STK6005 Просмотр технического описания (PDF) - Unspecified

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STK6005

Flat Panel Scaler

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STK6005

3. Synchronization to Input V-Sync and H-Sync:

EnSyncH {0x3D[7]} = 1

EnSyncV {0x3D[6]} = x

In this mode, the input timing also has impacted on the output horizontal and vertical timings. The

input V-Sync leading edge will also generate a lock event to lock the output display timing. Therefore, the

output vertical period will keep the same as the input vertical period. But the output horizontal period is

gained by (EmPHT / 16) cycles of input VCLK to keep output horizontal timing tracking to input

horizontal timing. The register EmPHT should be set to the value of input horizontal period (in pixels) *

RateV * 16, where the RateV = total input lines / total output lines. The register value of PHT will be

ignored. The register value of PVT should be set to maximum (0x7FF) value for this mode. For the

advantage of this mode, even when some errors result in the real output video clock (PCLK) and in the

ideal output video clock (VCLK * RateH * RateV), the buffer overrun or underrun will not happen

internally due to the accumulation of errors. For the disadvantage of this mode, each output horizontal

period may be somewhat different.

5.9 Contrast and Brightness Control

STK6005 can adjust the contrast and brightness of output pixels after scaling operation. Registers GainR,

GainG, and GainB adjust the contrast of red, green, and blue respectively for output pixels. Registers

DC_R, DC_G, DC_B adjust the brightness for output pixels. Gain registers are those with an 8-bit

unsigned value and DC registers are those in a 2’s complement format. The adjustment formula is listed

below:

Red (out) = Red(in) * GainR / 128 + DC_R

Green (out) = Green(in) * GainG / 128 + DC_G

Blue (out) = Blue(in) * GainB / 128 + DC_B

5.10 Gamma Correlation

STK6005 provides an 8-to-10 bits of the color look-up table for each color channel intended for Gamma

correction. A 10-bit output results in an improved color depth control. The 10-bit output is then

dithered down to 8 or 6 bits per color for display output. The Gamma look-up table (LUT) is user-

programmable to provide an arbitrary transfer function.

Before the Gamma LUT is programmed, the Gamma correction function should be disabled first and

then decides which Gamma LUTs of colors is to be programmed. The Gamma LUT will be written at the

same time if the GmaWE flag for respective color is set to 1. The programming steps are shown as below:

1. Disable Gamma correction function (set EnGamma flag to 0).

2. Set respective GmaWE flag of each color to 1 to enable programming.

3. Write start programming address into uWrGmaA register.

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