Maxim Maxim DS3232 Series, Общее описание устройства

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the slave address. Next follows a number of data
bytes. The slave returns an acknowledge bit after
each received byte. Data is transferred with the most
significant bit (MSB) first.
Data transfer from a slave transmitter to a master
receiver.
The first byte (the slave address) is trans-
mitted by the master. The slave then returns an
acknowledge bit. Next follows a number of data
bytes transmitted by the slave to the master. The
master returns an acknowledge bit after all received
bytes other than the last byte. At the end of the last
received byte, a not acknowledge is returned.
The master device generates all the serial clock puls-
es and the START and STOP conditions. A transfer is
ended with a STOP condition or with a repeated
START condition. Since a repeated START condition
is also the beginning of the next serial transfer, the
bus will not be released. Data is transferred with the
most significant bit (MSB) first.
DS3232
Extremely Accurate I
2
C RTC with
Integrated Crystal and SRAM
____________________________________________________________________ 17
...
A XXXXXXXX A 1101000 S 0 XXXXXXXX A XXXXXXXX A XXXXXXXX A P
<R/W> <WORD ADDRESS (n)> <DATA (n)> <DATA (n + 1)> <DATA (n + X)
S - START
A - ACKNOWLEDGE (ACK)
P - STOP
R/W - READ/WRITE OR DIRECTION BIT ADDRESS
DATA TRANSFERRED
(X + 1 BYTES + ACKNOWLEDGE)
MASTER TO SLAVE SLAVE TO MASTER
<SLAVE
ADDRESS>
Figure 3. Data Write—Slave Receiver Mode
...
A XXXXXXXX A 1101000 S 1 XXXXXXXX A XXXXXXXX A XXXXXXXX A P
S - START
A - ACKNOWLEDGE (ACK)
P - STOP
A - NOT ACKNOWLEDGE (NACK)
R/W - READ/WRITE OR DIRECTION BIT ADDRESS
DATA TRANSFERRED
(X + 1 BYTES + ACKNOWLEDGE)
NOTE: LAST DATA BYTE IS FOLLOWED BY A NACK.
MASTER TO SLAVE SLAVE TO MASTER
<R/W> <DATA (n)> <DATA (n + 1)> <DATA (n + 2)> <DATA (n + X)>
<SLAVE
ADDRESS>
Figure 4. Data Read—Slave Transmitter Mode
S - START
Sr - REPEATED START
A - ACKNOWLEDGE (ACK)
P - STOP
A - NOT ACKNOWLEDGE (NACK)
R/W - READ/WRITE OR DIRECTION BIT ADDRESS
<R/W> <WORD ADDRESS (n)> <SLAVE ADDRESS (n)>
<SLAVE
ADDRESS> <R/W>
A XXXXXXXX A 1101000 1101000 S Sr 0 A 1
DATA TRANSFERRED
(X + 1 BYTES + ACKNOWLEDGE)
NOTE: LAST DATA BYTE IS FOLLOWED BY A NACK.
MASTER TO SLAVE SLAVE TO MASTER
A XXXXXXXX XXXXXXXX A XXXXXXXX A XXXXXXXX A P
<DATA (n)> <DATA (n + 1)> <DATA (n + 2)> <DATA (n + X)>
...
Figure 5. Data Write/Read (Write Pointer, Then Read)—Slave Receive and Transmit