Linux-Ubuntu之RTC实时时钟显示
一，原理
这个RTC的和计数器差不多，往对应寄存器中放入初始化的时间，然后在时钟的作用下，进行累加，实现计时，首先对初始化的寄存器进行配置，将要放入的年月日时分秒转化为整形数据，把这个整形数据放入到寄存器中，便可进行计时，然后读时间，将寄存器中的值读出来，转化为年月日时分秒，将其放入数组中，运用屏幕显示字符函数，进行显示。
二，代码实现
c
/*rtc.h*/
#ifndef _DSP_RTC_H
#define _DSP_RTC_H
#include "imx6ul.h"
/*时间宏定义*/
#define SECONDS_IN_A_DAY 86400
#define SECONDS_IN_A_HOUR 3600
#define SECONDS_IN_A_MINUTE 60
#define DAYS_IN_A_YEAR 365
#define YEAR_RANGE_START 1970
#define YEAR_RANGE_END 2099
/*时间结构体*/
struct rtc_datetime{
unsigned short year;
unsigned char month;
unsigned char day;
unsigned char hour;
unsigned char minute;
unsigned char second;
};
/*rtc初始化*/
void rtc_init(void);
/*使能*/
void rtc_enable(void);
/*关闭使能*/
void rtc_disable(void);
/*判断润年*/
unsigned char rtc_isleapyear(unsigned short year);
/*将年月日时间转换为秒函数*/
unsigned int rtc_coverdate_to_seconds(struct rtc_datetime *datetime);
/*将相应秒数，写入到相应寄存器中*/
void rtc_in_register(struct rtc_datetime *rtctime);
/*将读出第秒数，转化为真的时间*/
void rtc_convertseconds_to_datetime(u64 seconds, struct rtc_datetime *datetime);
/*读寄存器值，从而得到时间*/
void rtc_out_register(struct rtc_datetime *rtctime);
#endif
/*rtc.c*/
#include "dsp_rtc.h"
/*rtc初始化*/
void rtc_init(void)
{
SNVS->HPCOMR |=(1<<31)|(1<<8);
struct rtc_datetime rtcDate;
rtcDate.year=2025;
rtcDate.month=1;
rtcDate.day=2;
rtcDate.hour=4;
rtcDate.minute=1;
rtcDate.second=0;
rtc_in_register(&rtcDate);
rtc_enable();//使能
}
/*使能*/
void rtc_enable(void)
{
SNVS->LPCR |=1<<0;
while((SNVS->LPCR & 0x01)==0);//当为0时候，一直在while里面循环
}
/*关闭使能*/
void rtc_disable(void)
{
SNVS->LPCR &=~(1<<0);
while((SNVS->LPCR & 0x01)==1);//为1的时候，一直循环
}
/*判断润年*/
unsigned char rtc_isleapyear(unsigned short year)
{
unsigned char value=0;
if(year % 400 == 0)
value = 1;
else
{
if((year % 4 == 0) && (year % 100 != 0))
value = 1;
else
value = 0;
}
return value;
}
/*将年月日时间转换为秒函数*/
unsigned int rtc_coverdate_to_seconds(struct rtc_datetime *datetime)
{
unsigned short i = 0;
unsigned int seconds = 0;
unsigned int days = 0;
unsigned short monthdays[] = {0U, 0U, 31U, 59U, 90U, 120U, 151U, 181U, 212U, 243U, 273U, 304U, 334U};
for(i = 1970; i < datetime->year; i++)
{
days += DAYS_IN_A_YEAR; /* 平年，每年365天 */
if(rtc_isleapyear(i)) days += 1;/* 闰年多加一天 */
}
days += monthdays[datetime->month];
if(rtc_isleapyear(i) && (datetime->month >= 3)) days += 1;/* 闰年，并且当前月份大于等于3月的话加一天 */
days += datetime->day - 1;
seconds = days * SECONDS_IN_A_DAY +
datetime->hour * SECONDS_IN_A_HOUR +
datetime->minute * SECONDS_IN_A_MINUTE +
datetime->second;
return seconds;
}
/*将相应秒数，写入到相应寄存器中*/
void rtc_in_register(struct rtc_datetime *rtctime)
{
unsigned int seconds = 0;
rtc_disable();//关闭使能
seconds=rtc_coverdate_to_seconds(rtctime);
/*放入寄存器中*/
SNVS->LPSRTCMR = (unsigned int)(seconds>>17);
SNVS->LPSRTCLR = (unsigned int)(seconds<<15);
}
/*将读出第秒数，转化为真的时间*/
void rtc_convertseconds_to_datetime(u64 seconds, struct rtc_datetime *datetime)
{
u64 x;
u64 secondsRemaining, days;
