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AD9984A R/G/B Clamp slect bit

Question asked by daisu on Dec 1, 2014
Latest reply on Dec 3, 2014 by joe.triggs

Hello all,


Please let me know your advice about ADV9984A 0x18[3:1] Red/Green/BLue Clamp select

Please let me know about the function of each Clamp described in datasheet P.26

 0x18[3:1]  000 = Clamp the Red/Green/Blue channel to ground.
 0x18[3:1] 111 = Clamp the Red/Green/Blue channel to midscale.


Our customer evaluates AD9984 at below condition
  1280 X 800 @60Hz( Pixclk=83.5MHz)
  VESA format
  Analoig RGB input (0-700mV)
  Digital output RGB4:4:4 ( each R/G/B  10bit)


Gain and offset are operated at the value as default setting described in datasheet when 0x18[3:1] is set to 111.
Gain and offset are  operated at MAX value when 0x18[3:1] is set to 000.

0x18[3:1] = 000 -> 111
 0x05     0x7F -> 0x4F
 0x06     0xC0 -> 0x00
 0x07     0x7F -> 0x4F
 0x08     0xC0 -> 0x00
 0x09     0x7F -> 0x4F
 0x0A     0xC0 -> 0x00
 0x0B     0xFF -> 0x01
 0x0C     0xE0 -> 0xC0
 0x0D     0xFF -> 0x01
 0x0E     0xE0 -> 0xC0
 0x0F     0xFF -> 0x01
 0x10     0xE0 -> 0xC0
 0x18     0x2E -> 0x78 


Is description of datasheet P.26 about 0x18[3:1] correct ?
is mean  the opposite  as below
  0: channel to midscale. 
  1: channel to ground.