DS90UB901Q_15 Datasheet, PDF (29/50 Pages) Texas Instruments – 10 - 43MHz 14 Bit Color FPD-Link III Serializer and Deserializer with Bidirectional Control Channel

DS90UB901Q, DS90UB902Q
www.ti.com
SNLS322E – JUNE 2010 – REVISED APRIL 2013
DISPLAY MODE OPERATION
In Display mode, I²C transactions originate from the controller attached to the Serializer. The I²C slave core in
the Serializer will detect if a transaction targets (local) registers within the Serialier or the (remote) registers within
the Deserializer or a remote slave connected to the I²C master interface of the Deserializer. Commands are sent
over the forward channel link to initiate the transactions. The Deserializer will receive the command and generate
an I²C transaction on its local I²C bus. At the same time, the Deserializer will capture the response on the I²C
bus and return the response as a command on the bidirectional control channel. The Serializer parses the
response and passes the appropriate response to the Serializer I²C bus.
The physical device ID of the I²C slave in the Serializer is determined by the analog voltage on the ID[x] input. It
can be reprogrammed by using the DEVICE_ID register and setting the bit . The device ID of the logical I²C
slave in the Deserializer is determined by programming the DES ID in the Serializer. The state of the ID[x] input
on the Deserializer is used to set the device ID. The I²C transactions between Ser/Des will be bridged between
the host controller to the remote slave.
To configure the devices for display mode operation, set the Serializer MODE pin to High and the Deserializer
MODE pin to Low. Before initiating any I²C commands, the Serializer needs to be programmed with the target
slave device address and Serializer device address. DES_DEV_ID Register 0x06h sets the Deserializer device
address and SLAVE_DEV_ID register 0x7h sets the remote target slave address. If the I²C slave address
matches any of registers values, the I²C slave will hold the transaction allowing read or write to target device.
Note: In Display mode operation, registers 0x08h~0x17h on Deserializer must be reset to 0x00.
CRC (CYCLIC REDUNDANCY CHECK) DETECTION
A 4-bit CRC per symbol is reserved for checking the link integrity during transmission. The reporting status pin
(PASS) is provided on the Deserializer side, which flags any mismatch of data transmitted to and from the
remote device. The Deserializer's PLL must first be locked (LOCK pin HIGH) to ensure the PASS status is valid.
This error detection handling generates an interrupt signal onto the PASS output pin; notifying the host controller
as soon as any errors are identified. When an error occurs, the PASS asserts LOW. CRC registers (CRC
ERROR B0/B1) are also available for managing the data error count.
The DS90UB901Q/902Q chipset provides several mechanisms (operations) for ensuring data integrity in long
distance transmission and reception. The data error detection function offers user flexibility and usability of
performing bit-by-bit and data transmission error checking. The error detection operating modes support data
validation of the following signals:
• Bidirectional Channel Control
• Control VSYNC and HSYNC signals across serial link
• Parallel video/pixel data across serial link
PROGRAMMABLE CONTROLLER
An integrated I²C slave controller is embedded in each of the DS90UB901Q Serializer and DS90UB902Q
Deserializer. It must be used to access and program the extra features embedded within the configuration
registers. Refer to Table 1 and Table 2 for details of control registers.
MULTIPLE DEVICE ADDRESSING
Some applications require multiple camera devices with the same fixed address to be accessed on the same I²C
bus. The DS90UB901/902 provides 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 ECU 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.
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