鈥?/div>
Three
interrupts are separately software-maskable
and testable
鈥?Time-of-day alarm once/second to once/day
鈥?Periodic rates from 122
碌s
to 500 ms
鈥?End of clock update cycle
DESCRIPTION
The DS12B887 Real Time Clock plus RAM is designed
to be a direct replacement for the DS1287A or
DS12887A. The DS12B887 is identical in form, fit, and
function to the DS1287A or DS12887A, with the excep-
tion of RCLR, and has an additional 64 bytes of general
purpose RAM. Access to this additional RAM space is
determined by the logic level presented on AD6 during
the address portion of an access cycle. A lithium energy
source, quartz crystal, and write-protection circuitry are
contained within a 24-pin dual in-line package. As such,
the DS12B887 is a complete subsystem replacing 16
components in a typical application. The functions
include a nonvolatile time-of-day clock, an alarm, a one-
hundred-year calendar, programmable interrupt,
square wave generator, and 114 bytes of nonvolatile
static RAM. The real time clock is distinctive in that
time-of-day and memory are maintained even in the
absence of power.
ECopyright
1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
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