DS1338.h

#ifndef DS1338_H
#define DS1338_H

#include <inttypes.h>
#include "Wire.h"

extern TwoWire Wire;

// #define INCLUDE_UNIT_TESTS

// For verbose output during units tests, define these in the
// main sketch.
// For example:
// 		#define p(...) Serial.print(__VA_ARGS__)
//		#define pln(...) Serial.println(__VA_ARGS__)

#ifndef p
#define p(...)
#endif

#ifndef pln
#define pln(...)
#endif

// Device address
#define DS1338_ADDR 0x68

// Registers
#define DS1338_REG_SECONDS 0x00
#define DS1338_REG_MINUTES 0x01
#define DS1338_REG_HOURS 0x02
#define DS1338_REG_DAY 0x03
#define DS1338_REG_DATE 0x04
#define DS1338_REG_MONTH 0x05
#define DS1338_REG_YEAR 0x06
#define DS1338_REG_CONTROL 0x07
#define DS1338_REG_RAM_BEGIN 0x08
#define DS1338_REG_RAM_END 0x3F

/**
If set, in an hour register (DS1338_REG_HOURS, DS1338_REG_A1_HOUR,
DS1338_REG_A2_HOUR, the hour is between 0 and 12, and the
(!AM)/PM bit indicates AM or PM.

If not set, the hour is between 0 and 23.
*/
#define DS1338_HOUR_12 (0x01 << 6)

/**
If DS1338_HOUR_12 is set:
- If set, indicates PM
- If not set, indicates AM
*/
#define DS1338_PM_MASK (0x01 << 5)

// If set, the oscillator has stopped since the last time
// this bit was cleared.
#define DS1338_OSC_STOP_FLAG (0x01 << 5)

// Set to disable the oscillator
#define DS1338_OSC_DISABLE (0x01 << 7)

/**
These options control the behavior of the SQW/(!INTB) pin. 
*/
#define DS1338_SQWE_FLAG (0x01 << 4)
#define DS1338_SQW_MASK (0x03)
#define DS1338_SQW_32768HZ (0x03)
#define DS1338_SQW_8192HZ (0x02)
#define DS1338_SQW_4096HZ (0x01)
#define DS1338_SQW_1HZ (0x00)

// Occurs when the number of I2C bytes available is less than the number requested.
#define READ_ERROR 5

#define decode_bcd(x) ((x >> 4) * 10 + (x & 0x0F))
#define encode_bcd(x) ((((x / 10) & 0x0F) << 4) + (x % 10))

#ifdef INCLUDE_UNIT_TESTS

uint8_t bcd_unit_testing();

#endif //INCLUDE_UNIT_TESTS

/** Represents a time and date. */
struct rtctime_t
{
  uint8_t second;
  uint8_t minute;
  uint8_t hour;
  uint8_t day;
  uint8_t month;
  uint8_t year;
};

void make_time(struct rtctime_t *time, uint8_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second);
void format_time_str(struct rtctime_t *time, char *buf);

#ifdef INCLUDE_UNIT_TESTING

int sub_str_to_int(char *str, char *buf, int start, int len);
uint8_t time_str_unit_testing();

#endif

uint8_t ds1338_read_time(struct rtctime_t *time);
uint8_t ds1338_write_time(struct rtctime_t *time);

uint8_t ds1338_read_ram(uint8_t address, uint8_t *data, uint8_t length);
uint8_t ds1338_write_ram(uint8_t address, uint8_t *data, uint8_t length);

uint8_t ds1338_enable_sqw(uint8_t frequence);
uint8_t ds1338_disable_sqw();

uint8_t ds1338_get_osf(uint8_t *osf);
uint8_t ds1338_clean_osf();

#endif