DS1554

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ORDERING INFORMATION

DS1554P-XXX

(5-Volt)

-70

70 ns access

-100

100 ns access

blank 32-pin DIP Module

P

34-pin PowerCap Module

board*

*DS1554WP-XXX

(3.3 Volt)

-120

120 ns access

-150

150 ns access

blank 32-pin DIP Module

P

34-pin PowerCap Module

board*

*DS9034PCX (PowerCap) Required:

must be ordered seperately

PIN DESCRIPTION

A0-A14

- Address Input

DQ0-DQ7

- Data Input/Outputs

IRQ

\FT

- Interrupt, Frequency Test Output

(Open Drain)

RST

- Power-On Reset Output

(Open Drain)

CE

- Chip Enable

OE

- Output Enable

WE

- Write Enable

- Power Supply Input

GND

- Ground

NC

- No Connection

X1, X2

- Crystal Connection

- Battery Connection

DESCRIPTION

The DS1554 is a full function, year 2000-compliant (Y2KC), real-time clock/calendar (RTC) with a RTC

alarm, watchdog timer, power-on reset, battery monitor, and 32k x 8 non-volatile static RAM. User

access to all registers within the DS1554 is accomplished with a bytewide interface as shown in Figure 1.

The RTC Registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour

BCD format. Corrections for day of month and leap year are made automatically.

The RTC Registers are double-buffered into an internal and external set. The user has direct access to the

external set. Clock/calendar updates to the external set of registers can be disabled and enabled to allow

the user to access static data. Assuming the internal oscillator is turned on, the internal set of registers are

continuously updated; this occurs regardless of external registers settings to guarantee that accurate RTC

information is always maintained.