AD9927 Analog Devices, AD9927 Datasheet - Page 56

• Manufacturer Part Number: AD9927
• Description: 14-Bit CCD Signal Processor
• Manufacturer: Analog Devices

AD9927
Read After Exposure
To read the CCD data after exposure, the SG should resume
normal activity while the SUBCK remains null. By default, the
AD9927 generates the VSG pulses in every field. When only a
single exposure and a single frame read is desired, such as is the
case in the preview mode, the VSG and SUBCK pulses can
operate in every field.
Other applications require that a greater number of frames are
read, in which case SUBCK must be masked until the readout is
Table 40. SUBCK and Exposure/Read Register Parameters
Register
SGMASK_NUM
SUBCKMASK_NUM
SUBCKMASK_SKIP1
SUBCKSTARTLINE
SUBCKNUM
SG_SUPPRESS
SUBCK_TOG1
SUBCK_TOG2
SUBCK_POL
SUBCKHP_TOG1
SUBCKHP_TOG2
1
Register is not VD updated but is updated at the start of the line after the sensor gate line.
1
1
1
Length
13b
13b
1b
13b
13b
1b
13b
13b
1b
13b
13b
Range
0 to 8191 no. of fields
0 to 8191 no. of fields
On/off
0, 2 to 8191 line location
1 to 8191 no. of pulses
On/off
0 to 8191 pixel locations
0 to 8191 pixel locations
Low/high
0 to 8191 pixel locations
0 to 8191 pixel locations
Rev. 0 | Page 56 of 100
Description
Exposure duration (number of fields to suppress VSG) for LS operation.
Exposure plus readout duration (number of fields to suppress SUBCK) for LS.
Suppress SG/SUBCK masks for one field (default = 0). Typically set to 1.
Line location to start the SUBCK pulses, relative to SGLINE location.
A value of 1 is invalid. See the SUBCK Start Line section.
Total number of SUBCKs per field, at 1 pulse per line. Must be <VDLEN.
Suppress the SG and allow SUBCK to finish at SUBCKNUM.
SUBCK Toggle Position 1.
SUBCK Toggle Position 2.
SUBCK start polarity.
Hi-precision SUBCK Toggle Position 1. Selectable as SG or VD updated.
Hi-precision SUBCK Toggle Position 2. Selectable as SG or VD updated.
finished. The SUBCKMASK_NUM register specifies the total
number of fields (exposure and read) to mask SUBCK. A 2-field
CCD frame read mode typically requires two additional fields of
SUBCK masking (SUBCKMASK_NUM = 2). A 3-field, 6-phase
CCD requires three additional fields of SUBCK masking after
the read begins (SUBCKMASK_NUM = 3).
Note that the SUBCKMASK_SKIP1 register setting allows
SUBCK pulses at the beginning of the field of exposure.