DS32C35 Maxim Integrated Products, Inc., DS32C35 Datasheet - Page 19

• Manufacturer Part Number: DS32C35
• Description: Accurate I2c Rtc With Integrated Tcxo/crystal/fram
• Manufacturer: Maxim Integrated Products, Inc.

2) Slave transmitter mode (DS32B35/DS32C35 read
Figure 3. Data Write—RTC Slave Receiver Mode
Figure 4. Data Read—RTC Slave Transmitter Mode
Figure 5. Data Write—DS32B35 FRAM Slave Receiver Mode
mode): The first byte is received and handled as in
the slave receiver mode. However, in this mode, the
direction bit indicates that the transfer direction is
reversed. The device transmits serial data on SDA
while the serial clock is input on SCL. START and
STOP conditions are recognized as the beginning
and end of a serial transfer (see Figure 4). The slave
address byte is the first byte received after the mas-
ter generates the START condition. The slave
address byte contains one of the 7-bit device
addresses. The slave address is 1101000 for the
RTC. For the DS32B35 FRAM, the first four bits are
1010, and the next three bits select one of eight
S - START
A - ACKNOWLEDGE
P - STOP
A - NOT ACKNOWLEDGE
R/W - READ/WRITE OR DIRECTION BIT ADDRESS = D1H
S - START
A - ACKNOWLEDGE
P - STOP
R/W - READ/WRITE BIT
S - START
A - ACKNOWLEDGE
P - STOP
R/W - READ/WRITE OR DIRECTION BIT ADDRESS = D0H
S
S
S
<SLAVE ADDRESS> <R/W>
<SLAVE ADDRESS> <R/W>
<SLAVE ADDRESS> <R/W> <WORD ADDRESS (n)>
1010A
1101000
1101000
10
A
9
A
8
0
0
1
A
A
A
<WORD ADDRESS (n)>
A
MASTER TO SLAVE
7
MASTER TO SLAVE
Accurate I
A
XXXXXXXX
<DATA (n)>
XXXXXXXX
6
SLAVE TO MASTER
A
5
A
____________________________________________________________________
4
A
3
A
2
A
1
A
0
A
A
A
<DATA (n + 1)>
<DATA (n + 1)
SLAVE TO MASTER
SLAVE TO MASTER
XXXXXXXX
<DATA (n)>
XXXXXXXX
XXXXXXXX
NOTE: LAST DATA BYTE IS FOLLOWED BY A NOT ACKNOWLEDGE (A) SIGNAL.
MASTER TO SLAVE
2
C RTC with Integrated
blocks of data (see Table 2). Each slave address is
followed by the direction bit (R/W), which is one for a
read. After receiving and decoding the slave address
byte, the device outputs an acknowledge on the SDA
line. The device then begins to transmit data starting
with the register address pointed to by the register
pointer. If the register pointer is not written to before
the initiation of a read mode, the first address that is
read is the last one stored in the register pointer. The
device must receive a "not acknowledge" to end a
read. The register pointer can be set prior to a data
read by initiating a slave receiver mode sequence,
with no data bytes transmitted after the register
address data.
A
A
A
(X + 1 BYTES + ACKNOWLEDGE)
(X + 1 BYTES + ACKNOWLEDGE)
TCXO/Crystal/FRAM
<DATA (n + 1)>
<DATA (n + 2)>
(X + 1 BYTES + ACKNOWLEDGE)
<DATA (n + 2)>
XXXXXXXX
XXXXXXXX
XXXXXXXX
DATA TRANSFERRED
DATA TRANSFERRED
DATA TRANSFERRED
A
A
A
...
...
...
<DATA (n + X)>
<DATA (n + X)
<DATA (n + X)>
XXXXXXXX
XXXXXXXX
XXXXXXXX
A
A
A
P
P
P
19