DS90UR916Q_13 Datasheet, PDF (17/45 Pages) Texas Instruments – 5 - 65 MHz 24-bit Color FPD-Link II Deserializer with Image Enhancement

DS90UR916Q
www.ti.com
SNOSB46E – MARCH 2011 – REVISED APRIL 2013
LUT contents. The user must define and load the contents of the LUT for each color (R,G,B). Regardless of the
color depth being driven (888, 666, 656), the user must always provide contents for 3 complete LUTs - 256
colors x 8 bits x 3 tables. Unused bits - LSBs -shall be set to “0” by the user.
When 24-bit (888) input data is being driven to a 24-bit display, each LUT (R, G and B) must contain 256 unique
8-bit entries. The 8-bit white balanced data is then available at the output of the DS90UR916 deserailizer, and
driven to the display.
When 18-bit (666) input data is being driven to an 18-bit display, the white balance feature may be used in one of
two ways. First, simply load each LUT with 256, 8-bit entries. Each 8-bit entry is a 6-bit value (6 MSBs) with the 2
LSBs set to “00”. Thus as total of 64 unique 6-bit white balance output values are available for each color (R, G
and B). The 6-bit white balanced data is available at the output of the DS90UR916 deserializer, and driven
directly to the display.
Alternatively, with 6-bit input data the user may choose to load complete 8-bit values into each LUT. This mode
of operation provides the user with finer resolution at the LUT output to more closely achieve the desired white
point of the calibrated display. Although 8-bit data is loaded, only 64 unique 8-bit white balance output values are
available for each color (R, G and B). The result is 8-bit white balanced data. Before driving to the output of the
deserializer, the 8-bit data must be reduced to 6-bit with an FRC dithering function. To operate in this mode, the
user must configure the DS90UR916 to enable the FRC2 function.
Examples of the three types of LUT configurations described are shown in Figure 16.
Enabling white balance.The user must load all 3 LUTs prior to enabling the white balance feature. The following
sequence must be followed by the user.
To initialize white balance after power-on:
1. Load contents of all 3 LUTs . This requires a sequential loading of LUTs - first RED, second GREEN, third
BLUE. 256, 8-bit entries must be loaded to each LUT. Page registers must be set to select each LUT.
2. Enable white balance
By default, the LUT data may not be reloaded after initialization at power-on.
An option does exist to allow LUT reloading after power-on and initial LUT loading (as described above). This
option may only be used after enabling the white balance reload feature via the associated serial bus control
register. In this mode the LUTs may be reloaded by the master controller via I2C. This provides the user with the
flexibility to refresh LUTs periodically , or upon system requirements to change to a new set of LUT values. The
host controller loads the updated LUT values via the serial bus interface. There is no need to disable the white
balance feature while reloading the LUT data. Refreshing the white balance to the new set of LUT data will be
seamless - no interruption of displayed data.
It is important to note that initial loading of LUT values requires that all 3 LUTs be loaded sequentially. When
reloading, partial LUT updates may be made. Refer to USING IMAGE ENHANCEMENT FEATURES for a
detailed description of the LUT loading and reloading procedures.
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