AD9983A/PCBZ Analog Devices Inc, AD9983A/PCBZ Datasheet - Page 32

• Manufacturer Part Number: AD9983A/PCBZ
• Description: Pb-free EVALUATION Kit AD9983A
• Manufacturer: Analog Devices Inc
• Series: Advantiv®r

Specifications of AD9983A/PCBZ

• Main Purpose: Video, Video Processing
• Embedded: No
• Utilized Ic / Part: AD9983A
• Primary Attributes: 3 x 8-Bit 140 MSPS ADC's
• Secondary Attributes: Integrated PLL & VCO
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

AD9983A
0x14—Bit[1] Vsync Duration Enable
This enables the Vsync duration block, which is designed to be
used with the Vsync filter. Setting the bit to 0 leaves the Vsync
output duration unchanged. Setting the bit to 1 sets the Vsync
output duration based on Register 0x15. Power-up duration is 0.
Table 29. Vsync Duration Enable
Vsync Duration Bit
0
1
0x15—Bits[7:0] Vsync Duration
This is used to set the output duration of the Vsync, and is
designed to be used with the Vsync filter. This is valid only if
Register 0x14, Bit 1 is set to 1. Power-up default is 10 DDR.
COAST AND CLAMP CONTROLS
0x16—Bits[7:0] Precoast
This register allows the internally generated coast signal to be
applied prior to the Vsync signal. This is necessary in cases
where pre-equalization pulses are present. The step size for this
control is one Hsync period. For precoast to work correctly, it is
necessary for the Vsync filter (0x14, Bit 2) and sync processing
filter (Register 0x20, Bit 1) both to be either enabled or disabled.
The power-up default is 00.
0x17—Bits[7:0] Postcoast
This register allows the internally generated Coast signal to be
applied following the Vsync signal. This is necessary in cases
where postequalization pulses are present. The step size for this
control is one Hsync period. For Postcoast to work correctly, it
is necessary for the Vsync filter (0x14, Bit 2) and sync
processing filter (0x20, Bit 1) both to be either enabled or
disabled. The power-up default is 00.
0x18—Bit[7] Coast Source
This bit is used to select the active Coast source. The choices are
the coast input pin or Vsync. If Vsync is selected, the additional
decision of using the Vsync input pin or the output from the
sync separator needs to be made (Register 0x14, Bits [7: 6]).
Table 30. Coast Source Selection Settings
Select
0
1
0x18—Bit[6] Coast Polarity Override
This register is used to override the internal circuitry that
determines the polarity of the coast signal going into the PLL.
The power-up default setting is 0.
Table 31. Coast Polarity Override Settings
Override Bit
0
1
Result
Vsync (internal coast)
COAST input pin
Result
Vsync output duration is unchanged
Vsync output duration is set by Register
0x15
Result
Coast polarity determined by chip
Coast polarity determined by user
Rev. 0 | Page 32 of 44
0x18—Bit[5] Coast Input Polarity
This register sets the input coast polarity when Bit 6 of
Register 0x18 = 1. The power-up default setting is 1.
Table 32. Coast Polarity Settings
Coast Polarity Bit
0
1
0x18—Bit[4] Clamp Source Select
This bit determines the source of clamp timing. A 0 enables the
clamp timing circuitry controlled by clamp placement and
clamp duration. The clamp position and duration is counted
from the leading edge of Hsync. A 1 enables the external clamp
input pin. The three channels are clamped when the clamp
signal is active. The polarity of clamp is determined by the
clamp polarity bit. The power-up default setting is 0.
Table 33. Clamp Source Selection Settings
Clamp Source
0
1
0x18—Bit[3] Red Clamp Select
This bit determines whether the red channel is clamped to
ground or to midscale. The power-up default setting is 0.
Table 34. Red Clamp Select Settings
Clamp
0
1
0x18—Bit[2] Green Clamp Select
This bit determines whether the green channel is clamped to
ground or to midscale. The power-up default setting is 0.
Table 35. Green Clamp Select Settings
Clamp
0
1
0x18—Bit[1] Blue Clamp Select
This bit determines whether the blue channel is clamped to
ground or to midscale. The power-up default setting is 0.
Table 36. Blue Clamp Select Settings
Clamp
0
1
Result
Clamp to ground
Clamp to midscale
Result
Clamp to ground
Clamp to midscale
Result
Coast polarity is negative
Coast polarity is positive
Result
Internally generated clamp
Externally provided clamp signal
Result
Clamp to ground
Clamp to midscale