test_i2c.c

基于I2C的RTC（实时时钟)的小程序,用c编写的,实现的是年历功能

/*******************************file : testi2c.c******************************
                        Version :  1.0
                        Function:  The access of the i2c based rtc
                        Auther: Haijian Cao
                        Copyright Reserved
                        2006.6.25
*******************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/stat.h>
//#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <linux/rtc.h>	//struct rtc_time

#define I2C_ADAPTER "/dev/i2c-0"
#define RTC_SLAVE_ADDR 0x68
#define I2C_SLAVE       0x0703	//This is the ioctl command of set i2c slave address
 
#define SET_DATE 0
#define SET_TIME 1
#define SET_DAY 2

const char * day[7]={"SUN","MON","TUS","WEN","THI","FRI","SAT"};

#ifndef BCD_TO_BIN
#define BCD_TO_BIN(val) ((val)=((val)&15) + ((val)>>4)*10)
#endif

int check_date(char * date,struct rtc_time * now_time);
int check_time(char * time,struct rtc_time * now_time);
void get_hard_time(struct rtc_time * now_time);
void set_hard_time(struct rtc_time * now_time,int tim_day);
unsigned char bin_to_bcd(unsigned char bin);

/*
Examples of the command line:
1. testi2c -d 2006-06-12	//set the data
2. testi2c -t 23:14:54		//set the time
3. testi2c -y 7			//set the day to Satday
*/
int main(int argc,char * argv[])
{
	struct rtc_time now_time;
	int temp;
	if(argc==1)
	{
	}
	else if(argc==3)
	{
		if(strcmp(argv[1],"-d")==0)
		{	
			if(check_date(argv[2],&now_time)==-1)
			{
				printf("usage: testi2c -d xxxx-xx-xx\n");
				return -1;
			}
			set_hard_time(&now_time,SET_DATE); //write the year,month,date to the ds1339
		}
		else if(strcmp(argv[1],"-t")==0)	
		{
			if(check_time(argv[2],&now_time)==-1)
			{
				printf("usage: testi2c -t xx:xx:xx\n");
				return -1;
			}
			set_hard_time(&now_time,SET_TIME); //write the hour,minute,second to the ds1339
		}
		else if (strcmp(argv[1],"-y")==0)
		{
			temp=atoi(argv[2]);
			if(temp>7||temp<1)
			{
				printf("usage : testi2c -y num\n");
				return -1;
			}
			now_time.tm_mday=temp;	
			set_hard_time(&now_time,SET_DAY);//write the day to the ds1339
		}
		else
		{
			printf("usage: testi2c [-d xxxx-xx-xx][-t xx:xx:xx][-y x]\n");
		}
	}
	else
	{
		printf("usage: testi2c [-d xxxx-xx-xx][-t xx:xx:xx][-y x]\n");
	}
	get_hard_time(&now_time);
}
/****************************************************************************
read the second,minute,hour,day,date,month,year from the ds1339 register,and
put them to the struct rtc_time,and disply
****************************************************************************/
void get_hard_time(struct rtc_time * now_time)
{
	int fd;
	int ret_value;
	int cur_addr=0x00;
	char read_buff[7]={0,0,0,0,0,0,0};

	if (now_time==NULL) return;
	fd=open(I2C_ADAPTER,O_RDWR);
	if(fd<0)
	{
		perror("Open I2C_ADAPTER:");
		exit(1);
	}
	ret_value=ioctl(fd,I2C_SLAVE,RTC_SLAVE_ADDR);	//set the slave address
	if (ret_value<0)				//of the ds1339
	{
		perror("Ioctl:");
		exit(1);
	}

	cur_addr=0x0;		//set the Read addr to 0x0
        ret_value=write(fd,&cur_addr,1); 
        if (ret_value<0)                
        {
                perror("Write:");
                exit(1);
        }

	ret_value=read(fd,read_buff,7);		//read 7 ds1339 registers 
	if (ret_value<0)			
	{
		perror("Read:");
		exit(1);
	}
//convert data reading from the ds1339 to the rtc_time
	now_time->tm_sec=BCD_TO_BIN(read_buff[0]);	//second

	now_time->tm_min=BCD_TO_BIN(read_buff[1]);	//minite

	read_buff[2]&=0x3f;				//delete the 12/24 flag
	now_time->tm_hour=BCD_TO_BIN(read_buff[2]);	//hour

	now_time->tm_mday=BCD_TO_BIN(read_buff[3]);	//day

	now_time->tm_wday=BCD_TO_BIN(read_buff[4]);	//date

	now_time->tm_mon=read_buff[5]&0x7f;		//delete the centry information
	now_time->tm_mon=BCD_TO_BIN(now_time->tm_mon);	//month

	now_time->tm_year=BCD_TO_BIN(read_buff[6]);	//year
	if(read_buff[5]&0x80) now_time->tm_year+=100;	//centry

	printf("%d-%d-%d %s %d:%d:%d\n",now_time->tm_year+1900,now_time->tm_mon,now_time->tm_wday,
		day[now_time->tm_mday-1],now_time->tm_hour,now_time->tm_min,now_time->tm_sec);	
}

