DS3231MZ+ MAXIM [Maxim Integrated Products], DS3231MZ+ Datasheet - Page 18

• Manufacturer Part Number: DS3231MZ+
• Manufacturer: MAXIM [Maxim Integrated Products]

±5ppm, I
Figure 9. I
To achieve the best results when using the DS3231M,
decouple the V
0.1FF and/or 1.0FF capacitors. Use a high-quality,
ceramic, surface-mount capacitor if possible. Surface-
mount components minimize lead inductance, which
improves performance, and ceramic capacitors tend to
have adequate high-frequency response for decoupling
applications.
18
A)
B)
C)
D)
TYPICAL I
EXAMPLE I
START
SINGLE BYTE WRITE
-WRITE CONTROL REGISTER
TO 44h
SINGLE BYTE READ
-READ CONTROL REGISTER
MULTIBYTE WRITE
-WRITE DATE REGISTER
TO "02" AND MONTH
REGISTER TO "11"
MULTIBYTE READ
-READ ALARM 2 HOURS
AND DATE VALUES
reads data with ACK or NACK as applicable, and
generates a STOP condition. See Figure 6 for a read
example using the repeated START condition to
specify the starting memory location.
Reading Multiple Bytes from a Slave: The read
operation can be used to read multiple bytes with a
single transfer. When reading bytes from the slave,
the master simply ACKs the data byte if it desires to
read another byte before terminating the transaction.
After the master reads the last byte it must NACK to
indicate the end of the transfer and then it generates
a STOP condition.
2
C WRITE TRANSACTION
2
MSB
C TRANSACTIONS
1
2
C Transactions
1
0
Applications Information
CC
ADDRESS
SLAVE
1
and/or V
2
0
START
START
START 1 1 0 1 0 0 0 0
START 1 1 0 1 0 0 0 0
Power-Supply Decoupling
C Real-Time Clock
0
1 1 0 1 0 0 0 0
1 1 0 1 0 0 0 0
0
BAT
D0h
D0h
D0h
D0h
READ/
WRITE
R/W
LSB
power supplies with
SLAVE
ACK
SLAVE
SLAVE
SLAVE
SLAVE
ACK
ACK
ACK
ACK
MSB
b7
0 0 0 0 1 1 1 0
0 0 0 0 1 1 1 0
0 0 0 0 0 1 0 0
0 0 0 0 1 1 0 0
b6
0Eh
0Eh
04h
0Ch
b5
REGISTER ADDRESS
b4
SLAVE
SLAVE
SLAVE
SLAVE
ACK
ACK
ACK
ACK
b3
0 0 0 0 0 0 1 0
0 1 0 0 0 1 0 0
REPEATED
REPEATED
b2
START
START
44h
02h
If communications during battery operation are not
required, the V
The 32KHZ and INT/SQW outputs are open drain and
therefore require external pullup resistors to realize logic-
high output levels. Pullup resistor values between 1kI
and 10MI are typical.
The RST output is also open drain, but is provided with
an internal 50kI pullup resistor (R
pullup resistors should not be added.
SDA is an open-drain output and requires an external
pullup resistor to realize a logic-high level.
Because the device does not use clock cycle stretching,
a master using either an open-drain output with a pullup
resistor or CMOS output driver (push-pull) could be used
for SCL.
The device contains Maxim’s redundant battery-charge
protection circuit to prevent any charging of the external
battery.
b1
LSB
b0
1 1 0 1 0 0 0 1
1 1 0 1 0 0 0 1
SLAVE
SLAVE
ACK
ACK
D1h
D1h
SLAVE
ACK
STOP
0 0 0 1 0 0 0 1
MSB
b7
SLAVE
SLAVE
ACK
ACK
11h
BAT
b6
SDA and SCL Pullup Resistors
decoupling capacitor can be omitted.
b5
VALUE
VALUE
DATA
DATA
SLAVE
ACK
Battery Charge Protection
Using Open-Drain Outputs
b4
DATA
b3
STOP
MASTER
MASTER
NACK
ACK
b2
b1
STOP
PU
VALUE
LSB
DATA
b0
) to V
SLAVE
ACK
CC
MASTER
NACK
. External
STOP
STOP