMER value will also be reset to 0 to avoid issues associated with timer overflow.

Parameters:

• config: config is a Timer_Config structure that has been filled out. The only parameter that must strictly be filled out for this function is the which_timer parameter so that the function can properly disable the correct timer.
• frequency:

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update_divider_Timer

Prototype:
void update_divider_Timer(Timer_Config config, Clock_Divider div);

Description:
The update_divider_Timer function will simply update the timer divider associated with the configuration parameter. This function will not modify the period register or the current TIMER value.

Parameters:

• config: config is a Timer_Config structure that has been filled out. The only parameter that must strictly be filled out for this function is the which_timer parameter so that the function can properly disable the correct timer.
• div:

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