Cp Data Path For Analog Mode; Pregain Block; Table 52: Settings Required To Support Extended Range Video Input - Analog Devices ADV7850 Hardware Manual

• The I C sequencer treats the three offset values as separate entities. To update all three offset values, a single sweep of I
2
to the CP Map, registers 0x77, 0x78, 0x79, and 0x7A is sufficient.
a_offset[9:0], Addr 44 (CP), Address 0x77[5:0]; Address 0x78[7:4]
This control is used to set the manual offset for channel A. This field stores an unsigned value. To change it, the register addresses 0x77
and 0x78 must be written to in this order with no I2C access inbetween.
Function
a_offset[9:0]
0x3FF 
Any other value
b_offset[9:0], Addr 44 (CP), Address 0x78[3:0]; Address 0x79[7:2]
This control is used to set the manual offset for channel B. This field stores an unsigned value. To change it, the register addresses 0x77
and 0x78 must be written to in this order with no I2C access inbetween.
Function
b_offset[9:0]
0x3FF 
Any other value
c_offset[9:0], Addr 44 (CP), Address 0x79[1:0]; Address 0x7A[7:0]
This control is used to set the manual offset for channel C. This field stores an unsigned value. To change it, the register addresses 0x79
and 0x7A must be written to in this order with no I2C access inbetween.
Function
c_offset[9:0]
0x3FF 
Any other value

9.5 CP DATA PATH FOR ANALOG MODE

Figure 82 to Figure 84 depict the data path of the video for analog mode. These figures depict the gains and offsets applied when using the
automatic control, op_656_range, and the manual options for setting the clamp level, gain, and offset.
The I 2 C settings are detailed in
than white' video levels.

Pregain Block

9.5.1
To compensate for signal attenuation in the analog front end of the ADV7850 and input buffer gain, a pregain block is provided in the CP
path. The pregain block is controlled by cp_mode_gain_adj[7:0], which represents an unsigned value in a 1.7 binary format. The range of
cp_mode_gain_adj[7:0] is 0 to 1.99.
The MSB of cp_mode_gain_adj[7:0] represents the integer part of the pregain value while the seven LSBs represents the fractional part of
the pregain value.
Rev. A May 2012
Description
Auto offset to channel A
Channel A offset
Description
Auto offset to channel B
Channel B offset
Description
Auto offset to channel C
Channel C offset
Table 52 for use when processing extended range video signals with 'blacker than black' and/or 'whiter

Table 52: Settings Required to Support Extended Range Video Input

I C Setting/Mode
2
op_656_range
alt_data_sat
Analog Modes
1
1
253
ADV7850
C writes
2