RTC Interface

Driver API for RTC (plib_rtc_16count.h) More...

Data Structures
struct	RTC_16COUNT_OBJECT
	RTC 16-bit counter object structure. More...

Typedefs
typedef uint32_t	RTC_16COUNT_INT_MASK
	RTC 16-bit counter interrupt mask type.
typedef void(*	RTC_16COUNT_CALLBACK) (RTC_16COUNT_INT_MASK int_cause)
	RTC callback function type for 16-bit counter mode.

Functions
void	RTC_16COUNT_Initialize (void)
	Initializes the RTC in 16-bit counter mode. This sets up the interrupt handler for RTC 16-bit counter mode.
void	RTC_16COUNT_SoftwareReset (void)
	Performs a software reset of the RTC module.
void	RTC_16COUNT_SetMode (void)
	Configures the RTC to operate in 16-bit counter mode.
void	RTC_16COUNT_Enable (void)
	Enables the RTC 16-bit counter.
void	RTC_16COUNT_Disable (void)
	Disables the RTC 16-bit counter.
void	RTC_16COUNT_SetPrescaler (uint16_t prescaler)
	Configures the RTC prescaler.
void	RTC_16COUNT_CorrectFrequency (int8_t correction)
	Applies frequency correction to the RTC.
void	RTC_16COUNT_EnableCountSync (void)
	Enables synchronization of the RTC counter.
void	RTC_16COUNT_DisableCountSync (void)
	Disables synchronization of the RTC counter.
void	RTC_16COUNT_SetCounter (uint16_t count)
	Sets the current value of the RTC counter.
void	RTC_16COUNT_SetCompare0 (uint16_t compare_value)
	Sets the compare value for Compare 0.
void	RTC_16COUNT_SetCompare1 (uint16_t compare_value)
	Sets the compare value for Compare 1.
void	RTC_16COUNT_SetPeriod (uint16_t period_value)
	Sets the period value for the RTC counter.
uint32_t	RTC_16COUNT_GetCounter (void)
	Gets the current value of the RTC counter.
uint16_t	RTC_16COUNT_GetPeriod (void)
	Gets the value of the RTC period register.
void	RTC_16COUNT_EnableInterrupt (RTC_16COUNT_INT_MASK interrupt_mask)
	Enables a specific RTC interrupt mask.
void	RTC_16COUNT_DisableInterrupt (RTC_16COUNT_INT_MASK interrupt_mask)
	Disables a specific RTC interrupt mask.
void	RTC_16COUNT_SetCallbackHandler (RTC_16COUNT_CALLBACK callback)
	Registers a callback function for RTC interrupts.
void	RTC_SetInterruptHandler (void(*callback)(void))
	Registers the RTC interrupt callback function. The callback function can be called from main.c for direct callback registration.

Variables
RTC_16COUNT_CALLBACK	RTC_16COUNT_OBJECT::timer16bit_callback
	Callback function pointer for RTC 16-bit counter interrupts.
RTC_16COUNT_INT_MASK	RTC_16COUNT_OBJECT::timer16int_cause
	Interrupt cause mask for the last RTC interrupt.

Description

Driver API for RTC (plib_rtc_16count.h)

Usage Example

The following example demonstrates typical usage of the RTC peripheral:

/*******************************************************************************
* @file configure_rtc_16count.c
*
* @brief Example usage for RTC 16-bit Counter Mode configuration.
*
* @details
* This Example usage demonstrates how to configure and use the RTC peripheral in
* 16-bit counter mode (Mode 1). The counter counts from 0 up to the period
* value and generates an overflow interrupt when it wraps around.
*
* How it works:
* 1. Initialize and reset the RTC peripheral.
* 2. Set Mode to 16-bit counter and configure the prescaler to divide the
*    RTC clock (0xA = divide by 1024).
* 3. Set the Period register (0x20) - the counter wraps at this value.
* 4. Set Compare0 (0x10) - triggers a compare match interrupt at the midpoint.
* 5. Set the initial counter value (0x9).
* 6. Enable overflow and compare match interrupts, register a callback.
* 7. Enable RTC and configure NVIC for interrupt handling.
*
* Available interrupts:
* - RTC_MODE1_INTENSET_OVF_Msk  : Counter overflow (counter reached period)
* - RTC_MODE1_INTENSET_CMP0_Msk : Compare 0 match
* - RTC_MODE1_INTENSET_CMP1_Msk : Compare 1 match
*
* Users can modify the prescaler, period, compare, and counter values as
* needed. Add application-specific logic inside the callback or main loop
* to handle the interrupt events.
*******************************************************************************/
 
