VV6501C001 STMicroelectronics, VV6501C001 Datasheet - Page 20

• Manufacturer Part Number: VV6501C001
• Description: IC SENSOR COLOR VGA CMOS 36CLCC
• Manufacturer: STMicroelectronics
• Type: CMOS Imagingr

Specifications of VV6501C001

• Pixel Size: 5.6µm x 5.6µm
• Active Pixel Array: 640H x 480V
• Frames Per Second: 30
• Voltage - Supply: 3V, 5V
• Package / Case: 36-CLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: 497-3883; VV6501C001

Functional Description
3.1.11 Exposure/gain control
20/60
The sensor does not contain any form of automatic exposure or gain control. To produce a correctly
exposed image, exposure and gain values must be calculated externally and written to the sensor
via the serial interface.
Exposure calculation
The exposure time for a pixel and the ADC range (therefore the gain) are programmable via the
serial interface. The explanation below assumes that the gain and exposure values are updated
together as part of a 5 byte serial interface auto-increment sequence.
Exposure time combines coarse, fine exposure, pixel rate also related to frame and line lengths, all
defined in
Example of exposure calculation in default VGA video mode
coarse exposure = 522
fine exposure = 762
Input clock frequency - Fclkin = 24MHz,
Pixel period = 2/(24 x 10
Calculation : exposure time = 8.33 x10
Frame length
Line length
Exposure
Coarse exposure
value
Fine exposure value
Pixel period
Exposure time
Table 6
.
Table 5: User programmable clock divider values
Number of lines per frame [default=524]
The frame length may be increased to 1023 by writing to the frame length register.
Number of pixels in a line [default = 762]
The line length may be increased to 1023 by writing to the line length register.
The pixel exposure time is determined by the course and fine exposure values
The number of lines a pixel exposes for.
Limited by frame length.
Coarse exposure value is in the range [0 - (frame length -2)].
Number of additional pixel periods a pixel exposes for.
Limited by line length.
Fine exposure value is in the range [11 - (line length)].
Determined by the input clock frequency (Fclkin) and user clk_div setting.
PixPeriod=(2*N)/Fclkin where N = clock divider ratio
PixPeriod x [(Coarse
6
) = 8.33 x10
Table 6: Definitions related to exposure
clk_div[3:0]
101X
110X
111X
-8
-8
s
x [(522 x 762) +762] = 33.2 ms
num_lines
x Line_Length
divide by
num_pixels
12
14
16
) + Fine
pixels
]
VV6501