The DS1375 digital real-time clock (RTC) is a low-power clock/calendar that does not require a crystal. The device operates from a digital clock input pin at one of four frequencies: 32.768kHz, 8.192kHz, 60Hz, or 50Hz. It maintains seconds, minutes, hours, day, date, month, and year information. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including corrections for leap year. The clock operates in either the 24-hour or 12-hour format with an AM/PM indicator. Two programmable time-of-day/date alarms, a programmable square-wave output, and 16 bytes of SRAM are provided. Address and data are transferred serially through a 2-wire bidirectional bus.