Virtuabotixrtc.h: Arduino Library

// Define your pins: (CLK, DAT, RST) // Using pins 7, 6, 5 as wired above virtuabotixRTC myRTC(7, 6, 5);

Behind these pins lies the DS1302 chip, a 32.768 kHz crystal, and a small battery (usually a CR2032). This battery keeps the clock running when the main Arduino power is off. virtuabotixrtc.h arduino library