RTC

RTC Demo Code Support List

This chapter introduces the details of the RTC demo code.

RTC Demo for Comparator Function

The description of RTC demo code 1 is shown in the following table.

RTC Demo Code 1 Description

Demo 1	rtc_demo.c
Sample Purpose	Demonstrate RTC comparator function.
File Path	sdk\src\sample\io_demo\rtc\comparator\rtc_demo.c
Function Entry	rtc_demo()
Expected Result	Print string rtc_handler in Debug Analyzer every 1536ms.

RTC Demo for Overflow Function

The description of RTC demo code 2 is shown in the following table.

RTC Demo Code 2 Description

Demo 2	rtc_overflow_demo.c
Sample Purpose	Demonstrate RTC count overflow function.
File Path	sdk\src\sample\io_demo\rtc\overflow\rtc_overflow_demo.c
Function Entry	rtc_overflow_demo()
Expected Result	For RTL87x3D, rtc_handler function is executed every 134217.728s. For RTL87x3E, rtc_handler function is executed every 524.288s.

RTC Demo for Tick Function

The description of RTC demo code 3 is shown in the following table.

RTC Demo Code 3 Description

Demo 3	rtc_tick_demo.c
Sample Purpose	Demonstrate RTC tick function.
File Path	sdk\src\sample\io_demo\rtc\tick\rtc_tick_demo.c
Function Entry	rtc_tick_demo()
Expected Result	rtc_handler function is executed every 31.25us.

RTC Demo for Calendar Function

The description of RTC demo code 4 is shown in the following table.

RTC Demo Code 4 Description

Demo 4	rtc_clock_demo.c rtc_clock_demo.h
Sample Purpose	Demonstrate RTC calendar functionality.
File Path	sdk\src\sample\io_demo\rtc\clock\rtc_clock_demo.c sdk\src\sample\io_demo\rtc\clock\rtc_clock_demo.h
Function Entry	rtc_clock_demo()
Expected Result	Press the Reset button on the EVB, string rtc_clock_sys_update: year 2022, month 9, day 29, hour 0, minute 1, second 0 will be printed in Debug Analyzer. Print the time information log in Debug Analyzer every one minute.

RTC Demo in Power Down Mode

The description of RTC demo code 5 is shown in the following table.

RTC Demo Code 5 Description

Demo 5	rtc_in_power_down_mode.c
Sample Purpose	Demonstrate RTC work in power down mode.
File Path	sdk\src\sample\io_demo\rtc\power_down\rtc_in_power_down_mode.c
Function Entry	rtc_in_power_down_mode()
Expected Result	When system is in idle state, it will enter power down mode automatically and print string app_dlps_enter_callback: 10 sec in Debug Analyzer. After 10 seconds, the system wakes up and prints string rtc_handler: RTC_INT_CMP0 and string rtc_handler: RTC_INT_CMP_1 in Debug Analyzer.

Functional Overview

RTC is an independent timer. RTC has a set of continuous counting counters to provide a calendar clock. It can be converted into the current time and date of the system by querying the counter value.

Feature List

• 32KHz clock source.

• 24-bit read-only counter (RTL87x3E and RTL87x3EP), 32-bit read-only counter (RTL87x3D).

• 12-bit prescaler.

• Support 4 comparator interrupts.

• Support overflow interrupt, indicating that the counter overflows and wraps around to 0.

• Support tick interrupt.

• Support wake-up system from low power mode.

• Support 8 comparators.

• 4 comparators can only be used to trigger wake-up.

• 4 comparators can be used to trigger wake-up and CPU NVIC.

Program Examples

Comparator Function Operation Flow

RTC comparator function initialization flow is shown in the following figure.

RTC Comparator Function Initialization Flow Chart

The codes below demonstrate the RTC comparator function initialization flow.

void driver_rtc_init(void)
{
   RTC_DeInit();
   RTC_SetPrescaler(RTC_PRESCALER_VALUE);
   RTC_SetComp(RTC_COMP_INDEX, RTC_COMP_VALUE);
   RTC_MaskINTConfig(RTC_INT_CMP_1, DISABLE);
   RTC_CompINTConfig(RTC_INT_CMP_1, ENABLE);
   RamVectorTableUpdate(RTC_VECTORn, RTC_Handler);

   /* Configure RTC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = RTC_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 3;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);

   /* Start RTC */
   RTC_SystemWakeupConfig(ENABLE);
   RTC_RunCmd(ENABLE);
}

RTC interrupt handle flow is shown in the following figure.

RTC Interrupt Handle Flow Chart

The codes below demonstrate the RTC interrupt handle flow.

void rtc_handler(void)
{
   IO_PRINT_TRACE0("rtc_handler");
   if (RTC_GetINTStatus(RTC_INT_CMP_1) == SET)
   {
      RTC_SetComp(RTC_COMP_INDEX, RTC_GetCounter() + RTC_COMP_VALUE);
      RTC_ClearCompINT(RTC_COMP_INDEX);
   }
}

Overflow Function Operation Flow

RTC overflow function initialization flow is shown in the following figure.

RTC Overflow Function Initialization Flow Chart

The codes below demonstrate the RTC overflow function initialization flow.

void driver_rtc_init(void)
{
   RTC_DeInit();
   RTC_SetPrescaler(RTC_PRESCALER_VALUE);
   RTC_MaskINTConfig(RTC_INT_OVF, DISABLE);

   RamVectorTableUpdate(RTC_VECTORn, rtc_handler);

   /* Config RTC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = RTC_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 2;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);

   /* Start RTC */
   RTC_RunCmd(ENABLE);
}

RTC interrupt handle flow is shown in the following figure.

RTC Interrupt Handle Flow Chart

The codes below demonstrate the RTC interrupt handle flow.

void rtc_handler(void)
{
   /* RTC overflow interrupt handle */
   if (RTC_GetINTStatus(RTC_INT_OVF) == SET)
   {
      // Add application code here

      RTC_ClearOverFlowINT();
   }
}

Tick Function Operation Flow

RTC tick function initialization flow is shown in the following figure.

RTC Tick Function Initialization Flow Chart

The codes below demonstrate the RTC tick function initialization flow.

void driver_rtc_init(void)
{
   RTC_DeInit();
   RTC_SetPrescaler(RTC_PRESCALER_VALUE);
   RTC_MaskINTConfig(RTC_INT_TICK, DISABLE);
   RTC_TickINTConfig(ENABLE);

   RamVectorTableUpdate(RTC_VECTORn, rtc_handler);

   /* Config RTC interrupt */
   NVIC_InitTypeDef NVIC_InitStruct;
   NVIC_InitStruct.NVIC_IRQChannel = RTC_IRQn;
   NVIC_InitStruct.NVIC_IRQChannelPriority = 2;
   NVIC_InitStruct.NVIC_IRQChannelCmd = ENABLE;
   NVIC_Init(&NVIC_InitStruct);

   /* Start RTC */
   RTC_RunCmd(ENABLE);
}

RTC interrupt handle flow is shown in the following figure.

RTC Interrupt Handle Flow Chart

The codes below demonstrate the RTC interrupt handle flow.

void rtc_handler(void)
{
   /* RTC overflow interrupt handle */
   if (RTC_GetINTStatus(RTC_INT_TICK) == SET)
   {
      // Add application code here

      RTC_ClearTickINT();
   }
}