#include "stm32f10x.h"

#include "mcu_systick.h"

#include "mcu_gpio.h"

#include "mcu_systick.h"

#include "mcu_rtc.h"

#include "stdio.h"

#include "common.h"

unsigned int rtcalarm;

void RTC_Configure(void);

/*

2013-05-04: RTC寄存器如果操作不当，可能会造成RTC计数器时钟变快(推测可能还是32K的RTC时钟可能被8M的内部RC替代了)，从而导致一系列的问题，如延时出错。

*/

// 初始化RTC时钟。

void rtc_init(void)

{

systick = 0;

// 检查备份寄存器中的RTC校准标志是否被设置，若未被设置，则校准RTC

if(BKP_ReadBackupRegister(BKP_DR1) != 0xA5A5)

{

/* Backup data register value is not correct or not yet programmed (when

the first time the program is executed) */

/* RTC Configuration */

RTC_Configure();

/* Adjust time by values entred by the user on the hyperterminal */

// Time_Adjust();

// 校准RTC后在备份寄存器中写入校准标志

BKP_WriteBackupRegister(BKP_DR1, 0xA5A5);

}

else // 若RTC已经被校准(备份寄存器在MCU关机但不断电情况下可保持内容)，则无需再校准

{

//启用PWR和BKP的时钟（from APB1）

RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);

//后备域解锁，以为内RTC处于后备域，操作其相关寄存器时需要先解锁

PWR_BackupAccessCmd(ENABLE);

#ifdef RTCClockSource_LSI

/* Enable LSI */

RCC_LSICmd(ENABLE);

/* Wait till LSI is ready */

while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET)

{

}

/* Select LSI as RTC Clock Source */

RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);

#endif

RCC_RTCCLKCmd(ENABLE);

//==========================================================

/* Check if the Power On Reset flag is set */

#if 0

if(RCC_GetFlagStatus(RCC_FLAG_PORRST) != RESET)

{

//printf("\r\n\n Power On Reset occurred....");

}

/* Check if the Pin Reset flag is set */

else if(RCC_GetFlagStatus(RCC_FLAG_PINRST) != RESET)

{

//printf("\r\n\n External Reset occurred....");

}

#endif

//printf("\r\n No need to configure RTC....");

/* Wait for RTC registers synchronization */

RTC_WaitForSynchro();

/*允许RTC报警中断*/

RTC_ITConfig(RTC_IT_ALR, ENABLE);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

}

/* Clear reset flags */

RCC_ClearFlag();

/*等待最后一条写指令完成*/

RTC_WaitForLastTask();

/* Display time in infinte loop */

//Time_Show();

RTC_SetAlarm(systick+SYSTICK_PERIOD);

}

// 配置RTC硬件。

void RTC_Configure(void)

{

/* Enable PWR and BKP clocks */

RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR | RCC_APB1Periph_BKP, ENABLE);

/* Allow access to BKP Domain */

PWR_BackupAccessCmd(ENABLE);

RCC_RTCCLKCmd(ENABLE);

/* Reset Backup Domain */

BKP_DeInit();

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

#ifdef RTCClockSource_LSI

/* Enable LSI */

RCC_LSICmd(ENABLE);

/* Wait till LSI is ready */

while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET);

/* Select LSI as RTC Clock Source */

RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);

#elif defined RTCClockSource_LSE

/* Enable LSE */

RCC_LSEConfig(RCC_LSE_ON);

/* Wait till LSE is ready */

while(RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET);

/* Select LSE as RTC Clock Source */

RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);

#endif

// 上电后需要校准RTC时钟，也即准确计算出RTC的周期时长。

RTC_Calibrate();

#ifdef RTCClockOutput_Enable

/* Disable the Tamper Pin */

BKP_TamperPinCmd(DISABLE); /* To output RTCCLK/64 on Tamper pin, the tamper functionality must be disabled */

/* Enable RTC Clock Output on Tamper Pin */

BKP_RTCCalibrationClockOutputCmd(ENABLE);

#endif

/*允许RTC报警中断*/

RTC_ITConfig(RTC_IT_ALR, ENABLE);

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

}

// 通过直接计算校准RTC时钟(使用0.01ms周期的systick测量再修正RTC预分频系数)。

void RTC_Calibrate(void)

{

unsigned int systick_sta;

unsigned int rtctick_lmt;

unsigned int prescaler = 0;

// 在使用systick测量RTC tick的周期长度之前，初始化systick

NVIC_SetPriority(SysTick_IRQn, 0);

SysTick_Init();

// 开始rtcalarm计数并使能rtcalarm中断

SysTick_Enable();

// 先设置默认的RTC预分频系数(rtc tike = ~1ms)

RTC_SetPrescaler(DEF_RTC_PRESCALER);

/* Enable RTC Clock */

RCC_RTCCLKCmd(ENABLE);

/* Wait for RTC registers synchronization */

RTC_WaitForSynchro();

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

// 测量RTC单周期长度持续~1秒

rtctick_lmt = systick+1000/SYSTICK_PERIOD;

// 记录测量前的systick值

systick_sta = systick;

// 测量1000个周期的rtc tick(~1s)

while(systick < rtctick_lmt);

prescaler = (DEF_RTC_PRESCALER * 1000)/((systick-systick_sta)/100);

// printf("prescaler = %d.\r\n", prescaler);

// 重新设置RTC预分频系数

RTC_SetPrescaler(prescaler);

/* Enable RTC Clock */

RCC_RTCCLKCmd(ENABLE);

/* Wait for RTC registers synchronization */

RTC_WaitForSynchro();

/* Wait until last write operation on RTC registers has finished */

RTC_WaitForLastTask();

// 校准完RTC时钟后，停止rtcalarm计数并禁止rtcalarm中断

SysTick_Disable();

// printf("RTC Clock calibrated.\r\n");

}