#include "plib_rtc_16count.h"
#include <pic32c.h>
#include <stdint.h>
#include <stdbool.h>
 
static volatile bool overflow_event = false;
static volatile bool mid_point_event = false;
 
/* RTC 16 bit counter callback function */
void RTC_EventCallback(RTC_16COUNT_INT_MASK int_cause){
    if ((int_cause & RTC_MODE1_INTENSET_CMP0_Msk) == RTC_MODE1_INTENSET_CMP0_Msk)
    {
        /* User operation (e.g., toggle GPIO, schedule task) */  
        mid_point_event = true;
    }
    if ((int_cause & RTC_MODE1_INTENSET_OVF_Msk) == RTC_MODE1_INTENSET_OVF_Msk)
    {
        /* User operation (e.g., toggle GPIO, schedule task) */  
        overflow_event = true;
    }
}
 
int32_t configure_rtc_16count(void)
{
    /* Configuration constants */
    const uint16_t prescaler = 0xAU;
    const uint16_t period = 0x20U;
    const uint16_t compare = 0x10U;
    const uint16_t start_counter = 0x9U;
    const uint32_t priority = 3U;
 
    RTC_16COUNT_Initialize();
    RTC_16COUNT_SoftwareReset();
    RTC_16COUNT_SetMode();
    RTC_16COUNT_SetPrescaler(prescaler);
    RTC_16COUNT_SetPeriod(period);
    RTC_16COUNT_SetCompare0(compare);
    RTC_16COUNT_SetCounter(start_counter);
    RTC_16COUNT_EnableInterrupt(RTC_MODE1_INTENSET_OVF_Msk);
    RTC_16COUNT_EnableInterrupt(RTC_MODE1_INTENSET_CMP0_Msk);
    RTC_16COUNT_SetCallbackHandler(&RTC_EventCallback);
    RTC_16COUNT_Enable();
 
    __DMB();
    __enable_irq();
    NVIC_SetPriority(RTC_IRQn, priority);
    NVIC_EnableIRQ(RTC_IRQn);
 
    return 0;
}

Typedef Documentation

RTC_16COUNT_CALLBACK

typedef void(* RTC_16COUNT_CALLBACK) (RTC_16COUNT_INT_MASK int_cause)

RTC callback function type for 16-bit counter mode.

RTC_16COUNT_INT_MASK

typedef uint32_t RTC_16COUNT_INT_MASK

RTC 16-bit counter interrupt mask type.

Function Documentation

RTC_16COUNT_CorrectFrequency()

void RTC_16COUNT_CorrectFrequency

(

int8_t

correction

)

Applies frequency correction to the RTC.

Parameters

correction

Signed correction value.

RTC_16COUNT_Disable()

void RTC_16COUNT_Disable

(

void

)

Disables the RTC 16-bit counter.

Returns

void

RTC_16COUNT_DisableCountSync()

void RTC_16COUNT_DisableCountSync

(

void

)

Disables synchronization of the RTC counter.

Returns

void

RTC_16COUNT_DisableInterrupt()

void RTC_16COUNT_DisableInterrupt

(

RTC_16COUNT_INT_MASK

interrupt_mask

)

Disables a specific RTC interrupt mask.

Parameters

interrupt_mask

Interrupt mask to disable.

