Analog Devices ADV7850 Hardware Manual page 243

clmp_a_man, Addr 44 (CP), Address 0x6C[7]
This control is used to enable manual clamping for channel A.
Function
clmp_a_man
0 
1
clmp_a[11:0], Addr 44 (CP), Address 0x6C[3:0]; Address 0x6D[7:0]
This control is used to set the manual clamp value for channel A. It is an unsigned 12-bit value to be subtracted from the incoming
video signal. The value programmed in this control is effective if clmp_a_man is set to 1. To change the clmp_a[11:0], the control
addresses 0x6C and 0x6D must be updated with the desired clamp value written to in this order and with no other I2C access
inbetween.
Function
clmp_a[11:0]
0x000 
0xFFF
To facilitate an external clamp loop for channels B and C, the internal clamp value determined by the digital fine clamp block can be
overridden by manual values programmed in the CP Map. Both channels B and C are either in manual or automatic mode. There is no
individual control for them.
The corresponding control values are clmp_bc_man, clmp_b[11:0], and clmp_c[11:0].
clmp_bc_man, Addr 44 (CP), Address 0x6C[6]
This control is used to enable manual clamping for channels B and C.
Function
clmp_bc_man
0 
1
clmp_b[11:0], Addr 44 (CP), Address 0x6E[7:0]; Address 0x6F[7:4]
This control is used to set the manual clamp value for channel B. This is an unsigned 12-bit value to be subtracted from the incoming
video signal. The value programmed in this control is effective if clmp_bc_man is set to 1. To change clmp_b[11:0], the control
addresses 0x6E and 0x6F must be updated with the desired clamp value written to in this order and with no other I2C access inbetween.
Function
clmp_b[11:0]
0x000 
0xFFF
clmp_c[11:0], Addr 44 (CP), Address 0x6F[3:0]; Address 0x70[7:0]
This control is used to set the manual clamp value for channel C. This is an unsigned 12-bit value to be subtracted from the incoming
video signal. The value programmed in this control is effective if clmp_bc_man is set to 1.To change clmp_c[11:0], the control addresses
0x6F and 0x70 must be updated with the desired clamp value written to in this order and with no other I2C access inbetween.
Rev. A May 2012
Description
Use digital fine clamp value determined by on-chip clamp loop
Ignore internal digital fine clamp loop result, use clmp_a[11:0]
Description
Minimum range,
...
Maximum range
Description
Use digital fine clamp value determined by on-chip clamp loop
Ignore internal digital fine clamp loop result, use clmp_b[11:0] for channel B and clmp_c[11:0]
for channel C
Description
Minimum range,
...
Maximum range
243
ADV7850