DS92LX2121 Datasheet, PDF (23/42 Pages) National Semiconductor (TI) – 10 - 50 MHz Channel Link III Serializer and Deserializer with Embedded Bi-Directional Control Channel

DS92LX2121, DS92LX2122
www.ti.com
SNLS330I – MAY 2010 – REVISED APRIL 2013
To start any data transfer, the DS92LX2121 / DS92LX2122 must be configured in the proper I2C mode. Each
device can function as an I²C slave proxy or master proxy depending on the mode determined by M/S pin. The
Ser/Des interface acts as a virtual bridge between the host device and the remote device. When the M/S pin is
set to HIGH, the device is treated as a slave proxy; and acts as a slave on behalf of the remote slave. When
addressing a remote peripheral or Serializer/ Deserializer (not wired directly to the host device), the slave proxy
will forward any byte transactions sent by the host controller to the target device. When M/S pin is set to LOW,
the device will function as a master proxy device, and acts as a master on behalf of the I²C master controller.
Note that the devices must have complementary settings for the M/S configuration. For example, if the Serializer
M/S pin is set to HIGH then the Deserializer M/S pin must be set to LOW and vice-versa.
Bus Activity:
Master
SDA Line S
Slave
Address
7-bit Address 0
Register
Address
Data
P
Bus Activity:
Slave
A
A
A
C
C
C
K
K
K
Figure 24. Write Byte
Bus Activity:
Master
Slave
Address
Register
Address
Slave
Address
SDA Line S
7-bit Address 0
S
7-bit Address 1
Bus Activity:
Slave
A
A
A
C
C
C
K
K
K
Figure 25. Read Byte
Data
N
A
C
K
P
SDA
SCL
START
MSB
1
7-bit Slave Address
2
6
LSB
ACK
R/W
Direction
Bit
Acknowledge
from the Device
MSB
7
8
9
1
Data Byte
2
LSB N/ACK
*Acknowledge
or Not-ACK
8
9
Repeated for the Lower Data Byte
and Additional Data Transfers
STOP
Figure 26. Basic Operation
SDA
SCL
S
START condition, or
START repeat condition
P
STOP condition
Figure 27. START and STOP Conditions
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