Pi RTC Module Seeed Studio Pi RTC Module is designed based on the clock chip DS1307. This DS1307 provides a real-time clock for Raspberry Pi via the I2C interface. The RTC module counts seconds, minutes, hours, date, month, day, and year information. This clock operates in a 24-hour or 12-hour format with an AM/PM indicator. A 3V CR1225 lithium cell is used in the battery holder to set the module timing when the Raspberry Pi is powered off.