DS1307 Based Real-Time Clock

Figure 1 

The project aims to create a standard desk clock that is based on an I2C Real-Time Clock IC DS1307 with a 4-digit 7-segment display.

The use of DS1307 IC on a bread board is easier compared to using the PIC16F88 microcontroller with built-in oscillator for a 32kHz watch crystal. It frees the main system for time-critical tasks and it has low power consumption. It is also an alternative source of power because even though the primary source of power is unavailable or OFF, it allows the time to be kept accurately. Some newer systems uses a super capacitor since they are rechargeable and can be soldered easily although the alternate source of power is normally a lithium battery. The DS1307 device uses an I2C interface while having 8 read/write registers where information are stored.

The crystal is put in the least noisy part of the board by using the DS1307 as it sets the crystal load capacitance which is critical in making the crystal oscillate at exactly 32kHz, thereby controlling its initial error. If the input voltage falls below, the DS1307 detects a power failure where it switches to the battery supply input automatically.

Rest of the project