NR8576AA Datasheet, PDF (10/10 Pages) Nippon Precision Circuits Inc – Real-time Clock Modules

Data Write
CLK
123
CE
WR
NR8576 Series
52 53 54
54+n
DATA
INPUT MODE
S1 S2 S4 S8 S10 S20 S40 FDT
second
y8 y10 y20 y40 y80
year
Data is input when WR is HIGH and CE is HIGH.
The seconds’ digit signal to the timer counter stops
on the first falling edge of CLK and the counter
remains stopped until the next rising edge of CE. The
1 Hz to 128 Hz frequency divider step counters are
reset during the interval between the first and second
rising edges of CLK.
The data is then input on DATA into the shift regis-
ter, starting with seconds’ digit LSB synchronized
with the rising edge of CLK.
After the final data is input into the shift register fol-
lowing 52 cycles, the shift register contents are trans-
ferred to the timer counters. Note that a data write
must contain 52 bits of input data. If CE goes LOW
before 52 bits are input, the input data is invalid. If
the input data exceeds 52 bits, data from the 53rd bit
is ignored (the first 52 bits remain valid).
The data write time should be completed after
t_CE ≤ 0.9 s.
If a data read occurs immediately after a data write, a
wait time (t_RCV) is required if CE has gone LOW.
Note that writing null data will cause incorrect oper-
ation. All bits must be valid data bits.
NIPPON PRECISION CIRCUITS INC. reserves the right to make changes to the products described in this data sheet in order to
improve the design or performance and to supply the best possible products. Nippon Precision Circuits Inc. assumes no responsibility for
the use of any circuits shown in this data sheet, conveys no license under any patent or other rights, and makes no claim that the circuits
are free from patent infringement. Applications for any devices shown in this data sheet are for illustration only and Nippon Precision
Circuits Inc. makes no claim or warranty that such applications will be suitable for the use specified without further testing or modification.
The products described in this data sheet are not intended to use for the apparatus which influence human lives due to the failure or
malfunction of the products. Customers are requested to comply with applicable laws and regulations in effect now and hereinafter,
including compliance with export controls on the distribution or dissemination of the products. Customers shall not export, directly or
indirectly, any products without first obtaining required licenses and approvals from appropriate government agencies.
NIPPON PRECISION CIRCUITS INC.
NIPPON PRECISION CIRCUITS INC.
4-3, Fukuzumi 2-chome
Koto-ku, Tokyo 135-8430, Japan
Telephone: [phone]
Facsimile: 03-3642-6698
NC9603CE 1997.06
NIPPON PRECISION CIRCUITS—10