DS1743

The DS1743 is a full function, year 2000-compliant (Y2KC), real-time clock/calendar (RTC) and 8k x 8 non-volatile static RAM. User access to all registers within the DS1743 is accomplished with a bytewide interface as shown in Figure 1. The Real Time Clock (RTC) information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the day of the month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data that can occur during clock update cycles. The double buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1743 also contains its own power-fail circuitry, which deselects the device when the V_CC supply is in an out of tolerance condition. This feature prevents loss of data from unpredictable system operation brought on by low V_CC as errant access and update cycles are avoided.