Cp Gain Operation - Analog Devices Advantiv ADV7619 Hardware User's Manual

Hardware User Guide
CLMP_C[11:0] , Addr 44 (CP), Address 0x6F[3:0]; Address 0x70[7:0]
Manual clamp value for Channel C. This field is an unsigned 12-bit value to be subtracted from the incoming video signal. This value
programmed in this register is effective if the CLMP_BC_MAN is set to 1. To change the CLMP_C[11:0], Register Address 0x6F and
Register Address 0x70 must be updated with the desired clamp value written to in this order and with no other I
Function
CLMP_C[11:0]
0x000 (default)
...
0xFFF

CP GAIN OPERATION

The digital gain block of the CP consists of three multipliers in the data paths of Channel A, Channel B, and Channel C, as well as one
single automatic gain control loop. The gain control can be operated in manual or automatic mode.
Features of Manual Gain Control
The gain values for the three channels can be programmed separately via I
Features of Automatic Gain Control
The gain value is determined automatically, based on a signal with an embedded horizontal synchronization pulse on Channel A. The
automatic gain control loop can be frozen, for example, after settling.
The gain value inputs are controlled via the OP_656_RANGE bit.
Manual Gain and Automatic Gain Control Selection
Figure 41 shows how the gain is applied to the video data processed by the CP section. The following gain configurations are available:
•
Automatic gain configuration in HDMI mode
This configuration is enabled by setting AGC_MODE_MAN to 0 and by setting the part in HDMI mode via PRIM_MODE[3:0]
and VID_STD[5:0] . In that case, the gain applied to the video data depends on the input and output range configuration. The input
range is set by control register INP_COLOR_SPACE and the read back register HDMI_COLORSPACE[3:0] as per Table 45. The
output color space is determined the control bit OP_656_RANGE .
•
Manual gain configuration
This configuration is enabled by setting AGC_MODE_MAN to 1 and GAIN_MAN to 1. In this case the gain applied to the video
data processed by the CP core is configured via the control registers A_GAIN[9:0] , B_GAIN[9:0] and C_GAIN[9:0]
Table 45. Input Ranges for HDMI Modes
INP_COLOR_SPACE
0b0000
0b0001
0b0010
0b0011
0b0100
0b0101
0b0110
0b0111
0b1111
0b1000 to 0b1110
Description
Minimum range
...
Maximum range
2
C registers. This is the recommended mode.
Input Range
16 to 235
0 to 255
16 to 235
16 to 235
0 to 255
0 to 255
0 to 255
0 to 255
16 to 235 if HDMI_COLORSPACE = 0b000
0 to 255 if HDMI_COLORSPACE = 0b001
16 to 235 if HDMI_COLORSPACE = 0b010
16 to 235 if HDMI_COLORSPACE = 0b011
0 to 255 if HDMI_COLORSPACE = 0b100
0 to 255 if HDMI_COLORSPACE = 0b101
0 to 255 if HDMI_COLORSPACE = 0b110
0 to 255 if HDMI_COLORSPACE = 0b111
Reserved
Rev. A | Page 119 of 204
UG-237
2
C access in between.
.