ADE3800SXL View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

ADE3800SXL

Analog LCD Display Engine for XGA and SXGA Resolutions with Embedded LVDS and RSDS Transmitters

STMicroelectronics 

ADE3800

Register Description by Block

4.13 Gamma (GAM)

The Gamma block implements three independent 256 point gamma curves for each of R, G, and B

channels.

Its features are as follows:

● 256x8b table per color channel stores 2’s complement difference to straight line

● 10b input/output (0 to 1023), range of delta = -128 to +127 (+/- 1/8th full scale)

● double LUT amplitude control to change range to 2 x (delta = -256 to +254)

● fast write mode for loading 3 tables with the same data

● glitch free write mode

● clipping on output to [0,1023]

● programmable offset_value added from offset_position0 to offset_position1 (inclusive).

gamma_out_r = gamma_in_r + lut_r + (offset_position0 <= gamma_in_r <= offset_position1) ?

offset_value: 0

gamma_out_g = gamma_in_g + lut_g + (offset_position0 <= gamma_in_g <= offset_position1) ?

offset_value: 0

gamma_out_b = gamma_in_b + lut_b + (offset_position0 <= gamma_in_b <= offset_position1) ?

offset_value: 0

Table 28: Gamma Registers

I2C Address Label Addr Mode Bits Rst

Description

GAM_CTRL

0C00 R/W

[3]

[2]

[1]

00 0*: delta range = -128 to +127

1: delta range = -256 to +254

0*: i2c to RAM transfer at selected i2c address only

1: i2c to RAM transfer the same value to Red, Green, and Blue

RAMs when selecting Red RAM addresses

0*: Write i2c to RAM allowed during active video

1: Write i2c to RAM during video blanking only (shadowed)

GAM_POSITION0

GAM_POSITION1

GAM_OFFSET

0C01 R/W

0C02 R/W

0C03 R/W

[0]

[7:0] 00

[7:0] 00

[5:0] 00

0*: gamma bypassed

1: gamma enabled

IF (gamma_in/4 >= offset_position0 && gamma_in/4 <=

offset_position1)

THEN offset = offset_value * 16

ELSE offset = 0

(gamma_out = gamma_in + lut + offset)

See offset_position0 for details

Multipled by 16. 2’s complement number represents –512 to

+496 inclusive.

See offset_position0 for details

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