The DP8573A is intended for use in microprocessor based systems where information is required for multi-tasking, data logging or general time of day/date information. This device is implemented in low voltage silicon gate microCMOS technology to provide low standby power in battery back-up environments. The circuit"s architecture is such that it looks like a contiguous block of memory or I/O ports organized as one block of 32 bytes. This includes the Control Registers, the Clock Counters, the Alarm Compare RAM, and the Time Save RAM.
●Time and date are maintained from 1/100 of a second to year and leap year in a BCD format, 12 or 24 hour modes. Day of week and day of month counters are provided. Time is controlled by an on-chip crystal oscillator requiring only the addition of the 32.768 kHz crystal and two capacitors.
●Power failure logic and control functions have been integrated on chip. This logic is used by the RTC to issue a power fail interrupt, and lock out the µP interface. The time power fails may be logged into RAM automatically when VBB > VCC. Additionally, two supply pins are provided. When VBB > VCC, internal circuitry will automatically switch from the main supply to the battery supply.
●The DP8573A"s interrupt structure provides three basic types of interrupts: Periodic, Alarm/Compare, and Power Fail. Interrupt mask and status registers enable the masking and easy determination of each interrupt.
● Full function real time clock/calendar
● 12/24 hour mode timekeeping
● Day of week counter
● Parallel resonant oscillator
● Power fail features
● Internal power supply switch to external battery
● Power Supply Bus glitch protection
● Automatic log of time into RAM at power failure
● On-chip interrupt structure
● Periodic, alarm, and power fail interrupts
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