CLOCKS

The DS1307 serial real-time clock (RTC) is a lowpower, full binary-coded decimal (BCD) clock/calendar plus 56 bytes of NV SRAM. Address and data are transferred serially through an I²C, bidirectional bus. The clock//calendar provides seconds, minutes, hours, day, date, month, and year information. 14 pages.

This application note describes crystal selection and layout techniques for connecting a 32,768Hz crystal to a real-time clock (RTC). It also provides information about oscillator circuit-design criteria, system design, and manufacturing issues. 8 pages.

A clock/calendar circuit based on a 2048-bit static CMOS RAM organized as 256 words by 8 bits. Addresses and data are transferred serially via the two-line bidirectional I²C-bus. 28 pages.