Timer Functions

Functions

This page contains information about the functions used within the timer peripheral library of SUBLIBinal. Please use the following list to read more about individual timer functions available.

Timer Functions:

• initialize_Timer
• disable_Timer
• enable_Timer
• update_period_Timer
• update_frequency_Timer
• update_divider_Timer

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initialize_Timer

Prototype
Error 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.

Return:

• 'ERR_INVALID_ENUM': This error code will be thrown if the enumeration of the parameter 'config.which_timer' is not a valid timer enumeration.
• 'ERR_TIMER_FREQ_UNATTAINABLE': This code will be thrown when a frequency is specified that the timer can not achieve (this will occur if the frequency is too low).
• 'ERR_NO_ERR': There is no error and the function completed successfully.

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disable_Timer

Prototype
Error disable_Timer(Timer_Type which_timer);

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

Parameters:

• which_timer: This is a 'Timer_Type' enumeration specifying which timer to use.

Return:

• 'ERR_INVALID_ENUM': This error code will be thrown if the enumeration of the parameter 'which_timer' is not a valid timer enumeration.
• 'ERR_NO_ERR': The function completed normally.

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enable_Timer

Prototype
Error enable_Timer(Timer_Type which_timer);

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:

• which_timer: This is a 'Timer_Type' enumeration specifying which timer to use.

Return:

• 'ERR_INVALID_ENUM': This error code will be thrown if the enumeration of the parameter 'which_timer' is not a valid timer enumeration.
• 'ERR_NO_ERR': The function completed normally.

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update_period_Timer

Prototype
Error update_period_Timer(Timer_Type which_timer, 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:

• which_timer: This is a 'Timer_Type' enumeration specifying which timer to use.
• period: The period parameter should be an integer that you would like the timer period to be set to.

Return:
This function may return the error code 'ERR_INVALID_PERIOD' if the supplied period parameter exceeds 65535 or falls below 1. Any value outside of these ranges is considered an invalid period value. Otherwise, the function will return 'ERR_NO_ERR'.

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update_frequency_Timer

Prototype
Error update_frequency_Timer(Timer_Type which_timer, 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:

• which_timer: This is a 'Timer_Type' enumeration specifying which timer to use.
• frequency: The frequency parameter is a value that the specified timer should be set to interrupt at.

Return:
This function may return an error code. The only error codes that this function may return will be 'ERR_TIMER_FREQ_UNATTAINABLE'. This code will be thrown when a frequency is specified that the timer can not achieve (this will occur if the frequency is too low). If this error occurs, the library will assign the divider to 256 and the period to 65535 (maximum period). Otherwise, this function will return 'ERR_NO_ERR' on successful completion.

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update_divider_Timer

Prototype:
Error update_divider_Timer(Timer_Type which_timer, 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:

• which_timer: This is a 'Timer_Type' enumeration specifying which timer to use.
• div: The div parameter is used to specify what the divider should be. Please note, if you are specifying a new divider for Timer_1, it will automatically upgrade to the closest divider available for timer 1. That is, if you attempt to update to Div_2, it will instead update to Div_8.

Return:
This function may return the error code 'ERR_INVALID_DIVIDER' if a divider is specified for timer_1 that timer_1 can not achieve. Timer 1 may only accept dividers of Div_1, Div_8, Div_64, or Div_256. Any other divider will cause an error. Otherwise, this function will return 'ERR_NO_ERR'.

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