Working with DS1307 Real-time Clock and ATtiny85 using USITWIX Library

Working with the DS1307 Serial Real-Time Clock using the USITWIX library for I2C / TWI on Atmel ATtiny85 / Tinusaur.

Let’s see how can we work with the DS1307 serial real-time clock using the USITWIX library for I2C / TWI on Atmel ATtiny85 / Tinusaur.

Bellow is the testing setup.

NOTE: We need the USB-to-Serial just for debugging – it isn’t essential part of the setup.

DS1307 Serial Real-Time Clock USITWIX Tinusaur.

There is no library yet to do that but with in the testing code there are few functions that could do the job.

Here is brief a description of the functions:

  • uint8_t ds1307_read_reg8(uint8_t reg_addr) – reads one byte of data from the specified register.
  • uint8_t ds1307_write_reg8(uint8_t reg_addr, uint8_t reg_data) – write one byte of data to the specified register.
  • uint8_t ds1307_init(void) – initializes the circuit by writing specific data into the registers.
  • uint8_t ds1307_setdatetime(uint16_t year, uint8_t month, uint8_t date, uint8_t weekday, uint8_t hour, uint8_t min, uint8_t sec) – sets date and time.
  • uint8_t ds1307_adjust(void) – this is helper function – it sets the date & time to a specific value – let’s not forget that a brand new circuit does not have correct date and time set.

DS1307 Serial Real-Time Clock ModuleThere are 2 additional functions that are used to convert data byte to and from BCD format.

  • static uint8_t bcd2bin (uint8_t val)
  • static uint8_t bin2bcd (uint8_t val)

This is direct link to the source code of the testing program:
https://bitbucket.org/tinusaur/ds1307tiny/src/default/ds1307tiny_test1/main.c

Source code available at: https://bitbucket.org/tinusaur/ds1307tiny

More information about the library will be available at its own page: DS1307tiny

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