
AD9920A
Rev. B | Page 96 of 112
COMPLETE REGISTER LISTING
When an address contains fewer than 28 data bits, all remaining bits must be written as 0s.
Table 52. AFE Registers
Address
Data
Bits
Default
Value
Default
Update
Type
Name
Description
0x00
[1:0]
0x03
SCK
STANDBY
Standby modes.
0 = normal operation (full power).
1 = Standby1 mode.
2 = Standby2 mode.
3 = Standby3 mode (lowest power).
[2]
0x01
CLPENABLE
0 = disable OB clamp.
1 = enable OB clamp.
[3]
0
CLPSPEED
0 = select normal OB clamp settling.
1 = select fast OB clamp settling.
[4]
0
FASTUPDATE
0 = ignore CDS gain.
1 = very fast clamping when CDS gain is updated.
[5]
0
PBLK_LVL
0 = blank data outputs to 0 during PBLK.
1 = blank data outputs to programmed clamp level during PBLK.
[6]
0
DCBYP
0 = enable input dc restore circuit during PBLK.
1 = disable input dc restore circuit during PBLK.
0x01
[0]
0
SCK
DOUTDISABLE
0 = data outputs are driven.
1 = data outputs are three-stated.
[1]
0
DOUTLATCH
0 = latch data outputs using DOUTPHASE register setting.
1 = output latch is transparent.
[2]
0
GRAYEN
1 = enable gray coding of digital data output.
[3]
0
Test
Set to 0.
0x02
[0]
0
VD
Test
Do not access, or set to 0.
0x03
[23:0]
0xFFFFFF
VD
Test
Do not access, or set to 0xFFFFFF.
0x04
[2:0]
0
VD
CDSGAIN
CDS gain setting.
0 = 3 dB.
4 = 0 dB.
6 = +3 dB.
7 = +6 dB.
All other values are invalid.
0x05
[9:0]
0x0F
VD
VGAGAIN
VGA gain. 6 dB to 42 dB (0.035 dB per step).
0x06
[9:0]
0x1EC
VD
CLAMPLEVEL
Optical black clamp level. 0 LSB to 255 LSB (0.25 LSB per step).
0x07
[27:0]
0
VD
Test
Do not access, or set to 0.
0x08
[27:0]
0
VD
Test
Do not access, or set to 0.
0x09
[27:0]
0
VD
Test
Do not access, or set to 0.
0x0A
[27:0]
0
VD
Test
Do not access, or set to 0.
0x0B
[27:0]
0
SCK
UNUSED
Do not access, or set to 0.
0x0C
[27:0]
0
SCK
Test
Do not access, or set to 0.
0x0D
[0]
0
VD
CLIDIVIDE
0 = do not divide CLI frequency.
1 = divide CLI frequency by 2.
[7:1]
0
Test
Do not access, or set to 0.
0x0E
[7:0]
0
SCK
Test
Set to 0.
[8]
0
VDHD_IE
VD/HD input enable. Set to 1 to enable VD/HD inputs for slave mode.
0x0F
[27:0]
0
VD
Test
Set to 0.