DS92LX1621_16 Datasheet, PDF (29/49 Pages) Texas Instruments – 10 - 50 MHz DC-Balanced Channel Link III Serializer and Deserializer with Bi-Directional Control Channel

DS92LX1621, DS92LX1622
www.ti.com
SNLS327I – MAY 2010 – REVISED JANUARY 2014
MULTIPLE DEVICE ADDRESSING
Some applications require multiple camera devices with the same fixed address to be accessed on the same I²C
bus. The DS92LX1621 / DS92LX1622 provide slave ID matching/aliasing to generate different target slave
addresses when connecting more than two identical devices together on the same bus. This allows the slave
devices to be independently addressed. Each device connected to the bus is addressable through a unique ID
by programming of the SLAVE_ID_MATCH register on Deserializer. This will remap the SLAVE_ID_MATCH
address to the target SLAVE_ID_INDEX address; up to 8 ID indexes are supported. The host controller must
keep track of the list of I²C peripherals in order to properly address the target device. In a camera application, the
microcontroller is located on the Deserializer side. In this case, the microcontroller programs the slave address
matching registers and handles all data transfers to and from all slave I²C devices. This is useful in the event
where camera modules are removed or replaced. For example in the configuration shown in Figure 30:
• Host device (FPGA, frame grabber, etc.) is the I²C master and has an I²C master interface
• The I²C protocol is bridged from DES A to SER A and from DES B to SER B
• The I²C interfaces in SER A and SER B are both master interfaces
If the master controller transmits I²C slave 0xA0, the DES A address 0xE0 will forward the transaction to remote
Camera A. If the controller transmits slave address 0xA2, the DES B 0xE2 will recognize that 0xA2 is mapped to
0xA0 and will be transmitted to the remote Camera B. If controller sends command to address 0xB2, the DES B
0xE2 will forward transaction to slave device 0xB0.
The Slave ID index/match is supported only in the camera mode (SER: M/S pin = L; DES: M/S pin = H). For
Multiple device addressing in display mode (SER: M/S pin = H; DES: M/S pin = L), use the I²C pass through
function.
Camera A
Slave ID: (0xA0)
DS92LX1621
DS92LX1622
CMOS
Image
Sensor
DIN[15:0]
PCLK
ROUT[15:0]
PCLK
SDA
SCL
2C /
EEPROM
Slave ID: (0xB0)
Camera B
Slave ID: (0xA0)
I²C
SER A: CAD(0xD0)
DS92LX1621
CMOS
Image
Sensor
DIN[15:0]
PCLK
I²C
SDA
SCL
DES A: CAD(0xE0)
SLAVE_ID1_MATCH(0xA0)
SLAVE_ID1_INDEX(0xA0)
SLAVE_ID2_MATCH(0xB0)
SLAVE_ID2_INDEX(0xB0)
DS92LX1622
ROUT[15:0]
PCLK
ECU
Module
2C/
EEPROM
Slave ID: (0xB0)
SDA
SCL
I²C
SER B: CAD(0xD2)
I²C
SDA
SCL
DES B: CAD(0xE2)
SLAVE_ID2_MATCH(0xA2)
SLAVE_ID2_INDEX(0xA0)
SLAVE_ID2_MATCH(0xB2)
SLAVE_ID2_INDEX(0xB0)
Figure 30. Multiple Device Addressing
2C
Master
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