/****************************************************************************
tim_date=0 : set the year,month,date
tim_date=1 : set the hour,minute,second
****************************************************************************/
void set_hard_time(struct rtc_time * now_time,int tim_date)
{
	int fd;
	int ret_value;
	char write_buff[4]={0,0,0,0};
	unsigned int w_count;	

	if (now_time==NULL) return;
//Set time
	if (tim_date==SET_TIME)		
	{		
		write_buff[0]=0;
		write_buff[1]=bin_to_bcd(now_time->tm_sec);
		write_buff[2]=bin_to_bcd(now_time->tm_min);
		write_buff[3]=bin_to_bcd(now_time->tm_hour);
		write_buff[3]&=0xbf;	//set the 12/24 flag
		w_count=4;
	}
//Set date
	else if(tim_date==SET_DATE)
	{
		write_buff[0]=0x04;
		write_buff[1]=bin_to_bcd(now_time->tm_wday);
		write_buff[2]=bin_to_bcd(now_time->tm_mon);
		if(now_time->tm_year>=100)
		{							//year 20xx
			write_buff[3]=bin_to_bcd(now_time->tm_year-100);
			write_buff[2]|=0x80;				//centry=1
		}
		else write_buff[3]=bin_to_bcd(now_time->tm_year);	//year 19xx
		w_count=4;
	}
//Set day
	else if(tim_date==SET_DAY)
	{
		write_buff[0]=0x03;
		write_buff[1]=now_time->tm_mday;
		w_count=2;
	}
	else return;

	fd=open(I2C_ADAPTER,O_RDWR);
	if(fd<0)
	{
		perror("Open I2C_ADAPTER:");
		exit(1);
	}
	ret_value=ioctl(fd,I2C_SLAVE,RTC_SLAVE_ADDR);	//set the slave address
	if (ret_value<0)				//of the ds1339
	{
		perror("Ioctl:");
		exit(1);
	}
	ret_value=write(fd,write_buff,w_count);   //write w_count-1 registers to the ds1339
 	if (ret_value<0)
	{
		perror("Write:");
		exit(1);
	}
	close(fd);
}
/******************************************************************************
check and get the year,month,date from the (char * date)
char * date format : 2006-10-25
******************************************************************************/
int check_date(char * date,struct rtc_time * now_time)
{
	char temp[5];
	unsigned int i;
	
//check the format
	if (strlen(date)!=10) return -1;
	if (date[4]!='-'||date[7]!='-') return -1;
	for (i=0;i<=9;i++)
	{
		if(i==4||i==7) i++;
		if (!isdigit(date[i])) return -1;
	}
//check and get the year,month,date
	for(i=0;i<=3;i++) temp[i]=date[i];
	temp[4]='\0';
	i=atoi(temp);
	if(i>2016||i<1900) return -1;
	now_time->tm_year=i-1900;	//year

	temp[0]=date[5];
	temp[1]=date[6];
	temp[2]='\0';
	i=atoi(temp);
	if(i>12) return -1;
	now_time->tm_mon=i;		//month

	temp[0]=date[8];
	temp[1]=date[9];
	temp[2]='\0';
	i=atoi(temp);
	if(i>31) return -1;
	now_time->tm_wday=i;		//date
}

/**************************************************************************************
check and get the hour,minute,second from the (char * time)
char * time format : 15:54:25
**************************************************************************************/
int check_time(char * time,struct rtc_time * now_time)
{
	char temp[3];
	unsigned int i;
//check the format
	if (strlen(time)!=8) return -1;
	if (time[2]!=':'||time[5]!=':') return -1;
	for (i=0;i<=7;i++)
	{
		if(i==2||i==5) i++;
		if (!isdigit(time[i])) return -1;
	}
//check and get the year,month,date
	temp[0]=time[0];
	temp[1]=time[1];
	temp[2]='\0';
	i=atoi(temp);
	if(i>23) return -1;
	now_time->tm_hour=i;	//hour

	temp[0]=time[3];
	temp[1]=time[4];
	temp[2]='\0';
	i=atoi(temp);
	if(i>59) return -1;
	now_time->tm_min=i;	//minute

	temp[0]=time[6];
	temp[1]=time[7];
	temp[2]='\0';
	i=atoi(temp);
	if(i>59) return -1;
	now_time->tm_sec=i;	//second
}
/**********************************************************************************
Convert from bin to bcd code
**********************************************************************************/
unsigned char bin_to_bcd(unsigned char bin)
{
	unsigned int temp;
	temp=bin;
	bin=temp % 10;
	temp=(temp / 10)<<4;
	return temp|bin;
}