unsigned short daysInYear;
/* 每个月的天数 */
unsigned char daysPerMonth[] = {0U, 31U, 28U, 31U, 30U, 31U, 30U, 31U, 31U, 30U, 31U, 30U, 31U};
secondsRemaining = seconds; /* 剩余秒数初始化 */
days = secondsRemaining / SECONDS_IN_A_DAY + 1; /* 根据秒数计算天数,加1是当前天数 */
secondsRemaining = secondsRemaining % SECONDS_IN_A_DAY; /*计算天数以后剩余的秒数 */
/* 计算时、分、秒 */
datetime->hour = secondsRemaining / SECONDS_IN_A_HOUR;
secondsRemaining = secondsRemaining % SECONDS_IN_A_HOUR;
datetime->minute = secondsRemaining / 60;
datetime->second = secondsRemaining % SECONDS_IN_A_MINUTE;
/* 计算年 */
daysInYear = DAYS_IN_A_YEAR;
datetime->year = YEAR_RANGE_START;
while(days > daysInYear)
{
/* 根据天数计算年 */
days -= daysInYear;
datetime->year++;
/* 处理闰年 */
if (!rtc_isleapyear(datetime->year))
daysInYear = DAYS_IN_A_YEAR;
else /*闰年，天数加一 */
daysInYear = DAYS_IN_A_YEAR + 1;
}
/*根据剩余的天数计算月份 */
if(rtc_isleapyear(datetime->year)) /* 如果是闰年的话2月加一天 */
daysPerMonth[2] = 29;
for(x = 1; x <= 12; x++)
{
if (days <= daysPerMonth[x])
{
datetime->month = x;
break;
}
else
{
days -= daysPerMonth[x];
}
}
datetime->day = days;
}
/*读寄存器值，从而得到时间*/
void rtc_out_register(struct rtc_datetime *rtctime)
{
uint64_t seconds = 0;
seconds = (uint64_t)((uint64_t)SNVS->LPSRTCMR<<17|SNVS->LPSRTCLR>>15);
rtc_convertseconds_to_datetime(seconds,rtctime);
}主函数：
c
#include "main.h"
#include "dsp_clk.h"
#include "dsp_led.h"
#include "dsp_delay.h"
#include "beep.h"
#include "dsp_key.h"
#include "dsp_int.h"
#include "dsp_exti.h"
#include "dsp_epit.h"
#include "dsp_uart.h"
#include "stdio.h"
#include "dsp_lcd.h"
#include "dsp_lcdapi.h"
#include "dsp_rtc.h"
int main(void)
{
// int b=0;
unsigned char kkkk=0;
struct rtc_datetime rtc_now_time;
char buf[160]={};
int_init();//中断初始化
imx6u_clkinit();//时钟初始化
key_init();//按键初始化
clk_enable();//时钟初始化
uart_init();//串口初始化
beep_init();//凤鸣器初始化
led_init();//led初始化
lcd_init();//LCD读ID号
rtc_init();//RTC初始化
tftlcd_dev.forecolor = LCD_RED;
tftlcd_dev.backcolor = LCD_WHITE;
// unsigned char *b,*c,*f;
// unsigned short *a;
// lcd_show_string(10,40,260,32,32,(char *)"Fucking high");
while(1)
{
tftlcd_dev.forecolor = LCD_RED;
//lcd_show_string(100,100,240,16,16,(char *)"2025.1.2");
rtc_out_register(&rtc_now_time);
sprintf(buf,"%d.%d.%d-%d:%d:%d\r\n",rtc_now_time.year,rtc_now_time.month,
rtc_now_time.day,rtc_now_time.hour,rtc_now_time.minute,rtc_now_time.second);
char *a;
*a=rtc_now_time.month;
// a=&rtc_now_time.year;
// b=&rtc_now_time.month;
// c=&rtc_now_time.day;
// f=&rtc_now_time.second;
lcd_show_string(140,140,240,32,32,(char *)buf);//屏幕显示时间
lcd_show_string(200,200,240,32,32,a);
printf("a=%d\r\n",*a);
printf("rtc_now_time.month=%d\r\n",rtc_now_time.month);
// lcd_clear(show_color[b]);
// b++;
// if(b==8) b=0;
led_mode(kkkk);
delay(1000);
kkkk = !kkkk;
}
return 0;
}三，小结
1.为什么这个显示不出来？
c
lcd_show_string(140,140,240,32,32,(char *)buf);//屏幕显示时间
lcd_show_string(200,200,240,32,32,a);// ?也设置为指针类型，并且数据打印出来是1，在屏幕上就是无法显示。