Display Control Unit (DCU)
MPC5606S Microcontroller Reference Manual, Rev. 7
Freescale Semiconductor 427
12.4.8 Gamma correction
The gamma table allows the user to define an arbitrary transfer function at the output of each color
component. The function (Equation 12-5) is applied to each pixel after all blending is complete and before
the data is driven to the TFT LCD panel. Gamma correction is optional and can be used to adjust the color
output values to match the gamut of a particular TFT LCD panel, or to perform data inversion or data
length reduction on each component.
output_color_component = gamma_table[input_color_component] Eqn. 12-5
The table is arranged as three separate memory blocks within the DCU memory map; one for each of the
three color components. Each memory block has one entry for every possible 8-bit value and the entries
are stored at 32-bit aligned addresses. This means that the upper 24 bits are not used while reading/writing
the gamma memories. See Figure 12-75 for details of the memory arrangement.
Figure 12-75. Gamma correction table organization
The gamma table can only be read or written when the DCU is not enabled or during the vertical blanking
period.
12.5 Timing, error and interrupt management
The DCU can detect and raise status and error flags when the status of the system changes and when
configuration or operational errors are detected.
0x0800
Blended
pixel
Gamma
adjusted
pixel
0x0C00
0x1000
RED
GREEN
BLUE
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