#ifndef __DS1302__
#define __DS1302__

#define low   0
#define high  1

#define DS1302_SCK P1_7
#define DS1302_IO  P2_7
#define DS1302_RST P1_2

#define DS1302_ADDR_YEAR     0x8C
#define DS1302_ADDR_WEEK     0x8A
#define DS1302_ADDR_MONTH    0x88
#define DS1302_ADDR_DAY      0x86
#define DS1302_ADDR_HOUR     0x84
#define DS1302_ADDR_MINUTE   0x82
#define DS1302_ADDR_SECOND   0x80

/**
 * 日期时间结构体
 */
typedef struct __DS1302_DATE_TIME__
{
  unsigned char year;
  unsigned char week;
  unsigned char month;
  unsigned char day;
  unsigned char hour;
  unsigned char minute;
  unsigned char second;
} ds1302_Datetime;

unsigned char to_bcd(unsigned char val)
{
  return ((val / 10) << 4 | (val % 10));
}

unsigned char from_bcd(unsigned char bcd)
{
  return ((bcd&0x70)>>4)*10 + (bcd&0x0F);
}

/**
 * ds1302
 * @param data 数据
 */
void ds1302_write(unsigned char data)
{
  unsigned char i;
  for(i=0; i<8; i++)
  {
    DS1302_SCK = low;
    DS1302_IO = data & 0x01;
    data >>= 1;
    DS1302_SCK = high;
  }
}

/**
 * 向指定地址写入数据
 * @param addr 地址
 * @param data 数据
 */
void ds1302_write_to_addr(unsigned char addr, unsigned char data)
{
  DS1302_RST = low;
  DS1302_SCK = low;
  DS1302_RST = high;
  ds1302_write(addr);
  ds1302_write(data);
  // 释放
  DS1302_RST = low;
  DS1302_IO = high;
  DS1302_SCK = high;
}

/**
 * 从指定地址读取数据
 * @param  addr [description]
 * @return      [description]
 */
unsigned char ds1302_read_from_addr(unsigned char addr)
{
  unsigned char i, value = 0;
  DS1302_RST = low;
  DS1302_SCK = low;
  DS1302_RST = high;
  ds1302_write(addr);
  for(i=0; i<8; i++)
  {
    DS1302_SCK = low;
    value >>= 1;
    if(DS1302_IO)
      value |= 0x80;
    DS1302_SCK = high;
  }
  // 释放
  DS1302_RST = low;
  DS1302_IO = high;
  DS1302_SCK = high;
  return value;
}

/**
 * 设置1302
 * @param attr  [description]
 * @param value [description]
 */
void ds1302_set_datetime(ds1302_Datetime *datetime)
{
  ds1302_write_to_addr(0x8E, 0x00);
  ds1302_write_to_addr(DS1302_ADDR_YEAR, to_bcd(datetime->year));
  ds1302_write_to_addr(DS1302_ADDR_WEEK, to_bcd(datetime->week));
  ds1302_write_to_addr(DS1302_ADDR_MONTH, to_bcd(datetime->month));
  ds1302_write_to_addr(DS1302_ADDR_DAY, to_bcd(datetime->day));
  ds1302_write_to_addr(DS1302_ADDR_HOUR, to_bcd(datetime->hour));
  ds1302_write_to_addr(DS1302_ADDR_MINUTE, to_bcd(datetime->minute));
  ds1302_write_to_addr(DS1302_ADDR_SECOND, to_bcd(datetime->second));
  ds1302_write_to_addr(0x8E, 0x10);
}

/**
 * 读取ds1302到datetime
 * @param datetime [description]
 */
void ds1302_get_datetime(ds1302_Datetime *datetime)
{
  datetime->year   = from_bcd(ds1302_read_from_addr(DS1302_ADDR_YEAR | 0x01));
  datetime->week   = from_bcd(ds1302_read_from_addr(DS1302_ADDR_WEEK | 0x01));
  datetime->month  = from_bcd(ds1302_read_from_addr(DS1302_ADDR_MONTH | 0x01));
  datetime->day    = from_bcd(ds1302_read_from_addr(DS1302_ADDR_DAY | 0x01));
  datetime->hour   = from_bcd(ds1302_read_from_addr(DS1302_ADDR_HOUR | 0x01));
  datetime->minute = from_bcd(ds1302_read_from_addr(DS1302_ADDR_MINUTE | 0x01));
  datetime->second = from_bcd(ds1302_read_from_addr(DS1302_ADDR_SECOND | 0x01));
}

#endif  // __DS1302__