DS90UH928Q-Q1 Datasheet, PDF (24/69 Pages) Texas Instruments – 5 MHz to 85 MHz 24-bit Color FPD-Link III to FPD-Link Deserializer With HDCP

DS90UH928Q-Q1
SNLS440C – MARCH 2013 – REVISED JULY 2016
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Feature Description (continued)
8.3.11.1.1 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 deserializer, and driven to the
display.
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 deserializer, and driven 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 deserializer to enable the FRC2 function.
Examples of the three types of LUT configurations described are shown in Figure 22.
8.3.11.1.2 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 control bus
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.
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