The DS1372 is a 32-bit binary up counter and 24-bit down counter with a unique 64-bit ID. The counters, ID, configuration, and status registers are accessed using an I 2 C serial interface. The DS1372 includes a SQW/INT open-drain output that can output either a square wave at one of four predefined frequencies, or it can output an active-low signal when the 24-bit down counter reaches 0.