RTC_16COUNT_Enable()

void RTC_16COUNT_Enable

(

void

)

Enables the RTC 16-bit counter.

Returns

void

RTC_16COUNT_EnableCountSync()

void RTC_16COUNT_EnableCountSync

(

void

)

Enables synchronization of the RTC counter.

Returns

void

RTC_16COUNT_EnableInterrupt()

void RTC_16COUNT_EnableInterrupt

(

RTC_16COUNT_INT_MASK

interrupt_mask

)

Enables a specific RTC interrupt mask.

Parameters

interrupt_mask

Interrupt mask to enable.

RTC_16COUNT_GetCounter()

uint32_t RTC_16COUNT_GetCounter

(

void

)

Gets the current value of the RTC counter.

Returns

Current counter value.

RTC_16COUNT_GetPeriod()

uint16_t RTC_16COUNT_GetPeriod

(

void

)

Gets the value of the RTC period register.

Returns

Period register value.

RTC_16COUNT_Initialize()

void RTC_16COUNT_Initialize

(

void

)

Initializes the RTC in 16-bit counter mode. This sets up the interrupt handler for RTC 16-bit counter mode.

Returns

void

RTC_16COUNT_SetCallbackHandler()

void RTC_16COUNT_SetCallbackHandler

(

RTC_16COUNT_CALLBACK

callback

)

Registers a callback function for RTC interrupts.

Parameters

callback

Pointer to the callback function.

RTC_16COUNT_SetCompare0()

void RTC_16COUNT_SetCompare0

(

uint16_t

compare_value

)

Sets the compare value for Compare 0.

Parameters

compare_value

Compare 0 match value.

Returns

void

RTC_16COUNT_SetCompare1()

void RTC_16COUNT_SetCompare1

(

uint16_t

compare_value

)

Sets the compare value for Compare 1.

Parameters

compare_value

Compare 1 match value.

Returns

void

RTC_16COUNT_SetCounter()

void RTC_16COUNT_SetCounter

(

uint16_t

count

)

Sets the current value of the RTC counter.

Parameters

count

Counter value to set.

Returns

void

RTC_16COUNT_SetMode()

void RTC_16COUNT_SetMode

(

void

)

Configures the RTC to operate in 16-bit counter mode.

Returns

void

RTC_16COUNT_SetPeriod()

void RTC_16COUNT_SetPeriod

(

uint16_t

period_value

)

Sets the period value for the RTC counter.

Parameters

period_value

Period register value.

Returns

void

RTC_16COUNT_SetPrescaler()

void RTC_16COUNT_SetPrescaler

(

uint16_t

prescaler

)

Configures the RTC prescaler.

This function sets the prescaler field in the RTC CTRLA register. The input parameter is NOT the actual division factor (e.g., 1024), but the encoded value corresponding to the PRESCALER bit field

For example:

• To achieve a division by 1024, pass the encoded value corresponding to DIV1024 (e.g., 0xB as per datasheet definition).

Note

The RTC must be disabled before calling this function.

Parameters

prescaler

Encoded PRESCALER field value (not the division factor).

RTC_16COUNT_SoftwareReset()

void RTC_16COUNT_SoftwareReset

(

void

)

Performs a software reset of the RTC module.

Returns

void

RTC_SetInterruptHandler()

void RTC_SetInterruptHandler

(

void(*)(void)

callback

)

Registers the RTC interrupt callback function. The callback function can be called from main.c for direct callback registration.

Parameters

[in]

callback

Pointer to user-defined RTC interrupt handler function. Pass NULL to unregister any existing callback.

Variable Documentation

timer16bit_callback

RTC_16COUNT_CALLBACK RTC_16COUNT_OBJECT::timer16bit_callback

Callback function pointer for RTC 16-bit counter interrupts.

timer16int_cause

RTC_16COUNT_INT_MASK RTC_16COUNT_OBJECT::timer16int_cause

Interrupt cause mask for the last RTC interrupt.