RX8804CE I2C-Bus Interface Real Time Clock Modules Epson RX8804CE I2C-Bus Interface Real Time Clock Modules have a built-in frequency adjusted 32.768kHz crystal unit and DTCXO. The modules feature an I2C-Bus interface (400kHz) and selectable clock output (32.768kHz, 1024Hz, 1Hz). The RX8804CE devices offer a 1.6V to 5.5V interface voltage range, a 1.5V to 5.5V temperature-compensated voltage range, and a 1.5V to 5.5V timekeeping range. Various functions include a full calendar, alarm, timer, and event detection.