ADV7181 AD [Analog Devices], ADV7181 Datasheet - Page 23

• Manufacturer Part Number: ADV7181
• Description: Multiformat SDTV Video Decoder
• Manufacturer: AD [Analog Devices]

SD_SAT_Cr[7:0] SD Saturation Cr Channel, Address 0xE4 [7:0]
This register allows the user to control the gain of the Cr
channel only, which in turn adjusts the saturation of the picture.
Table 22. SD_SAT_Cr Function
SD_SAT_Cr[7:0]
0x80 (default)
0x00
0xFF
SD_OFF_Cb[7:0] SD Offset Cb Channel, Address 0xE1 [7:0]
This register allows the user to select an offset for the Cb
channel only and adjust the hue of the picture. There is a
functional overlap with the Hue [7:0] register.
Table 23. SD_OFF_Cb Function
SD_OFF_Cb[7:0]
0x80 (default)
0x00
0xFF
SD_OFF_Cr [7:0] SD Offset Cr Channel, Address 0xE2 [7:0]
This register allows the user to select an offset for the Cr channel
only and adjust the hue of the picture. There is a functional
overlap with the Hue [7:0] register.
Table 24. SD_OFF_Cr Function
SD_OFF_Cr[7:0]
0x80 (default)
0x00
0xFF
BRI[7:0] Brightness Adjust, Address 0x0A [7:0]
This register controls the brightness of the video signal. It allows
the user to adjust the brightness of the picture.
Table 25. BRI Function
BRI[7:0]
0x00 (default)
0x7F
0x80
Description
Offset of the luma channel = 0IRE.
Offset of the luma channel = 100IRE.
Offset of the luma channel = –100IRE.
Description
Gain on Cr channel = 0 dB.
Gain on Cb channel = −42 dB.
Gain on Cb channel = +6 dB.
Description
0 offset applied to the Cb channel.
−312 mV offset applied to the Cb channel.
+312 mV offset applied to the Cb channel.
Description
0 offset applied to the Cr channel
−312 mV offset applied to the Cr channel
+312 mV offset applied to the Cr channel
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HUE[7:0] Hue Adjust, Address 0x0B [7:0]
This register contains the value for the color hue adjustment. It
allows the user to adjust the hue of the picture.
HUE[7:0] has a range of ±90°, with 0x00 equivalent to an
adjustment of 0°. The resolution of HUE[7:0] is 1 bit = 0.7°.
The hue adjustment value is fed into the AM color demodula-
tion block. Therefore, it only applies to video signals that contain
chroma information in the form of an AM-modulated carrier
(CVBS or Y/C in PAL or NTSC). It does not affect SECAM and
does not work on component video inputs (YPrPb).
Table 26. HUE Function
HUE[7:0]
0x00 (default)
0x7F
0x80
DEF_Y[5:0] Default Value Y, Address 0x0C [7:2]
When the ADV7181B loses lock on the incoming video signal
or when there is no input signal, the DEF_Y[5:0] register allows
the user to specify a default luma value to be output. This value
is used under the following conditions:
•
ADV7181B lost lock to the input video signal. This is the
intended mode of operation (automatic mode).
•
the video decoder. This is a forced mode that may be useful
during configuration.
The DEF_Y[5:0] values define the 6 MSBs of the output video.
The remaining LSBs are padded with 0s. For example, in 8-bit
mode, the output is Y[7:0] = {DEF_Y[5:0], 0, 0}.
DEF_Y[5:0] is 0x0D (Blue) is the default value for Y.
Register 0x0C has a default value of 0x36.
DEF_C[7:0] Default Value C, Address 0x0D [7:0]
The DEF_C[7:0] register complements the DEF_Y[5:0] value. It
defines the 4 MSBs of Cr and Cb values to be output if
•
•
The data that is finally output from the ADV7181B for the
chroma side is Cr[7:0] = {DEF_C[7:4], 0, 0, 0, 0}, Cb[7:0] =
{DEF_C[3:0], 0, 0, 0, 0}.
DEF_C[7:0] is 0x7C (blue) is the default value for Cr and Cb.
If DEF_VAL_AUTO_EN bit is set to high and the
The DEF_VAL_EN bit is set, regardless of the lock status of
The DEF_VAL_AUTO_EN bit is set to high and the
ADV7181B can’t lock to the input video (automatic mode).
DEF_VAL_EN bit is set to high (forced output).
Description (Adjust Hue of the Picture)
Phase of the chroma signal = 0°.
Phase of the chroma signal = –90°.
Phase of the chroma signal = +90°.
ADV7181B