The DS1386 is a nonvolatile static RAM with a
full-function real-time clock (RTC), alarm,
watchdog timer, and interval timer that are all
accessible in a byte-wide format. The DS1386
contains a lithium energy source and a quartz
crystal, which eliminates the need for any external
circuitry. Data contained within 8k or 32k by 8-bit
memory and the timekeeping registers can be read
or written in the same manner as byte-wide static
RAM. The timekeeping registers are located in the
first 14 bytes of memory space. Data is maintained
in the RAMified timekeeper by intelligent control
circuitry, which detects the status of VCC and write
protects memory when VCC is out of tolerance. The
lithium energy source can maintain data and real
time for over ten years in the absence of VCC.
Timekeeper information includes hundredths of
seconds, seconds, minutes, hours, day, date, month,
and year. The date at the end of the month is
automatically adjusted for months with less than 31
days, including correction for leap year.
The RAMified timekeeper operates in either 24-
hour or 12-hour format with an AM/PM indicator.
The watchdog timer provides alarm interrupts and
interval timing between 0.01 seconds and 99.99
seconds. The real-time alarm provides for preset
times of up to one week. Interrupts for both
watchdog and RTC operate when the system is
powered down. Either can provide system "wakeup”
signals.
Key Features
8kB or 32kB of User NV RAM
Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit, and Lithium Energy Source
Totally Nonvolatile With Over 10 Years of Operation in the Absence of Power
Watchdog Timer Restarts an Out-Of-Control Processor
Alarm Function Schedules Real-Time Related Activities such as System Wakeup
Programmable Interrupts and Square-Wave Output
All Registers are Individually Addressable via the Address and Data Bus
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