基于mini2440的RTC读写（裸机）

很多处理器都有RTC实时时钟功能，s3c2440也提供了这个功能，其功能主要是：实时时钟、闹钟、tick中断等。RTC的操作比较简单。读写时RTCCON最低位应设置为1，不读写时设置为0以免误修改RTC相应寄存器。

BCDSEC,BCDMIN,BCDHOUR,BCDDAY,BCDDATE,BCDMON,BCDYEAR可以设置和读取RTC的值，在编程中需要注意一秒只差的问题（具体可查看芯片手册），所以在BCDSEC值为0时需要重新读取RTC相应寄存器，防止误差，这点需要特别注意。

tick中断可为RTOS提供中断时钟，其周期计算如下：

可在TICNT设置相应位。达到周期产生中断。

闹钟功能在RTCALM允许使能。在ALMSEC、ALMMIN、ALMHOUR、ALMDATE、ALMMON、ALMYEAR中设置闹钟值，到达时间后产生相应中断。

还有一点需要注意，s3c2440的RTC以BCD码进行读写，所以要以十进制操作应做相应转换。RTC操作比较简单，这里不再作详细介绍，具体可查看芯片手册。测试：将相应时间写入RTC、设置相应tick中断和闹钟。通过串口显示相应时间。

代码如下：

main.c部分

#define  GLOBAL_CLK 1#include<string.h>#include "def.h"#include "option.h"#include "2440addr.h"#include "profile.h"#include "mmu.h"extern void RTC_Set(char year, char month, char week,char date, char hour, char min, char sec);extern void RTC_Read(char *year, char *month, char *week,char *date, char *hour, char *min, char *sec);extern void RTC_Alarm_Set(char year, char mon, char date,char hour, char min, char sec);extern void RTC_Init(void);extern void RTC_Tick(void);extern void RTC_Alarm(void);extern char tick_flag, alarm_flag;void delay(int num);void delay(int num){int i, j, k;for(i=0;i<num;i++)for(j=0;j<1000;j++)for(k=0;k<1000;k++);}void Main(void){char data[7] = {0};char *week_str[7] = {"Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"};char *week;int count = 0;rGPBCON=(1<<0);    rGPBDAT=(0<<0);//关闭蜂鸣器MMU_Init();//地址的重映射RTC_Init();RTC_Tick();RTC_Alarm();RTC_Set(13, 9, 6, 7, 19, 59, 12);RTC_Alarm_Set(13, 9, 7, 20, 0, 0);while ( 1 ){RTC_Read(&data[0], &data[1], &data[2], &data[3], &data[4], &data[5], &data[6]);switch ( data[2]){case 1 : week = week_str[0] ;break;case 2 : week = week_str[1];break;case 3 : week = week_str[2];break;case 4 : week = week_str[3];break;case 5 : week = week_str[4];break;case 6 : week = week_str[5];break;case 7 : week = week_str[6];break;default: break;}Uart_Printf("\n%d年,%d月,%d日,星期%s,%d点,%d分,%d秒\n",2000+data[0], data[1], data[3], week, data[4], data[5], data[6]);if (1 == alarm_flag){Uart_Printf("\nALARM：%d年,%d月,%d日,%d点,%d分,%d秒\n",2000+data[0], data[1], data[3], data[4], data[5], data[6]);alarm_flag = 0;}if (1 == tick_flag){count++;Uart_Printf("\nTICK：%d\n", count);tick_flag = 0;}delay(50);}}

RTC.c部分

#include "2440addr.h"/*定义用户中断标志*/char tick_flag = 0, alarm_flag = 0;void __irq RTC_alarm_interrupt(void);void __irq RTC_tick_interrupt(void);/*RTC初始化*/void RTC_Init(void){rINTMSK &= ~(1<<30 | 1<<8);//RTC中断使能pISR_TICK = (unsigned)RTC_tick_interrupt;pISR_RTC = (unsigned)RTC_alarm_interrupt;}/*RTC设置*/void RTC_Set(char year, char month, char week,char date, char hour, char min, char sec){rRTCCON = 1;rBCDYEAR = year;rBCDMON = ((month / 10)<<4) | (month % 10);rBCDDAY = week;rBCDDATE = ((date / 10)<<4) | (date % 10);rBCDHOUR = ((hour / 10)<<4) | (hour % 10);rBCDMIN = ((min / 10)<<4) | (min % 10);rBCDSEC = ((sec / 10)<<4) | (sec % 10);rRTCCON &= ~1;}/*读取RTC*/void RTC_Read(char *year, char *month, char *week,char *date, char *hour, char *min, char *sec){char i;rRTCCON = 1;*year = rBCDYEAR;*month = (rBCDMON>>4) * 10 + (rBCDMON & 0x0f);*week = rBCDDAY;*date = (rBCDDATE>>4) * 10 + (rBCDDATE & 0x0f);*hour = (rBCDHOUR>>4) * 10 + (rBCDHOUR & 0x0f);*min = (rBCDMIN>>4) * 10 + (rBCDMIN & 0x0f);if ((*sec = rBCDSEC) == 0){*year = rBCDYEAR;*month = (rBCDMON>>4) * 10 + (rBCDMON & 0x0f);*week = rBCDDAY;*date = (rBCDDATE>>4) * 10 + (rBCDDATE & 0x0f);*hour = (rBCDHOUR>>4) * 10 + (rBCDHOUR & 0x0f);*min = (rBCDMIN>>4) * 10 + (rBCDMIN & 0x0f);}*sec = (rBCDSEC>>4) * 10 + (rBCDSEC & 0x0f);rRTCCON &= ~1;}/*RTC tick时钟设置*/void RTC_Tick(void){rTICNT &= ~0xff;rTICNT |= (1<<7 | 63);}/*RTC 闹钟初始化*/void RTC_Alarm(void){rRTCALM &= ~0xff;rRTCALM |= 0xff;}/*RTC 闹钟设置*/void RTC_Alarm_Set(char year, char mon, char date,char hour, char min, char sec){rALMYEAR = year;rALMMON = ((mon / 10)<<4) | mon % 10;rALMDATE = ((date / 10)<<4) | date % 10;rALMHOUR = ((hour / 10)<<4) | hour % 10;rALMMIN = ((min / 10)<<4) | min % 10;rALMSEC = ((sec / 10)<<4) | sec % 10;}/*RTC 闹钟中断服务*/void __irq RTC_alarm_interrupt(void){rSRCPND |= 1<<30;//清除中断rINTPND |= 1<<30;alarm_flag = 1;//设置用户中断标志}/*RTC tick中断服务*/void __irq RTC_tick_interrupt(void){rSRCPND |= 1<<8;//清除中断rINTPND |= 1<<8;tick_flag = 1;//设置用户中断标志}

运行结果如下：

源代码下载地址：http://download.csdn.net/detail/a16839678/6232721