NOIP1SN5000A_16 Datasheet, PDF (35/75 Pages) ON Semiconductor – PYTHON 5.0/2.0 MegaPixels Global Shutter CMOS Image Sensors

NOIP1SN5000A
Target Illumination
The target illumination value is configured by means of
register desired_intensity as shown in Table 25.
Table 25. AEC TARGET ILLUMINATION
CONFIGURATION
Register
Name
Description
161[9:0]
desired_in-
tensity
Target intensity value, on 10−bit scale.
For 8−bit mode, target value is configured
on desired_intensity[9:2]
Color Sensor
The weight of each color can be configured for color
sensors by means of scale factors. Note these scale factor are
only used to calculate the statistics in order to compensate
for (off−chip) white balancing and/or color matrices. The
pixel values itself are not modified.
The scale factors are configured as 3.7 unsigned numbers
(0x80 = unity). Refer to Table 26 for color scale factors. For
mono sensors, configure these factors to their default value.
Table 26. COLOR SCALE FACTORS
Register
Name
Description
162[9:0] red_scale_factor
Red scale factor for AEC statistics
163[9:0]
green1_scale_factor Green1 scale factor for AEC
statistics
164[9:0]
green2_scale_factor Green2 scale factor for AEC
statistics
165[9:0] blue_scale_factor
Blue scale factor for AEC statistics
AEC Filter Block
The filter block low−pass filters the gain change requests
received from the statistics block.
The filter can be restarted by asserting the restart_filter
configuration of register 160.
AEC Enforcer Block
The enforcer block calculates the four different gain
parameters, based on the required total gain, thereby
respecting a specific hierarchy in those configurations.
Some (digital) hysteresis is added so that the (analog) sensor
settings don’t need to change too often.
Exposure Control Parameters
The several gain parameters are described below, in the
order in which these are controlled by the AEC for large
adjustments. Small adjustments are regulated by digital gain
only.
• Exposure Time
The exposure is the time between the global image array
reset de−assertion and the pixel charge transfer. The
granularity of the integration time steps is configured by the
mult_timer register.
NOTE: The exposure_time register is ignored when the
AEC is enabled. The register fr_length defines
the frame time and needs to be configured
accordingly.
• Analog Gain
The sensor has two analog gain settings. Typically the
AEC shall only regulate the first stage.
• Digital Gain
The last gain stage is a gain applied on the digitized
samples. The digital gain is represented by a 5.7 unsigned
number (i.e. 7 bits after the decimal point). While the analog
gain steps are coarse, the digital gain stage makes it possible
to achieve very fine adjustments.
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