Texas Instruments FPD Link III - DS90UB901Q & DS90UB902Q EVK SERDESUB-16USB/NOPB SERDESUB-16USB/NOPB Data Sheet
Product codes
SERDESUB-16USB/NOPB
6
SERDESUB-16USB User’s Guide
SNLU100 – April 2012
Bi-Directional Control Bus And I2C Modes:
In order to communicate and synchronize with remote devices on the I2C bus through the
bi-directional control channel, slave clock stretching must be supported by the I2C master
controller/MCU. The chipset utilizes bus clock stretching (holding the SCL line low) during
data transmission; where the I2C slave pulls the SCL line low prior to the 9th clock of
every I2C data transfer (before the ACK signal).
The bidirectional control bus supports is a I2C compatible interface that allows
programming of the DS90UB901Q, DS90UB902Q, or an external remote device (such as
a camera or display). Register programming transactions to/from the DS90UB901Q/902Q
chipset are employed through the clock (SCL) and data (SDA) lines. These two signals
have open drain I/Os and must be pulled-up to VDDIO by external resistors. The boards
have an option to use the on-board 1.0KΩ pull-up resistors tied to VDDIO or connected
through external pull-ups at the target Host. The appropriate pull-up resistor values will
depend upon the total bus capacitance and operating speed. The DS90UB901Q/902Q I2C
bus data rate supports up to 100 kbps according to I2C specification.
To start any data transfer, the DS90UB901Q/902Q 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 MODE (M_S) pin. Note the MODE pin is label as M_S on the PCB
boards. The Ser/Des interface acts as a virtual bridge between Master controller (MCU)
and the remote device. When the MODE (M_S) pin is set to High, the device is treated as
a slave proxy; acts as a slave on behalf of the remote slave. When addressing a remote
peripheral or Serializer/Deserializer (not wired directly to the MCU), the slave proxy will
forward any byte transactions sent by the Master controller to the target device. When
MODE (M_S) pin is set to Low, the device will function as a master proxy device; acts as a
master on behalf of the I2C master controller. Note that the devices must have
complementary settings for the MODE configuration. For example, if the Serializer MODE
(M_S) pin is set to High then the Deserializer MODE (M_S) pin must be set to Low and
vice-versa.
data transmission; where the I2C slave pulls the SCL line low prior to the 9th clock of
every I2C data transfer (before the ACK signal).
The bidirectional control bus supports is a I2C compatible interface that allows
programming of the DS90UB901Q, DS90UB902Q, or an external remote device (such as
a camera or display). Register programming transactions to/from the DS90UB901Q/902Q
chipset are employed through the clock (SCL) and data (SDA) lines. These two signals
have open drain I/Os and must be pulled-up to VDDIO by external resistors. The boards
have an option to use the on-board 1.0KΩ pull-up resistors tied to VDDIO or connected
through external pull-ups at the target Host. The appropriate pull-up resistor values will
depend upon the total bus capacitance and operating speed. The DS90UB901Q/902Q I2C
bus data rate supports up to 100 kbps according to I2C specification.
To start any data transfer, the DS90UB901Q/902Q 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 MODE (M_S) pin. Note the MODE pin is label as M_S on the PCB
boards. The Ser/Des interface acts as a virtual bridge between Master controller (MCU)
and the remote device. When the MODE (M_S) pin is set to High, the device is treated as
a slave proxy; acts as a slave on behalf of the remote slave. When addressing a remote
peripheral or Serializer/Deserializer (not wired directly to the MCU), the slave proxy will
forward any byte transactions sent by the Master controller to the target device. When
MODE (M_S) pin is set to Low, the device will function as a master proxy device; acts as a
master on behalf of the I2C master controller. Note that the devices must have
complementary settings for the MODE configuration. For example, if the Serializer MODE
(M_S) pin is set to High then the Deserializer MODE (M_S) pin must be set to Low and
vice-versa.
Demo Board Power Connections:
The Serializer and Deserializer boards must be powered by supplying power externally
through J3 (VDD) and J4 (VSS) on Serializer Board and J4 (VDD) and J5 (VSS) on
Deserializer board. Note +2.5V is the MAXIMUM voltage that should ever be applied to
the Serializer J3 or Deserializer J4 VDD terminal. Serializer JP1 VDDI and Deserializer
VDDIO JP1 must never exceed +4.0V. Damage to the device(s) can result if the voltage
maximum is exceeded.
through J3 (VDD) and J4 (VSS) on Serializer Board and J4 (VDD) and J5 (VSS) on
Deserializer board. Note +2.5V is the MAXIMUM voltage that should ever be applied to
the Serializer J3 or Deserializer J4 VDD terminal. Serializer JP1 VDDI and Deserializer
VDDIO JP1 must never exceed +4.0V. Damage to the device(s) can result if the voltage
maximum is exceeded.