Manual Filter Coefficient Programming - Analog Devices ADV7850 Hardware Manual

Function
dcm_filt_size[1:0]
00 
01
10
11
dcm_bandwidth[2:0], Addr A0 (VFE), Address 0x22[2:0]
A control to configure the DCM filter block.
Function
dcm_bandwidth[2:0]
000 
001
010
011
All others

8.2 MANUAL FILTER COEFFICIENT PROGRAMMING

The ADV7850 allows the user to fully program the DCM filters on each of the channels. The user can select between a 19/20 tap or 39/40
tap filter.
Follow these steps to manually program a channel. (In this example, Channel 2 is programmed with a 39 tap filter.)
1. Enable the selection of a manual filter by setting dcm_filt_en.
2. Select the filter option for manual coefficients (dcm_filt_sel -> 0x02).
3. Enable the channels that require a filter, for example, enable channel2 by selecting filt_sel2.
4. Set coeff_part_sel to 0x00 to write the first part of the coefficient which comprises of 10 values.
5. Store the values by setting coeff_part_sel to 1
6. Set coeff_part_sel to 0x01 to write the second part of the coefficients.
7. Store the values by setting coeff_part_sel to 1.
The manual coefficients are now stored and selected to be used on Channel 2.
dcm_filt_en, Addr A0 (VFE), Address 0x21[3]
This control is used to manually enable the DCM filter block.
Function
dcm_filt_en
1
0 
Rev. A May 2012
Description
Reserved
19/20 tap filter
29/40 tap filter
Reserved
Description
Reserved
Fs/2
Fs/4
Fs/8
Reserved
Mode Channel 0
CVBS CVBS
YC
Y
YUV
Y
RGB
G
CVBS-
SCART
CVBS
Description
Enable manual DCM filter control
Automatic control
Channel 1 Channel 2
C
V U
R B
G R
227
Channel 3
B
ADV7850